MicroRNA-29a functions as a potential tumor suppressor through directly targeting CDC42 in non-small cell lung cancer.

The expression and function of microRNA-29a (miR-29a) have been investigated in various types of cancer. In the present study, the expression, function and underlying molecular mechanism of miR-29a were investigated in non-small cell lung cancer (NSCLC). The expression level of miR-29a in NSCLC was determined using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Cell proliferation, migration and invasion ability were determined using Cell Counting Kit-8, cell migration and invasion assays, respectively. Bioinformatics analysis and dual-luciferase reporter assays were performed to determine whether cell division cycle 42 (CDC42) is a direct target gene of miR-29a. To assess CDC42 mRNA and protein expression following transfection with miR-29a, RT-qPCR and western blotting were performed. Following knockdown of CDC42, functional assays were performed to investigate the roles of CDC42 in NSCLC. The results demonstrated that miR-29a was downregulated in NSCLC and the decreased expression level of miR-29a was significantly associated with advanced tumor-node-metastasis classification and metastasis. In addition, upregulation of miR-29a inhibited cell proliferation, migration and invasion in NSCLC, whereas downregulation of miR-29a had the opposite effects. Furthermore, CDC42 was identified as a direct target gene of miR-29a in vitro. miR-29a was demonstrated to function as a tumor suppressor in NSCLC by directly targeting CDC42 and may be investigated further as a target therapy for NSCLC.