First Author | Martin KR | Year | 2002 |
Journal | Nutr Cancer | Volume | 43 |
Issue | 1 | Pages | 59-66 |
PubMed ID | 12467136 | Mgi Jnum | J:80270 |
Mgi Id | MGI:2445608 | Doi | 10.1207/S15327914NC431_7 |
Citation | Martin KR, et al. (2002) Timing of supplementation with the antioxidant N-acetyl-L-cysteine reduces tumor multiplicity in novel, cancer-prone p53 haploinsufficient Tg.AC (v-Ha-ras) transgenic mice but has no impact on malignant progression. Nutr Cancer 43(1):59-66 |
abstractText | Epidemiological studies support the protective role of dietary antioxidants in preventing cancer. However, emerging evidence suggests that antioxidant supplements may actually exacerbate carcinogenesis. We explored this paradox in a model containing two common genotypic characteristics of human cancers. We selected p53 haploinsufficient Tg.AC (v-Ha-ras) mice as a model, because it contains an activated, carcinogen-inducible ras oncogene and an inactivated p53 tumor suppressor gene. These mice develop chemically induced benign and malignant skin tumors rapidly. Mice were fed basal diet with or without 3% N-acetyl-L-cysteine (NAC) before and after topical application of the carcinogen benzo[a]pyrene (64 micrograms twice per week for 7 wk) until 50% of mice within a group displayed at least one lesion. Half each of mice fed the basal and the NAC-supplemented diet were then switched to the alternate diet. Mice fed the NAC-supplemented diet or switched from the NAC-supplemented to the basal diet displayed 38% and 26% reductions, respectively, in tumor multiplicity and a 15% reduction if switched from the basal to the NAC-supplemented diet. Although latency was unaffected, NAC induced a lag in tumor incidence, which exceeded 90% at 10 wk for all groups. The timing of NAC supplementation did not affect malignant progression. Thus dietary NAC was chemoprotective by slowing tumorigenesis but did not affect malignant conversion. |