351. Androgen Receptor Variants Mediate DNA Repair after Prostate Cancer Irradiation
- Author
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Yin, Yi, Li, Rui, Xu, Kangling, Ding, Sentai, Li, Jeffrey, Baek, GuemHee, Ramanand, Susmita G, Ding, Sam, Liu, Zhao, Gao, Yunpeng, Kanchwala, Mohammed S, Li, Xiangyi, Hutchinson, Ryan, Liu, Xihui, Woldu, Solomon L, Xing, Chao, Desai, Neil B, Feng, Felix Y, Burma, Sandeep, de Bono, Johann S, Dehm, Scott M, Mani, Ram S, Chen, Benjamin PC, and Raj, Ganesh V
- Subjects
Urologic Diseases ,Genetics ,Prostate Cancer ,Aging ,Cancer ,2.1 Biological and endogenous factors ,Aetiology ,Androgen Antagonists ,Animals ,Antineoplastic Agents ,Benzamides ,DNA Repair ,DNA-Activated Protein Kinase ,Humans ,Male ,Mice ,Mice ,Nude ,Nitriles ,Phenylthiohydantoin ,Prostatic Neoplasms ,Protein Kinase Inhibitors ,Radiation ,Ionizing ,Receptors ,Androgen ,Tumor Cells ,Cultured ,Xenograft Model Antitumor Assays ,Oncology and Carcinogenesis ,Oncology & Carcinogenesis - Abstract
In prostate cancer, androgen deprivation therapy (ADT) enhances the cytotoxic effects of radiotherapy. This effect is associated with weakening of the DNA damage response (DDR) normally supported by the androgen receptor. As a significant number of patients will fail combined ADT and radiotherapy, we hypothesized that DDR may be driven by androgen receptor splice variants (ARV) induced by ADT. Investigating this hypothesis, we found that ARVs increase the clonogenic survival of prostate cancer cells after irradiation in an ADT-independent manner. Notably, prostate cancer cell irradiation triggers binding of ARV to the catalytic subunit of the critical DNA repair kinase DNA-PK. Pharmacologic inhibition of DNA-PKc blocked this interaction, increased DNA damage, and elevated prostate cancer cell death after irradiation. Our findings provide a mechanistic rationale for therapeutic targeting of DNA-PK in the context of combined ADT and radiotherapy as a strategy to radiosensitize clinically localized prostate cancer. Cancer Res; 77(18); 4745-54. ©2017 AACR.
- Published
- 2017