Circular RNA ATXN7 is upregulated in non-small cell lung cancer and promotes disease progression

Circular RNAs (circRNAs) are a class of endogenous non-coding RNAs that is generated from back-splicing, and is characterized by a covalent closed loop without 3' and 5' ends. Recently, the biological function of circRNAs has received increasing attention; however, studies on circRNAs in non-small cell lung cancer (NSCLC) have rarely been reported. In the present study, the expression profiles of circRNAs in NSCLC were investigated, and the association between the circular RNA ATXN7 (circATXN7) expression level and clinicopathological characteristics of patients with NSCLC was assessed. In addition, the effects of circATXN7 on cell proliferation and invasion were examined. The results revealed that circATXN7 was upregulated in 45 NSCLC tissues compared with its expression in non-tumor tissues. However, there was no marked difference between the expression level of circATXN7 and the majority of the examined clinicopathological characteristics. It was also observed that the survival time of patients with high circATXN7 levels was shorter compared with that of patients with low circATXN7 levels, although the difference was not statistically significant (P>0.05). Furthermore, silencing of circATXN7 by small interfering RNA inhibited the proliferation and invasion of NSCLC cells in vitro. Taken together, the present study was the first to identify that circATXN7 was upregulated in NSCLC tumor tissues. Furthermore, the downregulation of circATXN7 markedly inhibited the proliferation and invasion abilities of NSCLC cells.