The MicroRNA hsa-let-7g Promotes Proliferation and Inhibits Apoptosis in Lung Cancer by Targeting HOXB1

PURPOSE: The goal of this study was to explore the effects of hsa-let-7g on cell proliferation and apoptosis, and elucidate its role in lung cancer development. MATERIALS AND METHODS: The expression levels of has-let-7g and HOXB1 in tissues and cells were measured by qRT-PCR. An inhibitor of hsa-let-7g or one targeting a control messenger RNA were transfected into A549 and H1944 lung cancer cells, and the effects of hsa-let-7g dysregulation on cell viability and apoptosis were analyzed using CCK-8 and apoptosis detection assays. HOXB1 was confirmed as the target gene of hsa-let-7g, based on luciferase reporter assay results. The relationship between hsa-let-7g and HOXB1 was confirmed by co-transfection of inhibitors of hsa-let-7g and HOXB1 followed by Western blot, CCK-8, and apoptosis detection assays. RESULTS: We observed high expression of hsa-let-7g in lung cancer tissues compared to the corresponding normal tissues, and generally higher expression of hsa-let-7g in patients with advanced tumor classification. The results of CCK-8 and apoptosis detection experiments showed that the inhibition of hsa-let-7g significantly inhibited proliferation of A549 and H1944 cells, but also promoted apoptosis. HOXB1 is a specific target of hsa-let-7g, and downregulation of HOXB1 in lung cancer cells reversed the suppressive effects caused by knocking down hsa-let-7g. CONCLUSION: These data collectively suggest that the expression of hsa-let-7g inhibits lung cancer cells apoptosis and promotes proliferation by down-regulating HOXB1. The results from this study demonstrate the potential of hsa-let-7g/HOXB1 axis as a therapeutic target for the treatment of lung cancer.