Cancer-associated fibroblasts derived extracellular vesicles promote angiogenesis of colorectal adenocarcinoma cells through miR-135b-5p/FOXO1 axis

ABSTRACT Colorectal adenocarcinoma (COAD) is a prevalent malignant tumor. Cancer-associated fibroblasts (CAFs)-derived extracellular vesicles (EVs) (CAFs-EVs) are implicated in COAD treatment. This study explored the mechanism of CAFs-EVs in COAD. CAFs and normal fibroblast (NFs) were isolated from COAD tissues and adjacent normal tissues. Vimentin, α-SMA, and FAP expressions were detected. EVs were isolated from CAFs and identified. SW480 and HCT116 cells were co-incubated with EVs. The EV uptake and COAD cell malignant behaviors were assessed. EV-treated SW480 and HCT116 cells were co-cultured with human umbilical vein endothelial cells (HUVECs). Extensive analyses were conducted to examine HUVEC proliferation, migration, and angiogenesis, and miR-135b-5p expression in COAD cells, and SW480 and HCT116 cells. CAFs were transfected with the miR-135b-5p inhibitor. miR-135b-5p downstream targets were predicted. FOXO1 expression in the co-culture system was determined and then overexpressed to evaluate its role in HUVECs mediated by COAD cells. COAD mouse model was established by transplanting SW480 cells into nude mice and injecting with EVs. Tumor growth rate, volume, and weight were examined. Ki67, VEGF, CD34, FOXO1 expressions, and VEGF content were detected. CAFs-EVs promoted COAD cell malignant behaviors and COAD cells-mediated HUVEC proliferation, migration, and angiogenesis. CAFs-EVs delivered miR-135b-5p into COAD cells. miR-135b-5p targeted FOXO1. Inhibition of miR-135b-5p in EVs or overexpression of FOXO1 partially reversed the effect of EVs on promoting COAD-induced angiogenesis. CAFs-EVs promoted tumor proliferation and angiogenesis of COAD in vivo. CAFs-EVs delivered miR-135b-5p into COAD cells to downregulate FOXO1 and promote HUVECs proliferation, migration, and angiogenesis.