Protein Arginine Methyltransferase 5 Promotes pICln-Dependent Androgen Receptor Transcription in Castration-Resistant Prostate Cancer
Abstract
The majority of advanced prostate cancer therapies aim to inhibit androgen receptor (AR) signaling. However, AR reactivation inevitably drives disease progression to castration-resistant prostate cancer (CRPC). Here we demonstrate that protein arginine methyltransferase 5 (PRMT5) functions as an epigenetic activator of AR transcription in CRPC, requiring cooperation with a methylosome subunit pICln. In vitro and in xenograft tumors in mice, targeting PRMT5 or pICln suppressed growth of CRPC cells. Full-length AR and AR-V7 transcription activation required both PRMT5 and pICln but not MEP50. This activation of transcription was accompanied by PRMT5-mediated symmetric dimethylation of H4R3 at the proximal AR promoter. Further, knockdown of PRMT5 abolished the binding of pICln (but not vice versa) to the AR proximal promoter region, suggesting that PRMT5 recruits pICln to the AR promoter to activate AR transcription. Differential gene expression analysis in 22Rv1 cells confirmed that PRMT5 and pICln both regulate the androgen signaling pathway. In addition, PRMT5 and pICln protein expression positively correlated with AR and AR-V7 protein expression in CRPC tissues and their expression was highly correlated at the mRNA level across multiple publicly available CRPC datasets. Our results suggest that targeting PRMT5 or pICln may be explored as a novel therapy for CRPC treatment by suppressing expression of AR and AR splice variants to circumvent AR reactivation.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Nov 13, 2020
- Source ID
- 10.1158/0008-5472.can-20-1228
Entities
People
- Andrew M Asberry
- Bennett D. Elzey
- Chang-deng Hu
- Chenglong Li
- Elena Beketova
- Jake L Owens
- Jiaoti Huang
- Jonathan Malola
- Jun Wan
- Qingfu Zhang
- Roberto Pili
- Sheng Liu
- Shuyi Fang
- Timothy L Ratliff
- Xuehong Deng
- Xufeng Chen
Organizations
- Duke University
- Indiana Clinical and Translational Sciences Institute
- Indiana University
- Indiana University Bloomington
- National Cancer Institute
- National Institutes of Health
- Purdue University
- Purdue University Center for Cancer Research
- University of Florida