Abstract
The molecular changes involved in the induction of apoptosis by vincristine in melanoma have not yet been well defined. Two human melanoma cell lines showing moderate (Mel-RM) and high (IgR3) sensitivity to vincristine were selected from a panel of eight melanoma lines for analysis. Induction of apoptosis was caspase dependent, and was associated with increases in mitochondrial membrane permeability. Vincristine upregulated the expression of Bax, Bak, PUMA, Noxa, p53 and p21 proteins, and downregulated and/or phosphorylated the Bcl-2 protein. Inhibitors of the Jun N-terminal kinase (JNK), but not p38 mitogen-activated protein kinase, significantly inhibited vincristine-induced apoptosis in both IgR3 and Mel-RM cells. In addition, vincristine induced phosphorylation and reduction in Bcl-2 was prevented by an inhibitor of JNK. Downregulation of mRNA for p53, PUMA or Bim by RNA interference had little or no influence on vincristine-induced apoptosis in IgR3 cells. In addition, silencing Bim mRNA did not affect vincristine-induced apoptosis in Mel-RM cells. These results suggest that vincristine-induced apoptosis of at least some melanoma cell lines is dependent on the activation of JNK. The results are consistent with the phosphorylation of Bcl-2 protein, resulting in the activation of Bax/Bak, release of cytochrome c from the mitochondria and the resulting activation of caspases.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Antineoplastic Agents, Phytogenic / pharmacology
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Apoptosis / drug effects*
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Apoptosis Regulatory Proteins / genetics
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Apoptosis Regulatory Proteins / metabolism
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Bcl-2-Like Protein 11
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Benzimidazoles / metabolism
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Blotting, Western
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Carbocyanines / metabolism
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Caspases / metabolism
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Cell Line, Tumor
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Dose-Response Relationship, Drug
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Enzyme Activation / drug effects
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Flow Cytometry
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Humans
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JNK Mitogen-Activated Protein Kinases / metabolism*
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Melanoma / enzymology
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Melanoma / metabolism
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Melanoma / pathology
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Membrane Potential, Mitochondrial / drug effects
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Membrane Proteins / genetics
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Membrane Proteins / metabolism
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Mitochondrial Membrane Transport Proteins / metabolism
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Phosphorylation / drug effects
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Proto-Oncogene Proteins / genetics
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Proto-Oncogene Proteins / metabolism
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Proto-Oncogene Proteins c-bcl-2 / genetics
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Proto-Oncogene Proteins c-bcl-2 / metabolism
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RNA, Messenger / genetics
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RNA, Messenger / metabolism
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Signal Transduction / drug effects
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Tubulin Modulators / pharmacology
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Tumor Suppressor Protein p53 / genetics
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Tumor Suppressor Protein p53 / metabolism
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Vincristine / pharmacology*
Substances
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Antineoplastic Agents, Phytogenic
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Apoptosis Regulatory Proteins
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BBC3 protein, human
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BCL2L11 protein, human
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Bcl-2-Like Protein 11
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Benzimidazoles
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Carbocyanines
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Membrane Proteins
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Mitochondrial Membrane Transport Proteins
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Proto-Oncogene Proteins
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Proto-Oncogene Proteins c-bcl-2
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RNA, Messenger
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Tubulin Modulators
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Tumor Suppressor Protein p53
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5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolocarbocyanine
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Vincristine
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JNK Mitogen-Activated Protein Kinases
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Caspases