lncRNA TTN-AS1 regulates the viability and invasion of lung adenocarcinoma A549 cell via miR-519d-3p/MMP2 pathway

AIM To investigate the expression level of long noncoding RNA （lncRNA） TTN antisense RNA 1 （TTN-AS1） in lung adenocarcinoma tissues and the effects of TTN-AS1 silencing on the viability and invasion of lung adenocarcinoma A549 cells. METHODS RT-qPCR was used to detect the expression of TTN-AS1， microRNA-519d-3p （miR-519d-3p） and matrix metalloproteinase 2 （MMP2） mRNA in 32 cases of lung adenocarcinoma and adjacent normal tissues. The untransfected A549 cells were divided into blank group， si-NC group （with si-NC transfection） and si-lncRNA group （with silencing of lncRNA TTN-AS1 expression）， with n=5 in each group. The effects of TTN-AS1 silencing on the viability and invasion of A549 cells were detected by CCK8 and Transwell methods. The targeting regulatory effects of TTN-AS1 on miR-519d-3p and miR-519d-3p on MMP2 were determined by dual-luciferase reporter assay， RNA immunoprecipitation test， RT-qPCR and Western blot. RESULTS The expression level of TTN-AS1 in 32 cases of lung adenocarcinoma tissues is notably higher than that in the adjacent normal tissues （P<0.05）. Silencing of TTN-AS1 in A549 cells significantly suppressed the cell viability and invasion. TTN-AS1 negatively regulated the expression of miR-519d-3p via sponging and absorbing miR-519d-3p. MMP2 is the target gene of miR-519d-3p and can be negatively regulated by miR-519d-3p. Overexpression of MMP2 partially reversed the inhibitory effect of TTN-AS1 silencing and miR-519d-3p overexpression on the invasion of A549 cells. CONCLUSION The lncRNA TTN-AS1 is overexpressed in lung adenocarcinoma tissues， and it regulates lung adenocarcinoma A549 cell viability and invasion via miR-519d-3p/MMP2 pathway.