Inositol and inositol hexaphosphate suppress cell proliferation and tumor formation in CD-1 mice

Abstract

In previous studies, we have shown that inositol hexaphosphate (InsP₆), a constituent of cereal diet, inhibited azoxymethane-induced experimental large intestinal cancer (LIC) in Fischer 344 rats. We now report a similar antineoplastic action of InsP₆ in CD-1 mice injected with 1,2-dimethylhydrazine (DMH). We had hypothesized that InsP₆ may bring about this effect by undergoing dephosphorylation to lower phosphorylated forms; the ready availability of Ins, to react with phosphates, may increase the total amount of the lower phosphorylated Ins and potentiate the action of InsP₆. LIC induced by DMH (15 mg/kg/week × 13) in mice given a mixture of 1% InsP₆ + 1% Ins show a significant reduction (P 6 treatment. Surprisingly, Ins, an in vitro growth promoting agent also caused a significant (P < 0.001) suppression of LIC. InsP₆ ± Ins also showed a concomitant reduction in the mitotic rate in the non-neoplastic epithelium. Body weight data did not suggest any overt toxic effect of long-term administration of InsP₆, Ins or InsP₆ ± Ins. Since InsP₆ is antineoplastic in two species of experimental animals, it should, in combination with Ins, be considered in our strategies for prevention of large intestinal cancer.