Modulation of NDEA activated ras expression and protein kinase C activity by nicotinamide

Nicotinamide, an amide derivative of vitamin B-3, was found to inhibit the increase in ras expression, protein kinase C (PKC) activity, and diacylglce rol. (DAG) levels in rats treated with N-nitrosodiethylamine (NDEA). It eff ectively modulated the carcinogen induced increase in the cytosol and the p articulate PKC activities but not the nuclear PKC activity. The DAG levels were also modulated by the endobiotic. It may serve as an ideal modulator o f carcinogenesis. Nicotinamide is currently under trial as a radio sensitiz er, and inhibition of these parameters may be one of the ways in which it c onfers radiosensitivity. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.