Effect of extracellular NADH on human tumor cell proliferation

We investigated the antiproliferative effects of extracellular nicotinamide adenine dinucleotide against human malignant CaCo-2 (colon carcinoma), Hep -2 (laringeal carcinoma), MCF-7 (breast carcinoma), CaSki (cervix carcinoma ) cell lines, as well as against murine fibrosarcoma and normal human embri onal fibroblast (HEF). NADH was very potent in the growth inhibition of mur ine fibrosarcoma and human Hep-2 cells, regardless of the dose applied Duri ng the observed period (4 or 5 days) only one dose of NADH was sufficient i n reducing the growth rate for up to 92%. It had no effect on the growth of other cell lilies tested The identification of DNA-fragmentation and p53 a nd Ki-67 genes expression suggest that the mechanism of NADH action is diff erent from disregulation of genes considered as checkpoints in cell cycle.