Abstract 1165: TRPM8 is avidly targeted for degradation in prostate cancer

Abstract

Abstract Transient receptor potential melastatin 8 (TRPM8) is a cold-sensing receptor and a hallmark Ca2+ channel of the prostate epithelium. The TRPM8 mRNA is overexpressed in early prostate tumors with high androgen levels, while anti-androgen therapy greatly reduces its expression. Thus, androgens, which are at the crossroads of several signaling pathways, appear to be associated with TRPM8-mediated Ca2+ signaling. Although, TRPM8 mRNA levels are upregulated during prostate cancer progression, this upregulation is not adequately translated to the TRPM8 protein levels. We identified that the lower TRPM8 protein abundance and activation in LNCaP cells is associated with increased ubiquitination and loss of TRPM8 from the plasma membrane (PM). The mass-spectrometry analysis of TRPM8, immunoprecipitated from LNCaP cells identified ubiquitin-like modifier-activating enzyme 1 (UBA1). PYR-41, a potent inhibitor of the initial enzyme in the ubiquitination cascade, UBA1, increased TRPM8 activity on the PM of LNCaP cells. Our data indicate that PMTRPM8 plays a protective role in prostate cancer progression accompanied by enhanced activation of p53 and Caspase-9. In addition, we found that the promoter region of trpm8 possesses putative binding sites for p53 and that the overexpression of p53 increased the TRPM8 mRNA levels. Our findings support previous studies that suggest the fine balance between AR and p53 expression that regulates androgen-dependent growth of prostate cancer. Thus, we hypothesize that TRPM8 activity significantly contributes to anti-tumor defense mechanism and may serve as a novel therapeutic target in prostate cancer. Citation Format: Swapna Asuthkar, Eleonora Zakharian. TRPM8 is avidly targeted for degradation in prostate cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1165.