Objective To investigate the effects of miR-15a-3p on the proliferation, apoptosis, migration and invasion of lung adenocarcinoma cells by regulating Twist basic helix-loop-helix transcription factor 1 (Twist1)/Jagged1/Notch/Kruppel-like factor 4 (KLF4) signaling pathway.

Methods The miR-15a-3p and Twist1 mRNA levels in lung adenocarcinoma tissues, adjacent tissues, lung adenocarcinoma cells lines (A549, HCC827) and human lung normal epithelial cells (BEAS-2B) were measured through RT-qPCR.A549 cells were divided into control group (untransfected), NC mimics group (transfected with NC mimics), miR-15a-3p mimics group (transfected with miR-15a-3p mimics), si-NC group (transfected with si-NC), si-Twist1 group (transfected with si-Twist1), miR-15a-3p mimics+pcDNA group (co-transfected with miR-15a-3p mimics and pcDNA), and miR-15a-3p mimics+pc-Twist1 group (co-transfected with miR-15a-3p mimics and pc-Twist1).Cell proliferation was measured using CCK-8 assay, apoptosis was measured through TUNEL apoptosis kit, cell migration and invasion abilities were evaluated by Transwell assay, the targeting relationship between miR-15a-3p and Twist1 was measured through dual luciferase reporter assay, and the protein expression levels of Twist1, Jagged1, Notch and KLF4 were examined by Western blotting.

Results In lung adenocarcinoma tissues and cell lines, miR-15a-3p expression was decreased, and Twist1 mRNA level was increased (P < 0.05).After A549 cells were transfected with miR-15a-3p mimics or si-Twist1 to up-regulate miR-15a-3p or down-regulate Twist1, the cell proliferation rates at 24 h, 48 h and 72 h were significantly decreased, and the ratio of TUNEL-positive cells was significantly increased, the numbers of cell migration and invasion were significantly decreased (P < 0.05).Twist1 was a downstream target gene of miR-15a-3p, and was directly negative-regulated by miR-15a-3p.Upregulation of Twist1 significantly reversed the inhibitory effect of miR-15a-3p overexpression on A549 cell progression.Overexpression of miR-15a-3p inhibited the expression of Jagged1, Notch, and KLF4, while the expression of Jagged1, Notch, and KLF4 were increased significantly after up-regulation of Twist1 (P < 0.05).

Conclusions MiR-15a-3p can target and inhibit the Twist1/Jagged1/Notch/KLF4 signaling pathway to reduce the proliferation, migration and invasion abilities and promote apoptosis of A549 cells.