Modifying effects of dietary exposure of
protocatechuic acid (PCA), a natural monophenolic compound, S-methylmethanethiosulfonate (
MMTS), an organosulfur compound newly isolated from cauliflower, and 5-hydroxy-4-(2-phenyl-(E)ethenyl)-2(5H)-furanone (KYN-54), a novel retinoidal
butenolide compound, on
4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) (10 micromol, [corrected] single i.p. injection)-induced pulmonary
carcinogenesis were examined in female A/J mice. Each of the test chemicals was given in diets during initiation or post-initiation phases (PCA, 1000 ppm;
MMTS, 100 ppm;
KYN-54, 200 ppm). All of these which had been proved to be chemopreventive mainly in digestive-organs
carcinogenesis did not exert any preventive effect in this model when the incidence or multiplicity of pulmonary
tumors (
adenomas) of mice given NNK and the test chemical at the termination of the experiment (4 months) was compared to that of mice exposed to the
carcinogen alone. In contrast, the multiplicity of lung
tumors of mice receiving
KYN-54 during the post-initiation phase was significantly larger than of the animals with NNK alone (P < 0.05), showing that
KYN-54 has a promoting effect on pulmonary
carcinogenesis in mice. These data indicate an organotropic activity of these compounds and suggest that candidate compounds for
cancer chemoprevention need to be carefully examined for effectiveness in multiple organs by different models.