ASCORBATE ON CELL-GROWTH AND DIFFERENTIATION

Ascorbate, an essential nutrient in humans, primates, and guinea pig, is involved in many cellular functions. Ascorbate also modulates cell growth and differentiation. Ascorbate can reduce or stimulate the grow th of tumor cells, depending on the cell type. The inhibitory effect i s not specific for the biological active isomer L-ascorbate, and isoas corbate and D-ascorbate are more effective in reducing cell growth tha n L-ascorbate. These results indicate that ascorbate has a cytotoxic e ffect by killing cells directly, rather a cytostatic one. However, onl y L-ascorbate is able to stimulate cell growth, but the mechanism of t his stimulation is still unknown. L-Ascorbate stimulates the in vitro differentiation of several mesenchyme-derived cell types by altering t he expression of multiple genes as the cell progresses through specifi c differentiation programs. Stimulation of collagen matrix at gene tra nscription, mRNA stabilization, hydroxylation, and secretion is a key role for L-ascorbate. L-Ascorbate also prevents cell transformation by stabilization of the differentiated state and cooperates with other a gents to induce differentiation in a leukemia cell line.