Paclitaxel (Taxol)-induced gene expression and cell death are both mediated by the activation of c-Jun NH2-terminal kinase (JNK/SAPK).
Paclitaxel (Taxol) is a novel anti-cancer drug that has shown efficacy toward several malignant tumors, particularly ovarian tumors. We reported previously that paclitaxel can induce interleukin (IL)-8 promoter activation in subgroups of ovarian cancer through the activation of both AP-1 and nuclear factor kappaB. Further analysis of paclitaxel analogs indicates that the degree of IL-8 induction by analysis correlates with the extent of cell death; however, IL-8 itself is not the cause of cell death. This suggests that pathways that lead to IL-8 and cell death may overlap, although IL-8 per se does not kill tumor cells. To decipher the upstream signals for paclitaxel-induced transcriptional activation and cell death, we studied the involvement of protein kinases that lead to the activation of AP-1, specifically the c-Jun NH2-terminal kinase (JNK1), p38, and the extracellular signal-regulated kinase 1 (ERK1). The role of IkappaB in paclitaxel-induced cell death was also analyzed. Paclitaxel activated JNK, and to a lesser degree p38, but not ERK1. Paclitaxel-induced IL-8 promoter activation was inhibited by dominant-inhibitory mutants of JNK, p38, and the super-repressor form of IkappaBalpha, but not by dominant-inhibitory forms of ERK1. Dominant-inhibitory mutants of JNK1 also greatly reduced paclitaxel-induced cell death, and the kinetics of JNK induction was closely followed by DNA fragmentation. These results indicate (i) that paclitaxel activates the JNK signaling pathway and (ii) that JNK activation is a common point of paclitaxel-induced gene induction and cell death.
Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7295, USA.
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Lee
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Li
D J
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Templeton
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JP
Ting
D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000235:genetics / Q000378:metabolism*; D016923:Cell Death; D004268:DNA-Binding Proteins / Q000378:metabolism; D004789:Enzyme Activation; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D020672:I-kappa B Proteins; D016209:Interleukin-8 / Q000096:biosynthesis / Q000235:genetics; D048031:JNK Mitogen-Activated Protein Kinases; D048728:MAP Kinase Kinase Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D008954:Models, Biological; D009154:Mutation; D000072000:NF-KappaB Inhibitor alpha; D010051:Ovarian Neoplasms / Q000378:metabolism*; D017239:Paclitaxel / Q000494:pharmacology*; D011401:Promoter Regions, Genetic; D017346:Protein Serine-Threonine Kinases / Q000235:genetics; D015398:Signal Transduction; D018808:Transcription Factor AP-1 / Q000378:metabolism; D015533:Transcriptional Activation; D014407:Tumor Cells, Cultured; D048051:p38 Mitogen-Activated Protein Kinases
D000972:Antineoplastic Agents, Phytogenic; D004268:DNA-Binding Proteins; D020672:I-kappa B Proteins; D016209:Interleukin-8; C000606204:NFKBIA protein, human; D018808:Transcription Factor AP-1; D000072000:NF-KappaB Inhibitor alpha; D017346:Protein Serine-Threonine Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D048728:MAP Kinase Kinase Kinase 1; C482576:MAP3K1 protein, human; D017239:Paclitaxel