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PDF file - 135K, JSI-124 inhibits stimulus-induced and constitutive JAK2/STAT3 phosphorylation and inhibits proliferation in GBM cells.

PDF file - 102K, JSI-124 induces the mRNA expression of inflammatory genes in human xenograft GBM cells and murine primary astrocytes.

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PDF file - 86K, JSI-124 induces the mRNA expression of inflammatory genes in human GBM cells.

PDF file - 82K, Effective inhibition of NF-κB using BAY-11 and shRNA knockdown.

Glioblastoma tumors are characterized by their invasiveness and resistance to therapies. The transcription factor signal transducer and activator of transcription 3 (STAT3) was recently identified as a master transcriptional regulator in the mesenchymal subtype of glioblastoma (GBM), which has generated an increased interest in targeting STAT3. We have evaluated more closely the mechanism of action of one particular STAT3 inhibitor, JSI-124 (cucurbitacin I). In this study, we confirmed that JSI-124 inhibits both constitutive and stimulus-induced Janus kinase 2 (JAK2) and STAT3 phosphorylation, and decreases cell proliferation while inducing apoptosis in cultured GBM cells. However, we discovered that before the inhibition of STAT3, JSI-124 activates the nuclear factor-κB (NF-κB) pathway, via NF-κB p65 phosphorylation and nuclear translocation. In addition, JSI-124 treatment induces the expression of IL-6, IL-8, and suppressor of cytokine signaling (SOCS3) mRNA, which leads to a corresponding increase in IL-6, IL-8, and SOCS3 protein expression. Moreover, the NF-κB–driven SOCS3 expression acts as a negative regulator of STAT3, abrogating any subsequent STAT3 activation and provides a mechanism of STAT3 inhibition after JSI-124 treatment. Chromatin immunoprecipitation analysis confirms that NF-κB p65 in addition to other activating cofactors are found at the promoters of IL-6, IL-8, and SOCS3 after JSI-124 treatment. Using pharmacological inhibition of NF-κB and inducible knockdown of NF-κB p65, we found that JSI-124–induced expression of IL-6, IL-8, and SOCS3 was significantly inhibited, showing an NF-κB–dependent mechanism. Our data indicate that although JSI-124 may show potential antitumor effects through inhibition of STAT3, other off-target proinflammatory pathways are activated, emphasizing that more careful and thorough preclinical investigations must be implemented to prevent potential harmful effects. Mol Cancer Res; 11(5); 494–505. ©2013 AACR.

PDF file - 75K, Inhibition of NF-κB does not prevent JSI-124 induced apoptosis.

PURPOSE The purpose of this study was to investigate the feasibility of using fused deposition modeling (FDM) three-dimensional (3D) printer to generate radiation compensators for high-resolution (~1 mm) intensity-modulated radiation therapy (IMRT) for small animal radiation treatment. We propose a novel method incorporating 3D-printed compensator molds filled with NaI powder. METHODS The inverse planning module of the computational environment for radiotherapy research (CERR) software was adapted to simulate the XRAD-225Cx irradiator, both geometry and kV beam quality (the latter using a phase space file provided for XRAD-225Cx). A nine-field IMRT treatment was created for a scaled-down version of the imaging and radiation oncology core (IROC) Head and Neck IMRT credentialing test, recreated on a 2.2-cm-diameter cylindrical phantom. Optimized fluence maps comprising nine fields and a total of 2564 beamlets were calculated at resolution of 1.25 × 1.25 mm2 . A hollow compensator mold was created (using in-house software and algorithm) for each field using 3D printing with polylactic acid (PLA) filaments. The molds were then packed with sodium iodide powder (NaI, measured density ρNaI = 2.062 g/cm3 ). The mounted compensator mold thickness was limited to 13.8 mm due to clearance issues with couch collision. At treatment delivery, each compensator was manually mounted to a customized block tray attached to the reference 40 × 40 mm2 collimator. Compensator reproducibility among three repeated 3D-printed molds was measured with Radiochromic EBT2 film. The two-dimensional (2D) dose distributions of the nine fields were compared to calculated 2D doses from CERR using gamma comparisons with distance-to-agreement criteria of 0.5-0.25 mm and dose difference criteria of 3-5%. RESULTS Good reproducibility of 3D-printed compensator manufacture was observed with mean error of ±0.024 Gy and relative dose error of ±4.2% within the modulated part of the beam. Within the limit of 13.8 mm compensator height, a maximum radiation blocking efficiency of 91.5% was achieved. Per field, about 45.5 g of NaI powder was used. Gamma analysis on each of the nine delivered IMRT fields using radiochromic films resulted in eight of nine treatment fields with >90% pass rate with 5%/0.5 mm tolerances. However, low gamma passing rate of 49-66% (3%/0.25 mm to 5%/0.5 mm) was noted in one field, attributed to fabrication errors resulting in over-filling the mold. The nine-field treatment plan was delivered in under 30 min with no mechanical or collisional issues. CONCLUSIONS We show the feasibility of high spatial resolution IMRT treatment on a small animal irradiator utilizing 3D-printed compensator shells packed with NaI powder. Using the PLA mold with NaI powder was attractive due to the ease of 3D printing a PLA mold at high geometric resolution and the well-balanced attenuation properties of NaI powders that prevented the mold from becoming too bulky. IMRT fields with 1.25-mm resolution are capable with significant fluence modulation with relative dose accuracy of ±4.2%.

PURPOSE Radiochromic film remains a useful and versatile clinical dosimetry tool. Current film options are single use. Here, we introduce a novel prototype two-dimensional (2D) radiochromic sheet, which optically clears naturally at room temperature after irradiation and can be reused. We evaluate the sheets for potential as a 2D dosimeter and as a radiochromic bolus with capability for dose measurement. METHODS A novel derivative of reusable Presage® was manufactured into thin sheets of 5 mm thickness. The sheets contained 2% cumin-leucomalachitegreen-diethylamine (LMG-DEA) and plasticizer (up to 25% by weight). Irradiation experiments were performed to characterize the response to megavoltage radiation, including dose sensitivity, temporal decay rate, consistency of repeat irradiations, intra and inter-sheet reproducibility, multi-modality response (electrons and photons), and temperature sensitivity (22°C to 36°C). The local change in optical-density (ΔOD), before and after radiation, was obtained with a flat-bed film scanner and extracting the red channel. Repeat scanning enabled investigation of the temporal decay of ΔOD. Additional studies investigated clinical utility of the sheets through application to IMRT treatment plans (prostate and a TG119 commissioning plan), and a chest wall electron boost treatment. In the latter test, the sheet performed as a radiochromic bolus. RESULTS The radiation induced OD change in the sheets was found to be proportional to dose and to exponentially decay to baseline in ~24 h (R2 = 0.9986). The sheet could be reused and had similar sensitivity (within 1% after the first irradiation) for at least eight irradiations. Importantly, no memory of previous irradiations was observed within measurement uncertainty. The consistency of dose response from photons (6 and 15 MV) and electrons (6-20 MeV) was found to be within calibration uncertainty (~1%). The dose sensitivity of the sheets had a temperature dependence of 0.0012 ΔOD/°C. For the short (1 min) single field IMRT QA verification, good agreement was observed between the Presage sheet and EBT film (gamma pass rate 97% at 3% 3 mm dose-difference and distance-to-agreement tolerance, with a 10% threshold). For the longer (~13 min) TG-119 9-field IMRT verification the gamma agreement was lower at 93% pass rate at 5% 3 mm, 10% threshold, when compared with Eclipse. The lower rate is attributed to uncertainty arising from signal decay during irradiation and indicates a current limitation. For the electron cutout treatment, both Presage and EBT agreed well (within 2% RMS difference) but differed from the Eclipse treatment plan (~7% RMS difference) indicating some limitations to the Eclipse modeling in this case. The worst case estimates of uncertainty introduced by the signal decay for deliveries of 2, 5, and 10 min are 0.6%, 1.4%, and 2.8% respectively. CONCLUSIONS Reusable Presage sheets show promise for 2D dose measurement and as a radiochromic bolus for in vivo dose measurement. The current prototype is suitable for deliveries of length up to 5 min, where the uncertainty introduced by signal decay is anticipated to be ~1% (worst case 1.4%), or for longer deliveries where there is no temporal modulation (e.g. physical compensators, or open beams). Additionally, spatial resolution is limited by sheet thickness and scanner resolution, resulting in a practical resolution of 0.8 mm.

To demonstrate proof of principle of visualizing delivered 3-dimensional (3D) dose distribution using kilovoltage (kv) cone beam computed tomography (CBCT) mounted onboard a linear accelerator. We apply this technique as a unique end-to-end verification of multifocal radiosurgery where the coincidence of radiation and imaging systems is quantified comprehensively at all targets.Dosimeters (9.5-cm diameter N-isopropylacrylamide) were prepared according to standard procedures at one facility and shipped to a second (remote) facility for irradiation. A 4-arc volumetric modulated arc therapy (VMAT) multifocal radiosurgery plan was prepared to deliver 20 Gy with 6-MV photons to 6 targets (1-cm diameter). A dosimeter was aligned via CBCT and irradiated, followed by 3 CBCT scans acquired immediately, with total time between pre-CBCT and final CBCT30 minutes. Image processing included background subtraction and low-pass filters. A dose-volume structure was created per target with the same volume as the planned prescription dose volume, and their spatial agreement was quantified using volume centroid and the Jaccard index. For comparison, 5 diagnostic computed tomography (CT) scans were also acquired after24 hours with the same spatial analysis applied; comparison with planned doses after absolute dose calibration also was conducted.Regions of high dose were clearly visualized in the average CBCT with a contrast-to-noise ratio of 1.7 ± 0.7, which increased to 5.8 ± 0.5 after image processing, and 11.9 ± 3.7 for average diagnostic CT. Centroids of prescription isodose volumes agreed with the root mean square difference of 1.1 mm (range, 0.8-1.7 mm) for CBCT and 0.7 mm (0.4-0.8 mm) for diagnostic CT. The dose was proportional to density above 10 to 12 Gy with a 3D gamma pass rate of 94.0% and 99.5% using 5% for 1-mm and 3% for 2-mm criteria, respectively (threshold = 15 Gy, using global dose criteria).This work demonstrates for the first time the potential to visualize in 3D delivered dose using onboard kV-CBCT (0.5 × 0.5 × 1 mm

Background Cardiac and cerebrovascular complications are major causes of adverse outcomes following thoracic endovascular aortic repair (TEVAR). The benefits of statins have been established, but little is known about their impact on patients undergoing TEVAR. We investigated whether chronic statin use protected against early postoperative major adverse cardiac and cerebrovascular events (MACCEs) after TEVAR. Methods We retrospectively reviewed 211 patients who underwent TEVAR between February 2013 and March 2017 classified into two groups, those with acute aortic syndrome (AAS, N.=79) and those without (non-AAS, N.=132). Patients were subdivided according to preoperative statin therapy for ≥3 months or not. The primary endpoint was 30-day MACCE, defined as myocardial infarction, stroke, arrhythmia, cardiovascular death, or cerebrovascular death. Acute kidney injury (AKI) occurrence within 48 hours was also evaluated. Multivariate logistic regression analysis was performed to identify independent risk factors for MACCEs and AKI. Results Incidence of MACCEs (1% vs. 11%, P=0.019) was significantly lower in the statin group than in the no-statin group in non-AAS patients. Multivariate logistic regression analysis revealed statin use (odds ratio 0.85, 95% confidence interval 0.01-0.95, P=0.046) as an independent predictor for MACCE in non-AAS patients. The AKI incidence was significantly higher in the statin group than in the no-statin group in AAS patients (44% vs. 15%, P=0.018). Conclusions In patients undergoing TEVAR, chronic statin use was associated with reduced 30-day MACCEs in non-AAS patients, but not in AAS patients. It might rather be associated with increased risk of AKI in AAS patients.

PURPOSE: This work investigates a new approach to enhance radiotherapy through a photo therapeutic agent activated by Cherenkov light produced from the megavoltage photon beam. The process is termed Radiotherapy Enhanced with Cherenkov photo-Activation (RECA). RECA is compatible with various photo-therapeutics, but here we focus on use with psoralen, an ultraviolet activated therapeutic with extensive history of application in superficial and extracorporeal settings. RECA has potential to extend the scope of psoralen treatments beyond superficial to deep seated lesions. METHODS AND MATERIALS: In vitro studies in B16 melanoma and 4T1 murine breast cancer cells were performed to investigate the potential of RT plus RECA versus RT alone for increasing cytotoxicity (local control) and increasing surface expression of major histocompatibility complex I (MHC I). The latter represents potential for immune response amplification (increased antigen presentation), which has been observed in other psoralen therapies. Cytotoxicity assays included luminescence and clonogenics. The MHC I assays were performed using flow cytometry. In addition, Cherenkov light intensity measurements were performed to investigate the possibility of increasing the Cherenkov light intensity per unit dose from clinical megavoltage beams, to maximize psoralen activation. RESULTS: Luminescence assays showed that RECA treatment (2 Gy at 6 MV) increased cytotoxicity by up to 20% and 9.5% for 4T1 and B16 cells, respectively, compared with radiation and psoralen alone (ie, Cherenkov light was blocked). Similarly, flow cytometry revealed median MHC I expression was significantly higher in RECA-treated cells, compared with those receiving radiation and psoralen alone (approximately 450% and 250% at 3 Gy and 6 Gy, respectively, P << .0001). Clonogenic assays of B16 cells at doses of 6 Gy and 12 Gy showed decreases in tumor cell viability of 7% (P = .017) and 36% (P = .006), respectively, when Cherenkov was present. CONCLUSION: This work demonstrates for the first time the potential for photo-activation of psoralen directly in situ, from Cherenkov light generated by a clinical megavoltage treatment beam.

PURPOSE Cherenkov light during MV radiotherapy has recently found imaging and therapeutic applications but is challenged by relatively low fluence. Our purpose is to investigate the feasibility of increasing Cherenkov light production during MV radiotherapy by increasing photon energy and applying specialized beam-hardening filtration. METHODS GAMOS 5.0.0, a GEANT4-based framework for Monte Carlo simulations, was used to model standard clinical linear accelerator primary photon beams. The photon source was incident upon a 17.8 cm3 cubic water phantom with a 94 cm source to surface distance. Dose and Cherenkov production was determined at depths of 3-9 cm. Filtration was simulated 15 cm below the photon beam source. Filter materials included aluminum, iron, and copper with thicknesses of 2-20 cm. Histories used depended on the level of attenuation from the filter, ranging from 100 million to 2 billion. Comparing average dose per history also allowed for evaluation of dose-rate reduction for different filters. RESULTS Overall, increasing photon beam energy is more effective at improving Cherenkov production per unit dose than is filtration, with a standard 18 MV beam yielding 3.3-4.0× more photons than 6 MV. Introducing an aluminum filter into an unfiltered 2400 cGy/min 10 MV beam increases the Cherenkov production by 1.6-1.7×, while maintaining a clinical dose rate of 300 cGy/min, compared to increases of ~1.5× for iron and copper. Aluminum was also more effective than the standard flattening filter, with the increase over the unfiltered beam being 1.4-1.5× (maintaining 600 cGy/min dose rate) vs 1.3-1.4× for the standard flattening filter. Applying a 10 cm aluminum filter to a standard 18 MV, photon beam increased the Cherenkov production per unit dose to 3.9-4.3× beyond that of 6 MV (vs 3.3-4.0× for 18 MV with no aluminum filter). CONCLUSIONS Through a combination of increasing photon energy and applying specialized beam-hardening filtration, the amount of Cherenkov photons per unit radiotherapy dose can be increased substantially.