circFADS2 regulates lung cancer cells proliferation and invasion via acting as a sponge of miR-498

Abstract
CircRNAs could play critical functions in tumor progression. However, the expression and underlying mechanism of circRNAs in lung cancer progression remain poorly defined. In the present study, high-throughput microarray assay revealed that hsa-circRNA-100833 (identified as circFADS2) was markedly evaluated in lung cancer tissues, and it was further validated by ciRT-PCR. High expression of circFADS2 was correlated with advanced TNM stage, lymph node metastasis, poor differentiation, and shorter overall survival of NSCLC patients. In vitro assays results showed that circFADS2 inhibition suppressed lung cancer cells proliferation and invasion ability. Bioinformatics analysis showed that miR-498 contained the complementary binding region of circFADS2, which was confirmed by Dual-luciferase reporter assay. In addition, the expression of miR-498 was down-regulated and negatively associated with circFADS2 expression in nonsmall cell lung cancer. Furthermore, rescue assays showed that miR-498 inhibitors abolished the effects of circFADS2 inhibition on lung cancer cells progression. Taken together, our findings indicated that circFADS2 was an effective tumor promoter in lung cancer progression, and its functions were performed by regulating the expression of miR-498. These data suggested that circFADS2 could act as a target for lung cancer treatment.