Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P04626 (erbB-2)
 5,251 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Using a commercial kit with antibodies against the ectodomain of c-erbB-2 protein, we detected c-erbB-2 immunoreactivity in human serum. We found that the percentages of patients with elevated serum c-erbB-2 immunoreactivities were 35, 21, and 9% in breast, prostate, and ovarian carcinoma, respectively. The majority of the elevated immunoreactivities were associated with sera containing highly elevated tumor markers with the highest in breast carcinoma (35%) and lowest in ovarian cancer (9%). Excellent correlations were also observed between the serum levels of c-erbB-2 immunoreactivity and the dominant tumor markers in serial specimens from individual cancer patients. We could also detect the c-erbB-2 immunoreactivity in the cytosols prepared from the breast tumor tissue for estrogen and progesterone receptor (ER & PgR) measurements using the same commercial kit for serum studies, and the intact c-erbB-2 oncoprotein (p185) in the extracts of the tissue membrane fractions with a different kit designed for tissue extract. The level of c-erbB-2 immunoreactivity in the cytosol from 124 human breast tumor specimens had an excellent correlation with the cell membrane concentrations of p185 (gamma = 0.89). Most of the elevated cytosol c-erbB-2 immunoreactivities were also found to associate with breast tumor specimens containing low concentrations of ER & PgR. It appears that measuring the c-erbB-2 immunoreactivity potentially could be used as a prognostic marker without performing tissue biopsies and also as a serum tumor marker for managing cancer patients.
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PMID:Measurement of c-erbB-2 proteins in sera from patients with carcinomas and in breast tumor tissue cytosols: correlation with serum tumor markers and membrane-bound oncoprotein. 754 55

The erbB-2 oncogene encodes a transmembrane protein tyrosine kinase which plays a pivotal role in signal transduction and has been implicated when overexpressed in breast, ovarian, and gastric cancers. Naturally occurring benzoquinoid ansamycin antibiotics herbimycin A, geldanamycin (GDM), and dihydrogeldanamycin were found to potently deplete p185, the erbB-2 oncoprotein, in human breast cancer SKBR-3 cells in culture. Chemistry efforts to modify selectively the quinoid moiety of GDM afforded derivatives with greater potency in vitro and in vivo. Analogs demonstrated inhibition of p185 phosphotyrosine in cell culture and in vivo after systemic drug administration to nu/nu nude mice bearing Fisher rat embryo cells transfected with human erbB-2 (FRE/erbB-2). Specifically, dosed intraperitoneally at 100 mg/kg, 17-(allylamino)-17-demethoxygeldanamycin and other 17-amino analogs were effective at reducing p185 phosphotyrosine in subcutaneous flank FRE/erbB-2 tumors. Modifications to the 17-19-positions of the quinone ring revealed a broad structure-activity relationship in vitro.
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PMID:Inhibition of the oncogene product p185erbB-2 in vitro and in vivo by geldanamycin and dihydrogeldanamycin derivatives. 756 11

Overexpression of the erbB-2 oncogene has been linked to poor prognosis in breast, ovarian, and gastric cancers. Naturally occurring benzoquinoid ansamycin antibiotics herbimycin A, geldanamycin (GDM), and dihydrogeldanamycin were found to potently deplete p185, the erbB-2 oncoprotein, in human breast cancer SKBR-3 cells in culture. Chemistry efforts to modify selectively the ansa ring of GDM afforded derivatives with greater potency in vitro and in vivo. Analogs demonstrated inhibition of p185 phosphotyrosine in cell culture and in vivo after systemic drug administration to nu/nu nude mice bearing Fisher rat embryo cells transfected with human erbB-2. Functional group modification in the ansa ring was performed stereoselectively and regiospecifically without the need for protection strategies. Essential functional groups that were required for anti-erbB-2 activity were the 7-carbamate and the 2,3-double bond. Modification of the functional groups at the other positions was permitted. Structure-activity relationships are described for 1-5-, 7-9-, 11-, 15-, and 22-substituted geldanamycins.
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PMID:erbB-2 oncogene inhibition by geldanamycin derivatives: synthesis, mechanism of action, and structure-activity relationships. 756 12

We have identified and characterized c-erbB-2 protein molecules in sera from patients with carcinomas, in both cytosol and cell membrane extract from breast tumor tissue and in both the culture medium and cell extract of the SK-BR-3 cell line. These proteins were characterized by various chromatographic techniques and identified by the use of two immunoassays; one measures both the c-erbB-2 oncoprotein (p185) and its ectodomain (p120), and the other in-house assay reacts specifically for p185. We found that the majority of the immunoreactivity detected in the serum, tumor tissue cytosol, and conditioned cell medium was derived from the ectodomain molecule (p120) of the c-erbB-2 oncoprotein (p185), whereas only p185 was detected in the extracts from cell membrane of both tumor tissue and the SK-BR-3 cell line. The ectodomain molecules (p120) found in the serum, cytosol, and cell medium were very similar in terms of molecular size and charge property. The molecular weight was determined to be 120 kDa by the size exclusion HPLC method. Both p120 and p185 are glycoproteins and were retained by the ConA Sepharose column. Both molecules are also heterogeneous in charge and multiple peaks could be identified in the elution profiles of anion exchange HPLC and chromatofocusing. This information should not only facilitate the isolation of these molecules, but also improve preparation of specific antibodies, preparation of calibrators, and development of improved assays for these proteins.
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PMID:Identification and characterization of c-erbB-2 proteins in serum, breast tumor tissue, and SK-BR-3 cell line. 760 22

Epithelial ovarian cancer probably occurs due to activation of several different combinations of genes, which produce cancers that vary biologically and clinically. We tested this hypothesis in 100 consecutive ovarian carcinomas by molecular biology techniques at the DNA and protein levels in three genes (erbB-2, myc, ras), which are frequently altered in this tumor system. Abnormally high expression of erbB-2 gene encoded p185 protein was observed in 31% of the samples, while erbB-2 gene amplification was detected by Southern analysis in 8%. ErbB-2 abnormal gene expression did not significantly affect the clinical outcome of patients, conferring a marginal worsening of survival. In 25 out of 96 (26%) tumor samples there was myc amplification. Higher levels of the ras-encoded p21 protein than in normal ovaries and benign ovarian tumors were found in 45% of the samples. Simultaneous overexpression of p185 and p21 was associated with shorter disease free (p = 0.02) and overall survival (p = 0.04) at significance levels notably higher than those observed for these oncoproteins singly. In addition, survival of patients with myc amplification and high p185/p21 coexpression was significantly worse (p < 0.05) than that of patients with normal levels. Our data suggest that concurrent abnormal gene expression may act synergistically to endow ovarian tumor cells with a highly aggressive phenotype. Evaluation of these genes may be helpful in the biological characterization of ovarian cancer and in defining individual patient prognosis.
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PMID:Concurrent abnormal expression of erbB-2, myc and ras genes is associated with poor outcome of ovarian cancer patients. 765 38

Over-expression of the c-erbB-2 (HER-2/neu) gene product p185 occurs in 30% of breast and ovarian cancers. The p185 protein might serve as a target for serotherapy in that antibodies against different epitopes on the extracellular domain of p185 can inhibit growth of tumor cells in the absence of cellular or humoral effector mechanisms. To define epitopes of functional relevance, 11 monoclonal antibodies (MAbs) were evaluated for their ability to bind to the extracellular domain of p185. Results of competition studies with 125I-labeled and non-labeled antibodies indicated that 10 of 11 epitopes were grouped in a linear array. Antibodies against 7 epitopes inhibited anchorage-independent growth and antibodies against 2 of these epitopes also inhibited anchorage-dependent growth of SKBr3 breast-cancer cells that over-expressed p185. Treatment with antibodies exerted cytotoxic rather than cytostatic effects. When antibodies were used in combination, additive or supra-additive inhibition of anchorage-independent and anchorage-dependent growth was observed between pairs of antibodies. Growth inhibition did not relate to the affinity of the antibody or its isotype. Two antibodies that inhibited both anchorage-dependent and anchorage-independent growth also blocked binding of the HER-2/neu ligand, whereas 5 antibodies that inhibited only anchorage-independent growth had no effect on ligand binding. Inhibition of cell growth did not correlate with internalization of p185 or down-regulation of p185 on the cell surface. Fab fragments of active antibodies could also inhibit anchorage-independent growth of SKBr3. Thus, murine MAbs and their fragments recognized both immunochemically distinct and functionally distinct epitopes on the p185 molecule. Whereas inhibition of anchorage-dependent growth correlated with the ability of antibodies to block ligand binding, inhibition of anchorage-independent growth did not correlate with effects on ligand binding, internalization, cell-surface expression or cross-linking of p185.
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PMID:Antibody-induced growth inhibition is mediated through immunochemically and functionally distinct epitopes on the extracellular domain of the c-erbB-2 (HER-2/neu) gene product p185. 767 90

The c-erbB-2 proto-oncogene encodes a transmembrane glycoprotein with tyrosine kinase activity, p185erbB-2, that has been previously localized in some developing and mature epithelia. The possible occurrence of p185 in the inner enamel epithelium of rat tooth germ was here investigated immunocytochemically. Postmitotic functional ameloblasts displayed intense p185-immunoreactivity, thus suggesting that c-erbB-2 proto-oncogene is active during odontogenesis. The expression of this gene in differentiated and functional cells of the enamel organ suggests that its role is not restricted to mitotic events but may also be important in signalling pathways related to other cell activities.
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PMID:Expression of c-erbB-2 proto-oncogene-encoded protein (p185erbB-2) in functional rat ameloblasts. 774 63

Overexpression of HER-2/neu has been demonstrated in human ovarian cancer and correlated with poor prognosis. We previously found that the adenovirus type 5 early region 1A (E1A) gene product can repress overexpression and suppress the tumorigenic potential of the HER-2/neu-overexpressing cancer cells. To develop an efficient HER-2/neu-targeting gene therapy with E1A, a replication-deficient adenovirus containing the E1A gene, Ad.E1A(+), was used to transduce the HER-2/neu-overexpressing human ovarian cancer cell line SK-OV3.ip1. Tumor cell growth in vitro and colony formation in soft agarose were greatly inhibited by Ad.E1A(+) transduction. To test therapeutic efficacy in vivo, tumor-bearing mice were established by i.p. injection with ovarian cancer cells and treated by i.p. injection of 10(8) PFU viral solution containing either replication-deficient Ad.E1A(+); control virus Ad.E1A(-) which is the same adenovirus as Ad.E1A(+) except for E1A deletion, or just PBS. Ad.E1A(+) significantly prolonged survival in treated mice for 1 year (80%) whereas in control groups, all mice died of cancer within 4.5 months. Immunohistochemistry analysis indicated that Ad.E1A protein was expressed in tumor tissue and expression of HER-2/neu p185 protein was suppressed in vivo. As a control, another ovarian cancer cell line 2774, in which HER-2/neu is expressed at a basal level, was also inoculated i.p. following the same therapeutic procedure. Ad.E1A(+) could not prolong survival of 2774 cells, indicating that Ad.E1A(+) specifically targeted HER-2/neu-overexpressing tumor cells and functioned as an antitumor agent.
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PMID:HER-2/neu-targeting cancer therapy via adenovirus-mediated E1A delivery in an animal model. 776 Oct 95

The c-erbB-2 (HER-2, neu) oncogene has been implicated frequently in many human tumors. This oncogene codes for a 185-kDa protein that functions as a transmembrane growth factor receptor. Overexpression of the normal protein or point mutations in the transmembrane domain of the protein have been shown to have a transforming effect. Molecular structure studies of the transmembrane domain provide a plausible explanation for this transforming effect in both cases and relate this to the process of receptor dimerization in the membrane, degradation of the protein with release of the extracellular domain (ECD) into the extracellular environment, and aberrant signal transduction. The release of the ECD into the extracellular environment provides a potential biomarker for the study of signal transduction at the molecular level in vivo. The ECD can be quantitated immunologically in the serum of individuals with cancers associated with p185 overexpression and in individuals at risk for the development of such cancers and can be used to distinguish these individuals from normal, healthy controls. Identification of such individuals by their serum ECD levels combined with specific chemotherapeutic/chemoprophylactic interventions could allow for improvement treatment and prevention of c-erbB-2-related cancers.
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PMID:The c-erbB-2 protein in oncogenesis: molecular structure to molecular epidemiology. 784 90

Adenocarcinomas of the proximal stomach including the gastroesophageal junction are extremely virulent cancers which are increasing rapidly in incidence. Stage-for-stage proximal gastric cancers have a worse prognosis than do tumors of the body or antrum of the stomach. To further explore biological differences based on site, we studied 80 patients with locally advanced primary tumours of the proximal (n = 40) and distal stomach (n = 40) for amplification of the HER-2/neu proto-oncogene. None of 40 patients with proximal lesions had overexpression of HER-2/neu, whereas four of 40 (10%) distal adenocarcinomas had a 16-24-fold gene amplification (P = 0.04). In the adenocarcinomas from two patients, gene rearrangements were found in addition to amplification. HER-2/neu gene product p185 over-expression was found only in the amplified cases. All four patients with distal tumors and amplification had rapid progression of disease (median survival: 4.3 months). While it is unclear why HER-2/neu amplification is seen only in distal tumors, these data further support the hypothesis that biological differences between proximal and distal lesions are present. As is the case for other tumours, HER-2/neu amplification is associated with a poor prognosis for the individual patient.
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PMID:Amplification of HER-2/neu gene in human gastric adenocarcinomas: correlation with primary site. 785 55


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