Administration of green tea or caffeine enhances the disappearance of UVB-induced patches of mutant p53 positive epidermal cells in SKH-1 mice
- 7 April 2005
- journal article
- Published by Oxford University Press (OUP) in Carcinogenesis: Integrative Cancer Research
- Vol. 26 (8) , 1465-1472
- https://doi.org/10.1093/carcin/bgi086
Abstract
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 approximately 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 micromol) 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.Keywords
This publication has 22 references indexed in Scilit:
- Stimulatory Effect of Topical Application of Caffeine on UVB-Induced Apoptosis in the Epidermis of p53 and Bax Knockout MiceCancer Research, 2004
- Topical applications of caffeine or (−)-epigallocatechin gallate (EGCG) inhibit carcinogenesis and selectively increase apoptosis in UVB-induced skin tumors in miceProceedings of the National Academy of Sciences, 2002
- The IARC TP53 database: New online mutation analysis and recommendations to usersHuman Mutation, 2002
- Escaping the stem cell compartment: Sustained UVB exposure allows p53 -mutant keratinocytes to colonize adjacent epidermal proliferating units without incurring additional mutationsProceedings of the National Academy of Sciences, 2001
- Molecular pathology in basal cell cancer with p53 as a genetic markerOncogene, 1997
- Frequent clones of p53-mutated keratinocytes in normal human skinProceedings of the National Academy of Sciences, 1996
- Sunburn and p53 in the onset of skin cancerNature, 1994
- Mutation hotspots due to sunlight in the p53 gene of nonmelanoma skin cancers.Proceedings of the National Academy of Sciences, 1993
- Solar ultraviolet radiation effects on biological systemsPhysics in Medicine & Biology, 1991
- Natural UV-B radiation received by people with outdoor, indoor, and mixed occupations and UV-B treatment of psoriasisClinical and Experimental Dermatology, 1983