Unknown,Transcriptomics,Genomics,Proteomics

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EpCAM overexpression prolongs proliferative capacity of primary human breast epithelial cells and supports hyperplastic growth

ABSTRACT: Background: The Epithelial Cell Adhesion Molecule (EpCAM) has been shown to be strongly expressed in human breast cancer and cancer stem cells and its overexpression has been supposed to support tumor progression and metastasis. However, effects of EpCAM overexpression on normal breast epithelial cells have never been studied before. Therefore, we analyzed effects of transient adenoviral overexpression of EpCAM on proliferation, migration and differentiation of primary human mammary epithelial cells (HMECs). METHODS: HMECs were transfected by an adenoviral system for transient overexpression of EpCAM. Thereafter, changes in cell proliferation and migration were studied using a real time measurement system. Target gene expression was evaluated by transcriptome analysis in proliferating and polarized HMEC cultures. A Chicken Chorioallantoic Membrane (CAM) xenograft model was used to study effects on in vivo growth of HMECs. RESULTS: EpCAM overexpression in HMECs did not significantly alter gene expression profile of proliferating or growth arrested cells. Proliferating HMECs displayed predominantly glycosylated EpCAM isoforms and were inhibited in cell proliferation and migration by upregulation of p27KIP1 and p53. HMECs with overexpression of EpCAM showed a down regulation of E-cadherin. Moreover, cells were more resistant to TGF-beta1 induced growth arrest and maintained longer capacities to proliferate in vitro. EpCAM overexpressing HMECs xenografts in chicken embryos showed hyperplastic growth, lack of lumen formation and increased infiltrates of the chicken leukocytes. CONCLUSIONS: EpCAM revealed oncogenic features in normal human breast cells by, inducing resistance to TGF-beta1-mediated growth arrest and supporting a cell phenotype with longer proliferative capacities in vitro. EpCAM overexpression resulted in hyperplastic growth in vivo. Thus, we suggest that EpCAM acts as a prosurvival factor counteracting terminal differentiation processes in normal mammary glands. For each gene a representative transcript probe set was selected based on a score that combines average expression and variation of expression across all samples. Transcript probe sets with more than 4 probes were preferred. Differential expression analysis between EPCAM over-expressing and control cells (expressing GFP) was performed using a paired moderated t-test employing functions provided by Bioconductor's limma package. p-values were subsequently adjusted for multiple hypothesis testing using the method from Benjamini and Hochberg for a strong control of the false discovery rate.

ORGANISM(S): Homo sapiens

SUBMITTER: Johannes Rainer

PROVIDER: E-GEOD-37172 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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EpCAM overexpression prolongs proliferative capacity of primary human breast epithelial cells and supports hyperplastic growth.

Martowicz Agnieszka A Rainer Johannes J Lelong Julien J Spizzo Gilbert G Gastl Guenther G Untergasser Gerold G

Molecular cancer 20130610

<h4>Introduction</h4>The Epithelial Cell Adhesion Molecule (EpCAM) has been shown to be strongly expressed in human breast cancer and cancer stem cells and its overexpression has been supposed to support tumor progression and metastasis. However, effects of EpCAM overexpression on normal breast epithelial cells have never been studied before. Therefore, we analyzed effects of transient adenoviral overexpression of EpCAM on proliferation, migration and differentiation of primary human mammary epi ...[more]

PMID: 23758908

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Project description:Introduction: The Epithelial Cell Adhesion Molecule (EpCAM) has been shown to be strongly expressed in human breast cancer and cancer stem cells and its overexpression has been supposed to support tumor progression and metastasis. However, effects of EpCAM overexpression on normal breast epithelial cells have never been studied before. Therefore, we analyzed effects of transient adenoviral overexpression of EpCAM on proliferation, migration and differentiation of primary human mammary epithelial cells (HMECs). METHODS: HMECs were transfected by an adenoviral system for transient overexpression of EpCAM. Thereafter, changes in cell proliferation and migration were studied using a real time measurement system. Target gene expression was evaluated by transcriptome analysis in proliferating and polarized HMEC cultures. A Chicken Chorioallantoic Membrane (CAM) xenograft model was used to study effects on in vivo growth of HMECs. RESULTS: EpCAM overexpression in HMECs did not significantly alter gene expression profile of proliferating or growth arrested cells. Proliferating HMECs displayed predominantly glycosylated EpCAM isoforms and were inhibited in cell proliferation and migration by upregulation of p27KIP1 and p53. HMECs with overexpression of EpCAM showed a down regulation of E-cadherin. Moreover, cells were more resistant to TGF-beta1 induced growth arrest and maintained longer capacities to proliferate in vitro. EpCAM overexpressing HMECs xenografts in chicken embryos showed hyperplastic growth, lack of lumen formation and increased infiltrates of the chicken leukocytes. CONCLUSIONS: EpCAM revealed oncogenic features in normal human breast cells by, inducing resistance to TGF-beta1-mediated growth arrest and supporting a cell phenotype with longer proliferative capacities in vitro. EpCAM overexpression resulted in hyperplastic growth in vivo. Thus, we suggest that EpCAM acts as a prosurvival factor counteracting terminal differentiation processes in normal mammary glands. Differential expression was assessed with the moderated t-test (Bioconductor's limma package) with pairing of the samples by the donor. Raw p-values were adjusted for multiple hypothesis testing using the method from Benjamini and Hochberg for a strong control of the false discovery rate. EPCAM and GFP over-expression in proliferating mammary epithelial cells from two donors (6 and 8). Expression levels between EPCAM and control samples were compared to determine whether, and to which extent EPCAM over-expression alters the gene expression profile of the cells.

Project description:Background: The Epithelial Cell Adhesion Molecule (EpCAM) has been shown to be strongly expressed in human breast cancer and cancer stem cells and its overexpression has been supposed to support tumor progression and metastasis. However, effects of EpCAM overexpression on normal breast epithelial cells have never been studied before. Therefore, we analyzed effects of transient adenoviral overexpression of EpCAM on proliferation, migration and differentiation of primary human mammary epithelial cells (HMECs). METHODS: HMECs were transfected by an adenoviral system for transient overexpression of EpCAM. Thereafter, changes in cell proliferation and migration were studied using a real time measurement system. Target gene expression was evaluated by transcriptome analysis in proliferating and polarized HMEC cultures. A Chicken Chorioallantoic Membrane (CAM) xenograft model was used to study effects on in vivo growth of HMECs. RESULTS: EpCAM overexpression in HMECs did not significantly alter gene expression profile of proliferating or growth arrested cells. Proliferating HMECs displayed predominantly glycosylated EpCAM isoforms and were inhibited in cell proliferation and migration by upregulation of p27KIP1 and p53. HMECs with overexpression of EpCAM showed a down regulation of E-cadherin. Moreover, cells were more resistant to TGF-beta1 induced growth arrest and maintained longer capacities to proliferate in vitro. EpCAM overexpressing HMECs xenografts in chicken embryos showed hyperplastic growth, lack of lumen formation and increased infiltrates of the chicken leukocytes. CONCLUSIONS: EpCAM revealed oncogenic features in normal human breast cells by, inducing resistance to TGF-beta1-mediated growth arrest and supporting a cell phenotype with longer proliferative capacities in vitro. EpCAM overexpression resulted in hyperplastic growth in vivo. Thus, we suggest that EpCAM acts as a prosurvival factor counteracting terminal differentiation processes in normal mammary glands.

Project description:This dataset is part of the manuscript titled "The metabolic regulator ERRalpha, a downstream target of HER2/IGF1, as a therapeutic target in breast cancer" (in review). The expression data obtained in human mammary epithelial cells were used to generate a list of ERRalpha-regulated genes that was later refined in clinical breast cancer datasets to generate a clinically relevant signature of ERalpha activity (referred to as Cluster 3 signature). Using this signature of the estrogen-related receptor alpha (ERRa) to profile more than eight-hundred breast tumors, we found that patients with tumors exhibiting higher ERRa activity were predicted to have shorter disease free survival. Further, the ability of an ERRa antagonist, XCT790, to inhibit breast cancer cell proliferation correlates with the cellâs intrinsic ERRa activity. These findings highlight the potential of using the ERRa signature and antagonists in targeted therapy for breast cancer. Using a chemical genomic approach we determined that activation of the HER2/IGF1 signaling pathways upregulates the expression of PGC-1b, an obligate cofactor for ERRa activity. Knockdown of PGC-1b in HER2 positive breast cancer cells impaired ERRa signaling and reduced cell proliferation, implicating a functional role of PGC1b/ERRa in the pathogenesis HER2 positive breast cancer. Primary human mammary epithelial cells were a gift from Dr. J. Marks (Duke University, Durham, NC) and cultured in MEBM (Cambrex, East Rutherford, NJ) with MEGM bullet kit and supplemented with 5mg/ml transferrin and 10-5M isoproterenol. To generate ERR-alpha signature, hMECs were serum starved for 36h followed by infection with MOI=150 of adenoviruses expressing two variants of PGC1alpha, a protein ligand for ERRalpha: PGC-1alpha2x9 or PGC-1alpha L2L3M. PGC-1-2x9 is specific to ERRalpha, while PGC-1-L2L3M lacks the NR box and does not interact with ERRalpha or other nuclear receptors. The generation and purification of variant PGC-1alpha viruses were described previously (Gaillard et al., Molecular Cell 24:5, 2006). Comparable expression levels of the two PGC-1alpha variants were verified by Western immonoblot analysis (data not shown). RNA was collect 16h after infection and purified using RNeasy mini kit (Qiagen, Valencia, CA). Ten independent biological replicates from each virus infection were collected.

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EpCAM overexpression prolongs proliferative capacity of primary human breast epithelial cells and supports hyperplastic growth

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EpCAM overexpression prolongs proliferative capacity of primary human breast epithelial cells and supports hyperplastic growth.

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