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RESEARCH PRODUCT

Relationship of Dibenzo[a, l]pyrene-DNA Binding to the Induction of p53, p21WAFIand Cell Cycle Arrest in Human Cells in Culture

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Abstract The tumor suppressor protein p53 plays an important role in recognition of DNA damage and induction of subsequent cell cycle arrest. One of its target genes encodes the p21 WAFI protein which is involved in the mediation of growth arrest after DNA damage has occured. The exceptionally potent carcino-genic polycyclic aromatic hydrocarbon (PAH) dibenzo[a, l]pyrene (DB[a, l]P) and its ultimate metabolites, the fjord region (+)-syn- and (-)-anti-11,12-diol 13,14-epoxides (DB[a, l]PDE), were used in order to investigate DNA damage via adduct formation, subsequent induction of p53 and p21 WAFI , and cell growth behavior in human mammary carcinoma MCF-7 cells. Exposure of MCF-7 cells to 0.005 μM DB[a, l]P caused a total DNA binding of 25 pmol adducts/mg DNA (48 hrs after treatment) and a significant increase in the level of p53 (12–72 hrs after treatment). 48 hrs after exposure an increased amount of the p21 WAFI protein was detected and its level remained elevated for the time measured (168 hrs). Treat...