3175 - Pan-Cancer Epigenetic CRISPR/Cas9 Screening Identifies Men1 as an Radioresistance Target
Presenter(s)
B. Xiang1,2, X. Tao3, Y. Wang4, W. Liao5, S. Zhang6, and Y. Zhao1; 1Department of Radiation Oncology, Sichuan Cancer Hospital & Institute, Sichuan Cancer Center; Cancer Hospital affiliate to University of Electronic Science and Technology of China, Chengdu, China, 2School of Medicine, University of Electronic Science and Technology of China, Chengdu, China, 3University of electronics and technolodgy of China, chengdu, China, 4Sichuan Cancer Hospital and Research Institute, University of Electronic Science and Technology of China, Chengdu, China, Chengdu, China, 5Sichuan Cancer Hospital & Institute, Cancer Hospital affiliate to School of Medicine, University of Electronic Science and Technology of China, Chengdu, China, 6Sichuan Clinical Research Center for Cancer,Sichuan Hospital Cancer & Institute, Sichuan Cancer Center, University of Electronic Science and Technology of China, Chengdu, China
Purpose/Objective(s): Radioresistance limits the efficacy of radiotherapy, but the epigenetic determinants of this process remain poorly understood. Our objective was to screen pan-cancer epigenetic regulators associated with radiosensitivity and radioresistance.
Materials/Methods: Epigenetic Crispr screening was combined with second-generation sequence technology to identify epigenetic regulators of radiosensitivity and radioresistance. We performed epigenetic CRISPR-Cas9 screens in murnie cell lines Hepa1-6 (hepatic carcinoma), LLC1 (lung adenocarcinoma) and MC38 (colon carcinoma)to systematically discover epigenetic regulators of radioresistance through cell proliferation assay and colony formation assay. The functions of identified genes were further validated in radioresistant cells lines.
Results: In vitro CRISPR screens demonstrated that perturbation of Asf1b, Glyr1, H1f5, and Men1 enhanced radioresistance. MEN1 is a regulator of alternative splicing and prevents R-loop-induced genome instability through suppression of RNA polymerase II elongation. Ectopic MEN1 expression increased radiosensitivity in all cell lines.
Conclusion: In summary, we provide an atlas of the epigenetic regulators of radioresistance and demonstrate that modulation of epigenetic state can improve radiosensitivity.