title: Interplay of estrogen receptors and GPR30 for the regulation of early membrane initiated transcriptional effects: A pharmacological approach.
abstract: Estrogens exert their effect through ERα and ERβ intracellular transcription factors and rapid, usually membrane-initiated receptors, influencing cytosolic signaling and transcription. The nature of extranuclear estrogen elements has not been elucidated so far; classical or alternatively transcribed ER isoforms (ERα36, ERα46) anchored to the plasma membrane and GPR30 (GPER1) have been reported to exert early estrogen actions. Here, we used E2-BSA, an impermeable estradiol analog for a transcriptome analysis in four GREP1 positive breast cancer cell lines with different estrogen receptor profiles (T47D, MCF-7, MDA-MB-231 and SKBR3) in order to evaluate GPER1 transcriptional effects. Early effects of E2-BSA were assayed after 3h of incubation, in the absence/presence of ICI182,780 (ER-inhibitor) or G15 (GREP1-specific inhibitor). E2-BSA specifically modified 277-549 transcripts in the different cell lines. Two different clusters of transcripts could be identified: (1) the majority of transcripts were inhibited by both ICI182,780 and G15, suggesting an interaction of E2-BSA with a common ER-related element, or a direct ER-GPER1 interaction; (2) a small number of G15-only modified transcripts, in two cell lines (T47D and SKBR3 cells), indicative of specific GPER1-related effects. The latter transcripts were significantly related to pathways including FOXA2/FOXA3 transcription factor networks, RNA-Polymerases Transcription Regulation and lipid metabolism, while ICI/G15 inhibited transcripts affected pathways related to apoptosis, erythropoietin signaling, metabolic effects through the citric acid cycle, IL-4 and IL-5 mediated events and homologous DNA recombination. Finally, we review the current literature of GPER1 actions, in view of our results of ER-dependent and independent GPER1-modified pathways.
authors.affiliation: Laboratory of Experimental Endocrinology, University of Crete, School of Medicine, Greece. gnotas@med.uoc.gr
authors.forename: George
authors.initials: G
authors.lastname: Notas
authors.forename: Marilena
authors.initials: M
authors.lastname: Kampa
authors.forename: Vassiliki
authors.initials: V
authors.lastname: Pelekanou
authors.forename: Elias
authors.initials: E
authors.lastname: Castanas
mesh_terms: D001943:Breast Neoplasms; D045744:Cell Line, Tumor; D016000:Cluster Analysis; D004958:Estradiol / Q000031:analogs & derivatives / Q000494:pharmacology; D004967:Estrogens / Q000494:pharmacology; D005260:Female; D000077267:Fulvestrant; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D020411:Oligonucleotide Array Sequence Analysis; D020033:Protein Isoforms / Q000378:metabolism; D011960:Receptors, Estrogen / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism*; D043562:Receptors, G-Protein-Coupled / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism*; D012710:Serum Albumin, Bovine / Q000494:pharmacology; D059467:Transcriptome
chemical_list: D004967:Estrogens; C109584:GPER1 protein, human; D020033:Protein Isoforms; D011960:Receptors, Estrogen; D043562:Receptors, G-Protein-Coupled; C043090:estradiol-bovine serum albumin; D000077267:Fulvestrant; D012710:Serum Albumin, Bovine; D004958:Estradiol