Abstract:

Aim: Lung cancer is the leading cause of cancer-related deaths in men and women worldwide. Developments in early diagnostics and the number of new targeted agents have increased, lung cancer still cannot be diagnosed early and treated effectively. Therefore, accurate and reliable markers are needed for the diagnosis of lung cancer. Furthermore, studies showing the role and therapeutic potential of let-7b-5p in lung cancer seem to be quite limited. In this study, the expression level of let-7b-5p was increased by miRNA mimic applications in A549 cells to investigate the relationship between let-7b-5p and apoptosis-related genes. Materials and Methods: The genes involved in the apoptosis and predicted to target let-7b-5p were determined by bioinformatics tools from online databases. In order to increase the expression levels of let-7b-5p in A549 cells, let-7b-5p mimics were transfected into the cells with the HiPerFect transfection reagent. Then, expression levels of let-7b-5p and apoptosis related genes were determined by qPCR method. Results: It was found that the expression levels of BCL2, RB1, XIAP, CASP9, TP53 and PTEN genes decreased after increasing expression levels of let-7b-5p as compared to control groups in lung cancer cells. In contrast, the expression level of the BAX gene increased and no changes were observed in the expression levels of CASP3 and BCL2L1 genes. As a result of the in silico analysis, the TP53 gene was shown to have let-7b-5p binding site at two different positions in the 3’UTR region. Conclusion: In conclusion, our findings suggest that let-7b-5p can target genes involved in apoptosis and this miRNA might be an important biomarker for the diagnosis and/or treatment of lung cancer.

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