Inhibitory effect of over-expression of Lin28A on glycosis in human gastric cancer cells and the underlying mechanism

Abstract

Objective To explore the effects of over-expression of Lin28A on glycolysis of gastric cancer cells and the underlying mechanism. Methods Human gastric cancer BGC-823 cells in vitro were stably transfected with lentivirus-mediated over-expression of Lin28A. Lactic acid levels of cell culture medium were detected with biochemical method, phosphofructose kinase(PFK) levels in cells with ELISA, the expression levels of Lin28A, hypoxia-inducible factor (HIF)-1α, glucose transporter (GLUT)-1, and pyruvate kinase M2 (PKM2) were detected using Western blotting, and let-7a RNA using reverse transcription-PCR. Annexin V-allophycocyanin (APC) staining method was used to assess cell apoptosis. Results Compared with the normal control(CON) group and the negative control(NC) group, Lin28A protein level in the over-expression (OE) group was significantly higher (both P<0.001). RNA expression level of let-7a was significantly lower in the OE group than in the NC group (0.602±0.017 vs. 1.001±0.063, P=0.005 2). The levels of the HIF-1α, GLUT-1, PKM2 proteins were all significantly lower in the OE group than in the CON and the NC groups (all P<0.001). The lactic acid levels of cell culture medium in the CON, the NC, and the OE groups were (1.71±0.13), (1.53±0.11), (1.24±0.04)mmol/L, which was significantly lower in the OE group than in the CON group and the NC group (P=0.017 0, 0.031 0). Intracellular PFK level in the OE group was also significantly lower than in the CON group and the NC group [(1.79±0.05)mmol/L vs. (3.71±0.13)mmol/L, P=0.014 0; (1.79±0.05)mmol/L vs. (3.49±0.14)mmol/L, P=0.036 0]. Apoptosis rates of the CON, the NC, and the OE groups were 5.02%±0.14%, 7.16%±0.21%, 10.39%±0.37%, respectively, which was significantly higher in the OE group than in the CON group and the NC group (P=0.000 5, 0.000 7). Conclusion Over-expression of Lin28A can inhibit the expression of let-7a, and induce apoptosis of human gastric cancer cells by suppressing glycolysis of the cells. Key words: Lin28A; Gastric cancer; Glycolysis; Apoptosis