Expression, Clinical Significance, and Functional Determination of the transmembrane channel-like protein 8 (TMC8) in clear cell renal cell carcinoma

Abstract Background The TMC family is a group of transmembrane proteins that function as mechanotransduction devices in the spinal cords of animals. They are involved in the transmembrane transport of ions. Previous studies have shown that TMCs significantly influence the proliferation and cell cycle of human cancers. However, it is unclear how TMC8 affects the occurrence and progression of clear cell renal cell carcinoma (ccRCC). Methods To address this issue, we downloaded ccRCC RNA-seq data from the Cancer Genome Atlas Database. We screened for differentially expressed genes (DEGs) using R software and intersected them with TMC family genes to obtain co-expression genes. We then used survival analysis to identify TMC8 as the target molecule. We verified the significance of TMC8 expression levels in clinicopathological features, survival prognosis, and immune microenvironment using R software and multiple databases. We also screened the top 100 genes most relevant to TMC8 in ccRCC on the LinkedOmics online website and performed Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses using the DAVID database. We further analyzed the high- and low-expressed DEGs of TMC8 using R language and re-verified the gene set enrichment analysis (GSEA) enrichment pathway. To validate our results, we performed quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting (WB) to detect TMC8 expression in ccRCC cell lines. We also performed cell proliferation, invasion, migration, cell cycle, and apoptosis assays to verify the effect of TMC8 expression levels on ccRCC cells. Results Our results show that TMC8 is abundantly expressed in ccRCC and is correlated with poor prognosis and clinicopathological staging (P < 0.05). TMC8 expression is positively correlated with T cells, T helper cells, and cytotoxic T lymphocytes in ccRCC (P < 0.001). The enrichment analysis revealed that TMC8 and related genes were enriched in pathways relevant to primary immunodeficiency, Th1 and Th2 cell differentiation, and T17 cell differentiation. The GSEA analysis showed that high TMC8 expression is associated with several immunological pathways. Our experiments demonstrated that TMC8 deletion decreased the ability of ccRCC to proliferate, invade, migrate, and undergo apoptosis, and halted the cell cycle in the G0/G1 phase. Conclusions Our findings suggest that TMC8 plays a critical role in the development of ccRCC and has the ability to identify and forecast the prognosis of ccRCC patients.