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Estrogen (E2) and Progesterone (Pg) via their specific receptors, ER and PR respectively, are major determinants in the development and progression of endometrial malignancies. We have studied how E2 and the synthetic progestin R5020 affect genomic function in Ishikawa endometrial cancer cells. Using ChIPseq in cells exposed to the corresponding hormones, we identified cell specific binding sites for ER (ERbs) and PR (PRbs), mostly binding to independent sites and both adjacent to PAXbs. Long-range interactions (HiC) showed enrichment of PRbs and PAXbs, which we call progestin control regions (PgCRs) inside TADs with differentially progestin-regulated genes. Effects of hormone treatments on gene expression were detected by RNAseq. PgCRs correlate with open chromatin independently of hormonal stimuli. In summary, endometrial response to progestins in differentiated endometrial tumor cells results in part from binding of PR to compartmentalized PgCRs in hormone-independent open chromatin, which include binding of partner transcription factors, in particular PAX2.

Though the decidua serves a critical function in implantation, the hormonal regulated pathway in decidualization is still elusive. Here we describe in detail the regional distribution and the effects of progesterone receptors (PGR), estrogen receptors (ESR), and MAPK activation on decidualization. We showed an increase in PGR A, PGR B, ESR1, and phosphorylated MAPK3-1 proteins (p-MAPK3-1), but not in ESR2, in the decidual tissue up to Day 8 of pregnancy. PGR was predominantly found in the nuclei of mesometrial decidual cells and of undifferentiated stromal cells where it colocalizes with ESR2 and ESR1. In the antimesometrial decidua, all the receptors showed cytoplasmic localization. MAPK was activated exclusively in undifferentiated stromal cells of the junctional zone between the antimesometrial and mesometrial decidua and at the border of the antimesometrial decidua. Treatment with the progesterone antagonist onapristone and/or the estrogen antagonist faslodex reduced the extent of decidual tissue and downregulated the levels of PGR and ESR1. The expression level of ESR2 was affected only by the progesterone receptor antagonist, while neither the antiprogestin nor the antiestrogen significantly modified the p-MAPK3-1 level. The inhibition of MAPK3-1 phosphorylation by PD98059 impaired the extent of decidualization and the closure reaction of the implantation chamber, and significantly downregulated ESR1. These results confirm a role of both steroid receptors in the growth and differentiation of the different decidual regions and suggest a new function for p-MAPK3-1 in regulating expression levels of ESR1, thereby maintaining the proliferation capacity of stromal cells and limiting the differentiation process in specified regions of decidual tissues. Fil: Vallejo, Griselda. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); Argentina Fil: Mestre Citrinovitz, Ana Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); Argentina Fil: Moenckendiek. Verena. Universitat Duisburg - Essen; Alemania Fil: Grümmer, Ruth. Universitat Duisburg - Essen; Alemania Fil: Winterhager, Elke. Universitat Duisburg - Essen; Alemania Fil: Saragueta, Patricia Esther. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); Argentina

During the preimplantation phase of pregnancy the endometrial stroma differentiates into decidua, a process that implies numerous morphological changes and is an example of physiological transdifferentiation. Here we show that UIII rat endometrial stromal cells cultured in the presence of calf serum acquired morphological features of decidual cells and expressed decidual markers. To identify genes involved in decidualization we compared gene expression patterns of control and decidualized UIII cells using cDNA microarray. We found 322 annotated genes exhibiting significant differences in expression (>3-fold, fold discovery rate (FDR) >0.005), of which 312 have not been previously related to decidualization. Analysis of overrepresented functions revealed that protein synthesis, gene expression, and chromatin architecture and remodeling are the most relevant modified functions during decidualization. Relevant genes are also found in the functional terms differentiation, cell proliferation, signal transduction, and matrix/structural proteins. Several of these new genes involved in decidualization (Csdc2, Trim27, Eef1a1, Bmp1, Wt1, Aes, Gna12, and Men1) are shown to be also regulated in uterine decidua during normal pregnancy. Thus, the UIII cell culture model will allow future mechanistic studies to define the transcriptional network regulating reprogramming of stromal cells into decidual cells., Facultad de Ciencias Exactas