Green tea polyphenol epigallocatechin-3 gallate (EGCG) affects gene expression of breast cancer cells transformed by the carcinogen 7,12-dimethylbenz[a]anthracene.
Since the 1980s, the incidence of late-onset breast cancer has been increasing in the United States. Known risk factors, such as genetic modifications, have been estimated to account for approximately 5 to 10% of breast cancer cases, and these tend to be early onset. Thus, exposure to and bioaccumulation of ubiquitous environmental chemicals, such as polycyclic aromatic hydrocarbons (PAHs), have been proposed to play a role in this increased incidence. Treatment of female Sprague-Dawley rats with a single dose of the PAH 7,12-dimethylbenz[a]anthracene (DMBA) induces mammary tumors in approximately 90 to 95% of test animals. We showed previously that female rats treated with DMBA and given green tea as drinking fluid displayed significantly decreased mammary tumor burden and invasiveness and a significantly increased latency to first tumor. Here we used cDNA microarray analysis to elucidate the effects of the green tea polyphenol epigallocatechin-3 gallate (EGCG) on the gene expression profile in a DMBA-transformed breast cancer cell line. RNA was isolated, in quadruplicate, from D3-1 cells treated with 60 mug/mL EGCG for 2, 7, or 24 h and subjected to analysis. Semiquantitative RT-PCR and Northern blot analyses confirmed the changes in the expression of 12 representative genes seen in the microarray experiments. Overall, our results documented EGCG-altered expression of genes involved in nuclear and cytoplasmic transport, transformation, redox signaling, response to hypoxia, and PAHs.
Guo
Shangqin
S
Department of Biochemistry and Women's Health Interdisciplinary Research Center, Boston University School of Medicine, Boston, MA 02118-2394, USA.
Yang
Sanghwa
S
Taylor
Chad
C
Sonenshein
Gail E
GE
D015127:9,10-Dimethyl-1,2-benzanthracene / Q000037:antagonists & inhibitors* / Q000633:toxicity; D016588:Anticarcinogenic Agents / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000139:chemically induced / Q000235:genetics* / Q000517:prevention & control; D002273:Carcinogens / Q000037:antagonists & inhibitors*; D002392:Catechin / Q000031:analogs & derivatives* / Q000627:therapeutic use; D005260:Female; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D006801:Humans; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014407:Tumor Cells, Cultured
D016588:Anticarcinogenic Agents; D002273:Carcinogens; D015127:9,10-Dimethyl-1,2-benzanthracene; D002392:Catechin; C045651:epigallocatechin gallate