Objective To investigate the moderating effect and mechanism of gene expression of ring finger protein 44 (RNF44) on proliferation and apoptosis of gastric cancer cells.
Methods The gene and protein expressions of RNF44 in gastric cancer cell lines and normal gastric mucosa cells were detected; the gastric cancer MKN45 cell lines and AGS cell lines were transfected with shRNF44 virus and oeRNF44 virus respectively, and the gene and protein expressions of RNF44, conditions of cell proliferation and cell apoptosis, the protein expressions of protein kinase B (AKT) and phosphorylated protein kinase B (p-AKT) were determined; the effect of AKT pathway inhibitor LYS294002 on the proliferation, apoptosis and AKT signaling protein of RNF44 gene overexpression cells was determined; the tumor growth, Ki-67 expression, AKT and p-AKT protein expression were determined in nude mouse subcutaneous tumor model constructed by MKN45 cell line.
Results The gene and protein expression levels of RNF44 were the lowest in normal gastric mucosal GES-1 cells and the highest in gastric cancer MKN45 cell line. After transfected with lentivirus of RNF44 gene interference, the gene and protein expressions of RNF44 in MKN45 cell line decreased significantly, the cell proliferation ability decreased significantly, the apoptotic rate at early and late stages increased significantly, and the protein expressions of RNF44 and p-AKT decreased significantly (P < 0.05). After transfected with lentivirus of RNF44 gene overexpression, the gene and protein expression levels of RNF44 increased significantly in AGS cell line, the cell proliferation ability increased significantly, the apoptotic rate at early and late stages decreased significantly, and the protein expression levels of RNF44 and p-AKT increased significantly (P < 0.05). AKT inhibitors were able to reduce the proliferation ability of normal AGS cells or AGS cell lines with overexpression of the RNF44 gene, increase the apoptotic rate at early and late stages, and reduce the protein expression level of p-AKT. In the shRNF44 group, the size and mass of tumor tissues of nude mice were significantly lower than those in the shNC group, the expression of Ki-67 was significantly lower than that in the shNC group, and the protein expressions of RNF44 and p-AKT in tumor tissues were significantly lower than those in the shNC group (P < 0.05).
Conclusion The expression level of RNF44 gene has a moderating effect on the proliferation and apoptosis of gastric cancer cells. Overexpression of RNF44 can significantly inhibit tumor cell proliferation and promote apoptosis, while low expression of RNF44 can significantly promote tumor cell proliferation and inhibit apoptosis. RNF44 may play a moderating role by regulating the expression of p-AKT protein.
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