Mcl-1 cleavage and sustained phosphorylation of c-Jun-N-terminal kinase mediate melanoma apoptosis induced by 2-acetyl furanonaphthoquinone: roles of Bcl-2 and p53

Cancer Biol Ther. 2008 Aug;7(8):1206-11. doi: 10.4161/cbt.7.8.6217. Epub 2008 Aug 1.

Abstract

2-acetyl furanonaphthoquinone (FNQ) is a naturally occurring drug with enhanced toxicity versus glucose-starved tumor cells, which frequently show topoisomerase II drug resistance. Since loss of p53 tumor suppressor function or overexpression of the anti-apoptotic bcl-2 gene can decrease susceptibility to some cancer therapies, we now investigated the effect of FNQ against genetically matched C8161 melanoma cell lines transduced to express unequal levels of Bcl-2, or engineered to harbour a functional wt p53 for comparison with dominant-negative mutant p53 R175H. Cells with differing p53 genotype showed susceptibility to FNQ. However, this response was attenuated in those overexpressing mutant p53, although a brief p53 induction was early seen in FNQ-treated wt p53 cells. Cells susceptible to FNQ showed cleavage of anti-apoptotic Mcl-1, sustained activation of the c-Jun N-terminal Kinase (p-JNK), and apoptosis-associated PARP fragmentation, all of which were counteracted in bcl-2 overexpressing cells. Suppression of JNK activation with the specific inhibitor, SP600125 also prevented FNQ-mediated cell death. Our data suggests that Bcl-2, persistent JNK phosphorylation and cleavage of anti-apoptotic Mcl-1 are key events controlling susceptibility to FNQ.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antineoplastic Agents / pharmacology*
  • Apoptosis / drug effects*
  • Apoptosis / genetics
  • Caspases / genetics
  • Caspases / metabolism
  • Caspases / pharmacology
  • Cell Line, Tumor
  • Furans / pharmacology*
  • Humans
  • Melanoma / genetics
  • Melanoma / metabolism*
  • Mitogen-Activated Protein Kinase 9 / genetics
  • Mitogen-Activated Protein Kinase 9 / metabolism*
  • Mitogen-Activated Protein Kinase 9 / pharmacology
  • Naphthoquinones / pharmacology*
  • Phosphorylation / drug effects
  • Proto-Oncogene Proteins c-bcl-2 / antagonists & inhibitors
  • Proto-Oncogene Proteins c-bcl-2 / genetics
  • Proto-Oncogene Proteins c-bcl-2 / metabolism*
  • Tumor Suppressor Protein p53 / genetics
  • Tumor Suppressor Protein p53 / metabolism*
  • Tumor Suppressor Protein p53 / pharmacology
  • bcl-2-Associated X Protein / genetics
  • bcl-2-Associated X Protein / metabolism
  • bcl-2-Associated X Protein / pharmacology

Substances

  • 2-acetylfuranonaphthoquinone
  • Antineoplastic Agents
  • Furans
  • Naphthoquinones
  • Proto-Oncogene Proteins c-bcl-2
  • Tumor Suppressor Protein p53
  • bcl-2-Associated X Protein
  • Mitogen-Activated Protein Kinase 9
  • Caspases