Benzopyrene exposure disrupts DNA methylation and growth dynamics in breast cancer cells. Export

@article{citeulike:3325031, abstract = {Exposures to environmental carcinogens and unhealthy lifestyle choices increase the incidence of breast cancer. One such compound, benzo(a)pyrene (BaP), leads to covalent DNA modifications and the deregulation of gene expression. To date, these mechanisms of BaP-induced carcinogenesis are poorly understood, particularly in the case of breast cancer. We tested the effects of BaP exposure on cellular growth dynamics and DNA methylation in four breast cancer cell lines since disruptions in DNA methylation lead to deregulated gene expression and the loss of genomic integrity. We observed robust time- and concentration-dependent loss of proliferation, S phase and G2M accumulation and apoptosis in p53 positive MCF-7 and T47-D cells. We observed minimal responses in p53 negative HCC-1086 and MDA MB 231 cells. Furthermore, BaP increased p53 levels in both p53 positive cell lines, as well as p21 levels in MCF-7 cells, an effect that was prevented by the p53-specific inhibitor pifithrin-alpha. No changes in global levels of DNA methylation levels induced by BaP were detected by the methyl acceptor assay (MAA) in any cell line, however, methylation profiling by AIMS (amplification of intermethylated sites) analysis showed dynamic, sequence-specific hypo- and hypermethylation events in all cell lines. We also identified BaP-induced hypomethylation events at a number of genomic repeats. Our data confirm the p53-specific disruption of the cell cycle as well as the disruption of DNA methylation as a consequence of BaP treatment, thus reinforcing the link between environmental exposures, DNA methylation and breast cancer.}, address = {Department of Biochemistry, University of Western Ontario, Canada.}, author = {Sadikovic, B. and Rodenhiser, D. I.}, citeulike-article-id = {3325031}, citeulike-linkout-0 = {http://dx.doi.org/10.1016/j.taap.2006.06.012}, citeulike-linkout-1 = {http://view.ncbi.nlm.nih.gov/pubmed/16926039}, citeulike-linkout-2 = {http://www.hubmed.org/display.cgi?uids=16926039}, day = {1}, doi = {10.1016/j.taap.2006.06.012}, issn = {0041-008X}, journal = {Toxicology and applied pharmacology}, keywords = {benzopyrene, breast, exposure, global, methylation, toxicology}, month = {November}, number = {3}, pages = {458--468}, posted-at = {2008-09-23 20:00:34}, priority = {2}, title = {Benzopyrene exposure disrupts DNA methylation and growth dynamics in breast cancer cells.}, url = {http://dx.doi.org/10.1016/j.taap.2006.06.012}, volume = {216}, year = {2006} }

TY - JOUR ID - citeulike:3325031 L3 - citeulike-article-id:3325031 N2 - Exposures to environmental carcinogens and unhealthy lifestyle choices increase the incidence of breast cancer. One such compound, benzo(a)pyrene (BaP), leads to covalent DNA modifications and the deregulation of gene expression. To date, these mechanisms of BaP-induced carcinogenesis are poorly understood, particularly in the case of breast cancer. We tested the effects of BaP exposure on cellular growth dynamics and DNA methylation in four breast cancer cell lines since disruptions in DNA methylation lead to deregulated gene expression and the loss of genomic integrity. We observed robust time- and concentration-dependent loss of proliferation, S phase and G2M accumulation and apoptosis in p53 positive MCF-7 and T47-D cells. We observed minimal responses in p53 negative HCC-1086 and MDA MB 231 cells. Furthermore, BaP increased p53 levels in both p53 positive cell lines, as well as p21 levels in MCF-7 cells, an effect that was prevented by the p53-specific inhibitor pifithrin-alpha. No changes in global levels of DNA methylation levels induced by BaP were detected by the methyl acceptor assay (MAA) in any cell line, however, methylation profiling by AIMS (amplification of intermethylated sites) analysis showed dynamic, sequence-specific hypo- and hypermethylation events in all cell lines. We also identified BaP-induced hypomethylation events at a number of genomic repeats. Our data confirm the p53-specific disruption of the cell cycle as well as the disruption of DNA methylation as a consequence of BaP treatment, thus reinforcing the link between environmental exposures, DNA methylation and breast cancer. IS - 3 JF - Toxicology and applied pharmacology SN - 0041-008X AD - Department of Biochemistry, University of Western Ontario, Canada. EP - 468 TI - Benzopyrene exposure disrupts DNA methylation and growth dynamics in breast cancer cells. VL - 216 SP - 458 KW - benzopyrene KW - breast KW - exposure KW - global KW - methylation KW - toxicology AU - Sadikovic, B AU - Rodenhiser, DI PY - 2006/11/01/ UR - http://dx.doi.org/10.1016/j.taap.2006.06.012 ER -