Objective  To investigate the expression of miR-508-3p in lung cancer tissues, explore the effects of proliferation activity, invasion ability and apoptosis rate and mechanisms.

  Methods  Quantitative polymerase chain reaction (qPCR) and western blotting were used to detect the expressions of miR-508-3p and paired box gene 2(PAX2) in lung cancer tissues, and the correlation between them was analyzed. miR-508-3p mimics (miR-508-3p group), mimic negative control miR-NC (miR-NC group), PAX2 siRNA si- PAX2 (si- PAX2 group), siRNA negative control (si-NC group), miR-508-3p inhibitor anti-miR-508-3p (anti-miR-508-3p group), inhibitor negative control anti-miR-NC (anti-miR-NC group), co-transfected miR-508-3p and PAX2 overexpression plasmid pcDNA- PAX2 (miR-508-3p+pcDNA- PAX2 group), co-transfected miR-508-3p and blank plasmid pcDNA-NC (miR-508-3p+pcDNA-NC group) were transfected into lung cancer A549 cells and blank (NC) group was established. Methyl tetrazolium (MTT) assay was used to detect cell proliferation activity in 24 to 72 h; transwell chamber and flow cytometry were used to detect cell invasion ability and apoptosis rate, western blotting was used to detect A549 cell invasion-related matrix metalloproteinase-2 (MMP-2) and apoptosis-related B lymphocytoma-2(Bcl-2) and Bcl-2 associated X protein(Bax). The dual luciferase activity was used to evaluate the actions of targeted regulation of PAX2 by miR-508-3p.

  Results  The expression of miR-508-3p in lung cancer tissue was lower than that in adjacent tissues, and the expression of PAX2 mRNA and PAX2 protein was significantly higher than that in adjacent tissues (P < 0.05). The expression of PAX2 protein and miR-508-3p was negatively correlated (P < 0.05). Compared with the blank group, the expression of Bax and apoptosis rate of the miR-508-3p group were increased, and the expressions of MMP-2 and Bcl-2 proteins, proliferation activity and invasion ability were decreased (P < 0.05). Compared with si-NC group, the expressions of PAX2, MMP-2 and Bcl-2 in the si- PAX2 group were decreased, the expression of Bax and apoptosis rate were increased, and the proliferation activity and invasion ability were decreased (P < 0.05). MiR-508-3p targeted PAX2 and regulated the expression of PAX2. PAX2 could reverse the effects of miR-508-3p on the proliferation, invasion and apoptosis of A549 cells.

  Conclusion  MiR-508-3p is under-expressed in lung cancer tissues, its overexpression can reduce the proliferation and invasion of A549 cells and induce cell apoptosis. The mechanism is related to the targeted regulation of PAX2 gene.