Inositol-phosphate-induced enhancement of natural killer cell activity correlates with tumor suppression

Abstract

In recent studies, we have demonstrated that inositol hexaphosphate (InsP₆) inhibits experimental colon carcinogenesis. Since natural killer (NK) cells are involved in tumor cell destruction, we investigated the effect of InsP₆ on murine NK cell activity. We show that; (i) 1,2-dimethylhydrazine (DMH), a colon carcinogen, depresses NK activity; (ii) in vivo treatment of mice with InsP₆ enhances baseline NK activity and reverses DMH-induced depressed NK activity with an inverse correlation (r = −0.9811) with tumor incidence, (iii) short-term in vitro treatment of spleen cells and NK-enriched fraction with InsP₆ also enhances NK cytotoxicity in a dose-dependent manner, (iv) inositol potentiates the action of IasP6. Our data suggest yet another important role of inositol phosphates in the regulation of cellular activity.