Objective:To investigate the effect of lncRNA AC132217.4 on the proliferation and invasion of liver cancer MHCC97-H cells and its molecular mechanism.Methods:The TCGA database was used to analyze the differential expression of AC132217.4 in liver cancer tissue and adjacent tissue, and to analyze the relationship between the expression level of AC132217.4 and the overall survival of liver cancer patients. Transfection of pcDNA-AC132217.4 plasmid into MHCC97-H cells was defined as AC132217.4 group, transfection of pcDNA plasmid into MHCC97-H cells was defined as negative control (NC) group, respectively. The proliferation and invasion ability of MHCC97-H cells were detected by MTT method and Matrigel invasion assay. The binding site between AC132217.4 and miR-18a-5p was analyzed by starBase v2.0 software and dual luciferase reporter gene assay. Real-time quantitative PCR (RT-qPCR) detected the differential expression of miR-18a-5p in the two groups of MHCC97-H cells. The expression of epithelial-mesenchymal transition protein was detected by Western-blotting. Measurement data with normal distribution were expressed as mean±standard deviation ( ± s), and t-test was used for comparison between the two groups. Results:Compared with adjacent tissues, the expression of AC132217.4 was down-regulated in liver cancer tissues ( P<0.01). Compared with liver cancer patients with low expression of AC132217.4, the overall survival of liver cancer patients with high AC132217.4 expression was longer ( P<0.05). The pcDNA-AC132217.4 plasmid significantly inhibited the proliferation of MHCC97-H cells ( P<0.05). The number of invasive cells in the NC group and AC132217.4 group were (131.30±12.55) and (37.45±7.77), respectively. The pcDNA-AC132217.4 plasmid significantly inhibited the invasive ability of MHCC97-H cells ( t=6.36, P<0.01). AC132217.4 directly complemented miR-18a-5p ( P<0.01). The expression of miR-18a-5p in MHCC97-H cells in AC132217.4 group (1.04±0.30) was significantly lower than that in NC group (6.13±0.75) ( t=6.27, P<0.01). Compared with the NC group, the expressions of epithelial phenotype proteins Cytokeratin and Claudin-1 in MHCC97-H cells in AC132217.4 group were up-regulated, while the expressions of mesenchymal phenotype proteins Vimentin, Slug and Snail were down-regulated. Conclusions:The expression of AC132217.4 is low in liver cancer tissue, and it is related to the overall survival of liver cancer patients. AC132217.4 might inhibit the proliferation and invasion of liver cancer MHCC97-H cells by sponge miR-18a-5p.

Objective To investigate the expression of miR-6768-5p in lung cancer tissue and its effect on the proliferation and invasion of lung cancer cells through targeted regulation of carboxypeptidase A4(CPA4).Methods The expression of miR-6768-5p in lung cancer tissues and adjacent tissues was analyzed u-sing the TCGA database.Quantitative real-time PCR(qPCR)was used to detect the expression of miR-6768-5p in human lung cancer cell lines(HCC1588,H1650,H1299,A549,HCC827)and normal alveolar epithelial cells(HPAEpiC cells).Lung cancer cells were transfected with NC mimics and miR-6768-5p mimics,respec-tively,and divided into NC group and miR-6768-5p group.The MTS assay and Matrigel invasion assay were used to detect the cell proliferation and invasion ability of each group,respectively.The putative binding sites of miR-6768-5p and CPA4 were verified using RNAhybrid software and dual-luciferase reporter gene experi-ment.The expression of CPA4 mRNA in each group of cells was detected by qPCR.The expression of AKT/c-MYC signaling pathway proteins in the cells of each group was analyzed by Western blot.Results Com-pared with the adjacent tissues,the relative expression level of miR-6768-5p in lung cancer tissues was signifi-cantly decreased,and the difference was statistically significant(P＜0.05).Compared with HPAEpiC cells,the relative expression level of miR-6768-5p was significantly decreased in lung cancer cell lines,and the differ-ence was statistically significant(P＜0.05).Compared with the NC group,the cell proliferation rate of miR-6768-5p group was significantly decreased(P＜0.05).The number of invasive cells in NC group and miR-6768-5p group was(131.30±12.55)and(37.45±7.77),respectively,and the number of invasive cells in miR-6768-5p group was significantly lower than that in NC group(P＜0.05).The relative expression level of CPA4 mRNA in H1299 cells of miR-6768-5p group was significantly lower than that in NC group(t=4.93,P＜0.05).Compared with the NC group,the expressions of AKT/c-myC signaling pathway proteins p-AKT,p-mTORC1,XIAP,MDM2 and C-myC proteins in miR-6768-5p group were significantly decreased.Conclusion The expression of miR-6768-5p is decreased in lung cancer tissues,and miR-6768-5p may inhibit the activation of AKT/c-MYC signaling pathway by targeting CPA4,and reduce the proliferation and invasion ability of lung cancer H1299 cells.