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Time-course effect of estradiol and ERa17p on Early Gene expression in SKBR3 cells

ABSTRACT: ERα17p is a synthetic peptide corresponding to the sequence P295LMIKRSKKNSLALSLT311 of the estrogen receptor alpha (ERα) and initially synthesized to mimic its calmodulin binding site. ERα17p was subsequently found to elicit estrogenic responses in E2-deprived ERα-positive breast cancer cells, increasing proliferation and E2-dependent gene transcription. Surprisingly, in E2-supplemented media, ERα17p induced apoptosis and modified the actin network, influencing thereby cell motility. Here, we report that ERα17p induces a massive early (3h) transcriptional activity in breast cancer cell lines SKBR3). Remarkably, about 75% of the significantly modified transcripts were also modified by E2, confirming the pro-estrogenic profile of ERα17p. The different ER spectra of the used cell lines allowed us to extract a specific ERα17p signature related to ERα and its variant ERα36. With respect to ERα, the peptide activates nuclear (cell cycle, cell proliferation, nucleic acid and protein synthesis) and extranuclear signaling pathways. In contrast, through ERα36 it exerts inhibitory events on inflammation and cell cycle and inhibition of EGFR signaling. This is the first work reporting ERα36 specific transcriptional effects. The fact that a number ERα17p-induced transcripts is different from those activated by E2 revealed that the apoptosis and actin modifying effects of ERα17p are independent from the ER-related actions of the peptide.

ORGANISM(S): Homo sapiens

PROVIDER: GSE39719 | GEO | 2012/07/31

SECONDARY ACCESSION(S): PRJNA171551

REPOSITORIES: GEO

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Project description:ERM-NM-117p is a synthetic peptide corresponding to the sequence P295LMIKRSKKNSLALSLT311 of the estrogen receptor alpha (ERM-NM-1) and initially synthesized to mimic its calmodulin binding site. ERM-NM-117p was subsequently found to elicit estrogenic responses in E2-deprived ERM-NM-1-positive breast cancer cells, increasing proliferation and E2-dependent gene transcription. Surprisingly, in E2-supplemented media, ERM-NM-117p induced apoptosis and modified the actin network, influencing thereby cell motility. Here, we report that ERM-NM-117p induces a massive early (3h) transcriptional activity in breast cancer cell lines SKBR3). Remarkably, about 75% of the significantly modified transcripts were also modified by E2, confirming the pro-estrogenic profile of ERM-NM-117p. The different ER spectra of the used cell lines allowed us to extract a specific ERM-NM-117p signature related to ERM-NM-1 and its variant ERM-NM-136. With respect to ERM-NM-1, the peptide activates nuclear (cell cycle, cell proliferation, nucleic acid and protein synthesis) and extranuclear signaling pathways. In contrast, through ERM-NM-136 it exerts inhibitory events on inflammation and cell cycle and inhibition of EGFR signaling. This is the first work reporting ERM-NM-136 specific transcriptional effects. The fact that a number ERM-NM-117p-induced transcripts is different from those activated by E2 revealed that the apoptosis and actin modifying effects of ERM-NM-117p are independent from the ER-related actions of the peptide. Cells after a 4h incubation with medium containing 10% charcoal stripped FBS were incubated with or without E2 (10-6M) or ERa17p in RPMI 1640 supplemented with 10% charcoal stripped FBS, for 3 hours. Total RNA was isolated using Nucleospin II columns (Macheray-Nagel, Dttren, Germany), according to the manufacturerM-bM-^@M-^Ys instructions. RNA was labeled and hybridized according to the Affymetrix protocol (Affymetrix Gene-Chip Expression Analysis Technical Manual), using the HGU133A plus 2 chip, analyzing a total of 54675 transcripts. Signals were detected by an Affymetrix microarray chip reader.

Project description:Cancer cell motility and invasiveness are fundamental characteristics of the malignant phenotype and are regulated through diverse signaling networks involving kinases and transcription factors. In this study, we identify a nuclear hormone receptor (ERα)-protein kinase (ERK5)-cofilin (CFL1) network that specifies the degree of breast cancer cell aggressiveness through coupling of actin reorganization and hormone receptor-mediated transcription. Using dominant negative and constitutively active forms, as well as small molecule inhibitors of ERK5 and MEK5, we show that hormone activation of estrogen receptor-α determines the nuclear versus cytoplasmic localization of the MAPK family member ERK5, which functions as a coregulator of ERα-gene transcription. Notably, ERK5 works with the actin remodeling protein, CFL1, and upon hormone exposure both became localized to transcription factories in the nucleus, verified by immunofluorescence and proximity ligation assays. Both factors facilitated PAF1 recruitment to the RNA Pol II complex and both ERK5 and CFL1 were required for regulation of gene transcription. By contrast, in cells lacking ERα, ERK5 and CFL1 localized to cytoplasmic membrane regions of high actin remodeling, promoting cell motility and invasion, thereby revealing a mechanism likely to contribute to the generally poorer prognosis of ERα-negative breast cancers. Our study uncovers the dynamic interplay of nuclear receptor-mediated transcription and actin reorganization in phenotypes of breast cancer aggressiveness, and highlights new prognostic biomarkers and suggests novel approaches for developing targeted therapies to moderate cancer aggressiveness. MCF-7 human breast adenocarcinoma cells were tranfected with control, and ERK5 siRNA for 72 hours and treated with 0.1% EtOH (Vehicle) or 10 nM E2 for 24 hours, and cDNA microarray analyses were carried out using Affymetrix [HG-U133A_2] Affymetrix Human Genome U133A 2.0 Array. siRNA knock-down, ligand treatment

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Time-course effect of estradiol and ERa17p on Early Gene expression in SKBR3 cells

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