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Transcription profiling of human MCF7 breast cancer cells MCF-7 two hours post incubation with heregulin (HRG)) vs. controls to detect HRG regulated genes

ABSTRACT: Heregulin beta-1 (HRG) is an extracellular ligand that activates mitogen-activated protein kinase (MAPK) and phosphatidylinositol-3-OH kinase (PI3K)/Akt signaling pathways through ErbB receptors. MAPK and Akt have been shown to phosphorylate the estrogen receptor (ER) at Ser-118 and Ser-167, respectively, thereby mimicking the effects of estrogenic activity such as estrogen responsive element (ERE)-dependent transcription. In the current study, integrative analysis was performed using two tiling array platforms, comprising histone H3 lysine 9 (H3K9) acetylation and RNA mapping, together with array comparative genomic hybridization (CGH) analysis in an effort to identify HRG-regulated genes in ER-positive MCF-7 breast cancer cells. Through application of various threshold settings, 333 (326 up-regulated and 7 down-regulated) HRG-regulated genes were detected. Prediction of upstream transcription factors (TFs) and pathway analysis indicated that 21% of HRG-induced gene regulation may be controlled by the MAPK cascade, while only 0.6% of the gene expression is controlled by ERE. A comparison with previously reported estrogen (E2)-regulated gene expression data revealed that only 12 common genes were identified between the 333 HRG-regulated (3.6%) and 239 E2-regulated (5.0%) gene groups. However, with respect to enriched upstream TFs, 4 common TFs were identified in the 14 HRG-regulated (28.6%) and 13 E2-regulated (30.8%) gene groups. These results indicated that while E2 and HRG may induce common TFs, the regulatory mechanisms that govern HRG- and E2-induced gene expression differ. Experiment Overall Design: MCF-7 human breast cancer cells were incubated 2hour after administration of 10nM of the growth hormones (heregulin (HRG)). Control was set as growth hormone non-treated cells.

ORGANISM(S): Homo sapiens

SUBMITTER: Hatakeyama Mariko

PROVIDER: S-ECPF-GEOD-8471 | biostudies-other |

REPOSITORIES: biostudies-other

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Project description:BackgroundAcquired resistance to endocrine therapy in breast cancer is a significant problem with relapse being associated with local and/or regional recurrence and frequent distant metastases. Breast cancer cell models reveal that endocrine resistance is accompanied by a gain in aggressive behaviour driven in part through altered growth factor receptor signalling, particularly involving erbB family receptors. Recently we identified that CD44, a transmembrane cell adhesion receptor known to interact with growth factor receptors, is upregulated in tamoxifen-resistant (TamR) MCF7 breast cancer cells. The purpose of this study was to explore the consequences of CD44 upregulation in an MCF7 cell model of acquired tamoxifen resistance, specifically with respect to the hypothesis that CD44 may influence erbB activity to promote an adverse phenotype.MethodsCD44 expression in MCF7 and TamR cells was assessed by RT-PCR, Western blotting and immunocytochemistry. Immunofluorescence and immunoprecipitation studies revealed CD44-erbB associations. TamR cells (± siRNA-mediated CD44 suppression) or MCF7 cells (± transfection with the CD44 gene) were treated with the CD44 ligand, hyaluronon (HA), or heregulin and their in vitro growth (MTT), migration (Boyden chamber and wound healing) and invasion (Matrigel transwell migration) determined. erbB signalling was assessed using Western blotting. The effect of HA on erbB family dimerisation in TamR cells was determined by immunoprecipitation in the presence or absence of CD44 siRNA.ResultsTamR cells overexpressed CD44 where it was seen to associate with erbB2 at the cell surface. siRNA-mediated suppression of CD44 in TamR cells significantly attenuated their response to heregulin, inhibiting heregulin-induced cell migration and invasion. Furthermore, TamR cells exhibited enhanced sensitivity to HA, with HA treatment resulting in modulation of erbB dimerisation, ligand-independent activation of erbB2 and EGFR and induction of cell migration. Overexpression of CD44 in MCF7 cells, which lack endogenous CD44, generated an HA-sensitive phenotype, with HA-stimulation promoting erbB/EGFR activation and migration.ConclusionsThese data suggest an important role for CD44 in the context of tamoxifen-resistance where it may augment cellular response to erbB ligands and HA, factors that are reported to be present within the tumour microenvironment in vivo. Thus CD44 may present an important determinant of breast cancer progression in the setting of endocrine resistance.

Project description:To compare the benefits of magnesium sulfate for 24 h (h) postpartum versus 6 h postpartum in patients who received magnesium sulfate (Mg) for less than 8 h before birth.A randomized, multicenter, open study was conducted between November 2013 and October 2016 in three teaching maternity hospitals in Panama. Pregnant women diagnosed with severe pre-eclampsia or pre-eclampsia with severe features at more than 20 weeks gestation were invited to participate. They were randomized to the following groups in a 1:1 ratio: A- continue Mg for 24 h after birth (control group); and B- receive Mg for 6 h after birth (experimental group). The primary endpoint and variable was seizure (eclampsia) in the first 72 h postpartum.During the study period, 284 patients agreed to participate in the study; 143 were randomized to receive Mg for 24 h postpartum and 141 to receive Mg for 6 h postpartum. There were no significant differences in the baseline characteristics of the two groups studied. There was no eclampsia in the entire population; therefore, there was no significant difference in the primary variable. Two secondary variables showed a significant difference: time to onset of ambulation, which was 14 h shorter (p = 0.0001) in the group that received 6 h of postpartum Mg, and time to initiation of breastfeeding, which was 11 h earlier (p = 0.0001) in the group that received 6 h of postpartum Mg. There were not significant differences between the groups with respect to total complications or any particular complication. There were no cases of maternal death.Maintaining Mg for 6 h postpartum is equally effective in preventing eclampsia as receiving Mg for 24 h postpartum in patients with severe pre-eclampsia who receive less than 8 h of Mg treatment before birth. The onset of maternal ambulation and initiation of breastfeeding are faster in patients who only receive Mg for 6 h postpartum.The study was registered at clinical-trials.gov, number NCT02317146 . Date of registration: December 11, 2014. This study was registered at clinical trials after the beginning of recruitment of patients.

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Transcription profiling of human MCF7 breast cancer cells MCF-7 two hours post incubation with heregulin (HRG)) vs. controls to detect HRG regulated genes

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