Background:
Lung cancer is a social problem of increasing concern, and
non-small cell lung cancer (NSCLC) accounts for 80%-85% incidence of
lung cancer.
Cisplatin (DDP) is reported as a first-line
chemotherapy drug for NSCLC, but the resistance has became a main obstacle for NSCLC treatment. The high level of
circular RNA circ_0076305 was related to the DDP resistance in NSCLC. However, the mechanism of circ_0076305 remains unclear in DDP resistance of NSCLC. Materials and Methods: Exosomes were detected by a transmission electron microscope and nanoparticle tracking analysis. The
protein levels of CD63, CD81,
P-glycoprotein (P-gp), Lung resistance-related
protein, and
ATP-binding cassette subfamily C member 1 (ABCC1) were examined by Western blot assay. Circ_0076305, microRNA-186-5p (miR-186-5p), and ABCC1 levels were tested by real-time quantitative polymerase chain reaction. DDP resistance was examined by 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium
bromide assay. The binding relationship between miR-186-5p and circ_0076305 or ABCC1 was predicted by
circRNA interactome or starBase, and then verified by dual-
luciferase reporter and
RNA immunoprecipitation assays. The effect of circ_0076305 on DDP resistance in NSCLC was examined by xenograft
tumor model in vivo. Results: Circ_0076305 was increased in NSCLC cell-derived exosomes, DDP-resistant NSCLC tissues and cells. Circ_0076305 knockdown elevated DDP sensitivity in vitro. Mechanically, circ_0076305 enhanced ABCC1 expression through sponging miR-186-5p, thus regulating DDP resistance of NSCLC. Furthermore, circ_0076305 silencing improved DDP sensitivity of NSCLC in vivo. Conclusion: The results from this study disclosed that circ_0076305 knockdown improved DDP sensitivity by the miR-186-5p/ABCC1 axis in NSCLC, hinting a potential
circRNA-targeted
therapy for NSCLC.