miR-181a-3p inhibits malignant biological behavior of non-small cell lung cancer via down-regulating RAD21 expression

Abstract

Lung cancer is one of the most common malignant tumors in the world, and it has become the first cause of death from malignant tumors in the Chinese urban population. Non-small cell lung cancer (NSCLC) is one of the main types, accounting for about 80% of all lung cancers. MicroRNA (miRNA) is a non-coding RNA with a length of about 22 nt, which can block the translation process of the protein by targeted binding with mRNA at the post-transcriptional level. Cumulative studies have shown that a variety of miRNAs play an important role in the occurrence and development of NSCLC. This study first found through UALCAN and Starbase databases that miR-181a-3p expression was abnormally low in NSCLC, which indicates that patient have a poor survival rate. Consistent results were also detected in the clinical samples we collected. In addition, we found that RAD21 was a downstream target of miR-181a-3p, and RAD21 was significantly highly expressed in NSCLC clinical samples. In NSCLC, the expression level of miR-181a-3p and RAD21 showed a negative correlation. Furthermore, we used CCK-8 kit, Annexin V-FITC/PI kit, Transwell and Wound-Healing assay to explore the effect of miR-181a-3p/RAD21 molecular axis on the malignant biological behavior of A549 cells. The results showed that knocking-down RAD21 significantly inhibited A549 cell proliferation, invasion and wound healing and induced its apoptosis, while knocking-down miR-181a-3p would rescue biological behaviors of A549 cells. In summary, we found for the first time that miR-181a-3p inhibits the proliferation, invasion and migration of NSCLC cells and induces their apoptosis by inhibiting the expression level of RAD21. It is suggesting that the miR-181a-3p/RAD21 molecular axis can be used as a target for the diagnosis and treatment of NSCLC.