Hypoxic colorectal cancer‐derived extracellular vesicles deliver microRNA‐361‐3p to facilitate cell proliferation by targeting TRAF3 via the noncanonical NF‐κB pathways

Abstract

BACKGROUND: Hypoxic tumour microenvironment (TME) is a key regulator in cancer progression. However, the communications between hypoxic cells and other components in TME during colorectal cancer (CRC) progression via extracellular vesicles (EVs) remain unclear. METHODS: ) and miR-361-3p on CRC growth were assessed using CCK-8 assays, colony formation assays, EdU assays, flow cytometric assays and mouse xenograft. Then, the specific mechanisms of miR-361-3p were investigated by RNA immunoprecipitation, luciferase reporter assay, Western blot, chromatin immunoprecipitation, immunohistochemistry and rescue experiments. RESULTS: The level of miR-361-3p expression was remarkably elevated in hypoxic EVs and can be transferred to CRC cells. Functional experiments exhibited that hypoxic EVs facilitated cell growth and suppressed cell apoptosis by transferring miR-361-3p of CRC. Hypoxia-inducible factor-1α induced the elevation of miR-361-3p levels in hypoxic EVs. Upregulated miR-361-3p in CRC inhibited cell apoptosis and facilitated cell growth by directly targeting TNF receptor-associated factor 3, which consequently activated the noncanonical NF-κB pathway. Moreover, the high expression of circulating exosomal miR-361-3p was correlated to worse prognosis of CRC patients. CONCLUSIONS: Altogether, the abnormality of exosomal miR-361-3p derived from hypoxia acts vital roles in the regulation of CRC growth and apoptosis and can be an emerging prognostic biomarker and a therapeutic target for CRC patients.