Vitamin C antagonizes the cytotoxic effects of antineoplastic drugs Journal Article


Authors: Heaney, M. L.; Gardner, J. R.; Karasavvas, N.; Golde, D. W.; Scheinberg, D. A.; Smith, E. A.; O'Connor, O. A.
Article Title: Vitamin C antagonizes the cytotoxic effects of antineoplastic drugs
Abstract: Vitamin C is an antioxidant vitamin that has been hypothesized to antagonize the effects of reactive oxygen species-generating antineoplastic drugs. The therapeutic efficacy of the widely used antineoplastic drugs doxorubicin, cisplatin, vincristine, methotrexate, and imatinib were compared in leukemia (K562) and lymphoma (RL) cell lines with and without pretreatment with dehydroascorbic acid, the commonly transported form of vitamin C. The effect of vitamin C on viability, clonogenicity, apoptosis, P-glycoprotein, reactive oxygen species (ROS), and mitochondrial membrane potential was determined. Pretreatment with vitamin C caused a dose-dependent attenuation of cytotoxicity, as measured by trypan blue exclusion and colony formation after treatment with all antineoplastic agents tested. Vitamin C given before doxorubicin treatment led to a substantial reduction of therapeutic efficacy in mice with RL cell-derived xenogeneic tumors. Vitamin C treatment led to a dose-dependent decrease in apoptosis in cells treated with the antineoplastic agents that was not due to up-regulation of P-glycoprotein or vitamin C retention modulated by antineoplastics. Vitamin C had only modest effects on intracellular ROS and a more general cytoprotective profile than N-acetylcysteine, suggesting a mechanism of action that is not mediated by ROS. All antineoplastic agents tested caused mitochondrial membrane depolarization that was inhibited by vitamin C. These findings indicate that vitamin C given before mechanistically dissimilar antineoplastic agents antagonizes therapeutic efficacy in a model of human hematopoietic cancers by preserving mitochondrial membrane potential. These results support the hypothesis that vitamin C supplementation during cancer treatment may detrimentally affect therapeutic response. ©2008 American Association for Cancer Research.
Keywords: controlled study; protein expression; human cell; cisplatin; doxorubicin; dose response; drug efficacy; nonhuman; antineoplastic agents; methotrexate; neoplasms; mouse; animals; mice; cell death; cell viability; imatinib; animal experiment; animal model; mitochondrial membrane potential; vincristine; antineoplastic activity; cytotoxicity; dose-response relationship, drug; drug resistance, neoplasm; mice, inbred icr; mice, scid; tumor cells, cultured; xenograft model antitumor assays; drug antagonism; drug mechanism; reactive oxygen metabolite; ascorbic acid; dehydroascorbic acid; leukemia cell line; cytoprotection; drug elimination; glycoprotein p; k562 cells; lymphoma cell line; acetylcysteine; membrane depolarization
Journal Title: Cancer Research
Volume: 68
Issue: 19
ISSN: 0008-5472
Publisher: American Association for Cancer Research  
Date Published: 2008-10-01
Start Page: 8031
End Page: 8038
Language: English
DOI: 10.1158/0008-5472.can-08-1490
PUBMED: 18829561
PROVIDER: scopus
PMCID: PMC3695824
DOI/URL:
Notes: --- - "Cited By (since 1996): 38" - "Export Date: 17 November 2011" - "CODEN: CNREA" - "Source: Scopus"
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  1. Mark L Heaney
    94 Heaney
  2. David Golde
    127 Golde
  3. Jeffrey Gardner
    34 Gardner
  4. Emily A Smith
    11 Smith