Role of the stress-activated/c-Jun NH2-terminal protein kinase pathway in the cellular response to adriamycin and other chemotherapeutic drugs.
c-Jun NH2-terminal protein kinase (JNK), a member of the mitogen-activated protein kinase family, is activated in response to many stressful stimuli including heat shock, UV irradiation, protein synthesis inhibitors, and inflammatory cytokines. In this study, we investigated whether JNK plays a role in the cellular response to different drugs commonly used in cancer chemotherapy. Treatment of human KB-3 carcinoma cells with Adriamycin resulted in a time- and dose-dependent activation of JNK of up to 40-fold. Treatment with vinblastine or etoposide (VP-16) also activated JNK, with maximum increases of 6.5- and 4.3-fold, respectively. Consistent with these findings, increased c-Jun phosphorylation was observed after drug treatment of cells. In contrast, none of the drugs significantly activated the extracellular response kinase/mitogen-activated protein kinase pathway. Since these drugs are transport substrates for the MDR1 gene product, P-glycoprotein, JNK was assayed in two multidrug-resistant (MDR) KB cell lines, KB-A1 and KB-V1, selected for resistance to Adriamycin and vinblastine, respectively. Relative to KB-3 cells, basal JNK activity was increased 7-fold in KB-A1 cells and 4-fold in KB-V1 cells, with no change in JNK protein expression, indicating that JNK is present in a more highly activated form in the MDR cell lines. Under conditions optimal for JNK activation, Adriamycin, vinblastine, and VP-16 all induced MDR1 mRNA expression in KB-3 cells. Our findings suggest that JNK activation is an important component of the cellular response to several structurally and functionally distinct anticancer drugs and may also play a role in the MDR phenotype.
Osborn
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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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TC
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000502:physiology; D000903:Antibiotics, Antineoplastic / Q000494:pharmacology*; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D004317:Doxorubicin / Q000494:pharmacology*; D018432:Drug Resistance, Multiple; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005047:Etoposide / Q000494:pharmacology*; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D010766:Phosphorylation; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D014407:Tumor Cells, Cultured; D014747:Vinblastine / Q000494:pharmacology*
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000903:Antibiotics, Antineoplastic; D004791:Enzyme Inhibitors; D016755:Proto-Oncogene Proteins c-jun; D012333:RNA, Messenger; D014747:Vinblastine; D005047:Etoposide; D004317:Doxorubicin; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases