Transient Receptor Potential Ankyrin 1 and Vanilloid 1 Receptor mRNAs Are Not Translated to Functional Ion Channels in Human Prostate Adenocarcinoma Cells

Transient receptor potential ankyrin 1 (TRPA1) and vanilloid 1 (TRPV1) have been implicated in cancer biology, but their functional relevance in prostate adenocarcinoma (PAC) remains unclear. Therefore, we characterized TRPA1/TRPV1 expression and function in benign prostatic hyperplasia (BPH), PAC tissues, and PAC cell lines with different characteristics and examined the effects of their agonists on cancer-cell viability. TRPA1 and TRPV1 transcripts were assessed by RNAscope in situ hybridization and RT-qPCR, channel activity by Fura-2-based Ca2+ imaging, and viability/proliferation by ATP-based luminescence and automated cell counting. TRPA1 and/or TRPV1 mRNAs were detected in PAC tissues and cell lines, but selective stimulation with allyl-isothiocyanate (AITC) or capsaicin did not evoke Ca2+ influx, indicating no detectable functional channel activity under our experimental conditions. Non-selective TRPA1 activators induced Ca2+ influx responses that were not inhibited by the receptor antagonist A-967079. AITC concentration dependently reduced viability and proliferation of the androgen-sensitive 22Rv1 and LNCaP cells, and these effects were not prevented by TRPA1 antagonists. Capsaicin had no effect at TRPV1-selective concentrations. Thus, transcript expression does not predict functional TRPA1/TRPV1 activity in PAC cells, and AITC reduces PAC-cell viability through TRPA1-independent mechanisms.