Efficacy of polyphenon E, red ginseng, and rapamycin on benzo(a)pyrene-induced lung tumorigenesis in A/J mice.

The objective of this investigation was to determine the efficacy of several novel agents in preventing lung tumorigenesis in mice. We evaluated polyphenon E, red ginseng, and rapamycin in A/J mice treated with the tobacco-specific carcinogen benzo(a)pyrene for their ability to inhibit pulmonary adenoma formation and growth. We found that treatment with polyphenon E exhibited a significant reduction on both tumor multiplicity and tumor load (tumor multiplicity x tumor volume) in a dose-dependent fashion. Polyphenon E (2% wt/wt) in the diet reduced tumor multiplicity by 46% and tumor load by 94%. This result provided key evidence in support of a phase II clinical chemoprevention trial of lung cancer. Administration of red ginseng in drinking water decreased tumor multiplicity by 36% and tumor load by 70%. The mammalian target of rapamycin inhibitor rapamycin showed significant efficacy against lung tumor growth in the tumor progression protocol and reduced tumor load by 84%. The results of these investigations demonstrate that polyphenon E, red ginseng, and rapamycin significantly inhibit pulmonary adenoma formation and growth in A/J mice.