Vitamin C has antagonistic effects on the activity of several antineoplastic drugs that might inhibit the drugs' therapeutic effectiveness, according to studies in cancer cells by researchers from the Sloan-Kettering Cancer Center and Columbia University, in New York City (Heaney ML et al. Cancer Res. 2008;68:8031-8038).
The researchers pretreated leukemia and lymphoma cells with dehydroascorbic acid, the commonly transported form of vitamin C. After exposing the cells to doxorubicin, cisplatin, vincristine, methotrexate, or imatinib, the investigators measured the effects of these antineoplastic drugs on viability, clonogenicity, apoptosis, P-glycoprotein, reactive oxygen species (ROS), and mitochondrial membrane potential.
Hildreth CJ. Vitamin C and Chemotherapy. JAMA. 2008;300(21):2476. doi:10.1001/jama.2008.738