Cancer-associated fibroblast-derived exosome miR-181b-3p promotes the occurrence and development of colorectal cancer by regulating SNX2 expression.

Tumor microenvironment (TME) (e.g., stromal cells) has been closely related to the pathological process of colorectal cancer (CRC). In TME, tumor-associated fibroblasts (CAFs) are the main stromal cells. The studies have showed that CAFs promoted tumor growth and metastasis in CRC and led to poor prognosis. Mounting evidence indicates that CAFs-mediated exosomes regulate the pathological process of neighboring tumor cells through the transmission of miRNAs. In our study, we aimed to explore the function of CAFs-derived exosome miR-181b-3p in CRC. First, the expression of miR-181b-3p in CRC was found to be up-regulated and its expression was dramatically up-regulated in CRC cells after co-incubation of CAFs-mediated exosomes with CRC cells. Then, it was found that the CAFs-derived exosomes were markedly enhanced the proliferation and migration of the CRC cells, and substantially reduced apoptosis. To elucidate the influence of CAFs-derived exosome miR-181b-3p on CRC, we overexpressed and knocked down the miR-181b-3p expression in CAFs, respectively. It was found that miR-181b-3p significantly increased the proliferation and migration of CRC cells. Furthermore, we conducted in vivo experiments. Finally, we demonstrated that CAF-derived exosome miR-181b-3p regulated sorting nexin 2 (SNX2) expression in CRC cells by bioinformatics prediction combined with luciferase reporter assay. Further cellular and animal experiments jointly elucidated that miR-181b-3p promoted the pathological process of CRC by SNX2 expression. In brief, our results demonstrated that CAFs-derived exosome miR-181b-3p promoted the pathogenesis of CRC by regulating SNX2 expression, which provides a novel idea for CRC treatment.