The malignant property of circHIPK2 for angiogenesis and chemoresistance in non-small cell lung cancer

Chemotherapy resistance limits the efficacy of cisplatin (DDP) when treating non-small cell lung cancer (NSCLC). Circular RNAs (circRNAs) confers a regulatory role in drug resistance. Innovatively, the regulatory role of circular RNA HIPK2 (circHIPK2) in DDP resistance was probed in the work. In this research, tumor tissues and matched normal tissues were obtained from 52 NSCLC patients, and the expressions of circHIPK2, miR-1249-3p and VEGFA in the tissues were detected by qPCR or Western Blot. Correlation analysis of circHIPK2 expression with survival prognosis and clinicopathological features was conducted. Parental NSCLC cell lines (A549, H460) and DDP-resistant cell lines (A549/DDP, H460/DDP) were selected, and the expression of circHIPK2, miR-1249-3p and VEGFA in the cells were detected. Cell IC50 value, proliferation, migration, invasion, apoptosis and angiogenesis were detected. Tumor xenografts were established to detect the role of circHIPK2 in vivo. The binding relationship between circHIPK2, miR-1249-3p and VEGFA was verified by dual luciferase reporter experiment, RNA pull down and RIP experiment. Our data showed that circHIPK2 and VEGFA were abnormally overexpressed and miR-1249-3p was underexpressed in DDP-resistant NSCLC tissues and cell lines. CircHIPK2 knockdown or miR-1249-3p upregulation inhibited DDP resistance, malignant behavior, and angiogenesis in NSCLC. CircHIPK2 by competitive absorption of miR-1249-3p mediated VEGFA. CircHIPK2 promoted the sensitivity of drug-resistant cells to DDP in NSCLC by regulating VEGFA. CircHIPK2 enhanced the growth of DDP-resistant NSCLC cells in vivo. In conclusion, circHIPK2 has the malignant property for angiogenesis and chemoresistance in NSCLC via the network of miR-1249-3p/VEGFA.