机构：[1]Department of Urology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA[2]University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA[3]Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA[4]Department of Urology, The Second Affiliated Hospital of Soochow University, Suzhou, China[5]Cancer Center, Southern Medical University, Guangzhou, China[6]Department of Urology, Peking University First Hospital and Institute of Urology, Peking University, Beijing, China[7]Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA[8]Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
Androgens are known to protect prostate cancer cells from DNA damage. Recent studies showed regulation of DNA repair genes by androgen receptor signaling in prostate cancers. ELL-associated factor 2 (EAF2) is an androgen-regulated tumor suppressor and its intracellular localization can be modulated by ultraviolet light, suggesting a potential role for EAF2 in androgen regulation of DNA repair in prostate cancer cells. Here we show that knockdown of EAF2 or its homolog EAF1 sensitized prostate cancer cells to DNA damage and the sensitization did not require p53. EAF2 knockout mouse prostate was also sensitized to gamma-irradiation. Furthermore, EAF2 knockdown blocked androgen repression of LNCaP or C4-2 cells from doxorubicin induction of gamma H2ax, a DNA damage marker. In human prostate cancer specimens, EAF2 expression was inversely correlated with the level of gamma H2ax. Further analysis showed that EAF2 and EAF1 are required for the recruitment and retention of Ku70/Ku80 to DNA damage sites and play a functional role in nonhomologous end-joining DNA repair. These findings provide evidence for EAF2 as a key factor mediating androgen protection of DNA damage via Ku70/Ku80 in prostate cancer cells.
基金：
This investigation was supported in part by the National Institutes of Health Grants
R01CA186780, 1 P50 CA180995, 1R50CA211242 and T32 DK007774 and a scholarship
from the Tippens Foundation (to LEP). This project used the UPCI Animal Facility, Flow
Cytometry and Tissue and Research Pathology Services (TARPS), and was supported in
part by award P30CA047904. We thank Dr Leland WK Chung for providing C4-2 cells and
Drs Javid Dar, Amy Deng, Tomoko Koya and Xinhui Wang for assistance in generating
the EAF1 antibody. We thank Marie Acquafondata, Jon Duboy, Anthony Green, Bratislav
Janjic, Marianne Notaro, Aiyuan Zhang and Katie Leschak for technical assistance. We
thank Dr Michael Epperly for assistance in designing and performing irradiation
experiments. We thank Dr Anil V Parwani for reviewing human prostate specimens and
Dr Lora H Rigatti for reviewing mouse prostate specimens. We also thank Drs Weijun Liu,
Susanne M Gollin and Dale W Lewis and all members of the Wang laboratory for
insightful discussion during this project and critical reading of the manuscript.
医学