Autocrinism of vascular endothelial growth factor in human hepatocellular carcinoma cell and its significance / 中国癌症杂志

ABSTRACT

Purpose: To explore the autocrinism of vascular endothelial growth factor ( VEGF) in human hepatocellular carcinoma cell and its significance. Methods: The expression of VEGF receptors was analyzed by reverse transcription-polymerase chain reaction (RT-PCR) in human hepatocellular carcinoma cell lines SMMC7721, HHCC and HepG2 in vitro. The expression of VEGF in human hepatocellular carcinoma cells was inhibited by synthetic antisense oligodeoxynucleotide (ODN). Phenotypic alterations in human hepatocellular carcinoma cells by antisense reduction of VEGF expression were observed. And the alterations for expression of VEGF receptors in human hepatocellular carcinoma cell membranes were analyzed by flow cytometry. Results: Flt-1 was expressed faintly in SMMC-7721 cell whereas KDR was expressed in HHCC cell and HepG2 cell in vitro. Compared to control, antisense ODN against VEGF inhibited HHCC cell proliferation in vitro in a dose-dependent manner and had no effects on SMMC-7721 cell and L929 cell. When the concentration of antisense ODN was 2.5 ?mol/L,5 ?mol/L and 10 ?mol/L, the proliferation of HHCC cell was inhibited by 26%, 41 % , and 50% respectively. Compared with control, flow cytometry analysis showed a decrease in cell number in S phase and a pre-apoptosis peak in HHCC cell treated by antisense ODN. There was no alteration of cell cycle in SMMC-7721 cell. The positive rate of KDR expression in HHCC cell membrane was 19. 2%, 29. 8% and 31. 2% in the antisense ODN, sense ODN and control groups, respectively. The expression of KDR in HHCC cell membrane was markedly inhibited by antisense ODN against VEGF compared with the control group, as measured by flow cytometry. There was no alteration for expression of Flt-1 in SMMC-7721 cell membrane. Conclusions: VEGF produced by human hepatocellular carcinoma cells acts directly upon human hepatocellular carcinoma in an autocrinal manner and may promote the proliferation and differentiation of human hepatocellular carcinoma cells via the activation of the KDR-dependent signaling pathway.