53 results on '"Huynh MA"'
Search Results
2. Effects of Rice Husk Biochar and Compost Amendments on Soil Phosphorus Fractions, Enzyme Activities and Rice Yields in Salt-Affected Acid Soils in the Mekong Delta, Viet Nam
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Doan Thi Truc Linh, Chau Minh Khoi, Karl Ritz, Nguyen Van Sinh, Nguyen Thi Kim Phuong, Huynh Mach Tra My, Tran Ba Linh, Dang Duy Minh, Thi Tu Linh, and Koki Toyota
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organic amendments ,phosphatase activity ,more labile forms of P ,rice yield ,Agriculture - Abstract
Given that rice husk biochar has been shown to modulate salinity in salt-affected acid soils, the objective of this study was to investigate the effects of organic amendment of salinized acid soils on P fractions, enzyme activities, and associated rice yield. Four treatments, viz. Rice–Rice–Rice, [RRR]; Fallow–Rice–Rice, [FRR]; Fallow–Rice–Rice + 3 Mg ha−1 of compost [FRR + Comp]; and Fallow–Rice–Rice + 10 Mg ha−1 of biochar [FRR + BC] were established at Ben Tre and Kien Giang sites, Viet Nam, over six consecutive crops. Soil properties at harvest of the sixth crop showed that there were diverse patterns of fractionation between P forms with respect to treatment. Overarchingly, biochar increased labile and moderately labile inorganic P and organic P by 30% to 70%, respectively, whilst compost had a relatively modest effect on these pools. Soil phosphatase activities at crop tillering increased following the FRR + Comp and FRR + BC treatments compared with those in RRR, except for acid phosphatase at Ben Tre. At harvest, there were no significant differences between the enzyme activities among the treatments. Rice yield was positively correlated with the more labile forms of P, soil C, and acid phosphatase activity. In the absence of organic amendments, there was no effect of triple versus double rice crops being grown in one-year cycle. Repeated application of biochar (10 Mg ha−1 × 5 times) showed potential to increase grain yields and total soil C in salt-affected acid soils, via modulation of P transformations to more plant-available forms.
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- 2023
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3. Đánh giá hiệu quả tài chính của một số hệ thống canh tác chủ yếu trên đất nhiễm mặn tại huyện Thạnh Phú, tỉnh Bến Tre và huyện U Minh Thượng, tỉnh Kiên Giang
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Thị Tú Linh, Châu Minh Khôi, Lê Minh Hoàng, Trần Trung Chánh, and Huỳnh Mạch Trà My
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Hệ thống canh tác ,hiệu quả tài chính ,luân canh ,nông hộ ,xâm nhập mặn ,Science - Abstract
Nghiên cứu được thực hiện nhằm mục tiêu đánh giá tác động của xâm nhập mặn đến hiệu quả tài chính của một số hệ thống cây trồng trên đất nhiễm mặn tại huyện Thạnh Phú, tỉnh Bến Tre và huyện U Minh Thượng, tỉnh Kiên Giang. Số liệu được thu thập thông qua phỏng vấn nông hộ và đánh giá nông thôn có sự tham gia. Kết quả nghiên cứu cho thấy hiện trạng canh tác tại khu vực nghiên cứu còn nhiều khó khăn do tác động của xâm nhập mặn và phèn mặn. Bên cạnh đó, trình độ học vấn của nông hộ thấp cũng là trở ngại không nhỏ trong sản xuất. Ngoài ra, hệ thống canh tác và hiệu quả tài chính ở hai huyện khác nhau. Tại huyện Thạnh Phú, tỉnh Bến Tre hệ thống chuyên canh rau cho lợi nhuận cao nhất, kế đến là chuyên canh dừa và lúa 2 vụ/năm thấp nhất. Tại huyện U Minh Thượng, tỉnh Kiên Giang, hệ thống lúa 2 vụ luân canh dưa lê cho lợi nhuận cao nhất, kế đến là lúa 3 vụ/năm và thấp nhất là lúa 2 vụ/năm.
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- 2021
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4. The Effect of Multiwalled Carbon Nanotubes on the Thermal Conductivity and Cellular Size of Polyurethane Foam
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Huynh Mai Duc, Dat Nguyen Huu, Trung Tran Huu, Lu Le Trong, Hai Luong Nhu, Hong Phan Ngoc, Thao Nguyen Van, Quynh Hoa Kieu Thi, and Giang Nguyen Vu
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Polymers and polymer manufacture ,TP1080-1185 - Abstract
Polyurethane (PU) foam is known as the popular material for the applications in many fields of industry and life. To improve the mechanical and thermal properties of this material, in this research, PU foam was reinforced with aniline-modified multiwalled carbon nanotubes (MWCNTs). Fourier transform infrared FTIR spectrum of modified MWCNTs showed the aniline was grafted on the surface of MWCNTs through the appearance of –NH2 stretches. The effect of MWCNTs with and without modification on the density, porosity, compressive strength, and heat conductivity of PU/MWCNT foam nanocomposites was investigated. The dispersibility of MWCNTs in the PU matrix was enhanced after modification with aniline. Compressive strength of PU nanocomposite reached the highest value after adding 3 wt.% of modified MWCNTs into PU foam. Besides, the water uptake of PU nanocomposites using 3 wt.% of MWCNTs was decreased to 13.4% as compared to that using unmodified MWCNTs. The improvement in thermal conductivity of PU/aniline-modified MWCNT nanocomposite was observed due to the change in the cellular size of PU foam in the presence of MWCNTs as shown by SEM images.
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- 2021
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5. Steroid-sensitive gene-1 is an androgen-regulated gene expressed in prostatic smooth muscle cells in vivo
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Marcantonio, D, primary, Chalifour, LE, additional, Alaoui-Jamali And H T Huynh, MA, additional, Alaoui-Jamali, MA, additional, and Huynh, HT, additional
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- 2001
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6. Evaluating Dose- and Time-Dependent Effects of Vitamin C Treatment on a Parkinson’s Disease Fly Model
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Huynh Man Anh, Dao My Linh, Vuu My Dung, and Dang Thi Phuong Thao
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Neurology. Diseases of the nervous system ,RC346-429 - Abstract
Parkinson’s disease (PD) is a common neurodegenerative disorder and characterized by progressive locomotive defects and loss of dopaminergic neurons (DA neuron). Currently, there is no potent therapy to cure PD, and the medications merely support to control the symptoms. It is difficult to develop an effective treatment, since the PD onset mechanism of PD is still unclear. Oxidative stress is considered as a major cause of neurodegenerative diseases, and there is increasing evidence for the association between PD and oxidative stress. Therefore, antioxidant treatment may be a promising therapy for PD. Drosophila with knockdown of dUCH, a homolog of UCH-L1 which is a PD-related gene, exhibited PD-like phenotypes including progressive locomotive impairments and DA neuron degeneration. Moreover, knockdown of dUCH led to elevated level of ROS. Thus, dUCH knockdown flies can be used as a model for screening of potential antioxidants for treating PD. Previous studies demonstrated that curcumin at 1 mM and vitamin C at 0.5 mM could improve PD-like phenotypes induced by this knockdown. With the purpose of further investigating the efficiency of vitamin C in PD treatment, we used dUCH knockdown Drosophila model to examine the dose- and time-dependent effects of vitamin C on PD-like phenotypes. The results showed that although vitamin C exerted neuroprotective effects, high doses of vitamin C and long-term treatment with this antioxidant also resulted in side effects on physiology. It is suggested that dose-dependent effects of vitamin C should be considered when used for treating PD.
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- 2019
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7. SỬ DỤNG PHƯƠNG PHÁP BÓN PHÂN ĐẠM THEO BẢNG SO MÀU LÁ TRONG CHẨN ĐOÁN NHU CẦU ĐẠM CỦA CÂY MÍA DỰA TRÊN SINH TRƯỞNG MÍA TRÊN ĐẤT PHÙ SA Ở ĐỒNG BẰNG SÔNG CỬU LONG
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Khương Nguyễn Quốc, Huỳnh Mạch Trà My, Ngô Ngọc Hưng, and Nguyễn Kim Quyên
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Bảng so màu lá ,năng suất mía ,sinh trưởng mía ,độ Brix ,nhu cầu đạm của cây mía ,Science - Abstract
Mục tiêu của nghiên cứu là xác định lượng đạm và thời gian bón đạm hợp lý cho tối ưu hóa sinh trưởng, năng suất và chất lượng mía. Thí nghiệm thừa số hai nhân tố trong bố trí khối hoàn toàn ngẫu nhiên với ba mức phân đạm và bốn phương pháp bón phân đạm được thực hiện ở huyện Cù Lao Dung và Long Mỹ. Kết quả thí nghiệm cho thấy, bón 300 kg đạm trên hecta theo so màu lá đã cho tối ưu sinh trưởng và năng suất ở Cù Lao Dung và Long Mỹ. Cụ thể, bằng phương pháp bón này đã gia tăng chiều cao, số lóng và chiều dài lóng mía nhưng không làm cải thiện độ Brix của mía ở cả hai địa điểm.
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- 2014
8. An Open Annotated Dataset and Baseline Machine Learning Model for Segmentation of Vertebrae with Metastatic Bone Lesions from CT.
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Haouchine N, Hackney DB, Pieper SD, Wells WM 3rd, Sanhinova M, Balboni TA, Spektor A, Huynh MA, Kozono DE, Doyle P, and Alkalay RN
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Automatic analysis of pathologic vertebrae from computed tomography (CT) scans could significantly improve the diagnostic management of patients with metastatic spine disease. We provide the first publicly available annotated imaging dataset of cancerous CT spines to help develop artificial intelligence frameworks for automatic vertebrae segmentation and classification. This collection contains a dataset of 55 CT scans collected on patients with various types of primary cancers at two different institutions. In addition to raw images, data include manual segmentations and contours, vertebral level labeling, vertebral lesion-type classifications, and patient demographic details. Our automated segmentation model uses nnU-Net, a freely available open-source framework for deep learning in healthcare imaging, and is made publicly available. This data will facilitate the development and validation of models for predicting the mechanical response to loading and the resulting risk of fractures and spinal deformity., Competing Interests: Competing interests The authors declare no conflict of interest.
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- 2024
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9. Role of Metastasis-Directed Therapy in Genitourinary Cancers.
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Lee KN and Huynh MA
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- Humans, Disease Management, Combined Modality Therapy methods, Treatment Outcome, Clinical Decision-Making, Urogenital Neoplasms therapy, Urogenital Neoplasms diagnosis, Urogenital Neoplasms pathology, Neoplasm Metastasis
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Opinion Statement: The treatment of oligometastatic genitourinary cancers is a rapidly advancing field with ablative radiotherapy as one of the critical treatment components. The oligometastatic disease state, which can be defined as 1-5 metastatic sites with a controlled primary, represents a distinct clinical state where comprehensive ablative local therapies may provide improved outcomes. Enhanced imaging has increased the number of patients identified with oligometastatic disease. Evidence for improved outcomes with metastasis-directed therapy (MDT) in oligometastatic genitourinary cancers is increasing, and previously published outcome data continues to mature with an increasing body of prospective data to inform the role of MDT in histology-specific settings or in the context of systemic therapy. In select patients, MDT can offer benefits beyond improved local control and allow for time off of systemic therapy, prolonged time until next therapy, or even the hope of cure. However, treatment decisions for locally ablative therapy must be balanced with consideration towards safety. There are exciting advances in technologies to target and adapt treatment in real-time which have expanded options for safer delivery and dose escalation to metastatic targets near critical organs at risk. The role of systemic therapies in conjunction with MDT and incorporation of tumor genetic information to further refine prognostication and treatment decision-making in the oligometastatic setting is actively being investigated. These developments highlight the evolving field of treatment of oligometastatic disease. Future prospective studies combining MDT with enhanced imaging and integrating MDT with evolving systemic therapies will enable the optimal selection of patients most likely to benefit from this "all-or-none" approach and reveal settings in which a combination of therapies could result in synergistic outcomes., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)
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- 2024
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10. Multi-institutional Analysis of Metastasis-directed Therapy with or Without Androgen Deprivation Therapy in Oligometastatic Castration-sensitive Prostate Cancer.
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Deek MP, Sutera P, Jing Y, Gao R, Rothman E, Day H, Chang D, Dirix P, Armstrong AJ, Campbell B, Lopez Campos F, Berenguer M, Ramotar M, Conde-Moreno A, Berlin A, Bosetti DG, Corcoran N, Koontz B, Mercier C, Siva S, Pryor D, Ost P, Huynh MA, Kroeze S, Stish B, Kiess A, Trock B, Tran PT, Gillessen S, and Sweeney C
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Background: Metastasis-directed therapy (MDT) is increasingly being used in oligometastatic castration-sensitive prostate cancer (omCSPC). However, it is currently unclear how to optimally integrate MDT with the standard of care of systemic hormonal therapy., Objective: To report long-term outcomes of MDT alone versus MDT and a defined course of androgen deprivation therapy (ADT) in omCSPC., Design, Setting, and Participants: Here, a multicenter, international retrospective cohort of omCSPC as defined by conventional imaging was reported., Outcome Measurements and Statistical Analysis: Biochemical progression-free survival (bPFS), distant progression-free survival (dPFS), and combined biochemical or distant progression-free survival (cPFS) were evaluated with Kaplan-Meier and multivariable Cox proportional hazard regression models., Results and Limitations: A total of 263 patients were included, 105 with MDT + ADT and 158 with MDT alone. The majority of patients had metachronous disease (90.5%). Five-year bPFS, dPFS, and cPFS were, respectively, 24%, 41%, and 19% in patients treated with MDT + ADT and 11% (hazard ratio [HR] 0.48, 95% confidence interval [CI] 0.36-0.64), 29% (HR 0.56, 95% CI 0.40-0.78), and 9% (HR 0.50, 95% CI 0.38-0.67) in patients treated with MDT alone. On a multivariable analysis adjusting for pretreatment variables, the use of ADT was associated with improved bPFS (HR 0.43, p < 0.001), dPFS (HR 0.45, p = 0.002), and cPFS (HR 0.44, p < 0.001)., Conclusions: In this large multi-institutional report, the addition of concurrent ADT to MDT appears to improve time to prostate-specific antigen progression and distant recurrence, noting that about 10% patients had durable control with MDT alone. Ongoing phase 3 studies will help further define treatment options for omCSPC., Patient Summary: Here, we report a large retrospective review evaluating the outcomes of metastasis-directed therapy with or without a limited course of androgen deprivation for patients with oligometastatic castration-sensitive prostate cancer. This international multi-institutional review demonstrates that the addition of androgen deprivation therapy to metastasis-directed therapy (MDT) improves progression-free survival. While a proportion of patients appear to have long-term disease control with MDT alone, further work in biomarker discovery is required to better identify which patients would be appropriate for de-escalated therapy., (Copyright © 2024 European Association of Urology. Published by Elsevier B.V. All rights reserved.)
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- 2024
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11. Prospective Evaluation of the Clinical Benefits of a Novel Tattoo-less Workflow for Nonspine Bone Stereotactic Body Radiation Therapy: Integrating Surface-Guidance With Triggered Imaging Reduces Treatment Time and Eliminates the Need for Tattoos.
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Zhou AZ, Conway L, Bartlett S, Marques A, Physic M, Czerminska M, Spektor A, Killoran JH, Friesen S, Bredfeldt J, and Huynh MA
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- Humans, Workflow, Cone-Beam Computed Tomography, Health Facilities, Radiotherapy Planning, Computer-Assisted, Radiosurgery, Tattooing
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Purpose: Oligometastatic disease has expanded the indications for nonspine bone stereotactic body radiation therapy (NSB SBRT). We investigated whether optical surface monitoring systems (OSMS) could enable tattoo-less setup and substitute for 2-dimensional/3-dimensional or cone beam computed tomography (CBCT)-based mid-imaging in NSB SBRT., Methods and Materials: OSMS was incorporated in parallel with an existing workflow using pretreatment CBCT and 2-dimensional/3-dimensional kV/kV mid-imaging beginning November 2019. The ability of OSMS to detect out-of-tolerance (>2 mm/>2°) and commanded couch shifts was analyzed. A workflow incorporating OSMS reference captures, CBCT for pretreatment verification, and OSMS/triggered imaging (TI) for intrafraction monitoring was developed for rib/sternum SBRT beginning November 2021 and all NSB SBRT beginning February 2022. Treatment time and CBCT-related radiation dose between the OSMS and the non-OSMS intrafraction monitoring group was analyzed pre- and post-OSMS/TI workflow adoption. All fractions were analyzed through statistical process control with use of an XmR chart of treatment time per quarter from February 2019 to February 2023. Special cause rules were based on Institute for Healthcare Improvement criteria., Results: From February 2019 to February 2023, 1993 NSB SBRT fractions were delivered, including 234 rib, 109 sternum, 214 ilium, and 682 multisite. Over 20 commanded shifts, OSMS could detect 2-mm shifts to within 0.4 mm 67% of the time and 0.8 mm 95% of the time. All NSB SBRT sites showed significant reductions in treatment time, including the greatest improvement in rib total treatment (21.6-13.4 minutes; P = 1.16 × 10
-17 ) and beam time (7.9-3.2 minutes; P = 7.32 × 10-27 ). Significant reductions in CBCT-related radiation were also observed for several NSB sites. These process improvements were associated with OSMS adoption., Conclusions: Adoption of a novel NSB SBRT workflow incorporating OSMS/TI for bone intrafraction motion monitoring reduced treatment time and CBCT-related radiation exposure while also allowing for more continuous intrafraction motion monitoring for NSB SBRT. OSMS/TI enabled the transition to a tattoo-less workflow., Competing Interests: Disclosures Mai Anh Huynh reports research funding, consulting fees, and travel reimbursement from ViewRay, Inc., and research funding from ImmuneSensor., (Copyright © 2023 American Society for Radiation Oncology. Published by Elsevier Inc. All rights reserved.)- Published
- 2024
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12. Registration of Longitudinal Spine CTs for Monitoring Lesion Growth.
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Sanhinova M, Haouchine N, Pieper SD, Wells WM 3rd, Balboni TA, Spektor A, Huynh MA, Guenette JP, Czajkowski B, Caplan S, Doyle P, Kang H, Hackney DB, and Alkalay RN
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Accurate and reliable registration of longitudinal spine images is essential for assessment of disease progression and surgical outcome. Implementing a fully automatic and robust registration is crucial for clinical use, however, it is challenging due to substantial change in shape and appearance due to lesions. In this paper we present a novel method to automatically align longitudinal spine CTs and accurately assess lesion progression. Our method follows a two-step pipeline where vertebrae are first automatically localized, labeled and 3D surfaces are generated using a deep learning model, then longitudinally aligned using a Gaussian mixture model surface registration. We tested our approach on 37 vertebrae, from 5 patients, with baseline CTs and 3, 6, and 12 months follow-ups leading to 111 registrations. Our experiment showed accurate registration with an average Hausdorff distance of 0.65 mm and average Dice score of 0.92.
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- 2024
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13. Clinical Outcomes Among Patients Treated With Stereotactic Body Radiation Therapy to Femur Metastases for Oligometastatic Disease Control or Reirradiation: Results From a Large Single-Institution Experience.
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Kwan C, Chen YH, Killoran JH, Ferrone M, Marcus KJ, Tanguturi S, Balboni TA, Spektor A, and Huynh MA
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Purpose: There are limited data regarding outcomes after stereotactic body radiation therapy (SBRT) for femur metastases, which was an exclusion criteria for the Stereotactic Ablative Radiotherapy for the Comprehensive Treatment of Oligometastatic Cancers (SABR-COMET) trial. We aimed to characterize clinical outcomes from a large single institution experience., Methods and Materials: Forty-eight patients with 53 lesions were consecutively treated with femur SBRT from May 2017 to June 2022. The Kaplan-Meier method and Cox proportional hazard models were used to characterize time-to-event endpoints and associations between baseline factors and clinical outcomes, respectively. Local control and locoregional control were defined as the absence of tumor progression within the radiation treatment field or within the treated femur, respectively., Results: Most patients had Eastern Cooperative Oncology Group performance status 0 to 1 (90%), prostate (52%) or breast/lung (17%) cancer, and 1 to 3 lesions (100%), including 29 proximal and 5 distal. Fifty-seven percent of the lesions were treated with concurrent systemic therapy. Median planning target volume was 49.1 cc (range, 6.6-387 cc). Planning target volume V100 (%) was 99% (range, 90-100). Fractionation included 18 to 20 Gy/1F, 27 to 30 Gy/3F, and 28.5-40 Gy/5F. Forty-two percent had Mirels score ≥7 and most (94%) did not have extraosseous extension. Acute toxicities included grade 1 fatigue (15%), pain flare (7.5%), nausea (3.8%), and decreased blood counts (1.9%). Late toxicities included fracture (1.9%) at 1.5 years and osteonecrosis (4%) from dose of 40 Gy in 5F and 30 Gy in 5F (after prior 30 Gy/10F). One patient (2%) required fixation postradiation for progressive pain. With median follow-up 19.4 months, 1- and 2-year rates of local control were 94% and 89%, locoregional control was 83% and 67%, progression-free survival were 56% and 25%, and overall survival were 91% and 73%. Fifty percent of local regional recurrence events occurred within 5 cm of gross tumor volume., Conclusions: Femur SBRT for oligometastatic disease control in well-selected patients was associated with good outcomes with minimal rates of acute and late toxicity. Patterns of local regional recurrence warrant consideration of larger elective volume coverage. Additional prospective study is needed., Competing Interests: Yu-Hui Chen reports receiving support from Dana-Farber Cancer Institute and is on the Hoosier Cancer Research Network Data Safety Monitoring Board. Tracy A. Balboni received grants from the National Institute of Health (NIH) National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) and John Templeton Foundation and is the American Society for Radiation Oncology Bone Metastases Guidelines Chair. Mai Anh Huynh received research funding from the Jay Harris Early Career Research Award, Dana-Farber Early Career Innovation Fund, ViewRay, Inc, Immune-Sensor, Inc., and is the Dana-Farber Cancer Institute Bone Metastases Pathways Champion. No other disclosures were reported., (© 2024 The Author(s).)
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- 2024
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14. Widening the therapeutic window for central and ultra-central thoracic oligometastatic disease with stereotactic MR-guided adaptive radiation therapy (SMART).
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Lee G, Han Z, Huynh E, Tjong MC, Cagney DN, Huynh MA, Kann BH, Kozono D, Leeman JE, Singer L, Williams CL, and Mak RH
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- Humans, Radiotherapy Planning, Computer-Assisted methods, Neoplasm Recurrence, Local, Magnetic Resonance Imaging methods, Radiosurgery methods, Thoracic Neoplasms radiotherapy, Radiation Injuries, Lung Neoplasms diagnostic imaging, Lung Neoplasms radiotherapy, Lung Neoplasms pathology
- Abstract
Background/purpose: Central/ultra-central thoracic tumors are challenging to treat with stereotactic radiotherapy due potential high-grade toxicity. Stereotactic MR-guided adaptive radiation therapy (SMART) may improve the therapeutic window through motion control with breath-hold gating and real-time MR-imaging as well as the option for daily online adaptive replanning to account for changes in target and/or organ-at-risk (OAR) location., Materials/methods: 26 central (19 ultra-central) thoracic oligoprogressive/oligometastatic tumors treated with isotoxic (OAR constraints-driven) 5-fraction SMART (median 50 Gy, range 35-60) between 10/2019-10/2022 were reviewed. Central tumor was defined as tumor within or touching 2 cm around proximal tracheobronchial tree (PBT) or adjacent to mediastinal/pericardial pleura. Ultra-central was defined as tumor abutting the PBT, esophagus, or great vessel. Hard OAR constraints observed were ≤ 0.03 cc for PBT V40, great vessel V52.5, and esophagus V35. Local failure was defined as tumor progression/recurrence within the planning target volume., Results: Tumor abutted the PBT in 31 %, esophagus in 31 %, great vessel in 65 %, and heart in 42 % of cases. 96 % of fractions were treated with reoptimized plan, necessary to meet OAR constraints (80 %) and/or target coverage (20 %). Median follow-up was 19 months (27 months among surviving patients). Local control (LC) was 96 % at 1-year and 90 % at 2-years (total 2/26 local failure). 23 % had G2 acute toxicities (esophagitis, dysphagia, anorexia, nausea) and one (4 %) had G3 acute radiation dermatitis. There were no G4-5 acute toxicities. There was no symptomatic pneumonitis and no G2 + late toxicities., Conclusion: Isotoxic 5-fraction SMART resulted in high rates of LC and minimal toxicity. This approach may widen the therapeutic window for high-risk oligoprogressive/oligometastatic thoracic tumors., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)
- Published
- 2024
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15. Knockdown of Chronophage in the nervous system mimics features of neurodevelopmental disorders caused by BCL11A/B variants.
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Yamaguchi M, Huynh MA, Chiyonobu T, and Yoshida H
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- Mammals, Repressor Proteins, Transcription Factors genetics, Drosophila Proteins genetics, Drosophila genetics, Intellectual Disability genetics, Neurodevelopmental Disorders genetics
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Neurodevelopmental disorders (NDD) are a group of disorders that include intellectual disability. Although several genes have been implicated in NDD, the molecular mechanisms underlying its pathogenesis remain unclear. Therefore, it is important to develop novel models to analyze the functions of NDD-causing genes in vivo. Recently, rare pathogenic variants of the B-cell lymphoma/leukemia11A/B (BCL11A/B) gene have been identified in several patients with NDD. Drosophila carries the Chronophage (Cph) gene, which has been predicted to be a homolog of BCL11A/B based on the conservation of the amino acid sequence. In the present study, we investigated whether nervous system-specific knockdown of Cph mimics NDD phenotypes in Drosophila. Nervous system-specific knockdown of Cph induced learning and locomotor defects in larvae and epilepsy-like behaviors in adults. The number of synaptic branches was also elevated in the larval neuromuscular junction without a corresponding increase in the number of boutons. Furthermore, the expression levels of putative target genes that are Drosophila homologs of the mammalian BCL11 target genes were decreased in Cph knockdown flies. These results suggest that Cph knockdown flies are a promising model for investigating the pathology of NDD-induced BCL11A/B dysfunction., Competing Interests: Declaration of competing interest The authors declare no conflict of interests and competing interests., (Copyright © 2023. Published by Elsevier Inc.)
- Published
- 2023
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16. A Prospective Study Assessing the Efficacy and Toxicity of Stereotactic Body Radiation Therapy for Oligometastatic Bone Metastases.
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Lee JH, Shi DD, Shin KY, Buckley E, Gunasti L, Hall E, Mann E, Spicer B, Chen YH, Hammoudeh L, Brennan V, Huynh MA, Spektor A, Krishnan MS, Balboni TA, and Hertan LM
- Abstract
Purpose: Stereotactic body radiation therapy (SBRT) is a promising treatment for oligometastatic disease in bone because of its delivery of high dose to target tissue and minimal dose to surrounding tissue. The purpose of this study is to assess the efficacy and toxicity of this treatment in patients with previously unirradiated oligometastatic bony disease., Methods and Materials: In this prospective phase II trial, patients with oligometastatic bone disease, defined as ≤3 active sites of disease, were treated with SBRT at Brigham and Women's Hospital/Dana Farber Cancer Center and Beth Israel Deaconess Medical Center between December 2016 and May 2019. SBRT dose and fractionation regimen were not protocol mandated. Local progression-free survival, progression-free survival, prostatic specific antigen progression, and overall survival were reported. Treatment-related toxicity was also reported., Results: A total of 98 patients and 126 lesions arising from various tumor histologies were included in this study. The median age of patients enrolled was 72.8 years (80.6% male, 19.4% female). Median follow-up was 26.7 months. The most common histology was prostate cancer (68.4%, 67/98). The most common dose prescriptions were 27/30 Gy in 3 fractions (27.0%, 34/126), 30 Gy in 5 fractions (16.7%, 21/126), or 30/35 Gy in 5 fractions (16.7%, 21/126). Multiple doses per treatment regimen reflect dose painting employing the lower dose to the clinical target volume and higher dose to the gross tumor volume. Four patients (4.1%, 4/98) experienced local progression at 1 site for each patient (3.2%, 4/126). Among the entire cohort, 2-year local progression-free survival (including death without local progression) was 84.8%, 2-year progression-free survival (including deaths as well as local, distant, and prostatic specific antigen progression) was 47.5%, and 2-year overall survival was 87.3%. Twenty-six patients (26.5%, 26/98) developed treatment-related toxicities., Conclusions: Our study supports existing literature in showing that SBRT is effective and tolerable in patients with oligometastatic bone disease. Larger phase III trials are necessary and reasonable to determine long-term efficacy and toxicities., Competing Interests: Tracy A. Balboni has research grants from the National Institutes of Health's National Institute of Arthritis and Musculoskeletal and Skin Diseases and the John Templeton Foundation. All other authors report no conflicts of interest., (© 2023 The Authors.)
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- 2023
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17. Field effect transistor based wearable biosensors for healthcare monitoring.
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Nguyen TT, Nguyen CM, Huynh MA, Vu HH, Nguyen TK, and Nguyen NT
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- Sweat chemistry, Saliva, Biomarkers analysis, Biosensing Techniques methods, Wearable Electronic Devices
- Abstract
The rapid advancement of wearable biosensors has revolutionized healthcare monitoring by screening in a non-invasive and continuous manner. Among various sensing techniques, field-effect transistor (FET)-based wearable biosensors attract increasing attention due to their advantages such as label-free detection, fast response, easy operation, and capability of integration. This review explores the innovative developments and applications of FET-based wearable biosensors for healthcare monitoring. Beginning with an introduction to the significance of wearable biosensors, the paper gives an overview of structural and operational principles of FETs, providing insights into their diverse classifications. Next, the paper discusses the fabrication methods, semiconductor surface modification techniques and gate surface functionalization strategies. This background lays the foundation for exploring specific FET-based biosensor designs, including enzyme, antibody and nanobody, aptamer, as well as ion-sensitive membrane sensors. Subsequently, the paper investigates the incorporation of FET-based biosensors in monitoring biomarkers present in physiological fluids such as sweat, tears, saliva, and skin interstitial fluid (ISF). Finally, we address challenges, technical issues, and opportunities related to FET-based biosensor applications. This comprehensive review underscores the transformative potential of FET-based wearable biosensors in healthcare monitoring. By offering a multidimensional perspective on device design, fabrication, functionalization and applications, this paper aims to serve as a valuable resource for researchers in the field of biosensing technology and personalized healthcare., (© 2023. The Author(s).)
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- 2023
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18. [Bacteria engineered to produce L-arginine potentiate cancer immunotherapy].
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Gautier C, Huynh MA, Peron C, and Pol J
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- Humans, Arginine therapeutic use, Bacteria, Immunotherapy, Neoplasms therapy
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- 2023
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19. Comparison of MR-soft tissue based versus biliary stent based alignment for image guidance in pancreatic SBRT.
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Han Z, Sudhyadhom A, Hsu SH, Hu YH, Mak RH, Huynh MA, van Dams RR, Tanguturi S, Venkatachalam V, Mancias JD, Mamon HJ, Martin NE, Lam MB, and Leeman JE
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- Humans, Retrospective Studies, Stents, Magnetic Resonance Spectroscopy, Radiotherapy Planning, Computer-Assisted methods, Radiotherapy Dosage, Pancreatic Neoplasms, Radiosurgery methods, Pancreatic Neoplasms diagnostic imaging, Pancreatic Neoplasms radiotherapy, Pancreatic Neoplasms surgery, Radiotherapy, Image-Guided methods
- Abstract
Purpose: The role of biliary stents in image-guided localization for pancreatic cancer has been inconclusive. To date, stent accuracy has been largely evaluated against implanted fiducials on cone beam computed tomography. We aim to use magnetic resonance (MR) soft tissue as a direct reference to examine the geometric and dosimetric impacts of stent-based localization on the newly available MR linear accelerator., Methods: Thirty pancreatic cancer patients (132 fractions) treated on our MR linear accelerator were identified to have a biliary stent. In our standard adaptive workflow, patients were set up to the target using soft tissue for image registration and structures were re-contoured on daily MR images. The original plan was then projected on treatment anatomy and dose predicted, followed by plan re-optimization and treatment delivery. These online predicted plans were soft tissue-based and served as reference plans. Retrospective image registration to the stent was performed offline to simulate stent-based localization and the magnitude of shifts was taken as the geometric accuracy of stent localization. New predicted plans were generated based on stent-alignment for dosimetric comparison., Results: Shifts were within 3 mm for 90% of the cases (mean = 1.5 mm); however, larger shifts up to 7.2 mm were observed. Average PTV coverage dropped by 1.1% with a maximum drop of 26.8%. The mean increase in V35Gy was 0.15, 0.05, 0.02, and 0.02 cc for duodenum, stomach, small bowel and large bowel, respectively. Stent alignment was significantly worse for all metrics except for small bowel (p = 0.07)., Conclusions: Overall discrepancy between stent- and soft tissue-alignment was modest; however, large discrepancies were observed for select cases. While PTV coverage loss may be compensated for by using a larger margin, the increase in dose to gastrointestinal organs at risk may limit the role of biliary stents in image-guided localization., (© 2023 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, LLC on behalf of The American Association of Physicists in Medicine.)
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- 2023
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20. Review of Prospective Trials Assessing the Role of Stereotactic Body Radiation Therapy for Metastasis-directed Treatment in Oligometastatic Genitourinary Cancers.
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Huynh MA, Tang C, Siva S, Berlin A, Hannan R, Warner A, Koontz B, De Meeleer G, Palma D, Ost P, and Tran PT
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- Male, Humans, Prospective Studies, Radiosurgery methods, Prostatic Neoplasms radiotherapy, Prostatic Neoplasms pathology, Urinary Bladder Neoplasms
- Abstract
Context: Emerging evidence supports the use of stereotactic body radiation therapy (SBRT) as metastatic-directed therapy (MDT) for oligometastatic genitourinary cancers; however, the prospective data to guide its application as an alternative standard of care remain limited., Objective: To review prospective trials that assess the role of SBRT for patients with genitourinary cancers within a modern framework of oligometastatic disease (OMD) and to highlight clinical scenarios where SBRT may offer a benefit to patients with metastatic cancer., Evidence Acquisition: We performed a critical review of PubMed and clinicaltrials.gov in April 2022 according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement, combined with expert input to identify prospective studies investigating the role of SBRT for oligometastatic prostate, renal, or bladder cancer., Evidence Synthesis: The most commonly studied application of SBRT has been for metachronous oligorecurrent hormone-sensitive prostate cancer (HSPC). Further prospective study is needed to define the role of SBRT in delaying time to next therapy or inducing synergy with other systemic therapies., Conclusions: SBRT has been associated with high rates of local control and minimal risk of toxicity with multiple trials assessing an MDT-alone approach for oligorecurrent HSPC. From a tumor-agnostic perspective, the clinical benefit of SBRT for OMD has been associated with the ability to extend overall survival. As methods of cancer detection and treatment evolve, expansion of studies that prospectively evaluate SBRT MDT, stratifying by tumor histology and oligometastatic state, is needed to inform optimal patient selection and treatment strategy., Patient Summary: We review outcomes from prospective trials assessing the role of stereotactic body radiation therapy (SBRT) for oligometastatic genitourinary cancers, which have predominantly investigated SBRT for oligorecurrent prostate cancer. Much work remains to define how SBRT alone compares with other standard of care treatments for prostate cancer or the role of SBRT in tumor control or delaying time to next therapy in oligometastatic renal and bladder cancer., (Copyright © 2022 European Association of Urology. Published by Elsevier B.V. All rights reserved.)
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- 2023
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21. A Drosophila model of the neurological symptoms in Mpv17-related diseases.
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Kodani A, Yamaguchi M, Itoh R, Huynh MA, and Yoshida H
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- Humans, Animals, Mice, Zebrafish genetics, Membrane Proteins genetics, DNA, Mitochondrial genetics, Mutation, Mitochondrial Proteins genetics, Drosophila genetics, Drosophila melanogaster genetics
- Abstract
Mutations in the Mpv17 gene are responsible for MPV17-related hepatocerebral mitochondrial DNA depletion syndrome and Charcot-Marie-Tooth (CMT) disease. Although several models including mouse, zebrafish, and cultured human cells, have been developed, the models do not show any neurological defects, which are often observed in patients. Therefore, we knocked down CG11077 (Drosophila Mpv17; dMpv17), an ortholog of human MPV17, in the nervous system in Drosophila melanogaster and investigated the behavioral and cellular phenotypes. The resulting dMpv17 knockdown larvae showed impaired locomotor activity and learning ability consistent with mitochondrial defects suggested by the reductions in mitochondrial DNA and ATP production and the increases in the levels of lactate and reactive oxygen species. Furthermore, an abnormal morphology of the neuromuscular junction, at the presynaptic terminal, was observed in dMpv17 knockdown larvae. These results reproduce well the symptoms of human diseases and partially reproduce the phenotypes of Mpv17-deficient model organisms. Therefore, we suggest that neuron-specific dMpv17 knockdown in Drosophila is a useful model for investigation of MPV17-related hepatocerebral mitochondrial DNA depletion syndrome and CMT caused by Mpv17 dysfunction., (© 2022. The Author(s).)
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- 2022
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22. Spinal Cord Delineation Based on Computed Tomography Myelogram Versus T2 Magnetic Resonance Imaging in Spinal Stereotactic Body Radiation Therapy.
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Hammoudeh L, Abunimer AM, Lee HY, Dee EC, Brennan S V, Yaguang P, Shin KY, Chen YH, Huynh MA, Spektor A, Guenette JP, and Balboni T
- Abstract
Purpose: Spinal cord delineation is critical to the delivery of stereotactic body radiation therapy (SBRT). Although underestimating the spinal cord can lead to irreversible myelopathy, overestimating the spinal cord may compromise the planning target volume coverage. We compare spinal cord contours based on computed tomography (CT) simulation with a myelogram to spinal cord contours based on fused axial T2 magnetic resonance imaging (MRI)., Methods and Materials: Eight patients with 9 spinal metastases treated with spinal SBRT were contoured by 8 radiation oncologists, neurosurgeons, and physicists, with spinal cord definition based on (1) fused axial T2 MRI and (2) CT-myelogram simulation images, yielding 72 sets of spinal cord contours. The spinal cord volume was contoured at the target vertebral body volume based on both images. The mixed-effect model assessed comparisons of T2 MRI- to myelogram-defined spinal cord in centroid deviations (deviations in the center point of the cord) through the vertebral body target volume, spinal cord volumes, and maximum doses (0.035 cc point) to the spinal cord applying the patient's SBRT treatment plan, in addition to in-between and within-subject variabilities., Results: The estimate for the fixed effect from the mixed model showed that the mean difference between 72 CT volumes and 72 MRI volumes was 0.06 cc and was not statistically significant (95% confidence interval, -0.034, 0.153; P = .1832). The mixed model showed that the mean dose at 0.035 cc for CT-defined spinal cord contours was 1.24 Gy lower than that of MRI-defined spinal cord contours and was statistically significant (95% confidence interval, -2.292, -0.180; P = .0271). Also, the mixed model indicated no statistical significance for deviations in any of the axes between MRI-defined spinal cord contours and CT-defined spinal cord contours., Conclusions: CT myelogram may not be required when MRI imaging is feasible, although uncertainty at the cord-to-treatment volume interface may result in overcontouring and hence higher estimated cord dose-maximums with axial T2 MRI-based cord definition., (© 2022 Published by Elsevier Inc. on behalf of American Society for Radiation Oncology.)
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- 2022
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23. Stereotactic Magnetic Resonance-Guided Adaptive Radiation Therapy (SMART) for Abdominopelvic Oligometastases.
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Yang DD, Brennan VS, Huynh E, Williams CL, Han Z, Ampofo N, Vastola ME, Sangal P, Singer L, Mak RH, Leeman JE, Cagney DN, and Huynh MA
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- Male, Humans, Radiotherapy Planning, Computer-Assisted methods, Retrospective Studies, Magnetic Resonance Spectroscopy, Radiosurgery adverse effects, Radiosurgery methods, Prostatic Neoplasms radiotherapy, Adenocarcinoma radiotherapy
- Abstract
Purpose: Stereotactic body radiation therapy can be an effective treatment for oligometastases. However, safe delivery of ablative radiation is frequently limited by the proximity of mobile organs sensitive to high radiation doses. The goal of this study was to determine the feasibility, safety, and disease control outcomes of stereotactic magnetic resonance-guided adaptive radiation therapy (SMART) in patients with abdominopelvic oligometastases., Methods and Materials: We identified 101 patients with abdominopelvic oligometastases, including 20 patients enrolled on phase 1 protocols, who were consecutively treated with SMART on a 0.35T magnetic resonance linear accelerator (MR linac) at a single institution from October 2019 to September 2021. Local control and overall survival were analyzed using the Kaplan-Meier method., Results: Overall, 114 tumors were treated. The most common histology was prostate adenocarcinoma (60 tumors [53.5%]), and 65 sites (57.0%) were centered in the pelvis. Ninety-one sites (79.8%) were treated to 8 Gy × 5, and 49 (43.0%) were treated with breath-hold respiratory gating. Online adaptation resulted in a clinically significant improvement in coverage or organ sparing in 86.6% of delivered fractions. The median time required for adaptation was 24 minutes, and the median time in the treatment room was 58 minutes. With median follow-up of 11.4 months, the 12-month local control was 93% and was higher for prostate adenocarcinoma versus other histologies (100% vs 84%; P = .009). The 12-month overall survival was 96% and was higher for prostate adenocarcinoma versus other histologies (100% vs 91%; P = .046). Three patients (3.0%) developed grade 3 toxic effects (colonic hemorrhage at 3.4 months and urinary tract obstructions at 10.1 and 18.4 months, respectively)., Conclusions: In this study, SMART was feasible, safe, and effective for delivering ablative radiation therapy to abdominopelvic metastases. Adaptive planning was necessary in the large majority of cases. The advantages of SMART warrant its further investigation as a standard option for the treatment of abdominopelvic oligometastases., (Copyright © 2022 Elsevier Inc. All rights reserved.)
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- 2022
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24. Patient and Treatment Factors Associated With Improved Local Control and Survival in Oligometastatic Bone Disease: Results From a Large Single-Institution Experience Using Stereotactic Body Radiation Therapy.
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Thomas MC, Chen YH, Fite E, Pangilinan A, Bubelo K, Spektor A, Balboni TA, and Huynh MA
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- Humans, Male, Progression-Free Survival, Retrospective Studies, Treatment Outcome, Bone Diseases, Neoplasms surgery, Radiosurgery adverse effects, Radiosurgery methods
- Abstract
Purpose: Limited data exist to guide optimal patient selection and treatment of bone metastases with curative intent despite the increasing application of stereotactic body radiation therapy (SBRT) for oligometastatic (OM) disease control and reirradiation (Re-RT)., Methods and Materials: Clinical characteristics for 434 patients consecutively treated with bone SBRT at a single institution from March 2011 to June 2020 were analyzed by OM, spine, and nonspine bone using Cox regression to determine association with local control (LC), progression-free survival (PFS), and overall survival (OS), and the Kaplan-Meier method to estimate PFS and OS., Results: Most patients had prostate (39%) or breast/lung (21%) cancer and 1 to 3 lesions (96%), with 651 lesions (spine 63%) treated for Re-RT (12%) or OMD (88%), including synchronous (10%), metachronous (28%), repeat (27%), or induced (23%) states as defined by The European Society for Radiotherapy and Oncology and European Organisation for Research and Treatment of Cancer criteria. Biologically effective dose (BED
10 ) ≥50 (hazard ratio, 0.68; 95% confidence interval, 0.48-0.96; P < .03) predicted improved LC among OM lesions and planning target volume (PTV) ≥150 cc (hazard ratio, 1.94; 95% confidence interval, 1.02-3.70; P < .04) predicted worse LC for nonspine bone. Prostate histology, performance status (PS) 0 to 1, and metastasis-free interval ≥2 year predicted improved PFS and OS (P < .05). Metachronous, synchronous, or repeat OM had higher PFS and OS (P ≤ .001) than induced OM. With median follow-up 25.7 months, 1- and 2-year PFS was 63% and 47% for OM and 36% and 25% for Re-RT; 1- and 2-year OS was 87% and 73% for OM and 58% and 43% for Re-RT. Acute toxicities included grade 1 to 2 pain flare (9%) and fatigue (14%). Late toxicities included fracture (1%) for OM and myelopathy (2.5%) or nerve pain (1.2%) for Re-RT., Conclusions: BED10 ≥50 for OM and PTV <150 cc for nonspine bone lesions was associated with improved LC. Prostate histology, PS 0 to 1, metastasis-free interval ≥2 years, and metachronous, synchronous, or repeat presentations per The European Society for Radiotherapy and Oncology and European Organisation for Research and Treatment of Cancer criteria predicted improved PFS and OS among OM patients treated with bone SBRT., (Copyright © 2022 Elsevier Inc. All rights reserved.)- Published
- 2022
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25. Retrospective Review of Outcomes After Radiation Therapy for Oligoprogressive Disease on Immune Checkpoint Blockade.
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Mahmood U, Huynh MA, Killoran JH, Qian JM, Bent EH, Aizer AA, Mak RH, Mamon HJ, Balboni TA, Gunasti L, Ott PA, Awad MM, and Schoenfeld JD
- Subjects
- B7-H1 Antigen therapeutic use, Humans, Immune Checkpoint Inhibitors therapeutic use, Retrospective Studies, Carcinoma, Non-Small-Cell Lung pathology, Lung Neoplasms drug therapy, Lung Neoplasms radiotherapy
- Abstract
Purpose: We retrospectively evaluated outcomes after radiation therapy for patients with oligoprogression on immune checkpoint inhibitors (ICI)., Methods and Materials: We identified patients irradiated to ≤5 progressive lesions while receiving ICI between 2010 and 2020. We excluded patients whose systemic therapy was switched after radiation but before progression. We evaluated predictors of local control (LC), progression-free survival (PFS) and overall survival (OS)., Results: We screened 1423 patients and identified 120 who were eligible; the most common histologies were lung cancer (n = 59) and melanoma (n = 36). The median number of oligoprogressive lesions was 1. For the median LC of irradiated oligoprogressive lesions, PFS and OS were not reached at 6.41 (4.67-7.66) and 29.80 (22.54-43.33) months, respectively. Tumor histology, radiated site, or radiation modality were not associated with LC, PFS, or OS. Local response to radiation (P < .0001) and radiation of newly developed lesions (P = .02) were associated with LC. Predictors of PFS on univariate and multivariate analyses were best response to radiation (P = .006) and high programmed death ligand 1 tumor proportion score (P = .02). On multivariate analyses, OS was associated with cumulative oligoprogressive lesion volumes (P = .02) and duration of ICI before oligoprogression (P = .03)., Conclusions: Promising outcomes were observed among patients irradiated for oligoprogression on ICI, especially those with a favorable local response, high tumor programmed death ligand 1 expression, and those receiving ICI for longer periods before oligoprogression. These data can help identify patients well suited for radiation therapy versus those who should switch systemic treatment., (Copyright © 2022 Elsevier Inc. All rights reserved.)
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- 2022
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26. Longitudinal symptoms and temporal trends in palliative care, palliative radiotherapy, and anti-cancer treatment near end of life among patients with metastatic cancer.
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Chen JJ, Shin KY, Hong PJ, Hertan LM, Krishnan MS, Roldan CS, Huynh MA, Spektor A, and Balboni TA
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- Death, Humans, Pain, Palliative Care, Retrospective Studies, Hospice and Palliative Care Nursing, Neoplasms radiotherapy
- Abstract
Background: Early specialty palliative care (PC) integration improves oncologic outcomes. We aimed to examine longitudinal relationships between specialty PC and palliative radiotherapy (RT), temporal distribution of symptoms, and predictors of earlier specialty PC., Methods: We retrospectively reviewed 135 patients with metastatic cancer who received palliative RT at our institution (7/2017-2/2018) and who had died by final study follow-up (6/2021). Descriptive statistics summarized frequencies of clinical visits and symptoms over relative survival time (quartiles 1-3: first 75% of life remaining from metastatic diagnosis to death versus quartile 4: last 25% of life remaining from metastatic diagnosis to death). Logistic regression analyses revealed predictors of receiving earlier (quartiles 1-3) versus later (quartile 4) specialty PC., Results: There were 16.3%, 10.4%, 26.7%, and 46.7% of palliative RT consultations, compared to 4.7%, 7.6%, 14.0%, and 73.7% of specialty PC visits, that occurred in quartiles 1, 2, 3, and 4, respectively. On multivariable analysis, pain significantly predicted for receiving earlier specialty PC [odds ratios (OR) =15.34; 95% confidence interval (CI): 2.16-324.23; P=0.020], while patients with ≥2 prior chemotherapy regimens were less likely to have received earlier specialty PC (OR =0.16; 95% CI: 0.04-0.58; P=0.009). The most common reasons for first specialty PC visit were addressing pain (61.0%) and goals of care (19.5%). Overall, 73.3% (99/135) of patients were referred to hospice and 9.6% (13/135) received either palliative RT, chemotherapy, or surgery within 30 days of death., Conclusions: Nearly 47% of palliative RT visits compared with 74% of specialty PC visits occurred in the last quarter of life from metastatic diagnosis to death. Multidisciplinary efforts are needed to manage longitudinal symptoms and offer goal-concordant care.
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- 2022
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27. Crucial Roles of Ubiquitin Carboxy-Terminal Hydrolase L1 in Motor Neuronal Health by Drosophila Model.
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Huynh TKT, Mai TTT, Huynh MA, Yoshida H, Yamaguchi M, and Dang TTP
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- Animals, Humans, Proteasome Endopeptidase Complex, Ubiquitin, Drosophila, Drosophila Proteins genetics, Motor Neurons, Ubiquitin Thiolesterase genetics
- Abstract
Aims: Ubiquitin carboxyl-terminal hydrolase L1 (UCH-L1) plays an important role in the ubiquitin-proteasome system and is distributed mostly in the brain. Previous studies have shown that mutated forms or reduction of UCH-L1 are related to neurodegenerative disorders, but the mechanisms of pathogenesis are still not well understood. To study its roles in motor neuronal health, we utilized the Drosophila model in which dUCH , a homolog of human UCH-L1 , was specifically knocked down in motor neurons. Results: The reduction of Drosophila ubiquitin carboxyl-terminal hydrolase (dUCH) in motor neurons induced excessive reactive oxygen species production and multiple aging-like phenotypes, including locomotive defects, muscle degeneration, enhanced apoptosis, and shortened longevity. In addition, there is a decrease in the density of the synaptic active zone and glutamate receptor area at the neuromuscular junction. Interestingly, all these defects were rescued by vitamin C treatment, suggesting a close association with oxidative stress. Strikingly, the knockdown of dUCH at motor neurons exhibited aberrant morphology and function of mitochondria, such as mitochondrial DNA (mtDNA) depletion, an increase in mitochondrial size, and overexpression of antioxidant enzymes. Innovation: This research indicates a new, possible pathogenesis of dUCH deficiency in the ventral nerve cord and peripheral nervous systems, which starts with abnormal mitochondria, leading to oxidative stress and accumulation aging-like defects in general. Conclusion: Taken together, by using the Drosophila model, our findings strongly emphasize how the UCH-L1 shortage affects motor neurons and further demonstrate the crucial roles of UCH-L1 in neuronal health. Antioxid. Redox Signal. 37, 257-273.
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- 2022
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28. Less Time Is Less Motion: Analysis of Practical Efficiencies Gained With a Modified Workflow Integrating Planar kV Midimaging With CBCT for Spine Stereotactic Body Radiation Therapy.
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Hu DY, Xu Y, Chen YH, Khosravi M, Lyatskaya Y, Bredfeldt JS, Hacker FL, Balboni TA, Spektor A, Cagney D, Mak R, and Huynh MA
- Abstract
Purpose: Our purpose was to optimize an image guided radiation therapy (IGRT) workflow to achieve practical setup accuracy in spine stereotactic body radiation therapy (SBRT). We assessed the time-saving efficiencies gained from incorporating planar kV midimaging as a surrogate for cone beam computed tomography (CBCT) for intrafraction motion monitoring., Methods and Materials: We selected 5 thoracic spine SBRT patients treated in 5 fractions and analyzed patient shifts captured by a modified IGRT workflow using planar kV midimaging integrated with CBCT to maintain a tolerance of 1 mm and 1°. We determined the frequency at which kV midimaging captured intrafraction motion as validated on repeat CBCT and assessed the potential time and dosimetric advantages of our modified IGRT workflow., Results: Patient motion, detected as out-of-tolerance shifts on planar kV midimaging, occurred during 6 of 25 fractions (24%) and were validated on repeat CBCT 100% of the time. Observed intrafraction absolute shifts (mean ± standard deviation) for the 25 fractions were 0.39 ± 0.21, 0.56 ± 0.22, and 0.45 ± 0.21 mm for lateral-longitude-vertical translations and 0.38 ± 0.12°, 0.32 ± 0.09°, and 0.47 ± 0.14° for pitch-roll-yaw rotation, which if uncorrected, could have significantly affected target coverage and increased spinal cord dose. The average times for pretreatment imaging, midtreatment verification, and total treatment time were 8.94, 2.81, and 16.21 minutes. Our modified IGRT workflow reduced the total number of CBCTs required from 120 to 35 (70%) and imaging dose from 126.2 to 43.4 cGy (65.6%) while maintaining high fidelity for our patient population., Conclusions: Accurate patient positioning was effectively achieved with use of multiple 2-dimensional-3-dimensional kV images and an average of 1 verification CBCT scan per fraction. Integration of planar kV midimaging can effectively reduce treatment time associated with spine SBRT delivery and minimize the potential dosimetric effect of intrafraction motion on target coverage and spinal cord dose., (© 2022 The Author(s).)
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- 2022
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29. Magnetic Resonance-Guided Prostate Stereotactic Body Radiation Therapy With Daily Online Plan Adaptation: Results of a Prospective Phase 1 Trial and Supplemental Cohort.
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Leeman JE, Cagney DN, Mak RH, Huynh MA, Tanguturi SK, Singer L, Catalano P, Martin NE, D'Amico AV, Mouw KW, Nguyen PL, King MT, Han Z, Williams C, and Huynh E
- Abstract
Purpose: Stereotactic magnetic resonance (MR)-guided adaptive radiation therapy (SMART) for prostate cancer allows for MR-based contouring, real-time MR motion management, and daily plan adaptation. The clinical and dosimetric benefits associated with prostate SMART remain largely unknown., Methods and Materials: A phase 1 trial of prostate SMART was conducted with primary endpoints of safety and feasibility. An additional cohort of patients similarly treated with prostate SMART were included in the analysis. SMART was delivered to 36.25 Gy in 5 fractions to the prostate ± seminal vesicles using the MRIdian linear accelerator system (ViewRay, Inc). Rates of urinary and gastrointestinal toxic effects and patient-reported outcome measures were assessed. Dosimetric analyses were conducted to evaluate the specific benefits of daily plan adaptation., Results: The cohort included 22 patients (n = 10 phase 1, n = 12 supplemental) treated in 110 fractions. Median follow-up was 7.9 months. Acute grade 2 urinary and gastrointestinal toxic effects were observed in 22.7% and 4.5%, respectively, and 4.5% and 0%, respectively, at last follow-up. No grade 3+ events were observed. Expanded Prostate Cancer Index-26 urinary obstructive scores decreased during SMART (mean, 9.3 points; P = .03) and returned to baseline by 3 months. No other significant changes in patient-reported outcome measures were observed. One-hundred percent of fractions required plan adaptation owing to exceeding organ-at-risk metrics (68%) or suboptimal target coverage (33%) resulting from anatomic changes. Minimum acceptable planning target volume, rectal, bladder, and urethra/bladder neck metrics were violated in 24%, 20%, 24%, and 33% of predicted plans, respectively; 0% of reoptimized plans violated metrics. Underlying causes for deficient dosimetry before reoptimization included changes in bladder filling, seminal vesicle position, prostate volume (median 4.7% increase by fraction 3; range, 0%-56%), and hotspots shifting into urethra/bladder neck., Conclusions: Prostate SMART results in low risk of acute toxic effects with improvements in target and organ-at-risk dosimetry. The clinical benefits resulting from daily plan adaptation, including urethra/bladder neck protection, warrant further investigation., (© 2022 The Authors.)
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- 2022
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30. Oligometastatic adenoid cystic carcinoma: Correlating tumor burden and time to treatment with outcomes.
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Tyan K, Bae JE, Lorch JH, Margalit DN, Tishler RB, Huynh MA, Jo VY, Haddad RI, Chau NG, Hanna GJ, and Schoenfeld JD
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- Humans, Retrospective Studies, Time-to-Treatment, Tumor Burden, Carcinoma, Adenoid Cystic diagnostic imaging, Carcinoma, Adenoid Cystic therapy
- Abstract
Background: There is limited information on the management and outcomes of oligometastases (OM) in adenoid cystic carcinoma (ACC)., Methods: Retrospective study of 42 patients with metastatic ACC of the head and neck. Imaging studies were analyzed to identify patients with OM (1-5 lesions) at any point during follow-up., Results: There was radiographic evidence of OM in 33/42 (79%) patients. Eighteen patients had OM when treated for metastases, with median overall survival (OS) of 36.0 versus 9.2 years for patients with polymetastases (6+ lesions, HR 0.38, 95%CI 0.14-0.89). Earlier locally ablative treatment, but not systemic treatment, of patients with OM predicted improved survival 3 years after metastasis (HR 0.15, 95%CI 0.02-0.63) and postponed systemic treatment by 80 more months (HR 0.22, 95%CI 0.07-0.71)., Conclusions: There is a considerable population of ACC patients with detectable oligometastases, and early locally ablative treatment of oligometastases may be associated with improved outcomes., (© 2021 Wiley Periodicals LLC.)
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- 2022
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31. Evaluating the Role of Stereotactic Body Radiation Therapy With Respect to Androgen Receptor Signaling Inhibitors for Oligometastatic Prostate Cancer.
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Brennan V, Spektor A, Sweeney C, Choudhury A, Rathkopf D, Pomerantz M, Hertan L, Nguyen P, Martin N, Balboni T, Huynh MA, and King M
- Abstract
Purpose: Outcomes of stereotactic body radiation therapy (SBRT) with respect to androgen receptor signaling inhibitors (ARSI) have not been characterized for oligometastatic prostate cancer. We sought to characterize prostate specific antigen (PSA) response and progression-free survival (PFS) after SBRT among men who have progressed on ARSI therapy in the oligometastatic castration-resistant setting., Methods and Materials: A single-institution retrospective analysis was performed for men with ARSI-resistant, oligometastatic, castrate-resistant prostate cancer (omCRPC). Intervention consisted of SBRT. PSA reduction greater than 50% and median PFS (PSA or radiographic progression) as determined by routine care comprised outcome measurements. Cox regression analysis was used to determine factors influencing PFS., Results: Thirty-five men with ARSI-resistant omCRPC and 65 lesions treated with SBRT were followed for a median of 17.2 months. In 63% of men PSA reduction greater than 50% was achieved. Median PFS was 9.0 months. Incomplete ablation (defined as the presence of untreated lesions after SBRT or receipt of prior palliative radiation therapy doses) was associated with worse PFS (hazard ratio 4.21 [1.74-10.19]; P < .01). For a subgroup of 22 men with complete ablation of metastatic sites with SBRT, the median PFS was 13.1 months. One-year overall survival was 93.1% (95% confidence interval, 84.4-100)., Conclusions: SBRT may augment the efficacy of ARSI in omCRPC, provided that all lesions receive ablative radiation doses. Future prospective study of SBRT for men receiving ARSI is warranted., (© 2021 The Authors.)
- Published
- 2021
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32. Patterns of Specialty Palliative Care Utilization Among Patients Receiving Palliative Radiation Therapy.
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Chen JJ, Rawal B, Krishnan MS, Hertan LM, Shi DD, Roldan CS, Huynh MA, Spektor A, and Balboni TA
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- Humans, Palliative Care, Quality of Life, Referral and Consultation, Retrospective Studies, Lung Neoplasms, Neoplasms radiotherapy
- Abstract
Context: Palliative radiation therapy (RT) is frequently used to ameliorate cancer-associated symptoms and improve quality of life., Objectives: To examine how palliative care (PC) as a specialty is integrated at the time of RT consultation for patients with advanced cancer., Methods: We retrospectively reviewed 162 patients with metastatic cancer who received palliative RT at our institution (7/2017-2/2018). Fisher's exact test identified differences in incidence of receiving any specialty PC. Logistic regression analyses determined predictors of receiving PC., Results: Of the 74 patients (46%) who received any specialty PC, 24 (32%) initiated PC within four weeks of RT consultation. The most common reasons for specialty PC initiation were pain (64%) and goals of care/end-of-life care management (23%). Referrals to specialty PC were made by inpatient care teams (48.6%), medical oncologists (48.6%), radiation oncologists (1.4%), and self-referring patients (1.4%). Patients with pain at RT consultation had a higher incidence of receiving specialty PC (58.7% vs. 37.4%, P = 0.0097). There was a trend toward decreased PC among patients presenting with neurological symptoms (34.8% vs. 50%, P = 0.084). On multivariable analysis, receiving specialty PC significantly differed by race (non-white vs. white, odds ratio [OR] = 6.295 [95% CI 1.951-20.313], P = 0.002), cancer type (lung vs. other histology, OR = 0.174 [95% CI 0.071-0.426], P = 0.0006), and RT consultation setting (inpatient vs. outpatient, OR = 3.453 [95% CI 1.427-8.361], P = 0.006)., Conclusion: Fewer than half of patients receiving palliative RT utilized specialty PC. Initiatives are needed to increase PC, especially for patients with lung cancer and neurological symptoms, and to empower radiation oncologists to refer patients to specialty PC., (Copyright © 2021 American Academy of Hospice and Palliative Medicine. Published by Elsevier Inc. All rights reserved.)
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- 2021
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33. Quantitative-qualitative analyses of patient-reported pain response after palliative radiation therapy.
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Shi DD, Balboni TA, Krishnan MS, Spektor A, Huynh MA, Shiloh RY, Skamene S, Zaslowe-Dude C, and Hertan LM
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- Adult, Aged, Aged, 80 and over, Female, Humans, Male, Middle Aged, Prospective Studies, Qualitative Research, Neoplasms radiotherapy, Pain chemically induced, Pain Measurement methods, Palliative Care methods, Patient Reported Outcome Measures
- Abstract
Purpose: While the 0-10 pain scale is often used to assess treatment response, it may not accurately reflect change in pain over time. The purpose of this study is to correlate pain improvement using the 0-10 pain scale to patients' perceived improvement in pain following palliative radiation therapy (RT), and to qualitatively characterize themes of pain assessment., Methods: Patients age ≥ 20 receiving RT for spinal metastases were enrolled. Patients rated their pain (0-10) at the treatment site at RT start, and 1 and 4 weeks post-RT completion. At 1 and 4 weeks post-RT, patients reported their perceived percent improvement in pain (pPIP) (0-100%), which was compared to calculated percent improvement in pain (cPIP) based on the 0-10 pain scores. At 4 weeks post-RT, 20 randomly selected patients participated in a qualitative pain assessment., Results: Sixty-four patients treated at 1-2 sites were analyzed. At 1 week post-RT completion, 53.7% (36/67) reported pPIP within 10 percentage points of cPIP, 32.8% (22/67) reported pPIP > 10 percentage points higher than cPIP, and 13.4% (9/67) reported pPIP > 10 percentage points lower than cPIP. Similar degrees of discordance were seen at 4 weeks post-RT. Qualitative analysis revealed five themes: pain quality (n = 19), activities (n = 9), function (n = 7), medication use (n = 2), and radiation side effects (n = 1)., Conclusions: About half of patients reported a pPIP substantially disparate from their cPIP, and the change in pain measured by the 0-10 scale tended to underestimate the degree of perceived pain improvement. Multiple themes were identified in qualitative analysis of pain response.
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- 2021
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34. Characteristics and Predictors of Radiographic Local Failure in Patients With Spinal Metastases Treated With Palliative Conventional Radiation Therapy.
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Chen JJ, Sullivan AJ, Shi DD, Krishnan MS, Hertan LM, Roldan CS, Huynh MA, Spektor A, Fareed MM, Lam TC, and Balboni TA
- Abstract
Purpose: Although local control is an important issue for longer-term survivors of spinal metastases treated with conventional external beam radiation therapy (EBRT), the literature on radiographic local failure (LF) in these patients is sparse. To inform clinical decision-making, we evaluated rates, consequences, and predictors of radiographic LF in patients with spinal metastases managed with palliative conventional EBRT alone., Methods and Materials: We retrospectively reviewed 296 patients with spinal metastases who received palliative EBRT at a single institution (2006-2013). Radiographic LF was defined as radiologic progression within the treatment field, with death considered a competing risk. Kaplan-Meier, cumulative incidence, and Cox regression analyses determined overall survival estimates, LF rates, and predictors of LF, respectively., Results: There were 182 patients with follow-up computed tomography or magnetic resonance imaging; median overall survival for these patients was 7.7 months. Patients received a median of 30 Gy in 10 fractions to a median of 4 vertebral bodies. Overall, 74 of 182 patients (40.7%) experienced LF. The 6-, 12-, and 18-month LF rates were 26.5%, 33.1%, and 36.5%, respectively, while corresponding rates of death were 24.3%, 38.1%, and 45.9%. Median time to LF was 3.8 months. Of those with LF, 51.4% had new compression fractures, 39.2% were admitted for pain control, and 35.1% received reirradiation; median time from radiation therapy (RT) to each of these events was 3.0, 5.7, and 9.2 months, respectively. Independent predictors of LF included single-fraction RT (8 Gy) (hazard ratio [HR], 2.592; 95% confidence interval [CI], 1.437-4.675; P = .002), lung histology (HR, 3.568; 95% CI, 1.532-8.309; P = .003), and kidney histology (HR, 4.937; 95% CI, 1.529-15.935; P = .008)., Conclusions: Patients experienced a >30% rate of radiographic LF by 1 year after EBRT. Single-fraction RT and lung or kidney histology predicted LF. Given the high rates of LF for patients with favorable prognosis, assessing the risk of death versus LF is important for clinical decision-making., (© 2021 Published by Elsevier Inc. on behalf of American Society for Radiation Oncology.)
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- 2021
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35. Characteristics of Patients and Treatment Recommendations from a Multidisciplinary Spinal Tumor Program.
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Huynh MA, Roldan C, Nunes P, Kelly A, Taylor A, Richards C, Fareed MM, Gorman D, Groff M, Ferrone M, Lu Y, Chi JH, Spektor A, and Balboni T
- Abstract
Objective: We describe characteristics of patient and treatment recommendations from a spinal tumor board at one institution, including representation from palliative care. Background: The impact of prospective multidisciplinary input for patients with spinal tumors is poorly understood despite their increasing complexity. Methods: We retrospectively reviewed 622 cases sequentially discussed at a weekly spinal tumor board, and abstracted patient and treatment information from the medical record and meeting minutes. Results: From April 2017 to February 2019, 622 cases representing 438 unique patients were discussed. The median age was 62 years (range 21-92). Most patients had spinal tumors originating from metastases (91.78%), including breast (14.3%), nonsmall cell lung cancer (13.4%), prostate (10.9%), and renal cell cancer (8.8%), and the remainder had primary central nervous system (4.3%) or benign tumors (3.9%). Sixty-five percent of patients were alive at last follow-up. Conventional external beam radiotherapy was the most common treatment recommendation (33.8%) followed by surgery (26.2%), stereotactic body radiation therapy (17.8%), imaging follow-up (16.6%), and vertebroplasty (15.9%). Palliative care was the primary treatment recommended for 4.5%, and no therapy recommended for 4.0%. Treatment recommendation involved two modalities for 29% of cases, and three in 1.3% of cases. In four cases, biopsy to confirm pathology changed management due to unexpected findings of osteomyelitis, hematopoiesis, or new diagnosis of plasmacytoma. Conclusions: Multidisciplinary input is integral to the optimal care of spinal tumor patients. The high risk of death highlights the need to prioritize modalities that optimize quality of life in the context of a patient's individual prognosis., Competing Interests: No competing financial interests exist., (© Mai Anh Huynh et al., 2020; Published by Mary Ann Liebert, Inc.)
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- 2020
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36. Translational and basic science opportunities in palliative care and radiation oncology.
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Huynh MA and Spektor A
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- Animals, Antineoplastic Agents, Immunological adverse effects, Antineoplastic Agents, Immunological pharmacology, Biomarkers, Tumor, Bone Neoplasms radiotherapy, Bone Neoplasms secondary, Brain Neoplasms radiotherapy, Brain Neoplasms secondary, Cancer-Associated Fibroblasts radiation effects, Combined Modality Therapy, Humans, Immune System radiation effects, Life Expectancy, Neoplasm Metastasis, Neoplasms pathology, Neoplasms therapy, Quality of Life, Radiation Oncology, Spinal Neoplasms radiotherapy, Spinal Neoplasms secondary, Tumor Microenvironment radiation effects, Antineoplastic Agents, Immunological therapeutic use, Cancer Pain radiotherapy, Neoplasms radiotherapy, Palliative Care methods, Translational Research, Biomedical organization & administration
- Abstract
Radiation therapy is commonly used in the metastatic setting to palliate pain, neurological deficits, bleeding and other complications of metastatic disease, allowing patients to live longer and have better quality of life. Despite the effective use of radiation and other palliative treatment modalities, many patients continue to experience poorly controlled pain and other serious sequelae of their disease, underscoring the need for additional research in this area. In this review we highlight recent developments impacting the fields of palliative care and radiation oncology and describe opportunities for research and innovation including studies of tumor microenvironment, identification of effective biomarkers of tumor response and combinatorial treatments with new systemic agents. It is our hope that progress in these fields will improve the lives of patients living with advanced malignancies.
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- 2019
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37. Evaluating the Potential of Portulaca oleracea L. for Parkinson's Disease Treatment Using a Drosophila Model with dUCH -Knockdown.
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Truong HKT, Huynh MA, Vuu MD, and Dang TPT
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Parkinson's disease (PD), which is characterized by the decreased motor function and the loss of dopaminergic neurons, is a common neurodegenerative disorder in elders. There have been numerous in vitro and in vivo models developed to study mechanisms of PD and screen potential drug. Recently, dUCH -knockdown Drosophila model has been established and showed potential for screening antioxidants for PD treatment. The dUCH-knockdown Drosophila model of PD mimics most of main PD pathologies such as dopaminergic neurons degeneration, locomotor dysfunction, and shortage of dopamine in the brain. Common purslane ( Portulaca oleracea L.) is a nutritious vegetable containing a variety of antioxidants, levodopa, and dopamine, a neurotransmitter closely related to PD. Purslane has been reported to exert neuroprotective effects against several neurotoxins including rotenone and 6-OHDA in PD models. However, the recent data have not provided sufficient evidence for using purslane to treat PD or decelerate disease progression. Therefore, in this study, we utilized dUCH -knockdown fly to evaluate the capacity of purslane extracts for PD treatment. The results showed that purslane extracts improved locomotor ability in the larval stage and decelerated disease progression in the adult stage. Additionally, purslane extracts also reduced dopaminergic neuron degeneration. Taken together, our data strongly demonstrated that purslane extracts effectively rescued PD-like phenotypes in the fly model. This result contributed a foundation for further study on the application of purslane in PD treatment.
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- 2019
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38. Palliative Radiation Therapy for Vertebral Metastases and Metastatic Cord Compression in Patients Treated With Anti-PD-1 Therapy.
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Fareed MM, Pike LRG, Bang A, Huynh MA, Taylor A, Spektor A, Awad MM, Ott PA, Krishnan M, Balboni TA, and Schoenfeld JD
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Background: There is increasing use of immune checkpoint blockade (ICB) across multiple cancer types, including in patients at risk for vertebral metastases and cord compression. These patients are often treated with palliative radiotherapy (PRT); however, data evaluating the combination of PRT and ICB in patients with vertebral metastases is limited. Furthermore, patients with cord compression are generally excluded from prospective clinical trials. Therefore, we retrospectively evaluated outcomes following PRT and PD-1 inhibition in patients with vertebral metastases. Methods: We performed a retrospective chart review of 37 consecutive patients (total 57 lesions) treated with radiation for vertebral metastases who also received PD-1 inhibition. Patient, treatment and outcomes data were abstracted from the medical records. Results: Histologies included non-small cell lung cancer ( n = 21), renal cell carcinoma ( n = 9) and melanoma ( n = 7). Out of 57 lesions,18 involved >1 segments of the vertebral column. There were isolated lesions in thoracic (16), lumbar (9), cervical (6), and sacral (8) vertebrae. Presenting symptoms included pain (19), numbness (10), and weakness (3). Eleven patients were asymptomatic. Radiologic cord compression was present in 12, epidural extension in 28 and compression fracture in 14. Eleven patients underwent surgical decompression prior to the onset of RT. Median radiation dose was 24 Gy (range 8-30 Gy). Stereotactic radiation was delivered in 4 patients; 33 patients received conformal RT. 21 patients received PD-1 inhibition after RT, 9 before RT and 7 with RT. Seven patients received concurrent CTLA-4 inhibitors with anti-PD-1 therapy. Treatment was in general well-tolerated. Toxicities included fatigue (6), transient pain flare (1), nausea/vomiting (1) and G1 skin changes (1). All patients reported some degree of pain relief. Numbness/weakness was improved in 6 of 13 patients with baseline symptoms (46%) and this was more likely in patients that received vertebral radiation after starting PD-1 inhibitors (71 vs. 17%, p = 0.04). Most patients (22 of 33 evaluable patients, 67%) had stability of irradiated lesions on subsequent follow up imaging performed at median of 30 days from RT, whereas 3 had a complete local response and 4 had a partial local response. Conclusions: We demonstrate that PRT administered to vertebral metastases was well-tolerated and effective in patients treated with PD-1 inhibitors. There was an encouraging rate of pain reduction and neurological improvement.
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- 2019
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39. Curcumin Effectively Rescued Parkinson's Disease-Like Phenotypes in a Novel Drosophila melanogaster Model with dUCH Knockdown.
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Nguyen TT, Vuu MD, Huynh MA, Yamaguchi M, Tran LT, and Dang TPT
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- Animals, Behavior, Animal drug effects, Drosophila drug effects, Drosophila metabolism, Drosophila melanogaster, Male, Oxidative Stress drug effects, Reactive Oxygen Species metabolism, Ubiquitin Thiolesterase genetics, Curcumin therapeutic use, Neuroprotective Agents therapeutic use, Parkinson Disease drug therapy, Parkinson Disease metabolism, Ubiquitin Thiolesterase deficiency
- Abstract
The relationship between oxidative stress and neurodegenerative diseases has been extensively examined, and antioxidants are considered to be a promising approach for decelerating disease progression. Parkinson's disease (PD) is a common neurodegenerative disorder and affects 1% of the population over 60 years of age. A complex combination of genetic and environmental factors contributes to the pathogenesis of PD. However, since the onset mechanisms of PD have not yet been elucidated in detail, difficulties are associated with developing effective treatments. Curcumin has been reported to have neuroprotective properties in PD models induced by neurotoxins or genetic factors such as α-synuclein , PINK1 , DJ-1 , and LRRK2 . In the present study, we investigated the effects of curcumin in a novel Drosophila model of PD with knockdown of dUCH, a homolog of human UCH-L1. We found that dopaminergic neuron-specific knockdown of dUCH caused impaired movement and the loss of dopaminergic neurons. Furthermore, the knockdown of dUCH induced oxidative stress while curcumin decreased the ROS level induced by this knockdown. In addition, dUCH knockdown flies treated with curcumin had improved locomotive abilities and less severe neurodegeneration. Taken together, with studies on other PD models, these results strongly suggest that treatments with curcumin are an appropriate therapy for PD related to oxidative stress.
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- 2018
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40. Oncogenic PKC-ι activates Vimentin during epithelial-mesenchymal transition in melanoma; a study based on PKC-ι and PKC-ζ specific inhibitors.
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Ratnayake WS, Apostolatos CA, Apostolatos AH, Schutte RJ, Huynh MA, Ostrov DA, and Acevedo-Duncan M
- Abstract
Melanoma is one of the fastest growing cancers in the United States and is accompanied with a poor prognosis owing to tumors being resistant to most therapies. Atypical protein kinase Cs (aPKC) are involved in malignancy in many cancers. We previously reported that aPKCs play a key role in melanoma's cell motility by regulating cell signaling pathways which induce epithelial-mesenchymal Transition (EMT). We tested three novel inhibitors; [4-(5-amino-4-carbamoylimidazol-1-yl)-2,3-dihydroxycyclopentyl] methyl dihydrogen phosphate (ICA-1T) along with its nucleoside analog 5-amino-1-((1R,2S,3S,4R)-2,3-dihydroxy-4-methylcyclopentyl)-1H-imidazole-4-carboxamide (ICA-1S) which are specific to protein kinase C-iota (PKC-ι) and 8-hydroxy-1,3,6-naphthalenetrisulfonic acid (ζ-Stat) which is specific to PKC-zeta (PKC-ζ) on cell proliferation, apoptosis, migration and invasion of two malignant melanoma cell lines compared to normal melanocytes. Molecular modeling was used to identify potential binding sites for the inhibitors and to predict selectivity. Kinase assay showed >50% inhibition for specified targets beyond 5 μM for all inhibitors. Both ICA-1 and ζ-Stat significantly reduced cell proliferation and induced apoptosis, while ICA-1 also significantly reduced migration and melanoma cell invasion. PKC-ι stimulated EMT via TGFβ/Par6/RhoA pathway and activated Vimentin by phosphorylation at S39. Both ICA-1 and ζ-Stat downregulate TNF-α induced NF-κB translocation to the nucleus there by inducing apoptosis. Results suggest that PKC-ι is involved in melanoma malignancy than PKC-ζ. Inhibitors proved to be effective under in-vitro conditions and need to be tested in-vivo for the validity as effective therapeutics. Overall, results show that aPKCs are essential for melanoma progression and metastasis and that they could be used as effective therapeutic targets for malignant melanoma.
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- 2018
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41. Influence of Comorbidity on the Risk of Mortality in Men With Unfavorable-Risk Prostate Cancer Undergoing High-Dose Radiation Therapy Alone.
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Huynh MA, Chen MH, Wu J, Braccioforte MH, Moran BJ, and D'Amico AV
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- Aged, Androgen Antagonists therapeutic use, Comorbidity, Humans, Male, Middle Aged, Proportional Hazards Models, Prospective Studies, Prostatic Neoplasms mortality, Radiotherapy Dosage, Risk, Prostatic Neoplasms radiotherapy
- Abstract
Purpose: To explore whether a subgroup of men with unfavorable-risk prostate cancer (PC) exists in whom high-dose radiation therapy (RT) alone is sufficient to avoid excess PC death due to competing risk from cardiometabolic comorbidity., Methods and Materials: This was a cohort study of 7399 men in whom comorbidity (including congestive heart failure, diabetes mellitus, or myocardial infarction) was assessed and recorded with T1-3NxM0 PC treated with brachytherapy with or without neoadjuvant RT, October 1997 to May 2013 at a single providing institution. Cox and competing risks regression analyses were used to assess whether men with unfavorable-intermediate/high-risk versus favorable-intermediate/low-risk PC were at increased risk of PC-specific, all-cause, or other-cause mortality (PCSM, ACM, OCM), adjusting for number of comorbidities, age at and year of brachytherapy, RT use, and an RT treatment propensity score., Results: After a median follow-up of 7.7 years, 935 men died: 80 of PC and 855 of other causes. Among men with no comorbidity, PCSM risk (adjusted hazard ratio [AHR] 2.74 [95% confidence interval (CI) 1.49-5.06], P=.001) and ACM risk (AHR 1.30 [95% CI 1.07-1.58], P=.007) were significantly increased in men with unfavorable-intermediate/high-risk PC versus favorable-intermediate/low-risk PC, with no difference in OCM (P=.07). Although PCSM risk was increased in men with 1 comorbidity (AHR 2.87 [95% CI 1.11-7.40], P=.029), ACM risk was not (AHR 1.03 [95% CI 0.78-1.36], P=.84). Neither PCSM risk (AHR 4.39 [95% CI 0.37-51.98], P=.24) or ACM risk (AHR 1.43 [95% CI 0.83-2.45], P=.20) was increased in men with 2 comorbidities., Conclusions: To minimize death from PC, high-dose RT alone may be sufficient treatment in men with 2 or more cardiometabolic comorbidities and unfavorable-intermediate- and high-risk PC., (Copyright © 2016 Elsevier Inc. All rights reserved.)
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- 2016
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42. Gleason Score 3 + 5 or 5 + 3 versus 4 + 4 Prostate Cancer: The Risk of Death.
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Huynh MA, Chen MH, Wu J, Braccioforte MH, Moran BJ, and D'Amico AV
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- Androgen Antagonists therapeutic use, Brachytherapy, Follow-Up Studies, Humans, Male, Neoplasm Grading, Propensity Score, Proportional Hazards Models, Prostatic Neoplasms therapy, Risk Factors, Survival Rate, Prostatic Neoplasms mortality, Prostatic Neoplasms pathology
- Abstract
Unlabelled: The International Society of Urological Pathology recommends that Gleason score (GS) 8 prostate cancer (PC) is one prognostic category, yet heterogeneity in cancer control potentially exists amongst men with GS 3+5/5+3 versus GS 4+4 PC. We compared PC-specific mortality (PCSM) and all-cause mortality (ACM) risk among men with GS 3+5/5+3 versus GS 4+4 PC using competing-risks and Cox regression analyses, adjusting for age, known PC prognostic factors, treatment, and a treatment propensity score. Between 1998 and 2012, 462 men with GS 8 PC were treated using brachytherapy with supplemental external-beam radiation therapy and/or androgen deprivation therapy at the Chicago Prostate Cancer Center. After a median follow-up of 7.6 yr, 118 men died, 26 of PC. PCSM (adjusted hazard ratio [AHR] 2.77, 95% confidence interval [CI] 1.13-6.80; p=0.026) and ACM (AHR 1.75, 95% CI 1.06-2.87; p=0.028) were significantly higher for men with GS 3+5/5+3 PC than for men with GS 4+4 PC. Subcategorizing GS 8 into PC with or without grade 5 should be considered as a stratification factor in randomized trials., Patient Summary: Long-term success rates for men with Gleason score 8 prostate cancer vary depending on whether the most aggressive type of cancer (grade 5) is present at biopsy., (Copyright © 2015 European Association of Urology. Published by Elsevier B.V. All rights reserved.)
- Published
- 2016
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43. TIF1γ protein regulates epithelial-mesenchymal transition by operating as a small ubiquitin-like modifier (SUMO) E3 ligase for the transcriptional regulator SnoN1.
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Ikeuchi Y, Dadakhujaev S, Chandhoke AS, Huynh MA, Oldenborg A, Ikeuchi M, Deng L, Bennett EJ, Harper JW, Bonni A, and Bonni S
- Subjects
- Amino Acid Sequence, Animals, Binding Sites genetics, Blotting, Western, Cell Culture Techniques, Cell Line, Epithelial Cells drug effects, Epithelial Cells metabolism, Epithelial-Mesenchymal Transition drug effects, Gene Expression drug effects, HEK293 Cells, Hep G2 Cells, Humans, Intracellular Signaling Peptides and Proteins metabolism, Mammary Glands, Animal cytology, Mammary Glands, Animal metabolism, Mice, Microscopy, Fluorescence, Molecular Sequence Data, Protein Binding, Proto-Oncogene Proteins metabolism, RNA Interference, Reverse Transcriptase Polymerase Chain Reaction, Sequence Homology, Amino Acid, Sumoylation drug effects, Transcription Factors metabolism, Transforming Growth Factor beta pharmacology, Ubiquitin-Protein Ligases metabolism, Epithelial-Mesenchymal Transition genetics, Intracellular Signaling Peptides and Proteins genetics, Proto-Oncogene Proteins genetics, Transcription Factors genetics, Ubiquitin-Protein Ligases genetics
- Abstract
Epithelial-mesenchymal transition (EMT) is a fundamental cellular process that contributes to epithelial tissue morphogenesis during normal development and in tumor invasiveness and metastasis. The transcriptional regulator SnoN robustly influences EMT in response to the cytokine TGFβ, but the mechanisms that regulate the fundamental role of SnoN in TGFβ-induced EMT are not completely understood. Here we employ interaction proteomics to uncover the signaling protein TIF1γ as a specific interactor of SnoN1 but not the closely related isoform SnoN2. A 16-amino acid peptide within a unique region of SnoN1 mediates the interaction of SnoN1 with TIF1γ. Strikingly, although TIF1γ is thought to act as a ubiquitin E3 ligase, we find that TIF1γ operates as a small ubiquitin-like modifier (SUMO) E3 ligase that promotes the sumoylation of SnoN1 at distinct lysine residues. Importantly, TIF1γ-induced sumoylation is required for the ability of SnoN1 to suppress TGFβ-induced EMT, as assayed by the disruption of the morphogenesis of acini in a physiologically relevant three-dimensional model of normal murine mammary gland (NMuMG) epithelial cells. Collectively, our findings define a novel TIF1γ-SnoN1 sumoylation pathway that plays a critical role in EMT and has important implications for our understanding of TGFβ signaling and diverse biological processes in normal development and cancer biology., (© 2014 by The American Society for Biochemistry and Molecular Biology, Inc.)
- Published
- 2014
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44. FOLFIRINOX in locally advanced pancreatic cancer: the Massachusetts General Hospital Cancer Center experience.
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Faris JE, Blaszkowsky LS, McDermott S, Guimaraes AR, Szymonifka J, Huynh MA, Ferrone CR, Wargo JA, Allen JN, Dias LE, Kwak EL, Lillemoe KD, Thayer SP, Murphy JE, Zhu AX, Sahani DV, Wo JY, Clark JW, Fernandez-del Castillo C, Ryan DP, and Hong TS
- Subjects
- Adult, Aged, Antineoplastic Combined Chemotherapy Protocols administration & dosage, Camptothecin administration & dosage, Combined Modality Therapy, Disease-Free Survival, Female, Humans, Irinotecan, Male, Massachusetts, Middle Aged, Neoplasm Staging, Oxaliplatin, Pancreatic Neoplasms pathology, Pancreatic Neoplasms radiotherapy, Treatment Outcome, Camptothecin analogs & derivatives, Fluorouracil administration & dosage, Leucovorin administration & dosage, Organoplatinum Compounds administration & dosage, Pancreatic Neoplasms drug therapy
- Abstract
The objective of our retrospective institutional experience is to report the overall response rate, R0 resection rate, progression-free survival, and safety/toxicity of neoadjuvant FOLFIRINOX (5-fluorouracil [5-FU], oxaliplatin, irinotecan, and leucovorin) and chemoradiation in patients with locally advanced pancreatic cancer (LAPC). Patients with LAPC treated with FOLFIRINOX were identified via the Massachusetts General Hospital Cancer Center pharmacy database. Demographic information, clinical characteristics, and safety/tolerability data were compiled. Formal radiographic review was performed to determine overall response rates (ORRs). Twenty-two patients with LAPC began treatment with FOLFIRINOX between July 2010 and February 2012. The ORR was 27.3%, and the median progression-free survival was 11.7 months. Five of 22 patients were able to undergo R0 resections following neoadjuvant FOLFIRINOX and chemoradiation. Three of the five patients have experienced distant recurrence within 5 months. Thirty-two percent of patients required at least one emergency department visit or hospitalization while being treated with FOLFIRINOX. FOLFIRINOX possesses substantial activity in patients with LAPC. The use of FOLFIRINOX was associated with conversion to resectability in >20% of patients. However, the recurrences following R0 resection in three of five patients and the toxicities observed with the use of this regimen raise important questions about how to best treat patients with LAPC.
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- 2013
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45. An isoform-specific SnoN1-FOXO1 repressor complex controls neuronal morphogenesis and positioning in the mammalian brain.
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Huynh MA, Ikeuchi Y, Netherton S, de la Torre-Ubieta L, Kanadia R, Stegmüller J, Cepko C, Bonni S, and Bonni A
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- Analysis of Variance, Animals, Blotting, Western, Cell Differentiation physiology, Cells, Cultured, Cerebellum cytology, Doublecortin Protein, Immunoprecipitation, Neurons cytology, Rats, Rats, Long-Evans, Cell Movement physiology, Cell Shape physiology, Cerebellum physiology, Forkhead Transcription Factors metabolism, Nerve Tissue Proteins metabolism, Neurons physiology, Transcription Factors metabolism
- Abstract
Control of neuronal positioning is fundamental to normal brain development. However, the cell-intrinsic mechanisms that govern neuronal positioning remain to be elucidated. Here, we report that the spliced protein products of the transcriptional regulator SnoN, SnoN1 and SnoN2, harbor opposing functions in the coordinate regulation of neuronal branching and positioning. Knockdown of SnoN2 stimulates axon branching in primary neurons and impairs migration of granule neurons in the rat cerebellar cortex in vivo. By contrast, SnoN1 knockdown suppresses SnoN2 knockdown-induced neuronal branching and strikingly triggers excessive migration of granule neurons in the cerebellar cortex. We also find that SnoN1 forms a complex with the transcription factor FOXO1 that represses the X-linked lissencephaly gene encoding doublecortin (DCX). Accordingly, repression of DCX mediates the ability of SnoN1 to regulate branching in primary neurons and granule neuron migration in vivo. These data define an isoform-specific SnoN1-FOXO1 transcriptional complex that orchestrates neuronal branching and positioning in the brain with important implications for the study of developmental disorders of cognition and epilepsy., (Copyright © 2011 Elsevier Inc. All rights reserved.)
- Published
- 2011
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46. Regulation of Cdh1-APC function in axon growth by Cdh1 phosphorylation.
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Huynh MA, Stegmüller J, Litterman N, and Bonni A
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- Analysis of Variance, Anaphase-Promoting Complex-Cyclosome, Animals, Animals, Newborn, Axons drug effects, Cadherins genetics, Carrier Proteins metabolism, Cell Cycle Proteins metabolism, Cell Movement drug effects, Cells, Cultured, Cyclin-Dependent Kinases metabolism, Enzyme Inhibitors pharmacology, Gene Expression Regulation drug effects, Gene Expression Regulation genetics, Green Fluorescent Proteins genetics, Leupeptins pharmacology, Mutation physiology, Phosphorylation drug effects, Phosphorylation genetics, Purines pharmacology, Rats, Rats, Long-Evans, Roscovitine, Time Factors, Transfection methods, Axons physiology, Cadherins metabolism, Neurons cytology, Ubiquitin-Protein Ligase Complexes physiology
- Abstract
The ubiquitin ligase Cdh1-anaphase promoting complex (Cdh1-APC) plays a key role in the control of axonal morphogenesis in the mammalian brain, but the mechanisms that regulate neuronal Cdh1-APC function remain incompletely understood. Here, we have characterized the effect of phosphorylation of Cdh1 at cyclin-dependent kinase (Cdk) sites on Cdh1-APC function in neurons. We replaced nine conserved sites of Cdk-induced Cdh1 phosphorylation with alanine (9A) or aspartate (9D) to mimic hypo- or hyper-phosphorylation, respectively. We found that the 9A mutation triggered the proteasome-dependent degradation of Cdh1, and conversely the 9D mutation stabilized Cdh1 in neuronal cells. However, the phosphomimic 9D Cdh1 protein failed to associate with the APC core protein Cdc27. In addition, whereas wild-type and 9A Cdh1 predominantly localized to the nucleus, the 9D Cdh1 protein accumulated in the cytoplasm in neurons. Importantly, in contrast to wild-type and 9A Cdh1, the 9D Cdh1 mutant failed to inhibit axon growth in primary cerebellar granule neurons. Collectively, our results suggest that phosphorylation of neuronal Cdh1 at Cdk sites triggers the stabilization of an inactive form of Cdh1 that accumulates in the cytoplasm, leading to the inhibition of Cdh1-APC function in the control of axon growth. Thus, phosphorylation of Cdh1 may represent a critical mechanism regulating Cdh1-APC function in the nervous system.
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- 2009
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47. A SnoN-Ccd1 pathway promotes axonal morphogenesis in the mammalian brain.
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Ikeuchi Y, Stegmüller J, Netherton S, Huynh MA, Masu M, Frank D, Bonni S, and Bonni A
- Subjects
- Analysis of Variance, Animals, Animals, Newborn, Cells, Cultured, Cerebellum cytology, Chlorocebus aethiops, E1A-Associated p300 Protein genetics, E1A-Associated p300 Protein metabolism, Gene Expression Regulation genetics, Green Fluorescent Proteins genetics, Humans, Intracellular Signaling Peptides and Proteins genetics, MAP Kinase Kinase 4 metabolism, MAP Kinase Kinase Kinases metabolism, Microarray Analysis methods, Morphogenesis genetics, Nerve Tissue Proteins genetics, RNA Interference physiology, RNA, Messenger metabolism, Rats, Rats, Long-Evans, Signal Transduction drug effects, Transcription Factors genetics, Transfection methods, Mitogen-Activated Protein Kinase Kinase Kinase 11, Axons physiology, Intracellular Signaling Peptides and Proteins metabolism, Morphogenesis physiology, Nerve Tissue Proteins metabolism, Neurons cytology, Signal Transduction physiology, Transcription Factors metabolism
- Abstract
The transcriptional corepressor SnoN is a critical regulator of axonal morphogenesis, but how SnoN drives axonal growth is unknown. Here, we report that gene-profiling analyses in cerebellar granule neurons reveal that the large majority of genes altered upon SnoN knockdown are surprisingly downregulated, suggesting that SnoN may activate transcription in neurons. Accordingly, we find that the transcriptional coactivator p300 interacts with SnoN, and p300 plays a critical role in SnoN-induced axon growth. We also identify the gene encoding the signaling scaffold protein Ccd1 as a critical target of SnoN in neurons. Ccd1 localizes to the actin cytoskeleton, is enriched at axon terminals in neurons, and activates the axon growth-promoting kinase JNK (c-Jun N-terminal protein kinase). Knockdown of Ccd1 in neurons reduces axonal length and suppresses the ability of SnoN to promote axonal growth. Importantly, Ccd1 knockdown in rat pups profoundly impairs the formation of granule neuron parallel fiber axons in the rat cerebellar cortex in vivo. These findings define a novel SnoN-Ccd1 link that promotes axonal growth in the mammalian brain, with important implications for axonal development and regeneration.
- Published
- 2009
- Full Text
- View/download PDF
48. ING2 as a novel mediator of transforming growth factor-beta-dependent responses in epithelial cells.
- Author
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Sarker KP, Kataoka H, Chan A, Netherton SJ, Pot I, Huynh MA, Feng X, Bonni A, Riabowol K, and Bonni S
- Subjects
- Amino Acid Motifs, Animals, Cell Line, Cell Proliferation drug effects, Epithelial Cells cytology, Homeodomain Proteins genetics, Humans, Intracellular Signaling Peptides and Proteins metabolism, Mink, Protein Binding, Proto-Oncogene Proteins metabolism, Receptors, Cytoplasmic and Nuclear genetics, Smad2 Protein genetics, Smad2 Protein metabolism, Transcription, Genetic drug effects, Transcription, Genetic genetics, Tumor Suppressor Proteins genetics, Epithelial Cells drug effects, Epithelial Cells metabolism, Homeodomain Proteins metabolism, Receptors, Cytoplasmic and Nuclear metabolism, Transforming Growth Factor beta pharmacology, Tumor Suppressor Proteins metabolism
- Abstract
Members of the ING (inhibitor of growth) family of chromatin modifying proteins (ING1-ING5) have emerged as critical regulators of gene expression and cellular responses, suggesting that the ING proteins may impinge on specific signal transduction pathways and their mediated effects. Here, we demonstrate a role for the protein ING2 in mediating responses by the transforming growth factor (TGF)-beta-Smad signaling pathway. We show that ING2 promotes TGF-beta-induced transcription. Both gain-of-function and RNA interference-mediated knockdown of endogenous ING2 reveal that ING2 couples TGF-beta signals to the induction of transcription and cell cycle arrest. We also find that the Smad-interacting transcriptional modulator SnoN interacts with ING2 and promotes the assembly of a protein complex containing SnoN, ING2, and Smad2. Knockdown of endogenous SnoN blocks the ability of ING2 to promote TGF-beta-dependent transcription, and conversely expression of SnoN augments ING2 enhancement of the TGF-beta response. Collectively, our data suggest that ING2 collaborates with SnoN to mediate TGF-beta-induced Smad-dependent transcription and cellular responses.
- Published
- 2008
- Full Text
- View/download PDF
49. TGFbeta-Smad2 signaling regulates the Cdh1-APC/SnoN pathway of axonal morphogenesis.
- Author
-
Stegmüller J, Huynh MA, Yuan Z, Konishi Y, and Bonni A
- Subjects
- Anaphase-Promoting Complex-Cyclosome, Animals, Cell Differentiation physiology, Cerebellar Cortex growth & development, Morphogenesis physiology, Rats, Rats, Long-Evans, Axons physiology, Nerve Tissue Proteins physiology, Signal Transduction physiology, Smad2 Protein physiology, Transcription Factors physiology, Transforming Growth Factor beta physiology, Ubiquitin-Protein Ligase Complexes physiology
- Abstract
Axon growth is critical to the establishment of neuronal connectivity. The E3 ubiquitin ligase Cdh1-anaphase-promoting complex (Cdh1-APC) and its substrate the transcriptional modulator SnoN form a cell-intrinsic pathway that orchestrates axonal morphogenesis in the mammalian brain. How the Cdh1-APC/SnoN pathway is controlled in the nervous system remained unknown. Here, we report that the TGFbeta-regulated signaling protein Smad2 plays a key role in regulating the Cdh1-APC/SnoN pathway in neurons. We find that Smad2 is expressed in primary granule neurons of the developing rat cerebellar cortex. The Smad signaling pathway is basally activated in neurons. Endogenous Smad2 is phosphorylated, localized in the nucleus, and forms a physical complex with endogenous SnoN in granule neurons. Inhibition of Smad signaling by several distinct approaches, including genetic knock-down of Smad2, stimulates axonal growth. Biochemical evidence and genetic epistasis analyses reveal that Smad2 acts upstream of SnoN in a shared pathway with Cdh1-APC in the control of axonal growth. Remarkably, Smad2 knock-down also overrides the ability of adult rat myelin to inhibit axonal growth. Collectively, our findings define a novel function for Smad2 in regulation of the Cdh1-APC/SnoN cell-intrinsic pathway of axonal morphogenesis, and suggest that inhibition of Smad signaling may hold therapeutic potential in stimulating axonal growth after injury in the CNS.
- Published
- 2008
- Full Text
- View/download PDF
50. Cell-intrinsic regulation of axonal morphogenesis by the Cdh1-APC target SnoN.
- Author
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Stegmüller J, Konishi Y, Huynh MA, Yuan Z, Dibacco S, and Bonni A
- Subjects
- Anaphase-Promoting Complex-Cyclosome, Animals, Animals, Genetically Modified, Animals, Newborn, Brain cytology, Cell Nucleus genetics, Cell Nucleus metabolism, Cerebellar Cortex cytology, Cerebellar Cortex growth & development, Cerebellar Cortex metabolism, Down-Regulation physiology, Growth Cones ultrastructure, Growth Inhibitors genetics, Intracellular Signaling Peptides and Proteins genetics, Macromolecular Substances metabolism, Nerve Tissue Proteins genetics, Organ Culture Techniques, Proteasome Endopeptidase Complex genetics, Proteasome Endopeptidase Complex metabolism, Proto-Oncogene Proteins genetics, RNA Interference physiology, Rats, Rats, Long-Evans, Repressor Proteins genetics, Repressor Proteins metabolism, Transcription Factors genetics, Ubiquitin-Protein Ligase Complexes genetics, Brain growth & development, Brain metabolism, Cell Differentiation physiology, Growth Cones metabolism, Growth Inhibitors metabolism, Nerve Tissue Proteins metabolism, Proto-Oncogene Proteins metabolism, Transcription Factors metabolism, Ubiquitin-Protein Ligase Complexes metabolism
- Abstract
Axonal growth is fundamental to the establishment of neuronal connectivity in the brain. However, the cell-intrinsic mechanisms that govern axonal morphogenesis remain to be elucidated. The ubiquitin ligase Cdh1-anaphase-promoting complex (Cdh1-APC) suppresses the growth of axons in postmitotic neurons. Here, we report that Cdh1-APC operates in the nucleus to inhibit axonal growth. We also identify the transcriptional corepressor SnoN as a key target of neuronal Cdh1-APC that promotes axonal growth. Cdh1 forms a physical complex with SnoN and stimulates the ubiquitin-dependent proteasomal degradation of SnoN in neurons. Knockdown of SnoN in neurons significantly reduces axonal growth and suppresses Cdh1 RNAi enhancement of axonal growth. In addition, SnoN knockdown in vivo suggests an essential function for SnoN in the development of granule neuron parallel fibers in the cerebellar cortex. These findings define Cdh1-APC and SnoN as components of a cell-intrinsic pathway that orchestrates axonal morphogenesis in a transcription-dependent manner in the mammalian brain.
- Published
- 2006
- Full Text
- View/download PDF
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