Pyr3 inhibits cell viability and PKCα activity to suppress migration in human bladder cancer cells.

Bladder cancer, more prevalent in men, has high recurrence rates in non-muscle-invasive forms and is highly lethal upon metastasis in muscle-invasive cases. Transient receptor potential canonical channels (TRPCs), specifically TRPC3, play a role in calcium signaling, influencing cancer cell behavior. This study examines the effects of Pyr3, a TRPC3 inhibitor, and TRPC3 knockdown on both muscle-invasive (T24) and non-muscle-invasive (RT4) bladder cancer cells. Pyr3 treatment reduced cell viability, migration, adhesion, and calcium influx in these cells. Additionally, Pyr3 treatment and siTRPC3 downregulated protein kinase C alpha (PKCα), phospho-PKCα, and protein phosphatase 2A (PP2A) levels. While PKC activator phorbol 12-myristate 13-acetate (PMA) could not restore Pyr3-induced viability loss, it reversed the migration inhibition. In a xenograft model, Pyr3 suppressed T24 cell viability, Ki67, phospho-PKCα, PP2A and TRPC3 expression. These findings suggest that Pyr3 inhibits bladder cancer cell migration through PKC signaling and holds potential as a therapeutic agent for bladder cancer.