Long noncoding RNA HOXA-AS2 promotes non-small cell lung cancer progression by regulating miR-520a-3p

The HOXA cluster antisense RNA 2 (HOXA-AS2) has recently been discovered to be involved in carcinogenesis in multiple cancers. However, the role and underlying mechanism of HOXA-AS2 in non-small cell lung cancer (NSCLC) yet need to be unraveled. HOXA-AS2 expression in NSCLC tissues and cell lines was detected using quantitative real-time PCR (qRT-PCR). Furthermore, the effects of HOXA-AS2 on NSCLC cell proliferation, apoptosis, migration, and invasion were assessed by MTS, flow cytometry, wound healing and transwell invasion assays, respectively. Starbase2.0 predicted and luciferase reporter and RNA immunoprecipitation (RIP) assays were used to validate the association of HOXA-AS2 and miR-520a-3p in NSCLC cells. Our results revealed that HOXA-AS2 in NSCLC tissues were up-regulated and cell lines, and were associated with poor prognosis and overall survival. Further functional assays demonstrated that HOXA-AS2 knockdown significantly inhibited NSCLC cell proliferation, induced cell apoptosis and suppressed migration and invasion. Starbase2.0 predicted that HOXA-AS2 sponge miR-520a-3p at 3'-UTR, which was confirmed using luciferase reporter and RIP assays. miR-520a-3p expression was inversely correlated with HOXA-AS2 expression in NSCLC tissues. In addition, miR-520a-3p inhibitor attenuated the inhibitory effect of HOXD-AS2-depletion on cell proliferation, migration and invasion of NSCLC cells. Moreover, HOXA-AS2 could regulate HOXD8 and MAP3K2 expression, two known targets of miR-520a-3p in NSCLC. These findings implied that HOXA-AS2 promoted NSCLC progression by regulating miR-520a-3p, suggesting that HOXA-AS2 could serve as a therapeutic target for NSCLC.