Microtubule inhibitors elicit differential effects on MAP kinase (JNK, ERK, and p38) signaling pathways in human KB-3 carcinoma cells.
Microtubule inhibitors are widely used in cancer chemotherapy, but the signaling mechanisms that link microtubule disarray to destructive or protective cellular responses are poorly understood. Because members of the mitogen-activated protein kinase (MAPK) family have been implicated in regulation of cell survival and cell death, we examined the extent and kinetics of activation of JNK, ERK, and p38 MAPKs in response to treatment of KB-3 carcinoma cells with several microtubule inhibitors. All four agents tested (vinblastine, vincristine, Taxol, and colchicine) caused significant (6- to 13-fold) activation of JNK, concomitant inactivation of ERK, and a reduction in basal p38 MAPK activity. JNK activation and ERK inactivation occurred prior to caspase 3 activation. The microtubule inhibitors also induced phosphorylation of Raf-1 kinase. SEK-1, upstream of JNK, was also activated and phosphorylated in response to the microtubule inhibitors, and sustained phosphorylation of three endogenous JNK substrates (c-Jun, ATF-2, and JunD) was observed. By comparison, the antitumor agent doxorubicin induced activation of JNK and p38 but had no effect on ERK activity or Raf-1. These data demonstrate that microtubule inhibitors elicit distinct and specific effects on MAPK-mediated signaling pathways and suggest in particular that coordinate and reciprocal alterations in JNK and ERK activities are important facets of the cellular response to microtubule disruption.
Stone
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Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, 72205-7199, USA.
Chambers
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D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D003078:Colchicine / Q000494:pharmacology*; D004317:Doxorubicin / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D005326:Fetal Proteins / Q000378:metabolism; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases; D020935:MAP Kinase Signaling System / Q000187:drug effects*; D008870:Microtubules / Q000187:drug effects*; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D017239:Paclitaxel / Q000494:pharmacology*; D010766:Phosphorylation / Q000187:drug effects; D019908:Proto-Oncogene Proteins c-raf / Q000378:metabolism; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism; D036122:Receptor, EphA4; D013379:Substrate Specificity; D014407:Tumor Cells, Cultured; D014747:Vinblastine / Q000494:pharmacology*; D014750:Vincristine / Q000494:pharmacology*; D048051:p38 Mitogen-Activated Protein Kinases
D005326:Fetal Proteins; D014750:Vincristine; D014747:Vinblastine; D004317:Doxorubicin; D020794:Receptor Protein-Tyrosine Kinases; D036122:Receptor, EphA4; D019908:Proto-Oncogene Proteins c-raf; 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; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases; D017239:Paclitaxel; D003078:Colchicine