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Members of the ErbB family of receptors have been implicated in regulation of androgen receptor (AR) activity. Ebp1, an ErbB-3 binding protein recently cloned in our laboratory, possesses an LXXLL motif important in mediating interactions with nuclear hormone receptors. Therefore, we sought to determine if Ebp1 could bind AR and influence AR transcriptional(More)
Ectopic expression of ebp1, a member of the PA2G4 family, inhibits the proliferation and induces the differentiation of human breast and prostate cancer cell lines. Ebp1 inhibits transcription of E2F1 and androgen receptor regulated genes such as prostate specific antigen (PSA) through its interactions with histone deacetylases (HDACs). To further(More)
The ErbB2/3 heterodimer plays a critical role in breast cancer progression and in the development of endocrine resistance. EBP1, an ErbB3 binding protein, inhibits HRG-stimulated breast cancer growth, decreases ErbB2 protein levels and contributes to tamoxifen sensitivity. We report here that ectopic expression of EBP1 in Estrogen Receptor (ER) positive(More)
The ErbB3/4 ligand heregulin (HRG) profoundly affects cell growth and differentiation, but its mechanism of action is poorly understood. Ebp1, a protein isolated by its binding to ErbB3, inhibits cell growth and represses transcription of E2F-regulated cell cycle genes. Since Ebp1 shares 38% identity with a Schizosaccharomyces pombe DNA-binding protein, we(More)
Dysregulation of the developmental gene anterior gradient protein 2 (AGR2) has been associated with a metastatic phenotype, but its mechanism of action and control in prostate cancers is unknown. In this study, we show that overexpression of AGR2 promotes the motility and invasiveness of nonmetastatic LNCaP tumor cells, whereas silencing of AGR2 in the(More)
Down-regulation of the androgen receptor (AR) is being evaluated as an effective therapy for the advanced stages of prostate cancer. We report that Ebp1, a protein identified by its interactions with the ErbB3 receptor, down-regulates expression of AR and AR-regulated genes in the LNCaP prostate cancer cell line. Using microarray analysis, we identified six(More)
Aberrant activation of the androgen receptor (AR) by the ErbB2/ErbB3 heterodimer contributes to the development of hormone resistance in prostate cancer. EBP1, an ErbB3-binding protein, acts as an AR corepressor. As EBP1 is decreased in preclinical models of hormone-refractory prostate cancer, we studied the expression of EBP1 in human prostate cancer. We(More)
Androgen receptor (AR)-mediated pathways play a critical role in the development and progression of prostate cancer. However, little is known about the regulation of AR mRNA stability and translation, two central processes that control AR expression. The ErbB3 binding protein 1 (EBP1), an AR corepressor, negatively regulates crosstalk between ErbB3 ligand(More)
Plant organ size shows remarkable uniformity within species indicating strong endogenous control. We have identified a plant growth regulatory gene, functionally and structurally homologous to human EBP1. Plant EBP1 levels are tightly regulated; gene expression is highest in developing organs and correlates with genes involved in ribosome biogenesis and(More)
The ErbB2/3 heterodimer plays a critical role in breast cancer genesis and progression. EBP1, an ErbB3 binding protein, inhibits breast cancer growth but its effects on ErbB3 ligand mediated signal transduction or ErbB receptors is not known. We report here that ectopic expression of EBP1 in MCF-7 and AU565 breast cancer cell lines inhibited HRG-induced(More)