Wc. Cole et Kn. Prasad, CONTRASTING EFFECTS OF VITAMINS AS MODULATORS OF APOPTOSIS IN CANCER-CELLS AND NORMAL-CELLS - A REVIEW, Nutrition and cancer, 29(2), 1997, pp. 97-103
Individual vitamins can induce direct apoptosis or indirect apoptosis
via cell differentiation in cancer cells; however, they can also stimu
late antiapoptotic events in certain cancer cells. These effects depen
d on the dose, type, and form of vitamins and the type of tumor cells.
A mixture of antioxidant vitamins is more effective than individual v
itamins, and there is no evidence that such a mixture ever stimulates
antiapoptotic events in cancer cells. Vitamins in combination with non
vitamin, direct-acting, apoptotic agents (X-rays, chemotherapeutic age
nts, and hyperthermia) or in combination with nonvitamin, indirect-act
ing, apoptotic agents (adenosine 3',5'-cyclic monophosphate, butyric a
cid and interferon) produce a greater extent of apoptotic death in can
cer cells in culture. Certain antioxidant vitamins may reduce the effi
cacy of some chemotherapeutic agents on rodent fibrosarcoma cells. In
contrast to vitamin-induced apoptosis in cancer cells, normal cells ne
ver undergo apoptotic death after treatment with vitamins (not includi
ng retinoids). On the contrary vitamins protect normal cells against a
poptosis induced by a certain group of chemicals. The reasons for this
differential effect of vitamins on cancer and normal cells are unknow
n. The genetic regulation of apoptosis in cancer cells has not been ad
equately defined. Such studies would help in identifying molecular tar
gets that can be used to develop effective doses of vitamins or new dr
ugs to induce apoptosis selectively in cancer cells.