The intake of ascorbic acid killed cancer cells.
"Human pharmacokinetics data indicate that i.v. ascorbic acid (ascorbate) in pharmacologic concentrations could have an unanticipated role in cancer treatment. Our goals here were to test whether ascorbate killed cancer cells selectively, and if so, to determine mechanisms, using clinically relevant conditions," investigators in the United States reported.
"Cell death in 10 cancer and 4 normal cell types was measured by using 1-h exposures. Normal cells were unaffected by 20 mM ascorbate, whereas 5 cancer lines had EC50 values of <4 mM, a concentration easily achievable i.v. Human lymphoma cells were studied in detail because of their sensitivity to ascorbate (EC50 of .5 mM) and suitability for addressing mechanisms," explained Q. Chen and colleagues, U.S. National Institute of Diabetes and Digestive and Kidney Diseases.
"Extracellular but not intracellular ascorbate mediated cell death, which occurred by apoptosis and pyknosis/necrosis. Cell death was independent of metal chelators and absolutely dependent on H2O2 formation. Cell death from H2O2 added to cells was identical to that found when H2O2 was generated by ascorbate treatment. H2O2 generation was dependent on ascorbate concentration, incubation time, and the presence of .5-10% serum, and displayed a linear relationship with ascorbate radical formation. Although ascorbate addition to medium generated H2O2, ascorbate addition to blood generated no detectable H2O2 and only trace detectable ascorbate radical."
The researchers concluded, "Taken together, these data indicate that ascorbate at concentrations achieved only by i.v. administration may be a pro-drug for formation of H2O2, and that blood can be a delivery system of the pro-drug to tissues. These findings give plausibility to i.v. ascorbic acid in cancer treatment, and have unexpected implications for treatment of infections where H2O2 may be beneficial."
Chen and colleagues published their study in Proceedings of the National Academy of Sciences of the United States of America (Pharmacologic ascorbic acid concentrations selectively kill cancer cells: Action as a pro-drug to deliver hydrogen peroxide to tissues. Proc Natl Acad Sci USA, 2005;102(38):13604-13609).
For additional information, contact M. Levine, U.S. National Institute of Diabetes and Digestive and Kidney Diseases, Molecular & Clinic Nutrition Sect, NIH, Bldg 10, Room 4D52, MSC-1372, Bethesda, MD 20892, USA.
The publisher of the journal Proceedings of the National Academy of Sciences of the United States of America can be contacted at: National Academy Sciences, 2101 Constitution Avenue NW, Washington, DC 20418, USA.
Keywords: Bethesda, Maryland, United States, Apoptosis, Ascorbate, Cell Death, Lymphoma, Oncology, Pharmacokinetic, Pharmacology, Ascorbic Acid, Cancer Therapy, Pro-Drug, Drug Development.
This article was prepared by Biotech Week editors from staff and other reports. Copyright 2005, Biotech Week via NewsRx.com.
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