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Effect of green tea on p53 mutation distribution in ultraviolet B radiation-induced mouse skin tumors
Abstract:
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.
Insights
Green tea consumption significantly reduced skin tumors induced by ultraviolet B (UVB) radiation in mice. Analysis revealed distinct p53 gene mutation patterns in tumors from mice treated with green tea, suggesting a protective effect.
Area of Science:
- Dermatology
- Molecular Biology
- Cancer Research
Background:
- Ultraviolet B (UVB) radiation is a known carcinogen that induces skin tumors.
- The p53 tumor suppressor gene plays a critical role in preventing cancer by regulating cell growth and DNA repair.
- Green tea possesses antioxidant and anti-inflammatory properties that may offer photoprotection.
Purpose of the Study:
- To investigate the effect of green tea consumption on the incidence and volume of UVB-induced skin tumors in SKH-1 mice.
- To analyze the mutational profile of the p53 gene in skin tumors from mice exposed to UVB radiation, with and without green tea treatment.
Main Methods:
- SKH-1 mice were exposed to UVB radiation, with one group receiving green tea in their drinking water.
- Skin tumors were collected and analyzed for mutations in p53 exons 5-8 using polymerase chain reaction, single-strand conformation polymorphism, and direct sequencing.
- p53 immunohistochemistry was performed to corroborate sequencing results.
Main Results:
- Green tea administration significantly reduced the incidence and volume of UVB-induced skin tumors.
- UVB-induced tumors in mice without green tea treatment showed p53 mutations primarily in exons 5 and 8.
- UVB-induced tumors in mice treated with green tea exhibited a different p53 mutation distribution, including mutations in exon 6, which were not observed in the control group.
- All identified p53 mutations occurred at dipyrimidine sequences and were predominantly C-->T or T-->C transitions, consistent with UVB-induced DNA damage.
Conclusions:
- Green tea consumption demonstrates a protective effect against UVB-induced skin tumorigenesis in mice.
- Green tea may alter the mutational landscape of the p53 gene in UVB-induced skin tumors.
- The findings suggest that green tea constituents may interfere with UVB-induced DNA damage or modulate cellular responses to such damage, potentially through pathways involving the p53 gene.