Epigallocatechin-3-gallate enhances ischemia/reperfusion-induced apoptosis in human umbilical vein endothelial cells via AKT and MAPK pathways.
Epigallocatechin-3-gallate (EGCG), the major constituent of green tea, has been shown to promote apoptosis in cancer cells. However, the role of EGCG in endothelial cells following ischemia/reperfusion (I/R) injury remains unclear. In the present study, we investigated the mechanisms by which EGCG enhances I/R-induced cell growth inhibition and apoptosis in human umbilical vein endothelial cells (HUVECs). Our results showed that EGCG treatment caused cell proliferation inhibition during I/R injury, and this effect was associated with increased p27 and p21 levels and reduced cyclin D1 level. Moreover, treatment of cells with EGCG resulted in increase of caspase-3 and Bax and decrease of Bcl-2, enhancing I/R-induced apoptosis. Interestingly, EGCG decreased I/R-induced phosphorylation of AKT and its downstream substrates Foxo1 and Foxo3a and ERK1/2. In contrast, EGCG increased JNK1/2 and c-Jun phosphorylation. Furthermore, both wortamannin (PI3K inhibitor) and U0126 (MEK1/2 inhibitor) markedly enhanced EGCG-induced apoptosis during I/R, whereas SP600125 (JNK inhibitor) attenuated the action of EGCG. Taken together, our study for the first time suggest that EGCG is able to enhance growth arrest and apoptosis of HUVECs during I/R injury, at least in part, through inhibition of AKT and ERK1/2 and activation of JNK1/2 signaling pathways.
Zhang
Tianpeng
T
Department of Pathology, Chinese Academy of Medical Sciences, 100005, Beijing, China.
Yang
Dan
D
Fan
Yongna
Y
Xie
Ping
P
Li
Huihua
H
D017209:Apoptosis / Q000187:drug effects*; D002392:Catechin / Q000031:analogs & derivatives* / Q000494:pharmacology; D018797:Cell Cycle Proteins / Q000378:metabolism; D049109:Cell Proliferation / Q000187:drug effects; D042783:Endothelial Cells / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D004789:Enzyme Activation / Q000187:drug effects; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D000071161:Forkhead Box Protein O1; D000071316:Forkhead Box Protein O3; D051858:Forkhead Transcription Factors / Q000378:metabolism; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000187:drug effects; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D051057:Proto-Oncogene Proteins c-akt / Q000037:antagonists & inhibitors / Q000378:metabolism*; D015427:Reperfusion Injury / Q000201:enzymology* / Q000473:pathology; D014471:Umbilical Veins / Q000166:cytology*; D051028:bcl-2-Associated X Protein / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
D018797:Cell Cycle Proteins; C085126:FOXO1 protein, human; C499517:FOXO3 protein, human; D000071161:Forkhead Box Protein O1; D000071316:Forkhead Box Protein O3; D051858:Forkhead Transcription Factors; D051028:bcl-2-Associated X Protein; D002392:Catechin; C045651:epigallocatechin gallate; D051057:Proto-Oncogene Proteins c-akt; D048049:Extracellular Signal-Regulated MAP Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases