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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To identify mechanisms that allow p185HER2 expression in lung cancer, we performed Western, Southern, and Northern blot analyses of 14 cell lines derived from human non-small cell lung carcinomas and one cell line derived from a human mesothelioma. Human bronchiole epithelial cells and rat type II pneumocytes were found to express p185HER2 at low to undetectable levels by Western blot technique. In contrast, 13 lung cancer cell lines expressed p185HER2, and eight of these 13 expressed p185HER2 at levels at least 2-fold higher than that found in normal bronchiole epithelial cells or type II pneumocytes. Genomic Southern analysis showed that amplification of the HER2 gene was present in only one of the eight cell lines that expressed p185HER2 at these higher levels. Increased levels of steady-state HER2 mRNA occurred in the remaining seven cell lines. We conclude that in human non-small cell lung carcinoma cell lines the most common mechanism resulting in increased p185HER2 expression is due to mechanisms that increase HER2 mRNA levels, with HER2 gene amplification occurring less commonly.
Am J Respir Cell Mol Biol 1992 Apr
PMID:Mechanisms of p185HER2 expression in human non-small cell lung cancer cell lines. 131 50

Amplification of oncogenes in primary tumours may have prognostic and/or therapeutic significance for patients with breast cancer. We have studied HER2/neu and c-myc amplification together with steroid receptors in human primary breast tumours and related the outcome with (relapse-free) survival. A strong inverse correlation was found between HER2/neu amplification and the presence of oestrogen and progesterone receptors. Actuarial 5-years survival showed that breast cancer patients with c-myc amplification in their primary tumours experience a shorter relapse-free survival, especially in node-negative and in receptor-positive tumours, whereas HER2/neu amplification may be of prognostic value for overall survival in receptor-negative tumours. Overall, in our hands, c-myc amplification appeared to be a more potent prognosticator than HER2/neu amplification in human primary breast cancer.
J Steroid Biochem Mol Biol 1992 Sep
PMID:Prognostic factors in human primary breast cancer: comparison of c-myc and HER2/neu amplification. 135 12

Expression of the c-erbB-2 (neu, HER-2) oncogene is found to be subjected to hormonal and developmental regulation in normal as well as neoplastic mammary cells. We have previously reported that estrogens inhibit c-erbB-2 expression at both the mRNA and protein level in estrogen receptor (ER)-positive, but not in ER-negative, breast cancer cell lines. Reversion of c-erbB-2 inhibition is seen with tamoxifen. The effect on c-erbB-2 expression of several other hormones and factors, which influence mammary cell growth and differentiation, has been studied. Our observations indicate that, in normal and neoplastic mammary cells, c-erbB-2 expression is inversely related to cell proliferation. While estrogens, anti-estrogens and cAMP clearly regulate c-erbB-2 mRNA levels, epidermal growth factor dramatically decreases the c-erbB-2 protein without affecting the level of c-erbB-2 mRNA. Therefore, different signals converging in terms of cell proliferation regulate c-erbB-2 expression by different molecular mechanisms.
J Steroid Biochem Mol Biol 1992 Sep
PMID:Hormonal regulation of c-erbB-2 oncogene expression in breast cancer cells. 135 14

The erbB-2 (HER-2, neu) protooncogene is overexpressed on the surface of about 25% of human breast cancers. It is homologous to epidermal growth factor receptor and a putative growth factor receptor. Overexpression in breast, ovarian and gastric cancers is associated with a worse prognosis. We have recently discovered two ligands for this receptor. They both induce receptor phosphorylation. At low concentrations both induce clonogenic growth of overexpressing cells; at higher concentrations both are growth inhibitory. Both can overcome the inhibitory effects of both monoclonal antibodies directed against the ligand binding site and soluble extracellular domain. These ligands may form an attractive basis for antitumor therapy.
J Steroid Biochem Mol Biol 1992 Sep
PMID:The role of erbB-2 and its ligands in growth control of malignant breast epithelium. 135 15

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.
J Steroid Biochem Mol Biol 1992 Sep
PMID:Clinical breast cancer, new developments in selection and endocrine treatment of patients. 144 97

Abnormalities of some oncogenes, antioncogenes and losses of heterozygosity (LOH) of chromosome 11p, 17p, and 17q in colorectal carcinomas (CC) was studied. Amplification of ERBB-1/HER-1 oncogene was detected in 2 of 56 cases; ERBB-2/HER-2- in 4 of 62. There was a lack of evidence for C-MYC oncogene amplification (67 cases). LOH of chromosome 11p (HRAS-1 probe) was found in 2 of 37 informative (heterozygous) cases; such events were not accompanied by point mutations in "hot" codons (12th or 61st) in the remaining allele. Prevalence of A3 and A4 alleles of HRAS-1 oncogene (68 cases) as compared to healthy donors was noted. RB-1 (41 cases) and p53 (62 cases) suppressor genes did not show any alterations in Southern-blot analysis. LOH of chromosome 17p (YNZ-22 probe) was found in 15 of 26 heterozygous CC; 17q (THH-59 probe)--in 4 of 16. Analysis of 175th codon of p53 gene revealed only one case of mutation in 35 CC studied. Finally, we were able to detect genetic alterations in 23 of 40 (58%) CC, that were studied on each parameter using Southern-blot. We failed to find any correlation between various molecular abnormalities or clinical characteristics. The data obtained are in disagreement with the view concerning frequent involvement of p53 antioncogene in chromosome 17p deletions.
Mol Biol (Mosk)
PMID:[Complex characteristics of the alterations of oncogenes HER-2/ERBB-2, HER-1/ERBB-1, HRAS-1, C-MYC and antioncogenes p53, RB1, as well as deletions of loci of chromosome 17 in colon carcinoma]. 147 Jan 78

Monoclonal antibody (MAb) 4D5 was used to analyze the phosphorylation of p185HER2, the gene product of c-erbB-2/HER2, in SK-BR-3 cells. Culture in the continuous presence of 4D5 reduced the in vivo steady-state levels of p185HER2 phosphorylation by 80% in a dose-dependent manner, suggesting that MAb 4D5 may have interfered with the activation of phosphorylation of p185HER2. The observed MAb-mediated reduction of p185HER2 phosphorylation could not be completely accounted for by down-regulation. When cultures were grown under serum-free conditions, the steady-state levels of p185HER2 phosphorylation were reduced by 56%, and addition of 4D5 further inhibited phosphorylation to 20% of steady-state levels. With continuous exposure to increasing concentrations of newborn calf serum in these cultures, there was a linear increase in tyrosine-specific phosphorylation of p185HER2, reaching a 5.4-fold increase with 10% newborn calf serum. Phosphorylation of p185HER2 in the presence of newborn calf serum was not attributable to stimulation of the epidermal growth factor receptor by epidermal growth factor or by transforming growth factor-alpha. Extension of these observations to two other mammary carcinoma cell lines. MDA-MB-453 and BT-474, also demonstrated a significant capacity of serum to induce p185HER2 phosphorylation. The demonstration of antibody-mediated partial inhibition of phosphorylation under serum-free conditions suggests that mammary carcinoma cells may also produce and secrete a factor or factors which may activate p185HER2. Our observation that growth-inhibitory MAb 4D5 is able to reduce the phosphorylation of p185HER2 by newborn calf serum and by a cellular-derived factor(s) suggests the existence of a growth factor(s) which uses phosphorylation of p185HER2 as a signal transduction pathway to regulate cell proliferation.
Mol Cell Biol 1991 Feb
PMID:Regulation of phosphorylation of the c-erbB-2/HER2 gene product by a monoclonal antibody and serum growth factor(s) in human mammary carcinoma cells. 167 Dec 97

The product of the HER-2 proto-oncogene, p185HER-2, was found to be amplified approximately 10-fold in the human breast carcinoma cell line, BT474, compared to a cell line, HBL-100, derived from normal breast tissue. To explore the possible role of p185HER-2 in growth of the breast carcinoma cells, we investigated factors that may modulate cell growth and phosphorylation of the HER-2 protein product. Two growth factors, epidermal growth factor (EGF) and insulin, stimulated phosphorylation of the HER-2 protein product. In response to insulin, the phosphoserine and phosphothreonine content in p185HER-2 was transiently enhanced about 6-fold. When EGF was added to BT474 cells there was 2- to 3-fold enhanced phosphorylation of serine and threonine residues in p185HER-2 which was maintained for at least 60 min. Although p185HER-2 has been found to be phosphorylated on tyrosine residues following EGF treatment of several different cell types, we estimate that less than 1% of the protein contained phosphotyrosine in the BT474 cells.
Mol Cell Endocrinol 1990 Mar 05
PMID:Insulin and epidermal growth factor stimulate phosphorylation of p185HER-2 in the breast carcinoma cell line, BT474. 169 19

The neu gene in rat neuro/glioblastoma was found to be activated by a single point mutation in the DNA sequence encoding the transmembrane region of the neu-encoded p185 protein. The human homologue of the rat neu gene, termed c-erbB-2 or HER-2, can also be activated in vitro by a similar mutation in the corresponding region. Although the human neu gene was shown to be amplified/overexpressed in a large portion of human breast and ovarian cancer, no reports indicate that the human neu gene is activated by a point mutation in human tumor. To study the possible point mutation of neu gene in human tumors, we characterized the genomic structure in the transmembrane region of human neu gene, which in turn allowed us to determine DNA sequence in this region directly following DNA amplification by polymerase chain reaction. We analyzed 7 tumor cell lines (2 breast cancer, 1 neuroblastoma, 1 rhabdomyosarcoma, and 3 glioma) and 11 tumor tissue samples (8 breast and 3 ovarian cancers). No mutation was found in the transmembrane region of human neu gene. Our results suggest that unlike the rat neuro/glioblastoma, the single point mutation in the transmembrane region of the human neu gene is a rare event in human tumors. In this study, we developed a technique for direct DNA sequencing of the transmembrane region of the human neu gene. This technique makes it possible to screen a large number of tumor samples.
Mol Carcinog 1990
PMID:Direct sequencing analysis of transmembrane region of human Neu gene by polymerase chain reaction. 220 83

The HER2/c-erbB-2 gene encodes the epidermal growth factor receptorlike human homolog of the rat neu oncogene. Amplification of this gene in primary breast carcinomas has been show to correlate with poor clinical prognosis for certain cancer patients. We show here that a monoclonal antibody directed against the extracellular domain of p185HER2 specifically inhibits the growth of breast tumor-derived cell lines overexpressing the HER2/c-erbB-2 gene product and prevents HER2/c-erbB-2-transformed NIH 3T3 cells from forming colonies in soft agar. Furthermore, resistance to the cytotoxic effect of tumor necrosis factor alpha, which has been shown to be a consequence of HER2/c-erbB-2 overexpression, is significantly reduced in the presence of this antibody.
Mol Cell Biol 1989 Mar
PMID:p185HER2 monoclonal antibody has antiproliferative effects in vitro and sensitizes human breast tumor cells to tumor necrosis factor. 256 7


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