Activation of extracellular signal-regulated kinase and c-Jun-NH(2)-terminal kinase but not p38 mitogen-activated protein kinases is required for RRR-alpha-tocopheryl succinate-induced apoptosis of human breast cancer cells.
RRR-alpha-tocopherol succinate (vitamin E succinate, VES) is a potent, selective apoptotic agent for cancer cells but not normal cells. VES has been shown to inhibit the growth of a wide variety of tumor cells in cell culture and animal models. Studies addressing mechanisms of action of VES-induced apoptosis have identified transforming growth factor-beta, Fas/CD95-APO-1, and mitogen-activated protein kinase (MAPK) signaling pathway involvement. Here we show that MAPKs, the extracellular signal-regulated kinases (ERK), and the stress-activated protein kinases, c-Jun NH2-terminal kinases (JNK), but not p38, are critical mediators in VES-induced apoptosis of human breast cancer MDA-MB-435 cells. VES activates ERK1/2 and JNK both in level and duration of kinase activity. Expression of dominant negative mutants of ERK1, MAPK/ERK activator-1, or JNK1 but not p38 blocked phosphorylation of the substrate glutathione S-transferase-c-Jun and inhibited VES-induced apoptosis. Increased phosphorylation and transactivation activity of nuclear transcription factors c-Jun, ATF-2, and Elk-1 are observed after VES treatments; however, only c-Jun and ATF-2 appear to be involved in VES-induced apoptosis based on antisense blockage experiments. Collectively, these results imply a critical role for ERK1 and JNK1 but not p38 in VES-induced apoptosis of human MDA-MB-435 breast cancer cells.
Yu
W
W
Division of Nutrition/A2703, University of Texas at Austin, 78712, USA.
Liao
Q Y
QY
Hantash
F M
FM
Sanders
B G
BG
Kline
K
K
D051698:Activating Transcription Factor 2; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D001943:Breast Neoplasms / Q000188:drug therapy / Q000201:enzymology* / Q000473:pathology; D017362:Cyclic AMP Response Element-Binding Protein / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins; D004789:Enzyme Activation; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases; D048670:MAP Kinase Kinase 4; D020935:MAP Kinase Signaling System / Q000187:drug effects; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020929:Mitogen-Activated Protein Kinase Kinases / Q000235:genetics / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D016376:Oligonucleotides, Antisense / Q000235:genetics / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism; D024505:Tocopherols; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D015533:Transcriptional Activation / Q000187:drug effects; D014407:Tumor Cells, Cultured; D014810:Vitamin E / Q000031:analogs & derivatives* / Q000494:pharmacology*; D050807:ets-Domain Protein Elk-1; D048051:p38 Mitogen-Activated Protein Kinases
C497105:ATF2 protein, human; D051698:Activating Transcription Factor 2; D017362:Cyclic AMP Response Element-Binding Protein; D004268:DNA-Binding Proteins; C494112:ELK1 protein, human; D016376:Oligonucleotides, Antisense; D011518:Proto-Oncogene Proteins; D014157:Transcription Factors; D050807:ets-Domain Protein Elk-1; D014810:Vitamin E; D048031:JNK Mitogen-Activated Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D048670:MAP Kinase Kinase 4; D020929:Mitogen-Activated Protein Kinase Kinases; D024505:Tocopherols