Abstract: Objective To investigate the effect of exosomal miR-34c-5p derived from cancerassociated fibroblasts (CAFs) on the stem-like properties of gastric cancer (GC) cells. Methods Exosomes from primary cultured CAFs and paired normal fibroblasts (NFs) were collected and identified, and the differential expression of exosomal miR-34c-5p between CAFs and NFs was detected. The viability of GC cells was detected by CCK8 assay. The proliferation of GC cells was detected by colony formation assay. The invasive ability of GC cells was detected by Transwell assay. The sphere formation capability of GC cells was evaluated by sphere formation assay. The expression levels of stemness-related proteins were detected by Western blotting (WB) assay. Results The expression level of miR-34c-5p in CAFs derived exosomes was significantly decreased. miR-34c-5p from the CAFs-exo inhibited the proliferation, invasion and sphere formation of GC cells, and reduced the expression levels of SOX2, OCT4 and NANOG proteins, when compared with those in the CAFs-exo group (P< 0. 05). Conclusion The exosomal miR-34c-5p from CAFs inhibited the stem-like properties of GC cells.

Key words: cancer-associated fibroblasts, exosome, gastric cancer, miR-34c-5p, stemness