ABSTRACT
AIM:To investigate the role of miR-125b in regulating the sensitivity of CD133+ colorectal cancer cells to cisplatin.METHODS:The expression of miR-125b was detected by RT-qPCR in the routine SW480 cells and CD133+ SW480 cells.Flow cytometry analysis was performed to measure the percentage of CD133+ cell population in the SW480 cell line treated with miR-125b and cisplatin.MTT assay was performed to evaluate the effect of miR-125b on the cisplatin-induced cell death in the CD133+ SW480 cells.Bioinformatics and Western blot were performed to determine whether the expression of HAX-1 was regulated by miR-125b.JC-1 staining, Annexin V staining and Western blot analysis were used to study the pathway of apoptosis in the CD133+ SW480 cells co-treated with miR-125b and cisplatin.RESULTS:The expression of miR-125b was significantly lower in the CD133+ SW480 cells than that in the routine SW480 cells and normal colonic epithelial FHC cells.Treatment with cisplatin alone increased the percentage of CD133+ SW480 cell population.However, miR-125b significantly inhibited the enrichment of CD133+ cell population induced by cisplatin.In addition, the results of MTT assay showed that the anti-tumor effect of cisplatin was significantly enhanced when the miR-125b was transfected into the CD133+ SW480 cells.The results of Western blot indicated that the HAX-1 gene was the target of miR-125b.Furthermore, the apoptosis induced by the combination of miR-125b and cisplatin was dependent on the dysfunction of mitochondrial membrane, leading to the release of cytochrome C into the cytoplasm and the subsequently activation of apoptosis in the CD133+ SW480 cells.CONCLUSION:miR-125b increased the sensitivity of CD133+ colo-rectal cancer cells to cisplatin by down-regulating the expression of HAX-1.