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Resistance to 5-FU reduces its clinical efficacy for the treatment of colorectal cancer. Sphingosine-1-phosphate receptor 2 (S1PR2) has emerged as a potential target to reverse 5-FU-resistance by inhibiting the expression of dihydropyrimidine dehydrogenase (DPD). In this study, 38 novel S1PR2 antagonists based on aryl urea structure were designed and synthesized, and the structure-activity relationship was investigated based on the S1PR2 binding assay. Representative compound

Low-dose azacitidine (AZA) regimens, primarily 5-day AZA, have been used in lower risk myelodysplastic syndrome (LrMDS) but they have yet to be directly compared to the standard 7-day, uninterrupted dosing schedule.In this phase 2, multicenter, randomized trial, 55 patients with adult LrMDS (low and intermediate-1 risk by international prognostic scoring system [IPSS]) were randomly assigned and received either 5-day (n = 26) or 7-day (n = 29) AZA between March 2012 and August 2020. The trial was stopped prematurely because of the slow accrual of patients. The primary end point was the overall response rate (ORR) of the 5-day AZA as compared to that of the 7-day regimen.Median patient age was 59 years, and IPSS intermediate-1 risk comprised the majority (81.8%). The median number of cycles in both arms was six. In the ITT subset (n = 53), in each of the 5-day and 7-day arms, the ORR of 48.0% and 39.3%, hematologic improvement of 44.0% and 39.3%, and RBC transfusion independence of 35.3% and 40.0% were observed respectively, and none of these findings were significantly different between the two arms. A cytogenetic response rate was significantly higher in the 7-day arm (8.3% and 53.8%, p = .027). Survival and adverse events were similar between the groups, although gastrointestinal toxicities, grade ≥3 thrombocytopenia, and febrile neutropenia were less frequent in the 5-day arm.The 5-day AZA in LrMDS showed comparable efficacy to a 7-day regimen in terms of similar overall response and other outcomes, despite significantly higher rates of cytogenetic responses in the 7-day regimen.Azacitidine (75 mg/m

Bone marrow fibrosis in myelodysplastic syndromes (MDS) has been associated with poor outcome. However, these studies were conducted prior to the widespread use of azacitidine in the management of MDS. Our study aimed to assess whether treatment with azacitidine ameliorates the inferior outcome in MDS with fibrosis. A retrospective study of all patients diagnosed with MDS and treated with azacitidine over 3 years in two institutions was performed. A total of 21 patients were included in this study. Approximately half of these had moderate to severe bone marrow fibrosis at the start of treatment with azacitidine. The median overall survival was 34 months in patients with non-fibrotic bone marrow compared to 14 months in patients with fibrotic marrow (p=0.0007). Median event-free survival was 26 months versus 12 months (p=0.0027) in patients with non-fibrotic and fibrotic marrow, respectively. In multivariate analysis, bone marrow fibrosis was an independent factor in overall survival. Transfusion requirement was not different between the two groups. Despite the small sample size, we observed a worse outcome in azacitidine treated patients with MDS and fibrotic marrow. We suggest a prospective larger study to confirm the above finding.

Fluoropyrimidines, the major chemotherapeutic agents in various malignancies treatment, are metabolized by dihydropyrimidine dehydrogenase (DPD). DPD deficiency can lead to severe and sometimes fatal toxicity. In the present study, we developed a simple protocol to detect the DPYD*2A variant. Common side effects in patients treated with these drugs were also evaluated in a Kurdish population.We established a reverse-transcriptase polymerase chain reaction (RT-PCR) technique for detection of DPYD*2A. Sanger sequencing was used to confirm the results. 121 Kurdish patients receiving fluoropyrimidine derivatives were enrolled, and clinical information regarding the dosage and toxicity was analyzed.Our RT-PCR method was able to detect one patient with heterozygous state for DPYD*2A (0.8%). The most observed adverse drug reactions were tingling, nausea, and hair loss. The frequency of patients with the toxicity of grade 3 or worse was 6.6%.This was the first study that detect DPYD*2A polymorphism in the Kurdish population. Our method was successfully able to detect the DPYD*2A variant and, due to its simplicity and cost-effectiveness, it may be considered as an alternative to the current methods, especially in developing countries. Our detected polymorphism rate at 0.8% is comparable with other studies. Despite the low rate of DPYD*2A polymorphism, pharmacogenetics assessment before beginning the treatment process is highly recommended due to its association with a high risk of severe toxicity.

Pevonedistat; Chronic myelomonocytic leukemia Pevonedistat; Leucemia mielomonocítica crónica Pevonedistat; Leucèmia mielomonocítica crònica PANTHER is a global, randomized phase 3 trial of pevonedistat+azacitidine (n = 227) vs azacitidine monotherapy (n = 227) in patients with newly diagnosed higher-risk myelodysplastic syndromes (MDS; n = 324), higher-risk chronic myelomonocytic leukemia (n = 27), or acute myeloid leukemia (AML) with 20% to 30% blasts (n = 103). The primary end point was event-free survival (EFS). In the intent-to-treat population, the median EFS was 17.7 months with pevonedistat+azacitidine vs 15.7 months with azacitidine (hazard ratio [HR], 0.968; 95% confidence interval [CI], 0.757-1.238; P = .557) and in the higher-risk MDS cohort, median EFS was 19.2 vs 15.6 months (HR, 0.887; 95% CI, 0.659-1.193; P = .431). Median overall survival (OS) in the higher-risk MDS cohort was 21.6 vs 17.5 months (HR, 0.785; P = .092), and in patients with AML with 20% to 30% blasts was 14.5 vs 14.7 months (HR, 1.107; P = .664). In a post hoc analysis, median OS in the higher-risk MDS cohort for patients receiving >3 cycles was 23.8 vs 20.6 months (P = .021) and for >6 cycles was 27.1 vs 22.5 months (P = .008). No new safety signals were identified, and the azacitidine dose intensity was maintained. Common hematologic grade ≥3 treatment emergent adverse events were anemia (33% vs 34%), neutropenia (31% vs 33%), and thrombocytopenia (30% vs 30%). These results underscore the importance of large, randomized controlled trials in these heterogeneous myeloid diseases and the value of continuing therapy for >3 cycles. The trial was registered on clinicaltrials.gov as #NCT03268954. This study was sponsored by Takeda Development Centers Inc (TDCA; Lexington, MA).

Previous analyses using the SEER-Medicare database have reported substantial underutilization of hypomethylating agents (HMAs) among patients with higher-risk myelodysplastic syndromes (MDS), and an association between poor HMA persistence and high economic burden. We aimed to compare rates of hospitalizations and emergency room (ER) visits among patients with higher-risk MDS according to use or non-use of HMA therapy, and to explore factors associated with early discontinuation of HMA therapy.We used the 2010-2016 SEER-Medicare database to identify patients aged ≥66 years with a new diagnosis of refractory anemia with excess blasts (RAEB; a surrogate for higher-risk MDS) between 2011 and 2015. New hospitalizations and ER visits during the 12 months following MDS diagnosis were determined. Treatment discontinuation was defined as stopping HMA therapy before 4 cycles.Overall, 664 (55.8%) patients were HMA users and 526 (44.2%) non-users. Non-users had more hospitalizations (mean 0.47 vs. 0.30, P.001) and ER visits (mean 0.69 vs. 0.41, P = .005) per month than HMA users. Among HMA users, 193 (29.1%) discontinued HMA therapy before 4 cycles, and 91 (47.2%) of these after 1 cycle. Older age and poor performance status were associated with higher risk of HMA discontinuation.An increased rate of hospitalizations and ER visits occurred in HMA non-users vs. HMA users. Approximately one-third of patients discontinued HMA therapy early. Predictors of discontinuation included older age and poor performance status. Novel approaches are needed to improve utilization and persistence with HMA therapy and associated outcomes, particularly among these higher-risk groups.

PURPOSE: Patients who carry reduced-activity DPYD polymorphisms have increased fluoropyrimidine (FP) toxicity risk. Although pretreatment DPYD testing is recommended throughout most of Europe, it is not recommended in the United States, and adoption has been limited. The objective of this survey was to describe the current practice in the United States regarding pretreatment DPYD testing and understand the factors deterring oncologists from ordering testing. METHODS: Survey invitations were e-mailed to 325 medical oncologists practicing in the United States who are members of the SWOG Cancer Research Network Gastrointestinal Cancer, Breast Cancer, or Early Therapeutics Committees. Descriptive statistics were used to evaluate survey responses. RESULTS: Responses were collected from 59 (18.2%) US medical oncologists, of whom 98% strongly or somewhat agree that patients with dihydropyrimidine dehydrogenase (DPD) deficiency have increased toxicity risk and 96% would modify FP dosing for a patient with known DPD deficiency. However, only 32% strongly or somewhat agree that pretreatment DPYD testing is useful to inform FP treatment, 20% have ever ordered pretreatment testing, and 3% order testing for at least 10% of their FP-treated patients. The most important factors that deter oncologists from ordering testing were low prevalence of DPD deficiency (54%) and lack of clinical practice guideline recommendations (48%). CONCLUSION: Clinical adoption of pretreatment DPYD testing is extremely limited in the United States. Utilization may be substantially increased by inclusion in the oncology clinical practice guideline recommendations, coverage through health insurance, and potentially education of medical oncologists regarding available treatment modification guidelines.

Hand-foot syndrome (HFS) is a common adverse event in patients receiving capecitabine therapy for breast cancer, and the symptoms of HFS significantly impair patient quality of life. However, currently there are no effective drugs or measures to prevent and alleviate the occurrence of HFS.To assess the effectiveness of a novel soaking solution, a mixture solution of dexamethasone, gentamicin and vitamin B12, in patients with grade 2-3 HFS after capecitabine treatment for breast cancer.Patients with grade 2-3 HFS according to the National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE) were enrolled in this randomized, single-center, self-controlled trial. Each patient's right and left hands or feet were individually randomized to soak in either a novel soaking solution (treated hands or feet) or a placebo liquid (control hands or feet) for three times a day, each time for 15 minutes and for four weeks. Effectiveness was evaluated according to CTCAE grades, defined as a reduction of 1 or more CTCAE grades.A total of 60 patients were enrolled. The HFS CTCAE grade of the treated hands and feet at 4 weeks of HFS treatment was significantly decreased compared to that of the control hands and feet (P = .005). Significant differences were also observed between the treatment conditions in terms of the HFS effectiveness rate: treated group 80% and placebo group 51.7% (P = .001). No adverse or unexpected events were observed during the whole trial.Soaking affected hands or feet in a novel soaking solution safely and effectively reduced the severity of HFS following treatment with capecitabine for breast cancer.

Fluoropyrimidines (FP; 5-fluorouracil, capecitabine, and tegafur) are a commonly prescribed class of antimetabolite chemotherapies, used for various solid organ malignancies in over 2 million patients globally per annum. Dihydropyrimidine dehydrogenase (DPD), encoded by the DPYD gene, is the critical enzyme implicated in FP metabolism. DPYD variant genotypes can result in decreased DPD production, leading to the development of severe toxicities resulting in hospitalization, intensive care admission, and even death. Management of toxicity incurs financial burden on both patients and healthcare systems alike. Upfront DPYD genotyping to identify variant carriers allows an opportunity to identify patients who are at high risk to suffer from serious toxicities and allow prospective dose adjustment of FP treatment. This approach has been shown to reduce patient morbidity, as well as improve the cost-effectiveness of managing FP treatment. Upfront DPYD genotyping has been recently endorsed by several countries in Europe and the United Kingdom. This review summarizes current knowledge about DPD deficiency and upfront DPYD genotyping, including clinical and cost-effectiveness outcomes, with the intent of supporting implementation of an upfront DPYD genotyping service with individualized dose-personalization.

A 9-year-old boy with acute lymphoblastic leukemia experienced a hypersensitivity reaction (HSR) and acral erythema upon receiving high-dose methotrexate (HDMTX). Both HSR and acral erythema are uncommon adverse events of MTX therapy, and MTX has not been reported to cause HSRs in specific ethnic groups. We assessed the severity of each symptom and were successful in managing these adverse events for continuing subsequent HDMTX therapies. HSR appeared during the first and second HDMTX courses. Acral erythema occurred after the second and fourth courses. Desensitization by reducing the infusion rate and premedication allowed the continuation of HDMTX. Acral erythema improved with supportive care without dose reduction or interval lengthening. HSRs to MTX should be considered even during the first course. MTX-induced acral erythema is a self-limited reaction; therefore, the chemotherapeutic regimen should not be modified unless necessary.

Epigenetic dysregulation leads to aberrant DNA hypermethylation and is common in acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS). A large number of clinical trials in AML, MDS, and other hematologic malignancies have assessed hypomethylating agents (HMAs), used alone or in combination with other drugs, in the frontline, maintenance, relapsed/refractory, and peritransplant settings. Effective maintenance therapy has long been a goal for patients with AML in remission. Previous large, randomized clinical trials of maintenance with HMAs or other agents had not shown meaningful improvement in overall survival. Oral azacitidine (Oral-AZA [CC-486]) is approved in the United States, Canada, and European Union for treatment of adult patients with AML in first complete remission (CR) or CR with incomplete blood count recovery (CRi) following intensive induction chemotherapy who are ineligible for hematopoietic cell transplant. Regulatory approvals of Oral-AZA were based on outcomes from the randomized, phase III QUAZAR AML-001 trial, which showed a median overall survival advantage of 9.9 months with Oral-AZA versus placebo. Oral-AZA allows convenient extended AZA dosing for 14 days per 28-day treatment cycle, which is not feasible with injectable AZA. Focusing on AML and MDS, this report reviews the rationale for the use of orally bioavailable AZA and its potential use in all-oral combination therapy regimens; the unique pharmacokinetic and pharmacodynamic profile of Oral-AZA compared with injectable AZA; the clinical safety and efficacy of Oral-AZA maintenance therapy in patients with AML in first remission and for treatment of patients with active MDS; and ongoing Oral-AZA clinical trials.

We analyzed the treatment effects of chidamide and decitabine in combination with a HAG (homoharringtonine, cytarabine, G-CSF) priming regimen (CDHAG) in acute myeloid leukemia (AML) patients with TP53 mutation. Seven TP53 mutated AML patients were treated with CDHAG. The treatment effects were assessed using hemogram detection and bone marrow aspirate. The possible side effects were evaluated based on both hematological and non-hematological toxicity. Four of the seven patients were classified as having achieved complete remission after CDHAG treatment; one patient was considered to have achieved partial remission, and the remaining two patients were considered in non-remission. The overall response rate (ORR) to CDHAG was 71.4%. Regarding the side effects, the hematological toxicity level of the seven patients ranged from level III to level IV, and infections that occurred at lung, blood, and skin were recorded. Nausea, vomiting, liver injury, and kidney injury were also detected. However, all side effects were attenuated by proper management. The CDHAG regimen clearly improved the ORR (71.4%) of TP53-mutated AML patients, with no severe side effects.

Retrospective data suggest that gastric acid reduction by proton pump inhibitors (PPIs) impairs the dissolution and subsequent absorption of capecitabine, and thus potentially reduces the capecitabine exposure. Therefore, we examined prospectively the effect of esomeprazole on the pharmacokinetics of capecitabine. In this randomized crossover study, patients with cancer were assigned to 2 sequence groups, each consisting of 3 phases: capecitabine with esomeprazole administration 3 hours before (phase A), capecitabine alone (phase B), and capecitabine concomitant with cola and esomeprazole co-administration 3 hours before (phase C). The primary end point was the relative difference (RD) in exposure to capecitabine assessed by the area under the plasma concentration-time curve from zero to infinity (AUC0-inf) and analyzed by a linear mixed effect model. Twenty-two evaluable patients were included in the analysis. After esomeprazole, there was a 18.9% increase in AUC0-inf of capecitabine (95% confidence interval (CI) −10.0% to 57.0%, P = 0.36). In addition, capecitabine half-life was significantly longer after esomeprazole (median 0.63 hours vs. 0.46 hours, P = 0.005). Concomitant cola did not completely reverse the effects observed after esomeprazole (RD 3.3% (95% CI −16.3 to 27.4%, P = 1.00). Capecitabine exposure is not negatively influenced by esomeprazole cotreatment. Therefore, altered capecitabine pharmacokinetics do not explain the assumed worse clinical outcome of PPI-cotreated patients with cancer.

Chemotherapy is used for recurrent and metastatic colorectal cancer, but the response rate of 5-fluorouracil (5-FU), the standard treatment for colorectal cancer, is low. We hypothesized that thymidine phosphorylase (TYMP) expression, a rate-limiting activating enzyme of 5-FU, is regulated by methylation of the gene promoter region, and demethylation of TYMP would increase sensitivity to 5-FU.HCT116 colon cancer cells were treated with 5-aza-2'-deoxycytidine, a demethylating agent, and changes in TYMP transcription and sensitivity to 5-FU were evaluated.TYMP expression increased over 54-fold in HCT116 transfected with TYMP. The cytotoxicity of 5-FU increased up to 5.5-fold. In comparison, in HCT116 treated with 5-aza-2'-deoxycytidine, TYMP expression increased 5.8-fold. However, the cytotoxicity of 5-FU remained unchanged.Demethylating agent alone did not promote the cytotoxicity of 5-FU against colorectal cancer. To further increase the sensitivity to 5-FU, combination with adjuvant therapy focusing on metabolic pathways other than the TYMP pathway appear necessary.

Osteosarcoma is the most common bone sarcoma. Although surgery and chemotherapy are initially effective, the 5-year survival is approximately 60% to 80%, and has not improved over three decades. We have previously shown that methionine restriction (MR) induced by oral recombinant methioninase (o-rMETase), is effective against osteosarcoma in patient-derived orthotopic xenograft (PDOX) nude-mouse models. In the present report, the efficacy of the combination of oral o-rMETase and methotrexate (MTX) was examined in an osteosarcoma PDOX mouse model.An osteosarcoma-PDOX model was previously established by implanting tumor fragments into the proximal tibia of nude mice. The osteosarcoma PDOX models were randomized into four groups: control; o-rMETase alone; MTX alone; combination of o-rMETase and MTX. The mice were sacrificed after 4 weeks of treatment.The combination of o-rMETase and MTX showed significantly higher efficacy compared to the control group (p=0.04). The combination also showed significantly higher efficacy compared to MTX alone (p=0.04). No significant efficacy of o-rMETase alone or MTX alone compared to control was shown (p=0.21, 1.00, respectively). Only the combination of o-rMETase and MTX reduced the cancer-cell density in the osteosarcoma tumor.rMETase converted an osteosarcoma PDOX from MTX-resistant to MTX-sensitive and thereby shows future clinical potential.

Attempts to selectively starve cancers in the clinic have been made at least since the time of Warburg beginning 100 years ago. Calorie-restriction or low-carbohydrate diets have had limited success with cancer patients. Methionine restriction is another strategy to selectively starve cancer cells, since cancers are addicted to methionine, unlike normal cells. Methionine addiction of cancer is termed the Hoffman effect. Numerous preclinical studies over the past half century have shown methionine restriction to be highly effective against all major cancer types and synergistic with chemotherapy. Low-methionine medical diets can be effective in lowering methionine and have shown some clinical promise, but they are not palatable and thereby not sustainable. However, selectively choosing among plant-based foods allows a variety of low-methionine diets that are sustainable. Our laboratory has developed a methioninase that can be administered orally as a supplement and has resulted in anecdotal positive results in patients with advanced cancer, including hormone-independent prostate cancer, and other recalcitrant cancers. The question is whether methionine restriction through a low-methionine diet, or even greater methionine restriction with methioninase in combination with a low-methionine diet, is ready for prime time in the clinic, especially in combination with other synergistic therapy. The question will hopefully be answered in the near future, especially for advanced cancer patients who have failed all standard therapy.

We analyzed 526 consecutive acute myeloid leukemia patients refractory to or relapsing after chemotherapy. 270 patients received intensive salvage chemotherapy (IC), 97 azacitidine (AZA) and 159 best supportive care (BSC). Complete response was obtained in 37/19/0% (

Hypomethylating agents (HMA) like azacitidine are licensed for the treatment of acute myeloid leukemia (AML) patients ineligible for allogeneic hematopoietic stem cell transplantation. Biomarker-driven identification of HMA-responsive patients may facilitate the choice of treatment, especially in the challenging subgroup above 60 years of age. Since HMA possesses immunomodulatory functions that constitute part of their anti-tumor effect, we set out to analyze the bone marrow (BM) immune environment by next-generation sequencing of T cell receptor beta (TRB) repertoires in 51 AML patients treated within the RAS-AZIC trial. Patients with elevated pretreatment T cell diversity (11 out of 41 patients) and those with a boost of TRB richness on day 15 after azacitidine treatment (12 out of 46 patients) had longer event-free and overall survival. Both pretreatment and dynamic BM T cell metrics proved to be better predictors of outcome than other established risk factors. The favorable broadening of the BM T cell space appeared to be driven by antigen since these patients showed significant skewing of TRBV gene usage. Our data suggest that one course of AZA can cause reconstitution to a more physiological T cell BM niche and that the T cell space plays an underestimated prognostic role in AML. Trial registration: DRKS identifier: DRKS00004519

High‐dose methotrexate (HDMTX) pharmacokinetics (PKs), including the best estimated glomerular filtration rate (eGFR) equation that reflects methotrexate (MTX) clearance, requires investigation. This prospective, observational, single‐center study evaluated adult patients with lymphoma treated with HDMTX. Samples were collected at predefined time points up to 96 h postinfusion. MTX and 7‐hydroxy‐MTX PKs were estimated by standard noncompartmental analysis. Linear regression determined which serum creatinine‐ or cystatin C‐based eGFR equation best predicted MTX clearance. The 80 included patients had a median (interquartile range [IQR]) age of 68.6 years (IQR 59.2–75.6), 54 (67.5%) were men, and 74 (92.5%) were White. The median (IQR) dose of MTX was 7.6 (IQR 4.8–11.3) grams. Median clearance was similar across three dosing levels at 4.5–5.6 L/h and was consistent with linear PKs. Liver function, weight, age, sex, concomitant chemotherapy, and number of previous MTX doses did not impact clearance. MTX area under the curve (AUC) values varied over a fourfold range and appeared to increase in proportion to the dose. The eGFRcys (ml/min) equation most closely correlated with MTX clearance in both the entire cohort and after excluding outlier MTX clearance values (r = 0.31 and 0.51, respectively). HDMTX as a 4‐h infusion displays high interpatient pharmacokinetic variability. Population PK modeling to optimize MTX AUC attainment requires further evaluation. The cystatin C‐based eGFR equation most closely estimated MTX clearance and should be investigated for dosing and monitoring in adults requiring MTX as part of lymphoma management.

The survival rate of colorectal cancer patients is adversely affected by the selection of tumors resistant to conventional anti-cancer drugs such as 5-fluorouracil (5FU). Although there is mounting evidence that commensal gut microbiota is essential for effective colon cancer treatment, the detailed molecular mechanisms and the role of gut microbial metabolites remain elusive. The goal of this study is to decipher the impact and mechanisms of gut microbial metabolite, urolithin A (UroA) and its structural analogue, UAS03 on reversal of 5FU-resistant (5FUR) colon cancers.

An interaction between acute myeloid leukemia (AML) cells and endothelial cells in the bone marrow seems to play a critical role in chemosensitivity on leukemia treatment. The endothelial niche reportedly enhances the paracrine action of the soluble secretory proteins responsible for chemoresistance in a vascular endothelial growth factor A (VEGF-A)/VEGF receptor 2 (VEGFR-2) signaling pathway–dependent manner. To further investigate the contribution of VEGF-A/VEGFR-2 signaling to the chemoresistance of AML cells, a biochemical assay system in which the AML cells were cocultured with human endothelial EA.hy926 cells in a monolayer was developed. By coculture with EA.hy926 cells, this study revealed that the AML cells resisted apoptosis induced by the anticancer drug cytarabine. SU4312, a VEGFR-2 inhibitor, attenuated VEGFR-2 phosphorylation and VEGF-A/VEGFR-2 signaling–dependent endothelial cell migration; thus, this inhibitor was observed to block VEGF-A/VEGFR-2 signaling. Interestingly, this inhibitor did not reverse the chemoresistance. When VEGFR-2 was knocked out in EA.hy926 cells using the CRISPR–Cas9 system, the cytarabine-induced apoptosis of AML cells did not significantly change compared with that of wild-type cells. Thus, coculture-induced chemoresistance appears to be independent of VEGF-A/VEGFR-2 signaling. When the transwell, a coculturing device, separated the AML cells from the EA.hy926 cells in a monolayer, the coculture-induced chemoresistance was inhibited. Given that the migration of VEGF-A/VEGFR-2 signaling–dependent endothelial cells is necessary for the endothelial niche formation in the bone marrow, VEGF-A/VEGFR-2 signaling contributes to chemoresistance by mediating the niche formation process, but not to the chemoresistance of AML cells in the niche.

A 34-year-old patient had her first trimester Down syndrome scan followed by serial ultrasound scans which showed a single intrauterine pregnancy with multiple cystic areas in the anterior placenta. She presented in preterm labour with a breech presentation at 32 weeks and underwent an emergency caesarean section. She delivered a male infant weighing 1750 g. The placental histopathology showed a complete hyatidiform mole. At 4 weeks postpartum, beta-human chorionic gonadotrophin (Bhcg) levels rose from 460 to 836 mIU/mL over 1 week. Metastatic workup revealed prominent pelvic nodes and pulmonary nodules in both lungs. This was discussed at the Multi-Disciplinary Tumour Board and single-agent intramuscular methotrexate was recommended. After chemotherapy, she achieved Bhcg normalisation after three cycles. This case highlights the importance of clinical vigilance even in low-risk patients. Unexpected findings on ultrasound should involve multidisciplinary input with radiology colleagues. A high index of suspicion for gestational trophoblastic disease and close follow-up is imperative.

c(RGDyK)-based conjugates of gemcitabine (GEM) with the carbonate and carbamate linkages in the 6-OH group of GEM were synthesized for the targeted delivery of GEM to integrin α

Myelodysplastic syndromes (MDS) have a major impact on quality of life (QoL). We performed a

Oral hypomethylating agents (HMAs) represent a substantial potential boon for patients with myelodysplastic syndrome (MDS) who have previously required between 5 and 7 visits per month to an infusion clinic to receive therapy. For patients who respond to treatment, ongoing monthly maintenance visits represent a considerable burden to quality of life, and for those who are early in therapy, these sequential visits may tax transportation and financial resources that would be optimally distributed over the treatment cycle to facilitate transfusion support. The availability of oral HMAs may support the optimal application of these agents by contributing to adherence and lessening the burden of therapy, potentially encouraging patients to stay on longer-term treatment. Distinct pharmacokinetic profiles for the recently approved oral HMAs (oral azacitidine and decitabine-cedazuridine) result in differential toxicity profiles and have prompted their clinical trial development in lower- and higher-risk MDS, respectively.

Myeloid leukemia in children with Down syndrome (ML-DS) is associated with young age and somatic GATA1 mutations. Because of high event-free survival (EFS) and hypersensitivity of the leukemic blasts to chemotherapy, the prior Children’s Oncology Group protocol ML-DS protocol (AAML0431) reduced overall treatment intensity but lacking risk stratification, retained the high-dose cytarabine course (HD-AraC), which was highly associated with infectious morbidity. Despite high EFS of ML-DS, survival for those who relapse is rare. AAML1531 introduced therapeutic risk stratification based on the previously identified prognostic factor, measurable residual disease (MRD) at the end of the first induction course. Standard risk (SR) patients were identified by negative MRD using flow cytometry (

Background: The antimetabolite, 5-Fluorouracil (5-FU), is the only chemotherapeutic drug to significantly improve 12-month survival rates of patients with Colorectal Cancer (CRC). However, resistance to 5-FU is a major obstacle to effective treatment. The mechanism of 5-FU resistance has been discovered but is not fully known. Nuclear factor-erythroid 2-related factor 2 (Nrf2), a master regulator of cellular defense against oxidative and electrophilic stresses, is considered a major factor in 5-FU resistance. Objective: The current study was conducted to discuss the role and mechanisms of Nrf2 in 5-FU resistance and to search for medicines or compounds that can reverse Nrf2-mediated 5-FU resistance. Methods: Literature was obtained by defining specific search terms and searching several databases. Results: Previous study suggested that overactivation of Nrf2 contributed to 5-FU resistance by regulating many cytoprotective genes. Interestingly, several medicines and compounds can repress 5-FU resistance mediated of Nrf2. Conclusion: This review describes the major 5-FU-resistance mechanisms of Nrf2 and summarizes the medicines/ compounds that can overcome them.

During progression of myeloid neoplasms, the basophil compartment may expand substantially and in some of these patients, a basophilic leukemia is diagnosed. In patients with Ph-chromosome+ chronic myeloid leukemia, acceleration of disease is typically accompanied by marked basophilia. In other myeloid neoplasms, secondary leukemic expansion of basophils is rarely seen. We report on 5 patients who suffered from a myelodysplastic syndrome, myeloproliferative neoplasm, or acute leukemia and developed a massive expansion of basophils during disease progression. In 4 of 5 patients, peripheral blood basophil counts reached 40%, and the diagnosis “secondary basophilic leukemia” was established. As assessed by flow cytometry, neoplastic basophils expressed CD9, CD18, CD25, CD33, CD63, PD-L1, CD123, and CLL-1. In addition, basophils were found to display BB1 (basogranulin), 2D7, tryptase and KIT. In 4 of 5 patients the disease progressed quickly and treatment with azacitidine was started. However, azacitidine did not induce major clinical responses, and all patients died from progressive disease within 3 Y. In in vitro experiments, the patients´ cells and the basophilic leukemia cell line KU812 showed variable responses to targeted drugs, including azacitidine, venetoclax, hydroxyurea, and cytarabine. A combination of venetoclax and azacitidine induced cooperative antineoplastic effects in these cells. Together, secondary basophilic leukemia has a poor prognosis and monotherapy with azacitidine is not sufficient to keep the disease under control for longer time-periods. Whether drug combination, such as venetoclax+azacitidine, can induce better outcomes in these patients remains to be determined in future clinical studies.

5-fluorouracil (5-FU) and its pro-drug capecitabine are widely used anticancer agents. Most 5-FU catabolism is dependent on dihydropyrimidine dehydrogenase (DPD) encoded by the DPYD gene, and DPYD variants that reduce DPD function increase 5-FU toxicity. Most DPD deficient patients are heterozygous and can be treated with reduced 5-FU dosing. We describe a patient with a genotype associated with near complete absence of DPD function, and severe and likely fatal toxicity with 5-FU treatment. The patient was treated effectively with alternative systemic therapy. Routine pretreatment DPYD genotyping is recommended by the European Medicines Agency, and guidelines for use of 5-FU in DPD deficient patients are available. However, outside the province of Quebec, routine pretreatment screening for DPD deficiency remains unavailable in Canada. It is likely our patient would have died from 5-FU toxicity under the current standard of care, but instead provides an example of the potential benefit of DPYD screening on patient outcomes.

The present study was designed to evaluate the possible protective effects of melatonin (MEL) and/or L-carnitine (L-CAR) against methotrexate (MTX)-induced toxicity in isolated rat hepatocytes. Hepatocytes were prepared using collagenase techniques of perfusion and digestion of rat liver. Trypan blue uptake, as well as, glutathione (GSH), lipid peroxidation (LPO), nitric oxide (NO), and tumor necrosis factor-alpha (TNF-α) levels were measured. Caspase-3 activity was also assessed. Pre-incubation of hepatocytes with MEL (1 mM) and/or L-CAR (10 mM) 30 min prior to intoxication with MTX, significantly protected hepatocytes against toxicity. In addition, LPO, NO, TNF-α levels, and caspase-3 activity were decreased in comparison to the MTX-intoxicated group. Furthermore, the two drugs increased the MTX-depleted GSH level. MEL and L-CAR prevented MTX-induced hepatocytotoxicity, at least partly, by their antioxidative, antiinflammatory, and antiapoptotic effects. Further studies are recommended on the clinical pharmacologic and toxicologic effects of MEL and L-CAR in patients receiving MTX.

The adverse reactions caused by 6-thioguanine (6-TG) in anti-cancer treatment are closely related to the dose, leading to the urgent need for clinical monitoring of its concentration. In this work, a highly reproducible free-standing liquid membrane (FLM) surface-enhanced Raman spectroscopy (SERS) substrate was developed to detect 6-TG in human urine and serum quantitatively. Briefly, a prepared sample was adjusted to pH 2 and mixed with concentrated core–shell bimetallic nanoparticle (AgcoreAushell NP) suspension. The Au/Ag ratio of the AgcoreAushell NPs was optimized. Then the mixture was formed into an FLM using a custom mold. The relative standard deviation (RSD) of the experimental results can be stabilized below 10% (n ≥ 10). The R2 of the calibration curve in the range of 10 ~ 100 μg kg−1 was 0.988. In addition, the limit of detection (LOD) (3σ/k) of 6-TG was 5 μg kg−1. The FLM SERS platform has been successfully applied to the rapid and reliable analysis of 6-TG spiked in body fluids.

Background: Chemotherapy as part of colorectal cancer management can cause death to immunologically active tumor cell, but also it has immune suppressive effect. Phyllanthus niruri Linn is known to has immunomodulatory effect. This study was intended to prove P. niruri Linn effect on infiltrating dendritic cells and Neutrophil/lymphocyte ratios (NLRs) in Sprague–Dawley rats with colorectal cancer which were given capecitabine chemotherapy. Methods: The study was randomized post–test only control group design. The samples were 39 Sprague–Dawley male rats, with body weight around 170–220 grams, induced by 1,2-dimetylhydrazine (DMH) 30 mg/kgBW once per week subcutaneously. On 9th,11th and 13th week, there were four induced rats sacrificed each week to detect colorectal cancer (CRC) development. On the 13th week, all of the 4 sacrificed rats developed colon cancer, so the induction had to be stopped. The rest of 27 induced rats were randomly divided into three groups: control-group (K) were left untreated (9 rats), group P1 (9 rats) were given Capecitabine and group P2 (9 rats) were given Capecitabine with combination of P. niruri Linn extract 13.5 mg/kgBW orally. After 17th week, all rats were terminated and tumor lesion of colon were processed to be paraffin blocks and were stained with HE for evaluating the NLRs, and immunohistochemistry (S100) for evaluating infiltrating dendritic cells. Data was analyzed by using Oneway-Anova-test and post-Hoc LSD-test. Considered significant if p was

Background Gallbladder cancer (GBC) is known for its high malignancy and multidrug resistance. Previously, we uncovered that impaired integrity and stability of the elongator complex leads to GBC chemotherapy resistance, but whether its restoration can be an efficient therapeutic strategy for GBC remains unknown. Methods RT-qPCR, MS-qPCR and ChIP-qPCR were used to evaluate the direct association between ELP5 transcription and DNA methylation in tumour and non-tumour tissues of GBC. EMSA, chromatin accessibility assays, and luciferase assays were utilized to analysis the DNA methylation in interfering PAX5-DNA interactions. The functional experiments in vitro and in vivo were performed to investigate the effects of DNA demethylating agent decitabine (DAC) on the transcription activation of elongator complex and the enhanced sensitivity of gemcitabine in GBC cells. Tissue microarray contains GBC tumour tissues was used to evaluate the association between the expression of ELP5, DNMT3A and PAX5. Results We demonstrated that transcriptional repression of ELP5 in GBC was highly correlated with hypermethylation of the promoter. Mechanistically, epigenetic analysis revealed that DNA methyltransferase DNMT3A-catalysed hypermethylation blocked transcription factor PAX5 activation of ELP5 by disrupting PAX5-DNA interaction, resulting in repressed ELP5 transcription. Pharmacologically, the DNA demethylating agent DAC eliminated the hypermethylated CpG dinucleotides in the ELP5 promoter and then facilitated PAX5 binding and reactivated ELP5 transcription, leading to the enhanced function of the elongator complex. To target this mechanism, we employed a sequential combination therapy of DAC and gemcitabine to sensitize GBC cells to gemcitabine-therapy through epigenetic activation of the elongator complex. Conclusions Our findings suggest that ELP5 expression in GBC is controlled by DNA methylation-sensitive induction of PAX5. The sequential combination therapy of DAC and gemcitabine could be an efficient therapeutic strategy to overcome chemotherapy resistance in GBC.

Decitabine (DAC), a DNA methyltransferase (DNMT) inhibitor is a novel anti-cancer drug regulating epigenetic mechanisms. Similar to conventional anti-cancer drugs, drug resistance to DAC also has been reported, resulting in tumor recurrence. Our previous study using colorectal cancer HCT116 cells found the decrease in deoxycytidine kinase (dCK) (activation enzyme of DAC) and the increase in cytidine deaminase (inactivation enzyme of DAC) in acquired DAC-resistant HCT116 (HCT116/DAC) cells. The aim of our study was to clarify the involvement of dCK and CDA in DAC resistance. In order to tackle DAC resistance, it was also examined whether other DNMT inhibitors such as azacytidine (AC) and polyphenols are effective in DAC-resistant cancer cells. When dCK siRNA was transfected into HCT116 cells, IC50 value of DAC increased by about 74-fold and reached that of HCT116/DAC cells with attenuated dCK. dCK siRNA to HCT116 cells also abolished DNA demethylation effects of DAC. In contrast, CDA siRNA to HCT116 cells did not influence the efficacy of DAC. In addition, CDA siRNA to HCT116/DAC cells with increased CDA did not restore the compromised effects of DAC. These results suggested that attenuated dCK but not increased CDA mainly contributed to DAC resistance. Regarding dCK in HCT116/DAC cells, a point mutation with amino acid substitution was observed while the product size and expression of mRNA coding region did not change, suggesting that dCK protein was decreased by post-transcriptional regulation. AC and polyphenols showed no cross-resistance in HCT116/DAC cells. AC but not polyphenols exerted DNA demethylation effect. Among polyphenols, curcumin (Cur) showed the most synergistic cytotoxicity in combination with AC while DNA demethylation effect of AC was partly maintained. Taken together, combination of AC and Cur would be a promising alternative to tackle DAC resistance mainly due to attenuated dCK.

Introduction: Colorectal cancer is the third most common cancer type worldwide. Fluoropyrimidines and their prodrug-based regimens are widely applied as primary medications. The main enzyme responsible for the rate-limiting step in pyrimidine and for the 5-fluorouracil catabolism is dihydropyrimidine dehydrogenase (DPD). Aim: We aimed to screen DPD level and the changes of plasma antioxidant capacity of colorectal cancer patients on 5-fluorouracil regimen. Materials and methods: Human DPD Elisa Kit based on sandwich enzyme-linked immune-sorbent assay and spectrophotometric methods (FRAP and ABTS) were used in the study. Results: No statistically significant changes in plasma scavenging activity according to the results obtained in the ABTS system have been observed after evaluating all patients and considering DPD concentration. A decrease of the ferric reducing ability of patients’ plasma taken after the administered treatment was found. The increase of DPD level is accompanied by a decrease in the p values and therefore the statistical significance of the differences increases. Conclusions: Based on the aforementioned observations, it could be concluded that some aspects of plasma antioxidant capacity and individuals’ antioxidant status might be involved in the pathogenesis of the disease and could be altered by the activity of some enzymes. The cancer therapy in question, by the specificity of its mechanism of action, can modify patient’s oxidative status.

OBJECTIVE To investigate the efficacy and safety of additional S-1 chemotherapy to S-1 plus oxaliplatin (SOX) regimen chemotherapy for Stage III gastric carcinoma (GC) after radical resection. PATIENTS AND METHODS A total of 161 patients who were pathologically diagnosed as Stage III GC after D2 gastrectomy and received SOX regimen adjuvant chemotherapy between January 2012 and April 2016 were included in this retrospective study. SOX regimen postoperative chemotherapy was composed of Oxaliplatin and S-1, administrated every 3 weeks for 8 scheduled courses. After SOX chemotherapy, 76 patients preferred additional chemotherapy with S-1 (the ACT group), while additional S-1 chemotherapy was not given to the other 85 patients (control group). The ACT with S-1 was administrated every 3 weeks for 8 scheduled courses. Treatment was terminated in case of life-threatening adverse events or tumor progression, or patients' demand for termination. Progression-free survival (PFS), overall survival (OS), and adverse events were analyzed. RESULTS ACT group obtained markedly improved 3-year PFS [p = 0.04; hazard ratio (HR) for disease progression, 0.58; 95% confidence interval (CI), 0.34-0.98] and OS than the control group (p = 0.0469; HR for death, 0.56; 95% CI, 0.32-0.99). No chemotherapy-related mortality occurred. Patients of the ACT group suffered more common and severer hand-foot syndrome (HFS) (p = 0.02). CONCLUSIONS Additional S-1 chemotherapy may be helpful for improving the disease progression and survival for patients with Stage III GC after radical resection with an acceptable safety profile.

Purpose High-dose methotrexate (HDMTX)-associated acute kidney injury with delayed MTX clearance has been linked to an excess in MTX-induced toxicities. Glucarpidase is a recombinant enzyme that rapidly hydrolyzes MTX into non-toxic metabolites. The recommended dose of glucarpidase is 50 U/kg, which has never been formally established in a dose finding study in humans. Few case reports, mostly in children, suggest that lower doses of glucarpidase might be equally effective in lowering MTX levels. Methods Seven patients with toxic MTX plasma concentrations following HDMTX therapy were treated with half-dose glucarpidase (mean 25 U/kg, range 17–32 U/kg). MTX levels were measured immunologically as well as by liquid chromatography–mass spectrometry (LC–MS). Toxicities were assessed according to National Cancer Institute—Common Terminology Criteria for Adverse Events (CTCAE) v5.0. Results All patients experienced HDMTX-associated kidney injury (median increase in creatinine levels within 48 h after HDMTX initiation compared to baseline of 251%, range 80–455%) and showed toxic MTX plasma concentrations (range 3.1–182.4 µmol/L) before glucarpidase injection. The drug was administered 42–70 h after HDMTX initiation. Within one day after glucarpidase injection, MTX plasma concentrations decreased by ≥ 97.7% translating into levels of 0.02–2.03 µmol/L. MTX rebound was detected in plasma 42–73 h after glucarpidase initiation, but concentrations remained consistent at Conclusion Half-dose glucarpidase seems to be effective in lowering MTX levels to concentrations manageable with continued intensified folinic acid rescue.

Purpose Effectiveness and safety of clofarabine (one of the treatment mainstays in pediatric patients with relapsed/refractory acute lymphoblastic leukemia [ALL]) was assessed in Korean pediatric patients with ALL to facilitate conditional coverage with evidence development.Materials and Methods In this multicenter, prospective, observational study, patients receiving clofarabine as mono/combination therapy were followed up every 4-6 weeks for 6 months or until hematopoietic stem cell transplantation (HSCT). Response rates, survival outcomes, and adverse events were assessed.Results Sixty patients (2-26 years old; 65% B-cell ALL, received prior ≥ 2 regimen, 68.3% refractory to previous regimen) were enrolled and treated with at least one dose of clofarabine; of whom 26 (43.3%) completed 6 months of follow-up after the last dose of clofarabine. Fifty-eight patients (96.7%) received clofarabine combination therapy. Overall remission rate (complete remission [CR] or CR without platelet recovery [CRp]) was 45.0% (27/60; 95% confidence interval [CI], 32.4 to 57.6) and the overall response rate (CR, CRp, or partial remission [PR]) was 46.7% (28/60; 95% CI, 34.0 to 59.3), with 11 (18.3%), 16 (26.7%), and one (1.7%) patients achieving CR, CRp, and PR, respectively. The median time to remission was 5.1 weeks (95% CI, 4.7 to 6.1). Median duration of remission was 16.6 weeks (range, 2.0 to 167.6 weeks). Sixteen patients (26.7%) proceeded to HSCT. There were 24 deaths; 14 due to treatment-emergent adverse events.Conclusion Remission with clofarabine was observed in approximately half of the study patients who had overall expected safety profile; however, there was no favorable long-term survival outcome in this study.

RNF6 is a RING finger protein with oncogenic potential. In this study, we established colon-specific RNF6 transgenic (tg) mice, and demonstrated that RNF6 overexpression accelerated colorectal carcinogenesis compared to wild-type littermates in a chemically induced colorectal cancer (CRC) model. To understand whether transcriptional activity of RNF6 underlies its oncogenic effect, we performed integrated chromatin immunoprecipitation (ChIP)-sequencing and RNA-sequencing analysis to identify splicing factor 3b subunit 2 (SF3B2) as a potential downstream target of RNF6. RNF6 binds to the SF3B2 promoter and the overexpression of RNF6 activates SF3B2 expression in CRC cells, primary CRC organoids, and RNF6 tg mice. SF3B2 knockout abrogated the tumor promoting effect of RNF6 overexpression, whereas the reexpression of SF3B2 recused cell growth and migration/invasion in RNF6 knockout cells, indicating that SF3B2 is a functional downstream target of RNF6 in CRC. Targeting of RNF6-SF3B2 axis with SF3B2 inhibitor with pladienolide B suppressed the growth of CRC cells with RNF6 overexpression in vitro and in vivo. Moreover, the combination of 5-fluorouracil (5-FU) plus pladienolide B exerted synergistic effects in CRC with high RNF6 expression, leading to tumor regression in xenograft models. These findings indicate that tumor promoting effect of RNF6 is achieved mainly via transcriptional upregulation of SF3B2, and that RNF6-SF3B2 axis is a promising target for CRC therapy.

Long non-coding RNA (lncRNA) FOXD3-AS1 expression is upregulated in lung cancer; however, its effect and mechanism on 5-fluorouracil (5-FU) resistance remain unclear. In this study, we determined the effects of FOXD3-AS1-enriched exosomes derived from lung cancer cells on the proliferation, invasion, and 5-FU resistance of lung cancer cells. Online bioinformatics database analysis showed that FOXD3-AS1 was upregulated in lung cancer progression. Real-time quantitative PCR results confirmed that FOXD3-AS1 expression was upregulated in lung cancer tissues and cell lines, and FOXD3-AS1 was greatly enriched in lung cancer cell-derived exosomes. ELAV-like RNA-binding protein 1 (ELAVL1) was identified as an RNA-binding protein of FOXD3-AS1. The lung cancer cell-derived exosomes promoted A549 cell proliferation and invasion and inhibited apoptosis caused by 5-FU, and transfection of si-FOXD3-AS1 or si-ELAVL1 in exosome-incubated A549 cells reversed these effects. Moreover, exosome-incubated A549 cells were co-transfected with si-FOXD3-AS1 and pcDNA-ELAVL1, showing the same cell proliferation, invasion, and 5-FU resistance as those of A549 cells treated with lung cancer cell-derived exosomes alone. Mechanistic studies identified that lung cancer cell-derived exosomes activated the PI3K/Akt pathway, and transfection of si-FOXD3-AS1 or treatment with the PI3K inhibitor LY294002 reversed the activation of the PI3K/Akt axis induced by exosomes. In conclusion, our study revealed that lung cancer cell-derived exosomal FOXD3-AS1 upregulated ELAVL1 expression and activated the PI3K/Akt pathway to promote lung cancer progression. Our findings provide a new strategy for lung cancer treatment.

Background & Aims Intestinal mucositis, a severe complication of antineoplastic therapeutics, is characterized by mucosal injury and inflammation in the small intestine. Therapies for the prevention and treatment of this disease are needed. We investigated whether 2’-fucosyllactose (2’-FL), an abundant oligosaccharide in human milk, protects intestinal integrity and ameliorates intestinal mucositis. Methods A mouse small intestinal epithelial (MSIE) cell line, mouse enteroid cultures, and human gastrointestinal tumor cell lines (AGS and HT29) were co-treated with the chemotherapy agent 5-fluorouracil (5-FU) and 2’-FL. Mice were injected intraperitoneally with 5-FU to induce intestinal mucositis. 2’-FL was administered in the drinking water to mice before (pretreatment) or concurrently with 5-FU injection. Body weight and pathologic changes were analyzed. Results 2’-FL alleviated 5-FU inhibition of cell growth in MSIE cells, but not in AGS and HT29 cells. The 5-FU–induced apoptosis in MSIE cells and enteroids was suppressed by 2’-FL. Compared with 5-FU treatment alone, 2’-FL pretreatment protected against body weight loss, and ameliorated inflammation scores, proinflammatory cytokine production, shortening of villi, epithelial cell apoptosis, goblet cell loss, and tight junctional complex disruption in the small intestine. 2’-FL concurrent treatment had less of an effect on intestinal mucositis than 2’-FL pretreatment. Interestingly, no effect of 2’-FL was observed on 5-FU–induced S-phase arrest in MSIE, AGS, and HT29 cells. Neither pretreatment nor concurrent treatment with 2’-FL affected 5-FU–induced inhibition of proliferation in MSIE cells. Conclusions This study shows a novel direct effect of 2’-FL in protecting small intestinal epithelial cells against apoptosis stimulated by 5-FU, which may contribute to prevention of 5-FU–induced intestinal mucositis., Graphical abstract

OBJECTIVES This study aimed to enhance the sensitivity of pancreatic ductal adenocarcinoma cells by microRNA-34a (miR-34a)-mediated targeting of Notch 1. METHODS Cell viability was determined by using an MTT (3-(4,5)-dimethylthiahiazo(-2)-3,5-diphenytetrazoliumromide) assay. The expression levels of miR-34a and relevant mRNAs were determined using quantitative polymerase chain reaction. Protein levels were measured by Western blotting. Cellular stemness was assessed by cell invasiveness and sphere formation assays. A transplanted tumor model was established for in vivo experiments. RESULTS MicroRNA-34a enhanced gemcitabine sensitivity both in vivo and in vitro. MicroRNA-34a suppressed the stemness and proliferation of pancreatic cancer stem cells. MicroRNA-34a directly associated with Notch 1, which lies upstream of epithelial-mesenchymal transition signaling pathways. CONCLUSIONS MicroRNA-34a sensitized pancreatic cancer cells to gemcitabine treatment by inhibiting Notch 1 signaling in pancreatic cancer stem cells, indicating that miR-34a has the potential to be developed as a novel therapeutic agent for the treatment of gemcitabine-resistant pancreatic ductal adenocarcinoma cells.