miR-424-5p promotes the proliferation and metastasis of colorectal cancer by directly targeting SCN4B

Background: Colorectal cancer (CRC) is one of the most common malignancies worldwide usually diagnosed at advanced stages which causes poor prognosis of patients. Therefore, novel diagnostic biomarkers and therapeutic targets are urgently needed. Materials and methods: miR-424-5p was identified through integrated analysis of three public databases. Loss-of-function experiments in HT29 and SW480 cells and mouse xenograft models were performed to explore the regulatory role of miR-424-5p in CRC. Bioinformatics analysis was used for predicting targets of miR-424-5p and its functional and pathway enrichment analysis. Results: miR-424-5p expression was significantly upregulated in CRC tissues and cell lines and associated with prognosis of CRC patients. Experiments in vitro and in vivo showed miR-424-5p promotes CRC cell proliferation and metastasis by directly inhibiting SCN4B. Besides, CRC cells secret miR-424-5p into peripheral blood through exosomes and circulating exosomal miR-424-5p could discriminate CRC patients with early stage from healthy people with AUC value of 0.82. Conclusions: miR-424-5p serves as an oncogene in CRC and circulating exosomal miR-424-5p is a novel potential diagnostic biomarker of CRC patients.