The transient receptor potential canonical channels (TRPC) are a new family of Ca2+-permeable cationic channels controlling the Ca2+ influx response to the activation of the G-protein coupled receptor or the depletion of the internal Ca2+ store, which is related to the cellular signalling mechanisms of many hormones or growth factors. The role of TRPC channels in cancer development is still unclear. Therefore, we aimed to investigate the expression and role of TRPC channels in human ovarian cancer.
Human ovarian adenocarcinoma cells (SKOV3) were cultured with DMEM-F12 medium supplemented with 10% fetal calf serum, 100 units/ml penicillin and 100 μg/ml streptomycin, and maintained at 37 °C under 95% air and 5% CO2. The expression of TRPCs was detected by RT-PCR and western blotting. Cell proliferation was measured by WST-1 assay and cell counting.
TRPC1, TRPC4 and TRPC6 were detected by RT-PCR. The spliced variants of TRPC1, TRPC4 with exon 9 and 10 deletion and TRPC6 with exon 2 and exon 3 deletion were highly expressed in the ovary cancer cells. The proteins of TRPC1, TRPC4 and TRPC6 were also positive in human ovarian cancer cells using western blotting and immunostaining. 2-aminoethoxydiphenyl borate (2-APB), a broad-spectrum TRPC channel blocker, significantly inhibited SKOV3 cell proliferation in a concentration-dependent manner. To explore the contribution of individual TRPC isoforms, the specific TRPC functional antibodies and TRPC siRNAs were used. Blockade on TRPC1, TRPC4 and TRPC6 channels by specific TRPC channel blocking antibodies or siRNA significantly inhibited the cancer cell proliferation.
These results suggest that TRPC1, TRPC4 and TRPC6 are essential for human ovarian cancer cell proliferation. Functional splicing of TRPC isoforms may be important for regulating ovary cancer cell growth. The specific blockers for TRPC channels might be developed as potential new drug candidates for anticancer therapy.