Production and oestrogen regulation of FGF1 in normal and cancer breast cells.
To investigate the relationship between the FGF1 oestrogen regulation and the normal/cancer status of breast cells, we have studied FGF1 17beta-oestradiol regulation in normal, transformed and cancerous cells. Normal (NMEC), transformed (HBL-100) and cancerous (MCF-7, MDA-MB-231) human mammary epithelial cells express different levels of FGF1 mRNAs. Western blot analysis allowed us to characterize FGF1 as an 18 kDa form of this polypeptide. Using a neutralizing anti-FGF1 antibody we demonstrated that FGF1 is secreted by all mammary cells studied and stimulates their proliferation in an autocrine manner. We have examined the regulation of FGF1 mRNAs in response to 17beta-oestradiol. FGF1 mRNAs were upregulated in hormone-dependent NMEC but was not upregulated either in hormone-sensitive HBL-100 cells or in the hormone-dependent cancerous cell line MCF-7. However, enzyme linked immunosorbent assay indicated an increase of FGF1 protein in NMEC, HBL-100 and MCF-7 cells. We have also examined the 17beta-oestradiol regulation of the four alternatively spliced FGF1 mRNAs: 1.A, 1.B, 1. C and 1.D. Only 1.B transcripts were downregulated by 17beta-oestradiol in normal cells. These results show that 17beta-oestradiol regulates FGF1 mRNAs in a cell-specific manner, and that this regulation may be transcriptional or translational depending on cell phenotype. The specificity of oestradiol effects was checked using its receptor antagonist tamoxifen.
El Yazidi
I
I
Laboratoire de Chimie Biologique UMR 111 du CNRS, Université des Sciences et Technologies de Lille, 59655 Villeneuve d'Ascq Cedex, France.
Renaud
F
F
Laurent
M
M
Courtois
Y
Y
Boilly-Marer
Y
Y
D017398:Alternative Splicing; D019898:Autocrine Communication; D001940:Breast / Q000187:drug effects / Q000378:metabolism*; D001943:Breast Neoplasms / Q000378:metabolism*; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D016220:Fibroblast Growth Factor 1 / Q000096:biosynthesis* / Q000235:genetics; D006801:Humans; D008934:Mitogens / Q000096:biosynthesis / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis; D015854:Up-Regulation
D008934:Mitogens; D012333:RNA, Messenger; D016220:Fibroblast Growth Factor 1; D004958:Estradiol