To determine whether this overexpression contributes to the drug resistant phenotype, EGF receptor transfected ZR75B human breast cancer cells were examined.
To investigate the role of Raf-1 kinase expression and its activation in breast cancer, we studied three human breast cancer cell lines expressing varying amounts of EGF receptor to determine the level of Raf-1 protein and the proportion expressed in the higher molecular weight form.
Transforming growth factor alpha (TGF alpha) and Transforming growth factor beta-1 (TGF-beta 1) are growth regulatory for breast cancer cell lines in vitro and several studies have suggested that levels of the receptor for TGF alpha, the epidermal growth factor (EGFR) in tumour biopsies predict relapse and survival.
Epidermal growth factor family members are widely expressed in human breast cancer and are thought to play an important dual role in mammary gland development and tumorigenesis.
Four lines of evidence lead us to conclude that E2 induces BRCA1 primarily through an increase in DNA synthesis: (1) The kinetics and magnitude of induction are different from the directly E2 inducible gene, pS2; (2) Induction of BRCA1, but not pS2, is blocked by cycloheximide indicating that de novo protein synthesis is required; (3) Other hormonal and growth factor treatments that induce DNA synthesis have a similar effect, including IGF-1, EGF and DNA synthetic flares induced by tamoxifen and retinoic acid; (4) BRCA1 genomic fragments near the 5' end of the gene containing putative estrogen response elements fail to respond to E2 when transfected into breast cancer cell lines.
EGF-R expression was positively related with proliferation activity, suggesting that EGF-R could be involved in the regulation of breast cancer cell growth.
In this report we have studied arachidonic acid and linoleic acid metabolism in the human breast carcinoma cell line BT-20 which overexpresses both EGF receptor and the homologous erbB-2 oncogene product.
Therefore, we investigated the expression of EGF and TGF alpha mRNA in 146 breast cancer biopsies by slot blot analysis using specific 32P-labelled probes.
Furthermore, using gel retardation assay, we show that 12-O-tetradecanoylphorbol-13-acetate- and epidermal growth factor-induced AP-1 binding activity in breast cancer cells is inhibited by RME.
Furthermore, experiments with an EGF receptor-specific inhibitor indicated that the constitutive activation of Stat3 in these breast carcinoma cell lines is not necessarily dependent on signaling through the EGF receptor, although EGF stimulation further increases Stat3 activation.
Their effects on c-fos mRNA levels after induction by either epidermal growth factor (EGF) or the tumour promoting phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) was measured in human breast cancer-derived MDA-MB-468 cells.
We examined the effects of epidermal growth factor (EGF) on MDA-MB-468 cells to understand its mechanism of action in an EGF receptor-rich breast cancer cell line.
The epidermal growth factor (EFG) family of receptors and their respective ligands play a major role in breast cancer progression and are the targets of new therapeutic approaches.
Our results emphasized the usefulness of quantitative receptor determination suggesting the relative stability of EGF-R content during the clinical course of breast cancer, its independence from ER, its significant predictive and weak prognostic values, and a possible correlation with the aggressiveness of the disease, and response to non-endocrine treatments.
The authors investigated the effects of synthetic BN/GRP antagonists RC-3095 and RC-3940-II on tumor growth and the expression of mRNA for EGF receptors and three BN receptor subtypes in MDA-MB-468 human breast carcinoma.
The role of epidermal growth factor (EGF) in the regulation of estrogen receptor-alpha (ER-alpha) gene expression in the human breast cancer cell line MCF-7 was investigated.
These results indicate that breast cancer inhibition by P108 is independent of binding to hydrophobic ligands and is perhaps mediated by interference with EGF-dependent signaling pathways.
We examined transforming growth factor (TGF) alpha, epidermal growth factor (EGF) and EGF receptor (EGFR) expression and signaling in three drug resistant MCF-7 human breast cancer sublines and asked whether these pathways contribute to the drug resistance phenotype.
These results suggest that the binding of LHRH agonists and antagonists to their receptors inhibits the mitogenic signal transduction pathway of the EGF receptor in endometrial, ovarian, and breast cancer cell lines.
We undertook this study to determine whether epidermal growth factor (EGF) treatment could produce a signaling cascade resulting in phosphorylation of the forkhead transcription factor FKHR in a breast cancer cell line, MDA-MB-231.
Comparative studies of WIBC-9, three established non-IBC xenografts, and a human breast cancer cell line (SK-BR3) by reverse transcription-PCR, ELISA, and immunohistochemistry indicated that certain human genes (interleukin 8, vascular epidermal growth factor, basic fibroblast growth factor, angiopoietin 13, Flt-1, Tie-2, and Tie-1) and certain murine genes (integrin alpha(v)beta3, flt-1, tie-2, vascular epidermal growth factor, and CD31) were overexpressed in exposure to tumor cells.