Effects of capsaicin on induction of c-jun proto-oncogene expression in Fisher-344 rats by N-methyl-N '-nitro-N-nitrosoguanidine

N-Methyl-N'-nitro-N-nitrosoguanidine (MNNG) is a potent inducer of cellular stress leading to chromosomal aberrations, point mutations, and cell death . To study the effect of capsaicin on c-jun expression when given with MNNG to rats, Fisher-344 rats that had been administered MNNG were treated with capsaicin in their diet and organs were removed for measuring c-jun transc ripts. We show that pre- or post-treatment of capsaicin relative to MNNG ad ministration up- or down-regulates (depending on the organ) c-jun expressio n in a consistent pattern in most organs. In fact, we found in this study t hat capsaicin inhibits c-jun induction, stimulated by MNNG, in the spleen, heart, stomach and lung. Since MNNG, a methylating agent, is a powerful car cinogen that is very effective in the induction of c-jun mRNA, the results suggest that capsaicin uptake in the diet could play a role in inhibition o f tumorigenesis induced by MNNG. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.