Effect of green tea on p53 mutation distribution in ultraviolet B radiation-induced mouse skin tumors.
In the present study, administration of green tea to SKH-1 mice, via the drinking fluid, was found to significantly reduce the incidence and volume of ultraviolet B (UVB) radiation-induced skin tumors. Thirty-six skin tumors induced by UVB and 32 skin tumors induced by UVB, in mice treated with green tea in their drinking water, were collected and examined for the presence of mutations in the p53 gene. Polymerase chain reaction products from p53 exons 5-8 were screened by single-strand conformation polymorphism and direct sequence analyses. Eight of 36 UVB-induced tumors contained nine p53 mutations, with four in exon 5 and five in exon 8. In contrast, nine of 32 UVB-induced tumors in mice treated with green tea contained 11 p53 mutations, with two in exon 5, five in exon 6 and four in exon 8. All of the p53 mutations occurred at dipyrimidine sequences. These results were further corroborated by p53 immunohistochemistry. The most frequent mutations were C-->T or T-->C transitions, which are consistent with the genetic alterations caused by UVB exposure. Interestingly, mutations found in exon 6 of the p53 gene occurred only in tumors from the UVB/green tea group. Thus, the tumors observed in UVB/green-tea-treated mice have a different exon distribution of p53 mutations than tumors obtained from mice treated with UVB alone.
Department of Pathology, Medical College of Ohio, Toledo 43614, USA.
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Liu
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Wang
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Crist
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Wang
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Lou
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Huang
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Conney
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You
D000818:Animals; D016588:Anticarcinogenic Agents / Q000627:therapeutic use*; D018287:Carcinoma, Large Cell / Q000209:etiology / Q000235:genetics / Q000517:prevention & control; D002294:Carcinoma, Squamous Cell / Q000209:etiology / Q000235:genetics / Q000517:prevention & control; D003062:Codon; D005091:Exons; D005260:Female; D016158:Genes, p53; D007150:Immunohistochemistry; D051379:Mice; D008812:Mice, Hairless; D009154:Mutation; D009381:Neoplasms, Radiation-Induced / Q000209:etiology / Q000235:genetics* / Q000517:prevention & control*; D016133:Polymerase Chain Reaction; D012878:Skin Neoplasms / Q000209:etiology / Q000235:genetics* / Q000517:prevention & control*; D013662:Tea; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism; D014466:Ultraviolet Rays / Q000009:adverse effects*
D016588:Anticarcinogenic Agents; D003062:Codon; D013662:Tea; D016159:Tumor Suppressor Protein p53