Novel circular RNA hsa_circ_0036683 suppresses proliferation and migration by mediating the miR-4664-3p/CDK2AP2 axis in non-small cell lung cancer.

ABSTRACT

BACKGROUND: The aim of the present study was to investigate the function of novel circular RNA hsa_circ_0036683 (circ-36683) in non-small cell lung cancer (NSCLC). METHODS: RNA sequencing was used to screen out differentially expressed miRNAs. Expression levels of miR-4664-3p and circ-36683 were evaluated in lung carcinoma cells and tissues by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The effects of miR-4664-3p and circ-36683 on proliferation and migration were assessed using cell counting kit-8 (CCK-8), wound healing and transwell migration assays and xenograft experiments. The targeting relationship of circ-36683/miR-4664-3p/CDK2AP2 was assessed by luciferase reporter assays, western blot, qRT-PCR and argonaute2-RNA immunoprecipitation (AGO2 RIP). Co-immunoprecipitation (Co-IP), 5-ethynyl-2'-deoxyuridine (EdU) staining and CCK-8 were used to validate the indispensable role of CDK2AP2 in suppressing cell proliferation as a result of CDK2AP1 overexpression. RESULTS: By RNA sequencing, miR-4664-3p was screened out as an abnormally elevated miRNA in NSCLC tissues. Transfection of miR-4664-3p could promote cell proliferation, migration and xenograft tumor growth. As a target of miR-4664-3p, CDK2AP2 expression was downregulated by miR-4664-3p transfection and CDK2AP2 overexpression could abolish the proliferation promotion resulting from miR-4664-3p elevation. Circ-36683, derived from back splicing of ABHD2 pre-mRNA, was attenuated in NSCLC tissue and identified as a sponge of miR-4664-3p. The functional study revealed that circ-36683 overexpression suppressed cell proliferation, migration and resulted in G0/G1 phase arrest. More importantly, the antioncogenic function of circ-36683 was largely dependent on the miR-4664-3p/CDK2AP2 axis, through which circ-36683 could upregulate the expression of p53/p21/p27 and downregulate the expression of CDK2/cyclin E1. CONCLUSION: The present study revealed the antioncogenic role of circ-36683 in suppressing cell proliferation and migration and highlighted that targeting the circ-36683/miR-4664-3p/CDK2AP2 axis is a promising strategy for the intervention of NSCLC.