Redox regulation of PI3K/Akt and p53 in bovine aortic endothelial cells exposed to hydrogen peroxide.
To clarify the apoptotic and survival signal transduction pathways in activated vascular endothelial cells exposed to oxidative stress, the effects of inhibitors of signal transduction on hydrogen peroxide (H(2)O(2))-induced apoptosis in bovine aortic vascular endothelial cells (BAEC) were examined. Treatment of BAEC with 1 mM H(2)O(2) caused increases of DNA fragmentation, p53 expression, Bax/Bcl-2 ratio, and the activities of caspases 3 and 9. The increases of DNA fragmentation, Bax/Bcl-2 ratio, and caspase activities were abrogated by BAPTA-AM (an intracellular Ca(2+) chelator) and N-acetyl-L-cysteine (an antioxidant), and augmented by wortmannin [a phosphatidylinositol 3-kinase (PI3K) inhibitor]. The increase of the intracellular Ca(2+) concentration ([Ca(2+)](i)) observed in H(2)O(2)-stimulated cells was unaffected by wortmannin, suggesting that the potentiating effect of wortmannin on the apoptosis was not due to an alteration of [Ca(2+)](i). H(2)O(2) increased the levels of PI3K activity and Akt phosphorylation. Both were attenuated by wortmannin and, to a lesser extent, by genistein (a tyrosine kinase inhibitor) and suramin (a growth factor receptor inhibitor), but not affected by BAPTA-AM. These results suggest that H(2)O(2) induces Ca(2+)-dependent apoptosis and Ca(2+)-independent survival signals such as redox-regulated activation of PI3K/Akt, which is partly mediated by the activation of growth factor receptors in BAEC.
Laboratory of Biofluid Dynamics, Research Institute for Electronic Science, Hokkaido University, Sapporo 060-0812, Japan.
Koichi
K
Niwa
Osamu
O
Inanami
Tohru
T
Yamamori
Toshio
T
Ohta
Taku
T
Hamasu
Mikinori
M
Kuwabara
D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D001011:Aorta / Q000166:cytology*; D017209:Apoptosis; D002118:Calcium / Q000378:metabolism; D053148:Caspase 3; D053453:Caspase 9; D020169:Caspases / Q000378:metabolism; D002417:Cattle; D002478:Cells, Cultured; D002614:Chelating Agents / Q000494:pharmacology; D003553:Cystine / Q000031:analogs & derivatives* / Q000494:pharmacology; D053938:DNA Fragmentation; D004305:Dose-Response Relationship, Drug; D004533:Egtazic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000166:cytology*; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005786:Gene Expression Regulation; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D015151:Immunoblotting; D008954:Models, Biological; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D019869:Phosphatidylinositol 3-Kinases / Q000096:biosynthesis*; D017346:Protein Serine-Threonine Kinases / Q000096:biosynthesis*; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D015398:Signal Transduction; D013997:Time Factors; D016159:Tumor Suppressor Protein p53 / Q000096:biosynthesis*; D000077191:Wortmannin; D051028:bcl-2-Associated X Protein
D000730:Androstadienes; D000975:Antioxidants; D002118:Calcium; D053148:Caspase 3; D053453:Caspase 9; D020169:Caspases; D002614:Chelating Agents; D003553:Cystine; D004533:Egtazic Acid; D004791:Enzyme Inhibitors; D006861:Hydrogen Peroxide; D019869:Phosphatidylinositol 3-Kinases; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53; D000077191:Wortmannin; D051028:bcl-2-Associated X Protein; C070379:1,2-bis(2-aminophenoxy)ethane N,N,N',N'-tetraacetic acid acetoxymethyl ester; C030905:N-monoacetylcystine