TRPC5 expression promotes the proliferation and invasion of papillary thyroid carcinoma through the HIF-1α/Twist pathway

This study aimed to investigate the effect of TRPC5 on PTC (papillary thyroid carcinoma) proliferation and invasion. Immunofluorescence and western blot were used to evaluate the expression of TRPC5 in paraffin sections and clinical tissues. Overexpression and silencing of TRPC5 to generate the cells for in vitro experiments. Wound-healing assay, transwell invasion assay, MTT assay, and in vivo tumorigenicity assay were used to determine cell proliferation and cell migration in vitro and in vivo. Real-time PCR was used to test the expression of TRPC5. Western blot was used to test the expression of downstream factors: E-cadherin, Vimentin, MMP-9, MMP-2, TRPC5, ZEB, Snail, and Twist. The level of TRPC5 protein expression was higher in PTC than in adjacent normal thyroid tissue. TPC-1 cells overexpressing TRPC5 were more proliferative, had longer migration distances, and increased the number of invading cells. TPC-1 cells silenced with TRPC5 had a weaker proliferation capacity, shorter migration distances, and a reduced number of invading cells. Overexpression and silencing of TRPC5 modulated E-cadherin, Vimentin, MMP-9, MMP-2, TRPC5, and Twist, but did not affect ZEB and Snail. The results of tumor formation experiments in nude mice showed that inhibition of TRPC5 expression suppressed the volume and weight of transplanted tumors. TRPC5 induced papillary thyroid cancer metastasis and progression via up-regulated HIF-1α signaling in vivo and in vitro. High TRPC5 expression is a biomarker for lymph node metastasis at its early stages.