alpha 1,3 Fucosyltransferase-VII modifies the susceptibility of apoptosis induced by ultraviolet and retinoic acid in human hepatocarcinoma cells

摘要

The role of alpha 1,3fucosyltransferase-VII (alpha 1,3 FucT-VII) in cell apoptosis was studied in human hepatocellular carcinoma H7721 cells. After the cells were transfected with alpha 1,3 FucT-VII cDNA, the expression of apoptotic protease, procaspase-3, was decreased, while the anti-apoptotic proteins, phospho-PKB and phospho-Bad were increased as compared with mock (vector) transfected cells, indicating that alpha 1,3FucT-VII is a potential anti-apoptotic factor in H7721 cells. After "alpha 1,3FucT-VII" cells were irradiated by UV to induce apoptosis, the anti-apoptotic potential of alpha 1,3FucT-VII became more apparent, as evidenced by the less apoptotic cell % and active cleaved caspase-3, more phospho-p38 MAPK and JNK (two anti-apoptotic signaling molecules in H7721 cells responsible to UV stress) when compared with the "Mock" cells. In contrast, "alpha 1,3FucT-VII" cells facilitated the apoptosis induced by all-trans retinoic acid (ATRA), which was verified by the greater sub-G1 (apoptotic cells) peak in flow cytometry analysis, more expressions of active caspase-3 and pro-apoptotic protein Bax, as well as less expressions of anti-apoptotic proteins, Bcl-2 and Bcl-X-L. The up regulation of alpha 1,3FucT-VII mRNA and cell surface SLe(x)(alpha 1,3FucT-VII product) by UV and down regulation of them by ATRA was speculated to be one of the mechanisms that alpha 1,3FucT-VII decreased and increased the susceptibility of apoptosis induced by UV and ATRA respectively.