circ-LIMK1 regulates cisplatin resistance in lung adenocarcinoma by targeting miR-512-5p/HMGA1 axis

This study aimed to unveil the detailed role and new mechanism of circ-LIMK1 in lung adenocarcinoma. Real-time quantitative polymerase chain reaction was performed to analyze the expression of circ-LIMK1, miR-512-5p, and HMGA1. 3-(4,5)-Dimethylthiahiazo(-z-y1)-3,5-di-phenytetrazoliumromide assay was employed to test the half maximal inhibitory concentration of cisplatin (DDP). Western blot was used to measure the expression of HMGA1, multidrug resistance protein 1, mitochondrial 37S ribosomal protein, and vascular endothelial growth factor A. Colony formation assay, flow cytometry, transwell assay, and tube formation assay were performed to analyze cell functions. Animal models were established to assay the role of circ-LIMK1 in vivo. The expression of circ-LIMK1 was up-regulated in DDP-resistant tumor tissues and cells. Knockdown of circ-LIMK1 reduced DDP resistance, impaired cancer cell growth, migration, invasion, and angiogenesis. circ-LIMK1 targeted miR-512-5p, and HMGA1 was targeted by miR-512-5p. MiR-512-5p absence could restore the repressive effects of circ-LIMK1 knockdown on lung adenocarcinoma cell phenotypes. Overexpression of HMGA1 could restore the inhibitory effects of miR-512-5p enrichment on lung adenocarcinoma cell malignant phenotypes. Knockdown of circ-LIMK1 could reduce growth of DDP-resistant tumors in vivo. Collectively, circ-LIMK1 regulated DDP resistance in lung adenocarcinoma by targeting miR-512-5p/HMGA1 axis.