Inhibition of TRPC6 channel suppresses bladder cancer proliferation by disrupting store-operated calcium entry.

Despite its prevalence, bladder cancer (BC) remains an unsolved pathogenesis. It is believed that TRPC6 channels have unique electrophysiological properties that contribute to intracellular Ca2+  signalling and tumorigenesis in cells. However, the mechanism by which TRPC6 contributes to BC progression and intracellular Ca2+ homeostasis remains unclear. In this study, TRPC6 expressions in paired BC and adjacent normal tissues were measured by immunohistochemistry. A KEGG pathway enrichment analysis was conducted to determine TRPC6’s potential contribution to BC. Ca2+  imaging analysis was performed to explore the contribution of TRPC6 in the BC cell. Flow cytometry and Cell Counting Kit-8 assay were performed to explore the effects of TRPC6 on the proliferation of BC. The impacts of TRPC6 SOCE on PI3K/Akt/mTOR pathway were measured by western blot. Based on the above bunch of studies, TRPC6 was found to be overexpressed in human BC tissue, which correlated with poor survival rates for patient overall survival (OS). We used the TRPC6-specific antagonist SAR7334 to explore and reveal significant inhibition of BC cell proliferation. Mechanistically, TRPC6 mediated cytosolic Ca2+ and regulation of SOCE, leading to the activation of the IP3K/AKT/mTOR pathway. We found that SAR7334 arrested the phosphorylation of PI3K and Akt, thus causing a significant decrease in phosphorylated mTOR. Similar effects were observed for the SOCE-specific antagonist MRS1845. In contrast, the Akt inhibitor MK2206 did not alter the SOCE in BC cells. Our results indicate that the pharmacological inhibition of TRPC6 arrests tumour cell proliferation through SOCE targeting the PI3K/Akt/mTOR pathway.