MicroRNA Let-7c Inhibites The Proliferation Of Non-small Cell Lung Cancer By Targeting Cdc25A

Object:To study the role and specific mechanism of let-7c in non-small cell lung cancer,so as to provide a new direction for the diagnosis and treatment of non-small cell lung cancer.Methods:Culture the non-small cell lung cancer cells(A549 ? H1299)and normal bronchinal epithelial cell.Total RNA was extracted from the cultured cells using the Trizol Reagent.Detection of let-7c expression in the cultured cells by real-time fluorescent quantitative PCR.The expression of let-7c was up-regulated and down-regulated by lipofectamine transfection,and the effects of let-7c expression on proliferation and apoptosis of A549 and H1299 cells were detected by MTS and flow cytometry.Detect the expression of Cdc25 A gene and protein levels when the expression of let-7c was changed by real-time fluorescent quantitative PCR and western blot.Examine the impact on the proliferationand apoptosis of A549 and H1299 cells when cells was transfected with Cdc25 A si RNA.Results:The expression of let-7c in A549(0.247±0.1078)and H1299(0.156±0.1331)was significantly lower than that in normal epithelial cells(1±0.09),and the difference was statistically significant(P<0.05).Up-regulating let-7c expression,the proliferation of cancer cells was lower than that of negative control and the apoptosis rate was higher.Also down-regulating let-7c expression,the results were contrary to the above,all of the difference was statistically significant(P<0.05).Up-regulating let-7c expression,the expression level of Cdc25 A gene and protein was down-regulated,and down-regulating let-7c expression,the expression level of Cdc25 A gene and protein was up-regulated,the difference was statistically significant(P<0.05).The proliferation of the cancer cells tranfected with Cdc25 A si RNA was lower than the cells tranfected with negative control,and apoptosis rate was higher,the difference was statistically significant(P<0.05).Conclusion:the expression of let-7c was lower in non-small cell lung cancer cells.And up-regulating let-7c expression,the proliferation of cancer cells was reduced,the apoptosis rate was increased.Also down-regulating let-7c expression,the proliferation of cancer cells was increased,the apoptosis rate was decrease.All the results show that let-7c play a role of a tumor suppressor gene in non-small cell lung cancer cells.Up-regulating let-7c expression,both the gene and the protein of Cdc25 A were down-regulated;down-regulating let-7c expression,the results were contrary.The results indicate Cdc25 A may be the downstream target of let-7c.The proliferation of cancer cells was reduced and the apoptosis rate was increased when the cells were transfected with Cdc25 A si RNA,futher confirm that Cdc25 A was the downstearm target of let-7c.The study describes the specific mechanism of let-7c inhibition of NSCLC growth in order to provide a new target for molecular targeted therapy of NSCLC.