• 한국환경성돌연변이발암원학회지
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• 제25권1호
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• pp.6-12
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• 2005

Many compounds might become activated after absorption of UV light energy. In some cases, the resulting molecule may undergo further biological reaction of toxicological relevance related especially to the photo-carcinogenicity resulting from photo-genotoxicity. However, no regulatory requirements have been issued with the exception of guideline issued by the Scientific Committee of Cosmetology, Commission of the European Communities (SCC/EEC) on the testing of sunscreens for their photo-genotoxicity. Thus, the objectives of this study are to investigate the utility of photo-Ames assay for detecting photo-mutagens, and to evaluate its ability to predict rodent photo-carcinogenicity. Photo-Ames assay was performed on five test substances that demonstrated positive results in photo-carcinogenicity tests: 8-methoxypsoralen (photoactive substance that forms DNA adducts in the presence of ultraviolet A irradiation), chlorpromazine (an aliphatic phenothiazine an a-adr-energic blocking agent), lomefloxacin (an antibiotic in a class of drugs called fluoroquinolones), anthracene (a tricyclic aromatic hydrocarbon a basic substance for production of anthraquinone, dyes, pigments, insecticides, wood preservatives and coating materials) and retinoic acid (a retinoid compound closely related to vitamin A). Out of 5 test substances, 3 showed a positive outcome in photo-Ames assay. With this limited data set, an investigation into the predictive value of this photo-Ames test for determining the photo-carcinogenicity showed that photo-Ames assay has relatively low sensitivity (the ability of a test to predict carcinogenicity). Thus, to determine the use of in vitro genotoxicity tests for prediction of carcinogenicity,' several standard photo-genotoxicity assays should be compared for their suitability in detecting photo-genotoxic compounds.

• 한국환경성돌연변이발암원학회지
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• 제25권1호
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• pp.40-46
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• 2005

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) displays high toxicity in animals and has been implicated in human carcinogenesis. Although the mechanism of carcinogenesis by TCDD is unclear, it is considered to be a non-genotoxic compound and tumor promoter. In our experiment, we investigated the effects of TCDD on gene expression in mouse skin carcinogenesis. We used cDNA microarray to detect the differential gene expression in tumors induced in hairless mouse skin by MNNG plus TCDD protocol. We found that erb-2, c-ets2 and p27$^{kip1}$ were significantly up-regulated, but TNFR2, AKT-l, integrin $\beta$l, maspin, IGF-l, c-raf-l, Rb were significantly down-regulated, in tumor region, respectively. We also found that the expression of 53 genes involved in cen cycle, signal transduction, apoptosis, adhesion molecule, angiogenesis, and invasion, were changed two fold more, in tumor surrounding region. These data suggest that TCDD alters the expression of a large array of genes involved in apoptosis, cytokine production and angiogenesis in mouse skin carcinogenesis.