Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:O76050 (neu)
 3,969 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Established human mammary tumor cell lines constitute an important tool in the study of breast cancer. The aim of this work was to isolate and characterize two new mammary tumor cell lines, JCK and GCS, which were obtained from the pleural effusion and ascitic fluid, respectively, from two breast cancer patients. Both cell lines had some properties of transformed cells, namely immortalization and growth in soft agar. The carcinoma cells presented epithelial morphology shown by light and electron microscopy, and antigenic properties shown by different tumor markers such as a cytokeratin cocktail, carcinoembryonic antigen, epithelial membrane antigen, and human milk fat globule membrane antigen. A significant increase was also found (P greater than 0.05) in cell growth and 3H-thymidine incorporation into DNA in the JCK and GCS cell lines in the presence of 17 beta estradiol at concentrations of 10(-9) and 10(-7) M, respectively, after 5 days in culture. These cells presented estradiol receptor levels which were similar in the biopsies and the resulting cell lines. The aromatase activity was also similar in the JCK cell line and the original patient biopsy. However, there was a considerably higher aromatase activity in the GCS cell line than in the biopsy specimen. Southern hybridizations with the neu oncogene showed an additional 12 kb fragment in both cell lines, as also seen in patients with breast cancer. We conclude from these studies that this in vitro system may provide us with a way to study metastatic cells and improve clinical management of breast cancer patients.
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PMID:New cell lines of human breast cancer origin. 132 92

Breast cancer is the most common malignant tumor among women, comprising an estimated 24% of all cancer cases and 18% of all cancer deaths. At least half of the patients with primary breast cancer will ultimately die by metastatic disease. The tumor characteristics, the natural course of the disease and the response to therapy vary strongly. A number of recently detected cell biological parameters such as oncogenes/suppressor genes, growth factors and secretory proteins are more or less important prognostic factors, because they influence the characteristics and behavior of a tumor with respect to metastatic pattern, extent of cellular differentiation, growth rate and response to treatment. However, there is no clear consensus how best to identify patients at high or low risk. In our experience c-myc amplification and pS2 protein are strong prognosticators for relapse rate, while in advanced disease (apart from a negative estrogen/progesterone receptor/pS2 status) amplification of HER2/neu is a good prognosticator for failure to endocrine therapy. In the diagnosis of breast cancer, in vivo imaging of tumors by labeled hormones or other factors also forms a new development which might have implications for treatment too. With respect to treatment both endocrine and chemotherapy can cure a minority of patients with micrometastases, but in patients with advanced disease only a prolongation of (progression-free) survival can be reached. Response rates decrease with increasing tumor load. In the past decade a number of interesting new endocrine agents has been developed such as new (pure) (anti)steroidal agents, vitamins, aromatase inhibitors, analogs of peptide hormones, prolactin inhibitors and growth factor antagonists. However, less is known on the (potential) interaction between hormones, chemotherapeutic agents, retinoids, cytokins, growth factor antagonists and irradiation. Rapid detection of new powerful combination therapies are needed to improve treatment results during the nineties.
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PMID:Clinical breast cancer, new developments in selection and endocrine treatment of patients. 144 97

The possible role of a novel steroid receptor in ovarian malignancy was investigated. The evolutionarily conserved orphan steroid receptor COUP-TF (chicken ovalbumin upstream promoter transcription factor) was originally identified as a protein interacting with an upstream promoter element of the chicken ovalbumin gene. The human receptor protein was purified from a cervical cancer cell line. An immunocytochemical technique for the visualization of COUP-TF was developed using a specific polyclonal rabbit antibody. Four established ovarian cancer cell lines were evaluated. The patterns of COUP-TF expression were compared to the staining intensities of immunocytochemical assays for estrogen receptor (ER), androgen receptor (AR), aromatase, and HER2/neu. A comparison of the ovarian cancer cell lines showed differential expression of COUP-TF in the nucleus. The pattern of COUP-TF expression did not follow the profile of any of the other four variables. In agreement with transfection experiments showing reduction of activity of other steroid receptors by elevated COUP-TF levels, high COUP-TF expression correlated with low ER activity also in native ovarian cancer cells. These data represent the first reported evidence that COUP-TF-like proteins may play a role in the metabolism and possibly in the process of dedifferentiation of human ovarian cancer.
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PMID:Chicken ovalbumin upstream promoter transcription factor (COUP-TF): an orphan steroid receptor with a specific pattern of differential expression in human ovarian cancer cell lines. 790 49

Endocrine therapy remains an important approach to the treatment of metastatic breast cancer because of its effectiveness and excellent tolerability. In the last 10 years, a number of new endocrine therapies have been introduced. These include the luteinizing hormone-releasing hormone agonists, which produce menopausal changes in premenopausal women; the aromatase inhibitors, which prevent production of estrogen in postmenopausal women; and the estrogen receptor down-regulator fulvestrant (Faslodex), which is effective in postmenopausal women whose tumors have progressed following response to other selective estrogen receptor modulators. The endocrine cascade for the treatment of premenopausal women with metastatic disease now involves the concurrent or sequential combination of a luteinizing hormone-releasing hormone analogue and tamoxifen, whereas the cascade for the treatment of postmenopausal women can begin with tamoxifen followed by an aromatase inhibitor or with an aromatase inhibitor followed by tamoxifen. The optimal cascade following the use of an aromatase inhibitor and tamoxifen in postmenopausal women remains unclear, but fulvestrant and megestrol acetate or the use of an aromatase inactivator (exemestane) following an aromatase inhibitor are all available options with some activity. Over the next few years, clinical trials will clarify the optimal sequence of endocrine therapy for postmenopausal women. The use of estrogen and progesterone receptor status to select for endocrine therapy is undeniably crucial. HER2/neu overexpression may also predict response to endocrine therapy, but this remains controversial.
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PMID:Endocrine therapy of advanced disease: analysis and implications of the existing data. 1253 1

Endocrine therapy remains important in the adjuvant treatment of pre- and postmenopausal women. Adjuvant ovarian ablation with or without tamoxifen produces effects which are equivalent to those of CMF (cyclophosphamide, methotrexate and 5-fluorouracil) chemotherapy in premenopausal women with oestrogen receptor (ER) and/or progesterone receptor (PgR) positive breast cancer. Tamoxifen alone is also effective in these women. Concurrent use of tamoxifen and ovarian ablation may be even more effective, but more studies are needed. Tamoxifen remains a standard adjuvant therapy for postmenopausal women with ER and/or PgR positive tumours. Current information supports the use of 5 years of tamoxifen but additional studies comparing 5 years to longer duration are ongoing. The aromatase inhibitor (AI) anastrozole has now been demonstrated to be better than tamoxifen in preventing recurrence in early reports from the Arimidex vs Tamoxifen And the Combination (ATAC) Trial. Ongoing trials of this and other AIs before, after, concurrent with, or substituted for tamoxifen in the adjuvant setting may soon revolutionize our approach for postmenopausal women. Adjuvant bisphosphonates have been shown to reduce the incidence of bone metastases and improve survival in two of three published adjuvant trials and are being further studied. Her-2 neu status is being explored as a predictive factor for selection of endocrine therapy, but is not yet considered standard for this purpose.
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PMID:The best use of adjuvant endocrine treatments. 1465 27

Breast cancer represents a major health problem, with more than 1,000,000 new cases and 370,000 deaths yearly worldwide. In the last decade, in spite of an increasing incidence, breast cancer mortality has been declining in the majority of developed countries. This is the combined result of better education, widespread screening programmes and more efficacious adjuvant treatments. Better knowledge of breast cancer biology now allows the cosmetic, physical and psychological consequences of radical mastectomy to be spared in the majority of breast cancer patients. Use of the sentinel node technique is rapidly expanding and this will further reduce the extent and the consequences of surgery. Several clinico-pathological factors are used to discriminate between patients at low (<10%), average (10-40%) and high risk of relapse. Nodal status, tumour size, tumour grade and age are accepted universally as important factors to define risk categories. Newer factors such as uPA/PAI-1, HERer2-neu, proliferative indices and gene expression profile are promising and will allow better discrimination between patients at different risk. Endocrine manipulation with tamoxifen, ovarian ablation or both is the preferred option in the case of endocrine-responsive tumours. Tamoxifen administered for 5 years is the standard treatment for postmenopausal patients; tamoxifen plus ovarian ablation is more effective than tamoxifen alone for premenopausal women. Recent data demonstrate that, for postmenopausal patients, the aromatase inhibitors are superior to tamoxifen, with a different safety profile. At present, anastrozole can be used in the adjuvant setting in cases of tamoxifen intolerance or toxicity. Chemotherapy is the treatment of choice for steroid receptor-negative tumours. Polychemotherapy is superior to single agents and anthracycline-containing regimens are superior to CMF. Six courses of FEC or FAC or the sequential administration of four doses of anthracycline followed by four of CMF are the recommended regimens. New regimens including the taxanes have produced a further improvement in risk reduction and are reasonable therapeutic options. The taxanes have been approved for adjuvant therapy in the USA, while European approval is pending. Combined endocrine-chemotherapy is the standard adjuvant treatment in high-risk patients with endocrine-responsive tumours. Endocrine manipulation is usually administered after completion of the chemotherapy programme. For HER2-neu overexpressing tumours, several rapidly accruing trials are exploring the potential additive effect of trastuzumab, a monoclonal antibody directed against the extramembrane portion of the HER2 receptor. Primary chemotherapy is increasingly used in the treatment of locally advanced and operable breast cancer, with increased rates of breast-conserving surgery. A proportion of patients achieve a pathological complete response and these patients have significantly better long-term outcomes. Twenty-five to forty percent of breast cancer patients develop distant metastases. At this stage the disease is incurable; however, treatments can assure a significant prolongation of survival, symptomatic control and maintenance of quality of life. In the case of hormone receptor positivity and in the absence of visceral, life-threatening disease, endocrine manipulation is the treatment of choice. Active treatments include tamoxifen, ovarian ablation, aromatase inhibitors, pure anti-oestrogens and progestins. Aromatase inhibitors are the most active agents, but the choice and the sequence of endocrine therapies are also dictated by prior adjuvant treatment. Chemotherapy has to be preferred in cases of receptor-negative tumours, acquired resistance to hormones and aggressive visceral disease. Combination regimens are usually associated with higher response rates and sometimes survival prolongation, and this approach should be recommended in young patients with good performance status and visceral disease. On the other hand, single agents have a better tolerability profile and should be tand should be the treatment of choice when a careful balance between activity and tolerability is needed. For HER2-neu positive tumours, the combination of trastuzumab and chemotherapy is significantly superior to chemotherapy alone in terms of both response rates and survival. Other useful palliative treatments include bisphosphonates for the control of metastatic bone disease and radiotherapy for painful bone lesions or local relapses.
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PMID:The curability of breast cancer and the treatment of advanced disease. 1510 48

The aromatase enzyme, which converts androstenedione to oestrone, regulates the availability of oestrogen to support the growth of hormone-dependent breast tumours. In this study, we investigated the inhibitory effects of black tea polyphenols on aromatase activities. We found that black tea polyphenols, TF-1, TF-2 and TF-3, significantly inhibited rat ovarian and human placental aromatase activities. In addition, using an in vivo model, these black tea polyphenols also inhibited the proliferation induced by 100 nM dehydroepiandrosterone (DHEA) in MCF-7 cells. Transfection of HER2/neu in MCF-7 breast cancer cells appeared to be associated with an increased resistance of the cells to hormonal therapy. Interestingly, unlike the selective oestrogen receptor modulator (SERM) tamoxifen, black tea polyphenols had antiproliferation effects in breast cancer cells with hormonal resistance. The inhibitory effect of black tea polyphenols on hormone-resistant breast cancer cells suppressed the basal receptor tyrosine phosphorylation in HER2/neu-overexpressing MCF-7 cells. These findings suggest the use of black tea polyphenols may be beneficial in the chemoprevention of hormone-dependent breast tumours and represent a possible remedy to overcome hormonal resistance of hormone-independent breast tumours.
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PMID:Black tea polyphenol theaflavins inhibit aromatase activity and attenuate tamoxifen resistance in HER2/neu-transfected human breast cancer cells through tyrosine kinase suppression. 1534 93

Currently, the standard of care for estrogen receptor (ER)-positive breast cancer is 5 years of tamoxifen (TAM) or an aromatase inhibitor (AI) such as anastrozole. New studies indicate that extending antiestrogen therapy beyond 5 years with sequential regimens will improve disease-free survival. Based on the emerging concept that longer therapies are better, we have developed sequential models of tamoxifen-resistant breast cancer in vivo to mimic the clinical scenario of long-term antiestrogen therapy. The goal of the current study was to investigate the consequences of long-term treatment with tamoxifen on the growth of breast tumors in athymic mice. The results demonstrate that there are distinct phases of resistance to tamoxifen that correlate with time of treatment and expression of HER2/neu mRNA. In the treatment phase, 17beta-estradiol (E2) stimulated growth, while TAM inhibited growth of MCF-7 tumors (MCF-7E2). The withdrawal of treatment, mimicking the use of an AI, completely prevented growth. In Phase I resistance, the tumors (MCF-7TAMST) were growth-stimulated by either E2 or TAM, but inhibited by no treatment, fulvestrant, or E2 + fulvestrant. Phase II-resistant tumors (MCF-7TAMLT) were treated for more than 5 years and growth-stimulated by TAM. However, no treatment, fulvestrant, or E2 completely inhibited growth. Interestingly, the few tumors (MCF-7TAMLT) that survived in response to E2 were robustly re-stimulated by E2 after transplantation into new generations of athymic mice. These E2-stimulated tumors (MCF-7TAME) were inhibited by TAM in a dose-dependent similar to their parental tumors (MCF-7E2). In addition, the MCF-7TAME tumors were inhibited by either no treatment or fulvestrant. HER2/neu and HER3 mRNAs were over-expressed in TAM-stimulated MCF-7TAMLT tumors and remained high in E2-stimulated MCF-7TAME tumors. The data indicate that complete reversal of resistance to TAM can be achieved with the use of low dose E2 therapy. Also, these data suggest that over-expression of HER2/neu alone is insufficient to predict resistance to TAM. Based on the results, we suggest using an alternating treatment regimen, cycling antiestrogen with estrogen therapy to avoid drug-resistance.
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PMID:Reversal of tamoxifen resistant breast cancer by low dose estrogen therapy. 1586 Feb 67

Fulvestrant, an estrogen receptor antagonist with no known agonist effects, is effective and well tolerated in the treatment of hormone-sensitive breast cancer after antiestrogen failure in postmenopausal women. Numerous phase II and III clinical trials of fulvestrant that are designed to build on its efficacy in breast cancer and explore its value in other tumors are ongoing or in the final planning stage. Favorable safety, dose-response, and pharmacokinetic data led to the initiation of clinical trials to evaluate loading and higher doses with the aim of building on the well-defined efficacy of fulvestrant. Recently reported results of phase II trials by the North Central Cancer Treatment Group and the Swiss Group for Clinical Cancer Research support the clinical activity of fulvestrant after recurrence or progression on a nonsteroidal aromatase inhibitor, and 2 international phase III trials are ongoing in this setting. As a first-line treatment for metastatic disease, fulvestrant is currently being evaluated in combination with anastrozole versus anastrozole alone in 2 phase III trials, 1 by the Southwest Oncology Group and the other being conducted mainly in Scandinavia. Preclinical data have also led to randomized phase II trials of fulvestrant in combination with the epidermal growth factor receptor tyrosine kinase inhibitor, gefitinib, and the HER2/neu-targeted antibody trastuzumab. Additional phase II and III trials are currently evaluating fulvestrant plus tipifarnib, Theratope vaccine, or the dual kinase inhibitor, GW572016. Although fulvestrant is undergoing robust clinical development as a treatment for breast cancer, investigation of this agent in other types of solid tumors has only just begun.
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PMID:Current and future perspectives on fulvestrant. 1586 48

Breast cancers are a biologically heterogeneous group of mammary tumors with distinct natural histories and varied responses to established therapies. They have long been divided into those that are hormone sensitive [as defined by expression of the estrogen receptor alpha (ERalpha) and/or the progesterone receptor (PR)] and those that are not. Notably, only those breast cancers that express ERalpha and/or PR typically respond to hormonal therapy with tamoxifen, aromatase inhibitors, or the newer agent fulvestrant. More recently, the transmembrane tyrosine kinase receptor HER-2/neu was identified as an oncogene overexpressed by about 30% of breast cancers. These HER-2/neu-overexpressing breast cancers define a subset of breast tumors that are characteristically more aggressive, and women who develop them have a shorter survival. Trastuzumab (Herceptin), a humanized monoclonal antibody specific for HER-2/neu, has revolutionized the management of metastatic HER-2/neu-overexpressing breast cancers. As a single agent, it produces response rates similar to those of many single-agent chemotherapeutic agents active in metastatic breast cancer and has limited toxicity. Combining trastuzumab with chemotherapy can result in synergistic antitumor activity. The clear efficacy of trastuzumab against HER-2/neu-overexpressing metastatic breast cancer has led to a keen interest in testing its role in the management of early breast cancer, and multiple large clinical trials are currently in progress. This review summarizes the available clinical data on the use of trastuzumab in HER-neu-overexpressing breast cancer and briefly highlights emerging opportunities for innovative, trastuzumab-based breast cancer therapies.
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PMID:Trastuzumab: targeted therapy for the management of HER-2/neu-overexpressing metastatic breast cancer. 1589 Dec 69


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