Yinan Li1, Ning Xie1, Ruiqi Chen1, Ahn R Lee1, Jessica Lovnicki1, Emma A Morrison2, Ladan Fazli1, Qingfu Zhang3, Catherine A Musselman2, Yuzhuo Wang1, Jiaoti Huang4, Martin E Gleave1, Colin Collins1, Xuesen Dong5. 1. Vancouver Prostate Centre, Department of Urologic Sciences, University of British Columbia, Vancouver, BC, Canada. 2. Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA, USA. 3. Department of Pathology, Duke University School of Medicine, Durham, NC, USA; China Medical University, Shenyang, China. 4. Department of Pathology, Duke University School of Medicine, Durham, NC, USA. 5. Vancouver Prostate Centre, Department of Urologic Sciences, University of British Columbia, Vancouver, BC, Canada. Electronic address: xdong@prostatecentre.com.
Abstract
BACKGROUND: Prostate adenocarcinoma (AdPC) progression to treatment-induced neuroendocrine prostate cancer (t-NEPC) is associated with poor patient survival. While AdPC and t-NEPC share similar genomes, they possess distinct transcriptomes, suggesting that RNA splicing and epigenetic mechanisms may regulate t-NEPC development. OBJECTIVE: To characterize the role of alternative RNA splicing of the histone demethylase BHC80 during t-NEPC progression. DESIGN, SETTING, AND PARTICIPANTS: The expression of BHC80 splice variants (BHC80-1 and BHC80-2) were compared between AdPC and t-NEPC patient tumors. Regulatory mechanisms of RNA splicing of the BHC80 gene were studied, and the signal pathways mediated by BHC80 splice variants were investigated in t-NEPC cell and xenograft models. RESULTS: Global transcriptome analyses identified that the BHC80-2 variant is highly expressed in t-NEPC. Compared with the known histone demethylation activities of the BHC80 gene, we discovered a novel nonepigenetic action of BHC80-2, whereby BHC80-2 is localized in the cytoplasm to trigger the MyD88-p38-TTP pathway, which results in increased RNA stability of multiple tumor-promoting cytokines. While BHC80-2 does not induce neuroendocrine differentiation of cancer cells, it stimulates cell proliferation and tumor progression independent of androgen receptor signaling. Blockade of BHC80-2-regulated MyD88 signaling suppresses growth of several t-NEPC cell spheroid and xenograft models. CONCLUSIONS: Gain of function of BHC80-2 through alternative RNA splicing activates immune responses of cancer cells to promote t-NEPC development. PATIENT SUMMARY: The main obstacle to develop effective therapies for patients with t-NEPC is the lack of understanding on how t-NEPC is developed. Our study not only identifies a previously unknown BHC80-2-MyD88 signaling pathway that plays an important role during t-NEPC development, but also provides a proof of principle that targeting this signal pathway may offer an avenue to treat t-NEPC.
BACKGROUND:Prostate adenocarcinoma (AdPC) progression to treatment-induced neuroendocrine prostate cancer (t-NEPC) is associated with poor patient survival. While AdPC and t-NEPC share similar genomes, they possess distinct transcriptomes, suggesting that RNA splicing and epigenetic mechanisms may regulate t-NEPC development. OBJECTIVE: To characterize the role of alternative RNA splicing of the histone demethylase BHC80 during t-NEPC progression. DESIGN, SETTING, AND PARTICIPANTS: The expression of BHC80 splice variants (BHC80-1 and BHC80-2) were compared between AdPC and t-NEPC patienttumors. Regulatory mechanisms of RNA splicing of the BHC80 gene were studied, and the signal pathways mediated by BHC80 splice variants were investigated in t-NEPC cell and xenograft models. RESULTS: Global transcriptome analyses identified that the BHC80-2 variant is highly expressed in t-NEPC. Compared with the known histone demethylation activities of the BHC80 gene, we discovered a novel nonepigenetic action of BHC80-2, whereby BHC80-2 is localized in the cytoplasm to trigger the MyD88-p38-TTP pathway, which results in increased RNA stability of multiple tumor-promoting cytokines. While BHC80-2 does not induce neuroendocrine differentiation of cancer cells, it stimulates cell proliferation and tumor progression independent of androgen receptor signaling. Blockade of BHC80-2-regulated MyD88 signaling suppresses growth of several t-NEPC cell spheroid and xenograft models. CONCLUSIONS: Gain of function of BHC80-2 through alternative RNA splicing activates immune responses of cancer cells to promote t-NEPC development. PATIENT SUMMARY: The main obstacle to develop effective therapies for patients with t-NEPC is the lack of understanding on how t-NEPC is developed. Our study not only identifies a previously unknown BHC80-2-MyD88 signaling pathway that plays an important role during t-NEPC development, but also provides a proof of principle that targeting this signal pathway may offer an avenue to treat t-NEPC.
Authors: Mark P Labrecque; Lisha G Brown; Ilsa M Coleman; Bryce Lakely; Nicholas J Brady; John K Lee; Holly M Nguyen; Dapei Li; Brian Hanratty; Michael C Haffner; David S Rickman; Lawrence D True; Daniel W Lin; Hung-Ming Lam; Joshi J Alumkal; Eva Corey; Peter S Nelson; Colm Morrissey Journal: Cancer Res Date: 2021-07-26 Impact factor: 12.701