Dataset Information


Genes regulated by estrogen and 4-hydroxytamoxifen in MCF-7:PF cells

ABSTRACT: MCF-7:PF is a a new in vitro model of antihormone resistant breast cancer that exhibits the characteristics of acquired tamoxifen resistance in vivo. It is well known that estrogen (E2) induces apoptosis in long-term estrogen-deprived breast cancer cells, MCF-7:5C (PubMed References PMID:15862958, PMID:16333030). MCF-7:PF was derived from MCF-7:5C through inhibition of c-Src, which blocks E2-induced apoptosis, coverts E2 responses from apoptosis to proliferation. MCF-7:PF cell growth is stimulated by E2 and SERMS in an ERα-dependent manner. Abstract: A c-Src inhibitor blocks estrogen (E2)-induced stress and converts E2 responses from inducing apoptosis to stimulating growth in E2-deprived breast cancer cells. A resulting cell line, MCF-7:PF, is reprogrammed with features of functional estrogen receptor (ER) and over-expression of insulin-like growth factor-1 receptor beta (IGF-1Rβ). We addressed the question of whether the antiestrogenic selective ER modulator 4-hydroxytamoxifen (4-OHT) could target ER to prevent E2-stimulated growth in MCF-7:PF cells. Unexpectedly, 4-OHT stimulated cell growth in an ER-dependent manner. However, unlike E2, 4-OHT suppressed classic ER-target genes as does the pure antiestrogen ICI 182,780, even during growth stimulation. Chromatin-immunoprecipitation (ChIP) assay indicated that 4-OHT did not recruit ER or nuclear receptor coactivator 3 (SRC3) to the promoter of ER-target gene, pS2. Paradoxically, 4-OHT reduced total IGF-1Rβ but increased phosphorylation of IGF-1Rβ, which was responsible for the activation of the phosphatidylinositol-3 kinases (PI3K)/Akt signaling pathway. Mechanistic studies revealed that 4-OHT rapidly activated the non-genomic pathway through ER, but other membrane-associated proteins such as IGF-1Rβ and c-Src participated. Furthermore, 4-OHT was more potent than E2 to up-regulate membrane remodeling molecules and activated focal adhesion molecules to promote cell growth. Therefore, disruption of membrane-associated signaling completely abolished 4-OHT-stimulated cell growth, but not E2-stimulated cell growth. Despite continued suppression of classic ER-target genes, 4-OHT activated the complex network of cytoskeleton remodeling and extracellular matrix-related signaling which facilitated 4-OHT-stimulated cell growth. This study is the first to recapitulate a cellular model in vitro of acquired tamoxifen (TAM) resistance developed in athymic mice in vivo. Overall design: MCF-7:PF cells were treated with E2, 4-OHT, ICI 182,780, and combinations of E2 or 4-OHT with ICI 182,780 to examine ER-dependent and independent gene regulation patterns by E2 and 4-OHT

INSTRUMENT(S): Agilent-014850 Whole Human Genome Microarray 4x44K G4112F (Feature Number version)

SUBMITTER: Heather E. Cunliffe 

PROVIDER: GSE54171 | GEO | 2014-07-14



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Identification of gene regulation patterns underlying both oestrogen- and tamoxifen-stimulated cell growth through global gene expression profiling in breast cancer cells.

Fan Ping P   Cunliffe Heather E HE   Griffith Obi L OL   Agboke Fadeke A FA   Ramos Pilar P   Gray Joe W JW   Jordan V Craig VC  

European journal of cancer (Oxford, England : 1990) 20140915 16

A c-Src inhibitor blocks oestrogen (E2)-induced stress and converts E2 responses from inducing apoptosis to growth stimulation in E2-deprived breast cancer cells. A reprogrammed cell line, MCF-7:PF, results in a functional oestrogen receptor (ER). We addressed the question of whether the selective ER modulator 4-hydroxytamoxifen (4-OHT) could target ER to prevent E2-stimulated growth in MCF-7:PF cells.Expression of mRNA was measured through real-time RT-PCR. Global gene expression profile was an  ...[more]

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