Let-7a targets Rsf-1 to modulate radiotherapy response of non-small cell lung cancer cells through Ras-MAPK pathway.

PURPOSE: Radiotherapy is the most commonly selective medical treatment for non-small cell lung cancer (NSCLC) and the multiple underlying mechanisms are considered as the effectively theoretical foundation. Herein, we investigated the effects of let-7a targets Rsf-1 on modulating the radiotherapy response in NSCLC cells by Ras-MAPK pathway. METHODS: A549 cells were divided into different groups to investigate the role of let-7a and Rsf-1 on the radiotherapy response. The expression of let-7a and Rsf-1 were detected by RT-PCR. Bioinformatic analysis indicated that Rsf-1 is the target of let-7a. The binding site of let-7a in the Rsf-1 3'UTR was detected based on double luciferase reporter assay and Western blot. The cell variability and proliferation were assessed by MTT and colony formation assay. The expression levels of Ras-MARK signaling pathway related proteins were assessed by RT-PCR. RESULTS: RT-PCR results showed that radiotherapy could up-regulate the expression of let-7a, thereby reducing the expression of Rsf-1, and the correlation between the two factors was negatively correlated. At the same time, let-7a overexpression and Rsf-1 silencing could further reduce the activity of A549 cells after radiotherapy, have an inhibitory effect on cell proliferation and inhibit the expression of related proteins in the Ras-MAPK pathway. CONCLUSIONS: Rsf-1 is the target of Let-7a. The present study provides evidence that let-7a targeting Rsf-1 can modulate radiotherapy response in NSCLC cells through Ras-MAPK pathway.