Citrus pectin (CP) is a complex, highly branched, plant polysaccharide, which contains a backbone consisting of polygalacturonic acid and side chains consisting of pentose and hexose sugars. We have earlier modified citrus pectin into smaller structure by pH and temperature modification and named it MCP. MCP reduced the metastatic spread of mouse melanoma cells B16 F1, prostate cancer cells Mat-LyLu , breast cancer cells MDA-MB-435 and colon cancer cells LSLiM6 in various animal models. We questioned, whether MCP has only therapeutic effects or also preventive effects on tumor formation in mice. Therefore we selected two transgenic mouse model systems, which produce spontaneous tumors. B6.129-Apc tm1Rak mice carry a chain termination mutation in amino acid 1638 (exon 15) of the Apc gene. Mice homozygous to this mutation are embryonically lethal and heterozygous mice develop multiple colonic polyps, gastrointestinal adenomas and adenocarcinomas. The second transgenic mouse model used for prostate and mammary cancer contained a recombinant gene expressing the simian virus 40 early-region transforming sequences under the regulatory control of the rat prostatic steroid binding protein [C3(1)] gene. The female mice develop mammary tumors and the male offsprings develop prostate tumors. The mice were bred in the Wayne State University animal facility and separated after weaning in groups fed on water or MCP. The mammary tumors were studied after 6 months, and prostatic or intestinal tumors were observed after 8 months. Our results indicate that MCP does not have a preventive action on the growth of spontaneous mammary or prostate cancer, but it reduces the number of tumors of the small intestine significantly.

[Proc Amer Assoc Cancer Res, Volume 46, 2005]