Growth modulation of human leukemic, preleukemic, and myeloma progenitor cells by L-ascorbic acid

Article Abstract:

Myelodysplastic syndromes (MDS) are diseases that involve the abnormal growth of blood cells in the bone marrow. During the last two decades several studies have provided evidence that L-ascorbic acid (LAA) may play a role in regulating the rate of growth of these cells. Several studies have reported that LAA is required for the growth of mouse plasmacytoma cells and myeloma cells (abnormal blood cells that form tumors in the bone marrow), and that LAA enhances the growth of human leukemia cells. To investigate this issue further, malignant cells were obtained from two groups of patients and grown in culture. Leukemia cells were obtained from the bone marrow of 151 patients with acute myelocytic leukemia and myeloma cells were obtained from the bone marrow of 37 patients with MDS. Normal blood cells from the bone marrow of 24 healthy subjects were studied for comparison. Increasing concentrations of LAA were added to the cell cultures and the rates of cell growth were monitored. LAA altered the rate of growth in 50 percent of the cell cultures studied; in 35 percent of the cases, LAA increased the growth rate of the cells and in 15 percent of the cases, LAA decreased the growth rate. In some cases, LAA suppressed the growth rate of the cells obtained from the healthy subjects, but LAA never increased the rate of growth of these cells. The findings suggest that LAA can increase or decrease the growth rate of leukemia cells, but it can only decrease the rate of growth of normal cells. It is not clear why LAA increases leukemia cell growth in some patients and decreases it in others, but removing or adding LAA, respectively, may be a new therapeutic approach for treating patients with leukemia. (Consumer Summary produced by Reliance Medical Information, Inc.)

Drug therapy, Bone marrow cells, Myelodysplastic syndromes, Myeloid leukemia, Myelocytic leukemia

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Effect of ascorbic acid on incidence of spontaneous mammary tumors and UV-light-induced skin tumors in mice

Article Abstract:

Studies performed in both animals and humans have reported that ascorbic acid (vitamin C) reduces the incidence and severity of certain types of cancer. This article describes the results of a study designed to evaluate the effects of ascorbic acid on mammary tumors and skin tumors in seven-week-old RIII mice (a special strain that is infected with mammary tumor virus and develops mammary tumors spontaneously). In the first part of the study, the mice were placed on diets with different amounts of vitamin C and the rate of mammary tumor development was monitored. The mice that were fed diets without ascorbate (ascorbate-free diet) developed mammary tumors within an average of 83 weeks, while those on the high-ascorbate diet did not begin to develop tumors until 125 weeks. Fifty-six percent of the mice on the ascorbate-free diet developed mammary tumors, while 30 percent of the mice on the high-ascorbate diet developed tumors. In the second part of the study, the effect of ascorbic acid on the development of skin tumors was evaluated in hairless mice (a mutant strain that looses all hair by three weeks of age). The mice were exposed to radiation with ultraviolet light 5 days a week for 15 weeks. Within 18 weeks of the radiation treatments, 16 percent of the mice on the ascorbate-free diet had developed skin lesions that were greater than 10 millimeters in diameter, compared with only 3 percent of those on the high-ascorbate diet. These findings indicate that ascorbic acid delays the onset and reduces the incidence of mammary tumors and skin tumors in mice. (Consumer Summary produced by Reliance Medical Information, Inc.)

Research, Mice, mutant strains, Mutant mice, Tumors, Skin tumors, Breast tumors

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