ER17p is a peptide corresponding to the sequence P295LMIKRSKKNSLALSLT311 of the
ER17p is a peptide corresponding to the sequence P295LMIKRSKKNSLALSLT311 of the estrogen receptor alpha (ER) and initially found to interfere with ER\related calmodulin binding. use of ER17p as a selective peptidomimetic estrogen receptor modulator (PERM). transcription factors analysis revealed GLI2, THRB, STAT5A & B and FOXO4 as putatively activated by ER17p, while CREB1, NFB1 and STAT3 are down\regulated (Supplemental Table 3). The GLI transcription factor family is classically associated with the Hedgehog pathway. However, recent data (reviewed in Javelaud et?al., 2011) link TGF (a gene up\regulated in our data set) and GLI. Likewise, we recently reported that CREB and NFB are down\regulated in breast cancer cells, through E2 non\genomic pathways (Kampa et?al., 2012), providing evidence of opposite nuclear and extranuclear actions of estrogens. In the same context, the thyroid hormone receptor (THR), down\regulated in our study, has been reported to be affected by estrogens in fish (Filby et?al., 2006), but never before in humans. Furthermore, this is the first report identifying a link between FOXO4 and ER. Lastly, it should be stressed that we have already reported that STAT3 activation is a sustained effect of membrane\acting androgen (Pelekanou et?al., 2010) and estrogen (Kampa et?al., 2012), providing a link between membrane and nuclear estrogenic effects. 188.8.131.52. ER36\related signature of ER17p The ER36 938444-93-0 IC50 is an ER variant, initially identified in ER\negative cell lines (Wang et?al., 2005, 2006) as well as in triple\negative breast tumors (Pelekanou et?al., 2011b), in addition to KIAA1732 ER\positive breast cancer cells (Kampa et?al., 2012; Notas et?al., 2011; Pelekanou et?al., 938444-93-0 IC50 2011b). Its presence could explain some of the E2 effects, previously claimed as ER\independent. The ER17p sequence is conserved in ER36, suggesting that this receptor variant might be subjected to similar regulatory interactions, as ER. Although some reports identified fulvestrant (ICI 182,780, a pure ER antagonist) as an inert agent on ER36 (Ohshiro et?al., 2012; Wang et?al., 2006), in our hands it acted as an antagonist (Pelekanou et?al., 2011b, and unpublished observations), suggesting that the binding pocket of the ER36 receptor adopts a conformation similar to that of wild\type ER. Thus, ER17p may exert similar effects on this variant. In a previous study we have identified the transcriptional signature of ER36 in SKBR3 cells (Pelekanou et?al., 2011b), in which ER17p exerts proapoptotic effects and influences cell migration (Kampa et?al., 2011; Pelekanou et?al., 2011a). Here, we compared ER36\modified genes (Pelekanou et?al., 2011b) with either E2\ or ER17p\modified transcripts and identified a list of 218 commonly modified elements (Supplemental Table 4). Of interest, all these transcripts/genes were down\regulated by ER17p and E2, pointing\out ER36 as a mainly inhibitory receptor. Regulation of some of these genes was verified by qRT\PCR (Figure?6A). By comparing this list of transcripts in the T47D cells, equally positive for ER36 (Pelekanou et?al., 2011b), we identified 163 transcripts (75% of total) that were modified in a similar manner by ER17p, giving further weight to our approach, i.e., of a specific transcriptional signature of ER17p on the ER36 receptor (Supplemental Table 4). Figure 6 qRT\PCR verification of the E2\ and ER17p\modified genes, and immune pathways inhibited by ER36 activation in SKBR3 cells. A. Both E2 and ER17p inhibited the expression of ICAM1, RND, MAP3K8 and IRF1 … GO associated terms of ER36\related ER17p\regulated transcripts (Supplemental Table 4 and Supplemental Figure?5) revealed the down\regulation of genes involved in cell proliferation, apoptosis and immune\related processes. Interestingly, the same GO terms were found in the subset of 163 common genes between T47D and SKBR3 cells. NGF 938444-93-0 IC50 family, Ca2+\calmodulin, VEGF, death and apoptotic signaling (mediated by NRAGE, not previously identified in relation to estrogen), innate immunity and signaling through p38 isoforms, CREB and PLC are the main down\regulated pathways (Supplemental Table 4). A strict Gene Set Enrichment Analysis (GSEA) of the 218 transcripts recovered 29 genes, significantly down\regulated by the peptide. They were associated with (i) immunity and inflammatory processes; (ii) cell proliferation, invasiveness and apoptosis; (iii) actin cytoskeleton remodeling and (iv) signal transduction (Supplemental Table 4). For a number.