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Purpose: Pancreatic ductal adenocarcinoma (PDAC) is remarkably resistant to standard modalities, including radiotherapy. We hypothesized that metabolic reprogramming may underlie PDAC radioresistance, and moreover, that it would be possible to exploit these metabolic changes for therapeutic intent., Methods and Materials: We established two matched models of radioresistant PDAC cells by exposing the AsPC-1 and MIAPaCa-2 human pancreatic cancer cells to incremental doses of radiation. The metabolic profile of parental and radioresistant cells was investigated using Nanostring technology, labeled-glucose tracing by liquid chromatography-mass spectrometry, Seahorse analysis and exposure to metabolic inhibitors. The synergistic effect of radiation combined with a pentose-phosphate pathway inhibitor, 6-aminonicotinamide (6-AN) was evaluated in a xenograft model established by subcutaneous injection of radioresistant-AsPC-1 cells into nude mice., Results: The radioresistant cells overexpressed pyruvate dehydrogenase kinase (PDK) and consistently, displayed increased glycolysis and downregulated the tricarboxylic acid (TCA) cycle and oxidative phosphorylation. Metabolic flux through the pentose-phosphate pathway (PPP) was increased, as were levels of reduced glutathione; pharmacological inhibition of the PPP dramatically potentiated radiation-induced cell death. Furthermore, the combined treatment of radiation with the PPP inhibitor 6-AN synergistically inhibited tumor growth in-vivo., Conclusions: We provide a mechanistic understanding of the metabolic changes that underlie radioresistance in PDAC. Furthermore, we demonstrate that pancreatic cancer cells can be re-sensitized to radiation via metabolic manipulation, in particular, inhibition of the PPP. Exploitation of the metabolic vulnerabilities of radioresistant pancreatic cancer cells constitutes a new approach to pancreatic cancer, with a potential to improve clinical outcomes., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: [Y.R.L, A.S.S and E.G have declared funding support in the Funding statement. T.G has declared relationship with AstraZeneca, AbbVie, Curesponse and MSD Merck. Y.R.L. has received consultancy fees from Roche Genetech and Zola Therapeutics Inc., he has stock ownership in Protean Biodiagnostics Inc. None of these are of relevance to this work. All remaining authors have declared no conflicts of interest.]., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Introduction: We report the long-term results of RTOG 9801, a randomized trial investigating the ability of amifostine, a radioprotector, to reduce chemoradiation-induced esophagitis., Methods: Patients with stages II and IIIA/B non-small-cell lung cancer received induction paclitaxel 225 mg/m2 intravenously (IV) and carboplatin area under the curve (AUC) 6 both days 1 and 22, followed by concurrent weekly paclitaxel (50 mg/m2) and carboplatin (AUC 2), with hyperfractionated radiation therapy (69.6 Gy at 1.2 Gy BID). Patients were randomly assigned to amifostine (AM) 500 mg IV four times per week or no-AM during chemoradiotherapy. Stratification factors included age (<70 vs. ≥70 years), stage and performance status., Results: 243 patients (pts) were enrolled; 120 received AM, 123 received no-AM. Two pts on each arm were found ineligible. Overall, 85% of patients were ≤70 years; 75% had a KPS ≥90. 34% had squamous histology. With median follow-up of 96.3 months (for patients still alive), overall survival was identical (hazard ratio 1.03 (0.79-1.34), NS): five-year survival 17% in both arms. The incidence of late grade 3-5 toxicities was 16% in the AM arm and 19% in the control arm (hazard ratio 1.24 (0.66-2.32), NS). There was no significant difference between the arms regarding overall survival, disease-free survival or long-term toxicity., Conclusion: The chemoradiation regimen of carboplatin and paclitaxel produced long-term results in the multi-institutional setting comparable to other regimens. Amifostine did not appear to compromise survival. As done in RTOG 9801, more consistent reporting of long term toxicity is needed for comparison of different chemoradiation regimens., (Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.)

Background: The standard treatment for non-metastatic oral cavity squamous cell carcinoma (OCSCC) is surgical resection followed by post-operative radiotherapy (PORT) with/without chemotherapy in high risk patients. Given the substantial toxicity of PORT we assessed lymph node ratio (LNR) as a predictor of PORT benefit., Design: By using the Surveillance, Epidemiology and End Results (SEER) database, we analyzed all node positive OCSCC patients diagnosed between 1988 and 2007 who underwent neck dissection. LNR was categorized into three groups: < 6%, 6-12.5% and > 12.5%., Results: In 3091 subjects identified, median survival was 32, 25 and 16 months for LNR Groups 1, 2 and 3, respectively. On multivariate analysis, survival was associated with age, race, grade, tumor size, nodal stage, extra-capsular extension, use of PORT and LNR. When stratified by LNR group, PORT was associated with a survival benefit only in Group 3 (LNR > 12.5%): 2 year survival 25% vs 37%. No benefit to PORT was seen when the LNR ≤ 12.5%: 2 year survival 51% vs 54%., Conclusion: A low LNR is associated with extended survival in LN positive OCSCC. The survival benefit associated with PORT in this disease appears to be limited to those with a LNR > 12.5%. Validation is required prior to the clinical implementation of our findings., (Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.)