Objective: Using the gastric cancer cell line SGC7901, we constructed a cell line that overexpressed octamer-binding protein 4 (Oct4) and SRY-box 2 (Sox2) to explore the stem cell oncological and biological characteristics of these cells and to elucidate the mechanisms of Oct4 and Sox2 in cancer.
Methods: A lentiviral vector containing the Sox2 gene was constructed and transfected into a gastric cancer cell line overexpressing Oct4 (SGC7901-Oct4) to obtain a stably transfected cell line (SGC7901-Oct4-Sox2). Oct4 and Sox2 expression was detected by RT-PCR and Western blotting. The proliferation, drug resistance, migration, and invasion abilities of the cells were assessed using in vitro (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium), drug resistance, scratch-wound migration, transwell migration, transwell invasion, and spherical clone formation assays, and their tumorigenic ability was assessed using a tumor formation experiment in mice.
Results: Compared with the control group, the expression of Oct4, Sox2, CD44, and E-cadherin was significantly higher in the group that overexpressed Oct4 and Sox2, while the expression of c-Myc and Klf4 did not significantly change. The proliferation, drug resistance, migration, and invasion abilities were significantly enhanced in the overexpression group, and the tumorigenic ability in mice was also significantly enhanced, with significantly increased tumor size and weight.
Conclusion: The proliferation, drug resistance, migration, invasion, and tumorigenic abilities of SGC7901 cells overexpressing Oct4 and Sox2 were significantly improved. Oct4 and Sox2 play important roles in the proliferation, migration, invasion, and tumorigenicity of gastric cancer cells, and the two genes may be synergistic to a certain degree.
Keywords: stomach cancer SGC7901, Oct4, Sox2, stem cells