Abstract: Objective To investigate the effect of miR⁃93⁃5p targeting protein kinase membrane associated tyrosine/threonine 1 (PKMYT1) on the proliferation, migration and invasion of lung adenocarcinoma cells and its mechanism. Methods Plasmids inhibitor NC, miR⁃93⁃5p inhibitor, pcDNA, and pc⁃PKMYT1 were transfected into A549 cells by using LipofectamineTM 2000 and recorded as inhibitor NC group, miR⁃93⁃5p inhibitor group, pcDNA group, and pc⁃PKMYT1 group, respectively, while the untransfected cells were recorded as the control group. The expression level of miR⁃93⁃5p and PKMYT1 mRNA were detected by qRT⁃PCR. The targeting relationship between miR⁃93⁃5p and PKMYT1 was verified by using the double luciferase reporter gene assay. The cell proliferation ability was detected by CCK⁃8; the cell cycle was measured by the flow cytometry; the cell migration and invasion were detected by Transwell assay; and the expression levels of PKMYT1, Cyclin D1 and Cyclin B1 were detected by Western blot. Results Compared with BEAS⁃2B cells, the expression levels of miR⁃93⁃5p were increased in SPC⁃A⁃1 cells, A549 cells and LTEP⁃α⁃2 cells (all P<0.01), while the expressions of PKMYT1 mRNA and protein were decreased (all P<0.001). After 24 h transfection, compared with those of the control group and the inhibitor NC group, the proliferative activity of A549 cells, the proportion of S phase cells, the numbers of migrating cells, the numbers of invading cells and the protein levels of Cyclin D1 and Cyclin B1 in the miR⁃93⁃5p inhibitor group were decreased (all P<0.05), while the proportion of G2/M phase cells was increased (P<0.001). Double luciferase report gene assay showed that compared with the miR⁃93⁃5p NC+ 3'UTR⁃WT group, the relative activity of luciferase in the miR⁃93⁃5p mimic + 3'UTR⁃WT group was decreased (P<0.001). After 24 h transfection, compared with the pcDNA group, the proliferative activity of A549 cells, the proportion of S phase cells, the number of migrating cells, the number of invading cells and the protein levels of Cyclin D1 and Cyclin B1 in the pc⁃PKMYT1 group were decreased (all P<0.001), while the proportion of G2/M phase cells was increased (P<0.001). Conclusions Silence of miR⁃93⁃5p may inhibit the proliferation, migration and invasion of lung adenocarcinoma cells by up⁃regulating the PKMYT1 expression.

Key words: Lung adenocarcinoma, miR?93?5p, Protein kinase membrane associated tyrosine/threonine 1, Proliferation, Migration, Invasion