MiR-192/NKRF axis confers lung cancer cell chemoresistance to cisplatin via the NF-κB pathway

Background Chemoresistance influences the therapeutic effect of cisplatin and remains a major obstacle to its clinical use. MicroRNAs are associated with drug resistance of various tumors. However, the association between microRNAs and cisplatin in lung cancer remains largely unclear. Methods MicroRNA expression profile was identified by microRNA microarray between the lung cancer cisplatin-sensitive cell line A549 (A549) and cisplatin-resistant cell line A549/DDP (A549/DDP) and confirmed by quantitative real-time-PCR (qRT-PCR). In vitro loss- and gain-of-function studies were performed to reveal the biological function of miR-192 and related mechanism of the microRNA-192/NKRF axis in lung cancer cell cisplatin resistance. Results Increased miR-192 expression was detected in A549/DDP cells compared to A549. High miR-192 expression significantly suppressed apoptosis, enhanced proliferation, and conferred resistance to cisplatin in lung cancer cells. NF-kappa B repressing factor (NKRF), which is involved in the regulation of the NF-kappa B signaling pathway, was identified as a direct target of miR-192. Overexpression of miR-192 significantly increased the nuclear protein amount and transcriptional activation of NF-kappa B and expression of cIAP1, cIAP2, Bcl-xl and XIAP, whereas decreased miR-192 expression did the opposite. Inhibition of the NF-kappa B signal pathway by curcumin reversed the effect of upregulation of miR-192 on proliferation, apoptosis and cisplatin-resistance in lung cancer cells. These results indicated that miR-192/ NKRF axis enhances the cisplatin resistance of lung cancer cells through activating the NF-kappa B pathway in vitro. Conclusions MiR-192 plays a crucial role in cisplatin-resistance of lung cancer cells. Thus, MiR-192 may represent a therapeutic target for overcoming resistance to cisplatin-based chemotherapy in lung cancer.