miR-22 and miR-214 targeting BCL9L inhibit proliferation, metastasis, and epithelial-mesenchymal transition by down-regulating Wnt signaling in colon cancer

The epithelial-mesenchymal transition (EMT) is crucial for cancer progression. Evidence has shown that miR-22 and miR-214 play a key role in colon cancer progression; however, the underlying mechanism remains to be known. The effects of miR-22 and miR-214 on EMT are contradictory in different cancers, and whether miR-22 and miR-214 are involved in the colon cancer EMT process needs to be elucidated. In this study, we evaluated the exact role and the regulation mechanism of miR-22 and miR-214 in colon cancer. After transfection with miR-22 expression vector, the cell proliferation and migration capacity of HCT116 and RKO cells were significantly suppressed. Also, E-cadherin was increased and vimentin was decreased by miR-22 overexpression. Similar effects were also observed after miR-214 expression vector transfection. Dual-luciferase reporter confirmed that BCL9L is the target gene of both miR-22 and miR-214. Silencing of BCL9L inhibits cell proliferation and migration, and the expression of E-cadherin and vimentin was also altered by BCL9L knockdown, which was consistent with miR-22 or miR-214 transfection. Furthermore, miR-22 and miR-214 inhibited tumor growth in nude mice. Moreover, although the association between BCL9L's lower expression and longer survival time was statistically nonsignificant, a trend existed; further studies in a larger cohort are needed. Collectively, these data suggest that miR-22 and miR-214 inhibit cell proliferation, migration, and EMT of colon cancer, most likely by targeting BCL9L.-Sun, R., Liu, Z., Han, L., Yang, Y., Wu, F., Jiang, Q., Zhang, H., Ma, R., Miao, J., He, K., Wang, X., Zhou, D., Huang, C. miR-22 and miR-214 targeting BCL9L inhibit proliferation, metastasis, and epithelial-mesenchymal transition by down-regulating Wnt signliang in colon cancer.