Expression of the PEA3 group of ETS-related transcription factors in human breast-cancer cells.
The PEA3 group of transcription factors belongs to the ets family and is composed of 3 known members, PEA3, ERM and ER81, which are more than 95% identical within the DNA-binding ETS domain and exhibit 50% aa identity overall. Recently, transgenic mice bearing the c-erbB-2/neu oncogene have been shown to over-express PEA3 mRNA in mammary adenocarcinomas, suggesting a role for this gene family in mammary tumorigenesis. In the present work we characterized the mRNA expression levels of PEA3-group genes in a series of human epithelial breast cell lines. Each of the 3 genes was highly expressed in normal human HMEC 1001-7 and HMEC 219-4 cells. In breast-cancer cell lines, the 3 genes were highly expressed in the ER- MDA-MB-436, MDA-MB-330, MDA-MB-231 and BT-20 cell lines, but not in the ER+ MDA-MB-134-VI and ZR-75-1 cells. In an attempt to characterize the PEA3-group proteins in breast-cancer cells, we first produced and characterized specific antibodies against each of these 3 proteins. The anti-ERM and anti-ER81 antibodies recognized specific strong bands at approximately 72 kDa and 62 kDa, corresponding to ERM and ER81, respectively, in MDA-MB-231 and Hs-578T cells expressing significant levels of the 3 mRNAs. No protein was detected in MCF-7 cells expressing low levels of mRNA for PEA3-group-family genes, or in ZR-75-1 cells, where mRNA was undetectable by Northern blot. Although in vitro-translated PEA3 is specifically immunoprecipitated by anti-PEA3 anti-serum, we were unable to immunoprecipitate PEA3 protein from MDA-MB-231 and Hs-578T cells. In order to study the transcription factor activity of ERM, PEA3 and ER81 proteins in mammary-cancer cells, we tested their ability to transactivate a reporter plasmid containing 3 Ets-binding sites, and were able to show that, in all the breast-cancer cells tested, transfected ERM, PEA3 and ER81 are able to transactivate. Although the target genes of the PEA3 group of transcription factors in breast-cancer cells have yet to be determined, these genes have a potential role in the regulation of growth and the progression of human breast cancer.
Baert
J L
JL
Unité d'Oncologie Moléculaire, CNRS URA 1160, Institut Pasteur de Lille, France.
Monté
D
D
Musgrove
E A
EA
Albagli
O
O
Sutherland
R L
RL
de Launoit
Y
Y
D000818:Animals; D000918:Antibody Specificity; D001943:Breast Neoplasms / Q000276:immunology / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000276:immunology / Q000378:metabolism*; D015870:Gene Expression; D006801:Humans; D051379:Mice; D009363:Neoplasm Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D014162:Transfection; D014407:Tumor Cells, Cultured
D004268:DNA-Binding Proteins; C095239:ETV1 protein, human; C086680:ETV5 protein, human; C490641:Etv1 protein, mouse; C513242:Etv5 protein, mouse; D009363:Neoplasm Proteins; D012333:RNA, Messenger; D014157:Transcription Factors; C065788:transcription factor PEA3