SELECTIVE TOXICITY OF COMPOUNDS NATURALLY PRESENT IN FOOD TOWARD THE TRANSFORMED PHENOTYPE OF HUMAN COLORECTAL CELL-LINE HT29

It has previously been observed that allyl isothiocyanate, a compound naturally present in the diet, is more cytotoxic toward the human colo rectal adenocarcinoma cell line HT29 in its control transformed state than after exposure to sodium butyrate or to dimethylformamide, which slow growth and induce differentiation (detransformation). In the pres ent study, a range of other dietary compounds were assayed for such se lective toxicity. These compounds were chosen as constituents of foods tuffs that have been identified from epidemiologic studies as being po tentially antitumorigenic and also as having anticarcinogenic activity in experimental models. Benzyl and phenethyl isothiocyanate, benzyl t hiocyanate, and quercetin showed decreased toxicity towards HT29 after detransformation of the cells by one or both treatments, whereas no c hange was observed in the sensitivity to diallyl sulfide or diallyl di sulfide. It is proposed that the presence of such selectively toxic co mpounds in the diet may inhibit the development of tumors by interferi ng with the growth of preneoplastic lesions while having little effect on normal cells. The cumulative effects of these inhibitions may cont ribute to the chemopreventive properties of the parent foodstuffs obse rved in epidemiologic studies.