The molecular mechanisms underlying the acquisition of resistance to the antiestrogen Faslodex are poorly understood, although enhanced expression and activity of nuclear factor kappaB (NFkappaB) have been implicated as a critical element of this phenotype. The purpose of this study was to elucidate the mechanism by which NFkappaB up-regulation contributes to Faslodex resistance and to determin...

Phytoestrogens have been investigated as natural alternatives to hormone replacement therapy and their potential as chemopreventive agents. We investigated the effects of equol, genistein, and coumestrol on cell growth in fully estrogenized MCF7 cells, simulating the perimenopausal state, and long-term estrogen-deprived MCF7:5C cells, which simulate the postmenopausal state of a woman after yea...

The estrogen receptor alpha (ERα) is a ligand-activated transcription factor that possesses two activating domains designated AF-1 and AF-2 that mediate its transcriptional activity. The role of AF-2 is to recruit coregulator protein complexes capable of modifying chromatin condensation status. In contrast, the mechanism responsible for the ligand-independent AF-1 activity and for its synergist...

The aim of this study was to characterize the hematogeneous spread, in vivo, of breast cancer (BC) cell lines that express hormonal receptors (HR) comparing with triple-negative (TN) BC, particularly considering the lung and liver. Female Balb/c nu nu mice (n=30) were injected with two breast cancer cell lines (MCF7 and HCC1806). Nuclear medicine imaging with Technetium ((99m)Tc)-hydroxymethyle...

Breast cancer resistance to the antiestrogens tamoxifen (OHT) and fulvestrant is accompanied by alterations in both estrogen-dependent and estrogen-independent signaling pathways. Consequently, effective inhibition of both pathways may be necessary to block proliferation of antiestrogen-resistant breast cancer cells. In this study, we examined the effects of apigenin, a dietary plant flavonoid ...

Environmental contaminants might adversely affect human health by acting as endocrine disruptors and thus need to be identified. Our objective was to optimize the MCF7 cell proliferation assay to screen industrial chemicals for potential oestrogenic effects. Growth conditions, performance of the clone E3 and WT-MCF7 cells and five methods to derive proliferation indices were compared. The E3 ce...

Although rapid signaling by estrogen at the plasma membrane is established, it is controversial as to the nature of the receptor protein. Estrogen may bind membrane proteins comparable to classical nuclear estrogen receptors (ERs), but some studies identify nonclassical receptors, such as G protein-coupled receptor (GPR)30. We took several approaches to define membrane-localized estrogen-bindin...

Resistance to cytotoxic nucleoside analogues is a major problem in cancer treatment. The cellular mechanisms involved in this phenomenon have been studied for several years, and some factors have been identified. However, this resistance seems to be multifactorial and more studies are needed to gain better insight into this domain. For this purpose, we developed a gemcitabine-resistant cell lin...

Prostate, breast, and probably other epithelial tumors harbor inactivating mutations in the p53 tumor suppressor gene in the stromal cells, implying the nonautonomous action of p53 in carcinogenesis. We have tested this hypothesis by evaluating the tumorigenicity of MCF7 human breast cancer cells in severe combined immunodeficient mice that differ in their p53 status. Our results showed that, i...