SMAD3 promotes expression and activity of the androgen receptor in prostate cancer

  • Nucleic Acids Res. 2023 Feb 2;gkad043. doi: 10.1093/nar/gkad043.
Hee-Young Jeon  1  2 ,  Majid Pornour  1  2 ,  Hyunju Ryu  1  2 ,  Sudeep Khadka  1  2 ,  Rui Xu  1  3 ,  Jihyun Jang  4 ,  Deqiang Li  4 ,  Hegang Chen  5 ,  Arif Hussain  1  2  6 ,  Ladan Fazli  7 ,  Martin Gleave  7 ,  Xuesen Dong  7 ,  Furong Huang  8 ,  Qianben Wang  8 ,  Christopher Barbieri  9 ,  Jianfei Qi  1  2
Affiliations
  • 1. Department of Biochemistry and Molecular Biology, University of Maryland, Baltimore, MD, USA.
  • 2. Marlene and Stewart Greenebaum Comprehensive Cancer Center, Baltimore, MD, USA.
  • 3. Institute of Marine and Environmental Technology, University of Maryland, Baltimore, MD, USA.
  • 4. Department of Cardiac Surgery, University of Maryland, Baltimore, MD, USA.
  • 5. Department of Epidemiology and Public Health, University of Maryland, Baltimore, MD, USA.
  • 6. Baltimore VA Medical Center, Baltimore, MD, USA.
  • 7. Vancouver Prostate Centre, University of British Columbia, Vancouver, BC, Canada.
  • 8. Department of Pathology and Duke Cancer Institute, Duke University School of Medicine, Durham, NC, USA.
  • 9. Department of Urology, Weill Cornell Medical College, NY, NY, USA.
PMID: 36727462 DOI: 10.1093/nar/gkad043
Abstract

Overexpression of Androgen Receptor (AR) is the primary cause of castration-resistant prostate Cancer, although mechanisms upregulating AR transcription in this context are not well understood. Our RNA-seq studies revealed that SMAD3 knockdown decreased levels of AR and AR target genes, whereas SMAD4 or SMAD2 knockdown had little or no effect. ChIP-seq analysis showed that SMAD3 knockdown decreased global binding of AR to chromatin. Mechanistically, we show that SMAD3 binds to intron 3 of the AR gene to promote AR expression. Targeting these binding sites by CRISPRi reduced transcript levels of AR and AR targets. In addition, ∼50% of AR and SMAD3 ChIP-seq peaks overlapped, and SMAD3 may also cooperate with or co-activate AR for AR target expression. Functionally, AR re-expression in SMAD3-knockdown cells partially rescued AR target expression and cell growth defects. The SMAD3 peak in AR intron 3 overlapped with H3K27ac ChIP-seq and ATAC-seq peaks in datasets of prostate Cancer. AR and SMAD3 mRNAs were upregulated in datasets of metastatic prostate Cancer and CRPC compared with primary prostate Cancer. A SMAD3 PROTAC inhibitor reduced levels of AR, AR-V7 and AR targets in prostate Cancer cells. This study suggests that SMAD3 could be targeted to inhibit AR in prostate Cancer.

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