TRPV4 drives the progression of leiomyosarcoma by promoting ECM1 generation and co-activating the FAK/PI3K/AKT/GSK3β pathway.

PURPOSE: Leiomyosarcoma (LMS) is an aggressive mesenchymal malignant tumor with poor therapeutic options, but the molecular mechanisms underlying LMS remain largely unknown. Increasing evidence indicates that transient receptor potential vanilloid 4 (TRPV4) levels are closely related to the advancement of various malignant tumors through diverse molecular mechanisms. However, the roles and regulatory mechanisms of TRPV4 in LMS progression remain unclear. METHODS: Immunohistochemistry, Western blot, and immunofluorescence were used to investigate the relationship between TRPV4 expression and LMS. Survival analysis was conducted to evaluate the association between TRPV4 levels and prognosis in LMS patients. Intracellular Ca(2+) measurement, colony formation, CCK-8, wound healing and Transwell assays and peritoneal metastasis mouse model were used to verify the effect of TRPV4 activity and expression on LMS proliferation and metastasis. RNA-seq and proteomics were performed to explore the underlying mechanism. RESULTS: TRPV4 was upregulated in LMS tissues and cells and served as a novel prognostic factor. Moreover, TRPV4 overexpression enhanced cell proliferation, cell migration and invasion of LMS cells in vitro, as well as promoted tumor metastasis in vivo, which could be blocked by HC067047 intervention or TRPV4 knockdown. Combined RNA-seq and proteomics analysis of KEGG pathway indicated that ECM receptor interaction was obviously activated. Extracellular matrix protein 1 (ECM1) was identified as downstream gene of TRPV4. Mechanistically, TRPV4 overexpression increased ECM1 level and activated the FAK/PI3K/AKT/GSK3β pathway, which could be reversed by TRPV4 knockdown or LY294002 treatment. Moreover, ECM1 overexpression enhanced the activation of FAK/PI3K/AKT/GSK3β pathway. And simultaneous overexpression of TRPV4 and ECM1 synergistically activated this pathway. CONCLUSION: Our findings provide a novel mechanism by which TRPV4 directly activates Ca(2+)/FAK/PI3K/AKT/GSK3β pathway and further indirectly enhances the FAK/PI3K/AKT/GSK3β pathway through the promotion and secretion of ECM1 to promote LMS malignant progression. Targeting the TRPV4/FAK axis might be a promising potential strategy for prognosis and treatment of LMS.