Journal Article

Administration of green tea or caffeine enhances the disappearance of UVB-induced patches of mutant p53 positive epidermal cells in SKH-1 mice

Yao-Ping Lu, You-Rong Lou, Jie Liao, Jian-Guo Xie, Qing-Yun Peng, Chung S. Yang and Allan H. Conney

in Carcinogenesis

Volume 26, issue 8, pages 1465-1472
Published in print August 2005 | ISSN: 0143-3334
Published online April 2005 | e-ISSN: 1460-2180 | DOI: http://dx.doi.org/10.1093/carcin/bgi086
Administration of green tea or caffeine enhances the disappearance of UVB-induced patches of mutant p53 positive epidermal cells in SKH-1 mice

More Like This

Show all results sharing this subject:

  • Clinical Cytogenetics and Molecular Genetics

GO

Show Summary Details

Preview

Irradiation of female SKH-1 hairless mice with UVB (30 mJ/cm2) twice a week for 10–20 weeks resulted in the formation of a large number of cellular patches (>8 adjacent cells/patch) that are recognized with an antibody (Pab240) which recognizes mutated but not wild-type p53 protein. These patches are not recognized by an antibody (Pab1620) to wild-type p53 protein. The patches, which are considered putative early cellular markers of the beginning of tumor formation, started appearing after 4–6 weeks of UVB treatment, and multiple patches were observed after treatment for 10 weeks. The number and size of the patches increased progressively with continued UVB treatment. Discontinuation of UVB for 4 weeks resulted in an 80–90% decrease in the number of these patches. The number of the remaining patches did not decrease any further but remained relatively constant for at least 4–9 weeks. Oral administration of green tea (6 mg tea solids/ml) or caffeine (0.4 mg/ml) as the sole source of drinking fluid during irradiation with UVB, twice a week for 20 weeks, inhibited UVB-induced formation of mutant p53 positive patches by ∼40%. Oral administration of green tea (6 mg tea solids/ml) as the sole source of drinking fluid or topical applications of caffeine (6.2 µmol) once a day 5 days a week starting immediately after discontinuation of UVB treatment enhanced the rate and extent of disappearance of the mutant p53-positive patches. Topical applications of caffeine to the dorsal skin of mice pretreated with UVB for 20 weeks resulted in enhanced apoptosis selectively in focal basal cell hyperplastic areas of the epidermis (putative precancerous lesions), but not in areas of the epidermis that only had diffuse hyperplasia. Our studies indicate that the chemopreventive effect of caffeine or green tea may occur by a proapoptotic effect preferentially in early precancerous lesions.

Journal Article.  6539 words.  Illustrated.

Subjects: Clinical Cytogenetics and Molecular Genetics

Full text: subscription required

How to subscribe Recommend to my Librarian

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.