Circular RNA circ_0029589 regulates proliferation, migration, invasion, and apoptosis in ox-LDL-stimulated VSMCs by regulating miR-424-5p/IGF2 axis.

Abstract Background Circular RNAs (circRNAs) have been identified to be critical mediators in the progression of atherosclerosis (AS). However, the exact roles and molecular mechanism of circ_0029589 in AS are far from understood. Methods Vascular smooth muscle cells (VSMCs) stimulated by oxidized low-density lipoprotein (ox-LDL) were served as a cellular model of AS. The expression levels of circ_0029589, microRNA (miR)-424-5p, and insulin-like growth factor 2 (IGF2) were measured by quantitative real-time polymerase chain reaction (qRT-PCR) or western blot analysis. Cell proliferation was determined by Cell Counting Kit-8 (CCK-8) assay and colony formation assay. Cell apoptosis, migration and invasion were examined by flow cytometry and transwell assay. The relationship between miR-424-5p and circ_0029589 or IGF2 was predicted by starbase and verified by dual-luciferase reporter assay. Results Circ_0029589 and IGF2 were upregulated and miR-424-5p was downregulated in VSMCs treated with ox-LDL. Silence of circ_0029589 inhibited proliferation, migration and invasion but induced apoptosis in ox-LDL-treated VSMCs. MiR-424-5p was a target of circ_0029589 and its knockdown reversed the effects of circ_0029589 interference on proliferation, migration, invasion, and apoptosis in ox-LDL-stimulated VSMCs. IGF2 was a target of miR-424-5p and miR-424-5p overexpression suppressed proliferation, migration and invasion while promoted apoptosis in ox-LDL-treated VSMCs by downregulating IGF2. Circ_0029589 positively modulated IGF2 expression by sponging miR-424-5p. Conclusion Circ_0029589 silence might inhibit the progression of AS by regulating miR-424-5p/IGF2 axis, providing a novel mechanism for pathogenesis of AS.