Comprehensive Insights Into the Role of TRPM4 in Pan-Cancer Progression and Immune Regulation.

BACKGROUND: Transient receptor potential channel subfamily M member 4 (TRPM4) is a non-selective Na(+) permeable ion channel that regulates disease processes by enhancing sodium entry and membrane depolarization, but its role in tumors remains underexplored. The purpose of this study is to investigate the role of TRPM4 in pan-cancer progression and immune regulation. METHODS: The pan-cancer mRNA expression information of TRPM4 was obtained from TCGA and GTEx, and the protein expression information of TRPM4 was obtained from HPA database. STRING database was utilized to construct the protein-protein interaction network of TRPM4. Gene characterization of TRMP4 was analyzed by GSCA database. The relationship between TRPM4 and immune infiltration characteristics in pan-cancer was analyzed using TCGAplot. Multiple bulk RNA-seq and scRNA-seq datasets treated with PD-(L)1 were used to analyze the relationship between TRPM4 and immunotherapy response. Immunohistochemistry (IHC) and multiplex immunofluorescence (mIHC) were used to validate the expression of TRPM4 in tumor tissue from 19 lung adenocarcinoma patients in relation to the characteristics of immune cell infiltration. In vitro experiments were performed to validate the role of TRPM4 in human breast, lung adenocarcinoma, and esophageal cancer. RESULTS: TRMP4 expression is higher in most tumors than in normal tissues, and the association with prognosis varies with cancer type. TRPM4 correlates with multiple immune checkpoints as well as the degree of immune cell infiltration. Multiple datasets of anti-PD-(L)1 treatment suggested that high expression of TRPM4 was associated with worse treatment prognosis. The IHC and mIHC found that TRPM4 expression was negatively correlated with the level of M1 macrophage and T cell infiltration. In vitro experiments confirmed that knockdown of TRPM4 inhibited proliferation, invasion and migration of human breast, lung and esophageal cancer cells. CONCLUSION: TRPM4 plays a complex role in tumor progression and immunotherapeutic response, and targeting TRPM4 may offer promising strategies for inhibiting tumor progression and improving immunotherapy resistance.