Journal Article

Response of human mammary epithelial cells to DNA damage induced by BPDE: involvement of novel regulatory pathways

Aijin Wang, Jing Gu, Kimberly Judson-Kremer, K.Leslie Powell, Harsha Mistry, Padmaja Simhambhatla, C. Marcelo Aldaz, Sally Gaddis and Michael C. MacLeod

in Carcinogenesis

Volume 24, issue 2, pages 225-234
Published in print February 2003 | ISSN: 0143-3334
Published online February 2003 | e-ISSN: 1460-2180 | DOI: http://dx.doi.org/10.1093/carcin/24.2.225
Response of human mammary epithelial cells to DNA damage induced by BPDE: involvement of novel regulatory pathways

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The responses of a line of normal human mammary epithelial cells, HME87, to treatment with the ultimate carcinogen benzo[a]pyrene diol epoxide (BPDE) were analyzed using a directed gene expression analysis technique, RAGE. Under conditions where cell number was decreased by 50% 24 or 48 h post-treatment, flow cytometry demonstrated no establishment of a G1/S arrest nor induction of apoptosis; cells continued to enter S phase from G1 for at least 24 h but were blocked at G2/M. Using the RAGE technique, changes in gene expression were assayed for over 1000 genes, and multiple time-point data were collected for ~90 genes. In accord with the cell cycle studies, expression of the p21-WAF1 gene, the major mediator of p53-dependent G1/S arrest, did not increase until 24 h post-treatment. The expression of other target genes for transactivation by p53 was increased at early time points, including GADD45, an effector of the G2/M checkpoint, and WIP1. Analyses of proteins in treated cells indicated that p53 was phosphorylated at Ser15 but not at Ser20 within 30 min of treatment, and this correlated with an increase in the total amount of p53 protein. Significant expression changes were noted in a number of transcription factor genes, including ATF3 and E2A, genes that have not been previously connected to a response to DNA damage involving bulky chemical adducts. In addition, expression of the XPC gene was induced by BPDE treatment; the XPC product is thought to be involved in recognition of DNA damage by the nucleotide excision repair system.

Keywords: BPDE, 7r,8t-dihydroxy-9,10t-oxy-7,8,9,10-tetrahydrobenzo [a]pyrene; BrdU, 5-bromo-2-deoxyuridine; IR, ionizing radiation; JNK, jun N-terminal kinase; PAH, polycyclic aromatic hydrocarbon; PBS, phosphate-buffered saline; RAGE, rapid analysis of gene expression; SAPK, stress-activated protein kinase; UV, ultraviolet

Journal Article.  8853 words.  Illustrated.

Subjects: Clinical Cytogenetics and Molecular Genetics

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