Modulation of NF-κB/miR-21/PTEN Pathway Sensitizes Non-Small Cell Lung Cancer to Cisplatin

Background Platinum-based chemotherapy is a standard strategy for non-small cell lung cancer (NSCLC), while chemoresistance remains a major therapeutic challenge in current clinical practice. Our present study was aimed to determine whether inhibition of the NF-kappa B/miR21/PTEN pathway could increase the sensitivity of NSCLC to cisplatin. Methods The expression of miR-21 in NSCLC tissues was determined using in situ hybridization. Next, the effect of miR-21 on the sensitivity of A549 cells to cisplatin was determined in vitro. Whether miR-21 regulated PTEN expression was assessed by luciferase assay. Furthermore, whether NF-kappa B targeted its binding elements in the miR-21 gene promoter was determined by luciferase and ChIP assay. Finally, we measured the cell viability and apoptosis under cisplatin treatment when NF-kappa B was inhibited. Results An elevated level of miR-21 was observed in NSCLC lung tissues and was related to a short survival time. Exogenous miR-21 promoted cell survival when exposed to cisplatin, while miR-21 inhibition could reverse this process. The RNA and protein levels of PTEN were significantly decreased by exogenous miR-21, and the 30-untranslated region of PTEN was shown to be a target of miR-21. The expression of miR-21 was regulated by NF-kappa B binding to its element in the promoter, a finding that was verified by luciferase and ChIP assay. Hence, inhibition of NF-kappa B by RNA silencing protects cells against cisplatin via decreasing miR-21 expression. Conclusion Modulation of the NF-kappa B/miR-21/PTEN pathway in NSCLC showed that inhibition of this pathway may increase cisplatin sensitivity.