Study on the mechanism of long non-coding RNA migration inhibitory factor antisense RNA1 in regulating proliferation, invasion and metastasis of non-small cell lung cancer

Objective To explore the molecular mechanism by which long non-coding RNA (lncRNA) migration inhibitory factor antisense RNA1 (MIF-AS1)/microRNA (miRNAM miR)-370-3p/mitogen activated protein kinase 9 (MAP3K9) molecular axis regulates proliferation, invasion and migration of non-small cell lung cancer (NSCLC). Methods Twenty cancer samples of NSCLC patients were collected from Henan Provincial People’s Hospital from May 2017 to January 2019. There were 12 males and 8 females, aged (52.37±10.34) years. Real-time quantitative reverse transcriptase-polymerase chain reaction (RT-qPCR) and Western blotting were used to detect the expression levels of MIF-AS1, miR-370-3p and MAP3K9 in cancer tissues and 9 cell lines. NSCLC A549 cells were transfected with si-MIF-AS1, si-NC, si-MIF-AS1+ anti-miR-370-3p or si-MIF-AS1+ pcDNA-MAP3K9, respectively. Methyl thiazol tetrazolium (MTT) assay and Transwell assay were used to detect the proliferation, migration and invasion of transfected cells. Western blotting was used to detect the expression of Cyclin D1, p21, p27, matrix metalloproteinase (MMP)-2, MMP-9 and MMP-14 proteins. The dual luciferase reporter gene verified the targeting regulation of MIF-AS1 on miR-370-3p and miR-370-3p on MAP3K9. Results The expression of MIF-AS1 and MAP3K9 in NSCLC tissues (2.49±0.25 and 2.24±0.22) and A549 cells (2.54±0.24 and 2.31±0.23), H1299 cells (2.11±0.21 and 2.44±0.24) and PC-9 cells (2.26±0.23 and 2.16±0.22) was significantly higher than that in adjacent tissues (1.00±0.09 and 1.02±0.09) and normal lung epithelial cells BEAS-2B (1.01±0.09 and 1.00±0.09) (t=25.078, P<0.05; F=94.367, P<0.05). The expression of miR-370-3p in NSCLC tissues (0.42±0.04), A549 cells (0.34±0.03), H1299 cells (0.53±0.05), and PC-9 cells (0.44±0.04) was significantly lower than that in adjacent tissues (1.01±0.08) and BEAS-2B cells (1.00±0.08) (t=29.500, P<0.05; F=269.552, P<0.05). Transfection with si-MIF-AS1 significantly inhibited NSCLC cell proliferation (24 h: 0.27±0.03, 48 h: 0.36±0.03, 72 h: 0.48±0.04), invasion (24.33±3.14), migration (32.46±3.34) ability (P<0.01), up-regulated p21 (0.64±0.06), p27 (0.77±0.07) protein expression (t=17.441, P<0.05; t=17.726, P<0.05) and down-regulated Cyclin D1 (0.29±0.03), MMP-2 (0.25±0.03), MMP-9 (0.34±0.03) and MMP-14 (0.29±0.03) protein expression (t=17.732, P<0.05). The dual luciferase reporter gene confirmed that MIF-AS1 was bond to miR-370-3p and miR-370-3p was bond to MAP3K9. Transfection with si-MIF-AS1+ anti-miR-370-3p or si-MIF-AS1+ pcDNA-MAP3K9 inhibited the effects of si-MIF-AS1 on proliferation, invasion and migration of NSCLC cells. Conclusion LncRNA MIF-AS1 promotes proliferation, migration and invasion of NSCLCs by regulating miR-370-3p/MAP3K9 molecular axis. Key words: Non-small cell lung cancer; Long non-coding RNA migration inhibitory factor antisense RNA1; MicroRNA-370-3p; Mitogen activated protein kinase 9; Proliferation; Migration; Invasion