MiR-142-3p functions as a potential tumor suppressor directly targeting HMGB1 in non-small-cell lung carcinoma

Background: microRNAs (miRNAs) play a significant role in cancer development and progression by regulating the expression of oncogenes or tumor suppressor genes. Previous study using microarrays demonstrated that miR-142-3p was downregulated in patients with Non-small-cell lung carcinoma (NSCLC). However, the functional role of miR-142-3p in NSCLC is still unclear. Material and method: Real-time quantitative PCR was applied to evaluate the expression level of miRNA-142-3p in NSCLC and normal samples. The cell proliferation of NSCLC cells was analyzed by MTT and colony formation assay after miR-142-3p transfection. Luciferase activities assay, cotransfection and Western blot were used to reveal that the predicted target genes of miR-125b were direct and specific. Results: In this study, we demonstrate miR-142-3p was downregulated in NSCLC tissues and cell lines. We demonstrated that the overexpression of miR-142-3p inhibits NSCLC cell proliferation and induced cell apoptosis. Furthermore, we demonstrate HMGB1 was a directly target of miR-142-3p in NSCLC cells, and confirmed the target specificity between miR-142-3p and the HMGB1 3’-untranslated region by luciferase reporter assay. Conclusions: These results suggest that miR-142-3p may be a tumor suppressor through the downregulation of HMGB1 in NSCLC. miR-142-3p may be a tumor suppressor and a potential therapeutic agent for patients with NSCLC.