Mechanism of miR-21 via Wnt/β-catenin signaling pathway in human A549 lung cancer cells and Lewis lung carcinoma in mice

ObjectiveTo study the mechanism of effect of miR-21 via Wnt/β-catenin signaling pathway in human A549 lung cancer cells and Lewis lung carcinoma in mice.MethodsThe effect of miR-21 on A549 cells were detected by MTT method. MiR-21 expression levels were overexpressed or inhibited in A549 cells by transfecting with miR-21 mimics or inhibitors. Correlation among key molecules (Wnt1, β-catenin, CyclinD1 and miR-21) of mRNA and protein levels in Wnt/β-catenin signaling pathway were studied by Real-time PCR and Western blot hybridization assay. Invasive ability of A549 cells was determined via Transwell chamber cell invasion assay; the role of miR-21 in A549 cells was explored via the Wnt/β-catenin signaling pathway. A Lewis lung carcinoma animal model was established to detect miR-21 expressions in tumor animals and controlled animal tissues, and verify expression changes of the above molecules in the Wnt/β-catenin signaling pathway was determined in the animal level.ResultsMTT assay results showed that miR-21 overexpression could markedly enhance cell absorbance value; that is, miR-21 could increase the ability proliferation of A549 cells. β-catenin and CyclinD1 expression levels were significantly higher in miR-21 mimic transfected cells (P < 0.05), and Wnt1 gene had no significant change. Wnt1, β-catenin and CyclinD1 gene expression showed no significant change when miR-21 expression was suppressed, compared with controls. After cells were transfected with miR-21 mimics, cell invasion assay revealed that the perforated cells was significantly higher than the perforated cells in the control group (P < 0.01). Lewis lung assay revealed that miR-21 expression levels in the Lewis lung carcinoma were significantly higher; and at the same time, Wnt1, β-catenin and CyclinD1 gene expression levels were significantly increased, compared to controls.ConclusionsIn A549 human lung cancer cells and Lewis lung carcinoma in mice, key molecules β-catenin and CyclinD1of miR-21 expressions and the Wnt/β-catenin signaling pathway are positively correlated.