De Luca L M, Tarone R, Huynh M, Jones C S, Chen L C
Differentiation Control Section, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
Nutr Cancer. 1996;25(3):249-57. doi: 10.1080/01635589609514449.
In the two-stage protocol of skin carcinogenesis, the carcinogen 7,12-dimethylbenz[a]anthracene (DMBA) is applied to the skin of mice at around seven weeks of age. We previously performed DMBA initiation at three weeks of age to study the effect of pharmacological (30 micrograms/g diet) dietary retinoic acid (RA) on skin carcinogenesis. In this study we asked whether dietary pharmacological RA is equally effective against skin carcinogenesis when mice are initiated with (DMBA) at 7 weeks of age and then subjected to weekly applications of the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) or mezerein (MEZ) for 20 weeks. Similar to the three-week initiation protocol, high dietary RA inhibited papilloma incidence and yield in MEZ- but not in TPA-promoted female SENCAR mice. In addition, carcinoma incidence and yield were decreased by high dietary RA in TPA- as well as MEZ-treated mice. These data demonstrate that the high dietary RA diet is as effective in inhibiting papilloma and carcinoma formation when the DMBA is applied at seven weeks of age as at three weeks.
在皮肤癌发生的两阶段实验方案中，致癌物质7,12 - 二甲基苯并[a]蒽（DMBA）在小鼠约7周龄时涂抹于其皮肤上。我们之前在3周龄时进行DMBA启动实验，以研究药理剂量（30微克/克饮食）的膳食视黄酸（RA）对皮肤癌发生的影响。在本研究中，我们探讨当小鼠在7周龄时用（DMBA）启动，然后每周涂抹肿瘤促进剂12 - O - 十四烷酰佛波醇 - 13 - 乙酸酯（TPA）或芫花酯素（MEZ）持续20周时，膳食药理剂量的RA对皮肤癌发生的抑制效果是否相同。与3周龄启动方案类似，高剂量膳食RA抑制了MEZ诱导的雌性SENCAR小鼠的乳头瘤发生率和产量，但对TPA诱导的小鼠无效。此外，在TPA和MEZ处理的小鼠中，高剂量膳食RA均降低了癌的发生率和产量。这些数据表明，当在7周龄时涂抹DMBA时，高剂量膳食RA饮食在抑制乳头瘤和癌形成方面与在3周龄时涂抹一样有效。
