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-κB repressing factor (NKRF), which is involved in the regulation of the NF-κB 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-κB and expression of cIAP1, cIAP2, Bcl-xl and XIAP, whereas decreased miR-192 expression did the opposite. Inhibition of the NF-κB 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-κB 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.