L-ascorbic acid (vitamin C) induces the apoptosis of B16 murine melanoma cells via a caspase-8-independent pathway

Cancer Immunol Immunother. 2003 Nov;52(11):693-8. doi: 10.1007/s00262-003-0407-6. Epub 2003 Jun 24.


L-ascorbic acid (vitamin C) has been reported to play a role in the treatment and prevention of cancer. However, its specific mechanistic pathways remain obscure. This study was carried out to identify the sodium ascorbate-induced apoptotic pathway in B16F10 murine melanoma cells. Sodium ascorbate was found to induce the apoptosis of B16F10 murine melanoma in a time- and dose-dependent manner, and this was prevented by pretreatment with N-acetyl- L-cysteine (NAC), a well-known antioxidant. In fact, sodium ascorbate-treated B16F10 melanoma cells showed increased intracellular reactive oxygen species generation (ROS) levels. These results indicate that sodium ascorbate induced apoptosis in B16F10 murine melanoma cells by acting as a prooxidant. We examined the involvement of caspase-8 using a specific caspase-8 inhibitor (z-IETD-fmk) on the sodium ascorbate-induced apoptotic pathway. Cell death was found not to be inhibited by z-IETD-fmk treatment, indicating that sodium ascorbate-induced apoptosis is not mediated by caspase-8. In addition, we detected a reduction in the mitochondrial membrane potential during apoptosis and confirmed cytochrome-c release from mitochondria by immunoblotting. Taken together, it appears that the induction of a prooxidant state by sodium ascorbate and a subsequent reduction in mitochondrial membrane potential are involved in the apoptotic pathway of B16F10 murine melanoma cells, and that this occurs in a caspase-8-independent manner.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis
  • Ascorbic Acid / pharmacology*
  • Caspase 8
  • Caspase 9
  • Caspases / metabolism*
  • Cytochromes c / metabolism
  • Dose-Response Relationship, Drug
  • Melanoma, Experimental / pathology*
  • Membrane Potentials / drug effects
  • Mice
  • Mitochondria / drug effects
  • Oxidants / pharmacology
  • Reactive Oxygen Species / metabolism
  • Tumor Cells, Cultured


  • Oxidants
  • Reactive Oxygen Species
  • Cytochromes c
  • Casp8 protein, mouse
  • Casp9 protein, mouse
  • Caspase 8
  • Caspase 9
  • Caspases
  • Ascorbic Acid