Overexpression of GD3 synthase induces apoptosis of vascular endothelial ECV304 cells through downregulation of Bcl-2.
The disialoganglioside GD3 plays a major role in proliferation, differentiation, and apoptosis. It has been reported that ganglioside GD3 can induce apoptosis through bcl-2 mediated mitochondrial pathway. However, the relationship between ganglioside GD3 and B-cell/CLL lymphoma 2 (Bcl-2) is not fully understood. In this study, we have demonstrated that the downregulation of Bcl-2 by overexpression of CMP-NeuAc:GM3 alpha-2,8-sialyltransferase (GD3 synthase) results in an accelerated apoptosis in vascular endothelial cells (ECV304), as evidenced by DNA fragmentation and caspase-3 activation. In addition, phosphorylation of AKT and cyclic-AMP responsive element binding protein (CREB) was reduced by GD3 synthase overexpression. Moreover, the activation of CREB as a transcriptional factor was also inhibited, as evidenced by electrophoretic mobility shift assay. Therefore, we conclude that GD3 synthase has an apoptotic effect on ECV304 cells through downregulation of Bcl-2 expression via dephosphorylation of AKT and CREB.
Ha
Ki-Tae
KT
National Research Laboratory for Glycobiology, MOST and Department of Biochemistry and Molecular Biology, College of Oriental Medicine, Dongguk University, Kyungju City, Kyungbuk 780-714, South Korea.
Lee
Young-Choon
YC
Kim
Cheorl-Ho
CH
D017209:Apoptosis; D015153:Blotting, Western; D002461:Cell Line, Transformed; D017362:Cyclic AMP Response Element-Binding Protein / Q000037:antagonists & inhibitors / Q000378:metabolism; D015536:Down-Regulation; D024202:Electrophoretic Mobility Shift Assay; D004730:Endothelium, Vascular / Q000166:cytology / Q000201:enzymology*; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism*; D012799:Sialyltransferases / Q000378:metabolism*
D017362:Cyclic AMP Response Element-Binding Protein; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D012799:Sialyltransferases; C043662:alpha-N-acetylneuraminate alpha-2,8-sialyltransferase; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt