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)

The human epidermal growth factor receptor (HER or ErbB) family consists of four distinct members, including the epidermal growth factor (EGF) receptor (EGFR, HER1, or ErbB1), ErbB2 (HER2 or neu), ErbB3 (HER3), and ErbB4 (HER4). Activation of these receptors plays an important role in the regulation of cell proliferation, differentiation, and survival in several different tissues. Binding of a specific ligand to one of the ErbB receptors triggers the formation of specific receptor homo- and heterodimers, with ErbB2 being the preferred signaling partner. We analyzed the levels of various ErbB receptor messenger RNAs in a series of nontransformed cell lines by real time quantitative RT-PCR. The cell lines chosen were derived from a variety of tissues, including pancreas, lung, heart, and nervous system. Further, we measured biological responses in these cell lines upon treatment with EGF, betacellulin, and two types of neuregulins, heregulin and sensory and motor neuron-derived factor. All cell lines examined expressed detectable levels of ErbB2. High levels of expression of ErbB3 were correlated with responsiveness to heregulin and sensory and motor neuron-derived factor, whereas high levels of EGFR expression were correlated with responsiveness to EGF and betacellulin. Moreover, the sensitivity of a cell line to ErbB ligands was also correlated with the levels of expression of the appropriate ErbB receptors in that cell line. These results are consistent with our hypothesis that appropriate biological responsiveness to ErbB ligands is determined by the levels of expression of specific ErbB receptor combinations within a given tissue.
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PMID:Biological response to ErbB ligands in nontransformed cell lines correlates with a specific pattern of receptor expression. 983 11

Nuclear steroid/retinoid and memgbrane c-erbB receptor tyrosine kinase signaling control proliferation and differentiation of mammary epithelial cells. Recently, we reported that retinoic acids are efficient repressors of c-erbB-2 and -3, but not of c-erbB-1 gene expresson. Here we demonstrate that retinoid acid- mediated growth inhibition is accompanied with reduced expression of c-erbB-4/HER4 in T47D breast cancer cells as determined by FACS, Western, and RT-PCR. All-trans and 9-cis retinoic acid reduce c-erbB-4 expression to 30%-60% of control, depending on the concentration. Dexamethasone (Dex) is inactive on D3 (D3), in contrast, acts as a strong inducer, elevation more that twofold at the mRNA, but does not significantly affect cell growth. We concolude that retinoic acids are efficient growth inhibitors and repressors of cell growth and c-erbB-4, whereas D3 represents a highly efficient inducer of c-erbB-4 expression with affecting cell proliferation.
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PMID:Expression of c-erbB-4/HER4 is regulated in T47D breast carcinoma cells by retinoids and vitamin D3. 1038 75

The product of the HER-2/neu proto-oncogene, HER2, is the second member of the human epidermal growth factor receptor (HER) family of tyrosine kinase receptors and has been suggested to be a ligand orphan receptor. Ligand-dependent heterodimerization between HER2 and another HER family member, HER1, HER3 or HER4, activates the HER2 signaling pathway. The intracellular signaling pathway of HER2 is thought to involve ras-MAPK, MAPK-independent S6 kinase and phospholipase C-gamma signaling pathways. However, the biological consequences of the activation of these pathways are not yet completely known. Amplification of the HER2 gene and overexpression of the HER2 protein induces cell transformation and has been demonstrated in 10% to 40% of human breast cancer. HER2 overexpression has been suggested to associate with tumor aggressiveness, prognosis and responsiveness to hormonal and cytotoxic agents in breast cancer patients. These findings indicate that HER2 is an appropriate target for tumor-specific therapies. A number of approaches have been investigated: (1) a humanized monoclonal antibody against HER2, rhuMAbHER2 (trastuzumab), which is already approved for clinical use in the treatment of patients with metastatic breast cancer; (2) tyrosine kinase inhibitors, such as emodin, which block HER2 phosphorylation and its intracellullar signaling; (3) active immunotherapy, such as vaccination; and (4) heat shock protein (Hsp) 90-associated signal inhibitors, such as radicicol derivatives, which induce degradation of tyrosine kinase receptors, such as HER2.
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PMID:Biological and clinical significance of HER2 overexpression in breast cancer. 1118 Jul 65

Overexpression of the HER2 (neu/c-erbB-2) oncogene frequently coincides with an aggressive clinical course of certain human adenocarcinomas. Expression and secretion of aberrant HER2 splice variants has been reported in various cell lines and tissues and can interfere with the oncogenic HER2 activity. Here we demonstrate, using two different approaches, that expression of a truncated 100 kDa HER2 variant which encodes the extracellular domain of HER2 (HER-ECD) inhibits growth factor-mediated tumour cell proliferation. A HER2-ECD cDNA encoding the truncated variant was overexpressed in MCF7 breast cancer cells. HER2-ECD overexpression decreased spontaneous proliferation of MCF7 cells as well as heregulin-mediated soft agar colony formation. Concomitantly, heregulin-induced phosphorylation of HER4 as well as downstream activation of p44/p42 MAP-kinases was decreased. To confirm these data, ribozymes were targeted to the 3'-untranslated region of the 2.3 kb HER2-ECD mRNA which is spontaneously expressed in MKN7 gastric cancer cells. HER2-ECD-targeted ribozymes downregulated HER2-ECD expression and enhanced EGF-mediated soft agar colony formation of MKN7 cells. In parallel, EGF-induced activation of p44/p42 MAP-kinases and activation of c-Fos expression were increased in ribozyme-transfected MKN7 cells. Finally, in RT-PCR we found a trend towards a progressive loss of 2.3 kb HER2-ECD mRNA expression in more advanced gastric tumours. These data show that the HER2-ECD variant inhibits growth factor-mediated tumour cell proliferation suggesting an important role during the progression of human cancer.
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PMID:Expression of a truncated 100 kDa HER2 splice variant acts as an endogenous inhibitor of tumour cell proliferation. 1136 Jan 94

EGFr/HER1 and c-erbB-2/HER2 expression are associated with poor prognosis in breast cancer. The type I receptor tyrosine kinase (RTK) family to which they belong has four members (HER1-4). In this study, expression of HER1-4 and oestrogen receptor (ER) expression were determined by immunohistochemistry in 220 breast carcinomas. Elevated expression of HER1 was observed in 16.4%, HER2 in 22.8%, HER3 in 17.5%, and HER4 in 11.9% of these tumours. Patients whose tumours overexpressed HER1, 2 or 3 had reduced survival (p= <0.001), whereas those whose tumours overexpressed HER4 had increased survival (p=0.013); 38.6% of cases overexpressed one or more of HER1, 2 or 3. HER4 was rarely overexpressed with other HERs (1.4% of cases). Cox's multiple regression analysis demonstrated that overexpression of HER1/2/3, HER4, and standard prognostic indicators independently affected survival. HER1-3 expression was related to ER negativity (p<0.0001, chi2). Patients with ER-positive, HER1-3-positive tumours had a significantly poorer survival (p<0.001) than those with ER-positive/HER-negative or HER4-positive tumours. Expression of HER RTKs displays complex interactions between different family members. There is a strong interaction, in terms of survival, between HER expression and ER expression. The development of HER-targeted agents (eg Herceptin, Iressa), and agents targeted at the downstream signalling pathways, therefore provides new possibilities in the treatment of breast cancer.
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PMID:Expression of the HER1-4 family of receptor tyrosine kinases in breast cancer. 1284 22

Novel palliative strategies for patients with androgen-independent prostate cancer (AIPC) include targeting the epidermal growth factor receptor (EGFR) family. The aim of the present study was to investigate intrapatient changes of EGFRs during the development of AIPC. In total, 106 symptomatic AIPC patients were identified in whom prostatic biopsies (adenocarcinoma) were available both before the start of androgen deprivation (PRTR biopsy) and after the development of AIPC (AIPC biopsy). All four known subgroups of the EGFR family were determined by immunohistochemistry (IHC): c-erbB-1 (EGFR), c-erbB-2 (HER2/neu), c-erbB-3 (HER3) and c-erbB-4 (HER4). Moderate to strong membrane-specific staining was recorded semiquantitatively (<10% vs >/=10%=IHC stained tumour cells: 'negative' vs 'positive' staining). The medical records were reviewed for clinical variables. During the development of AIPC, intrapatient changes occurred in two opposite directions for each of the four EGFRs: negativity changed to positivity, and vice versa, statistically significant only for the increase of c-erbB-1 expression (P=0.001). The c-erbB-2 expression in the AIPC biopsy was associated with a significantly shorter survival from the time of the AIPC biopsy (P=0.029). Our results support ongoing therapeutic attempts of EGFR inhibition in subgroups of patients with prostate cancer. Further research is needed to understand the function of EGFRs in this malignancy.
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PMID:Expression of the epidermal growth factor receptor family in prostate carcinoma before and during androgen-independence. 1473 92

The epidermal growth factor system has been associated to prognosis in patients with bladder cancer based mainly on the expression of the epidermal growth factor (EGF) receptor 1 (EGFR) and HER2 and their activating ligands. Since limited information exists concerning the expression of other parts of the EGF system, we examined the expression of the receptors HER3 and HER4 and their activating ligands, the heregulins (HRGs), in bladder cancer patients. Biopsies from bladder cancer tumours were obtained from 88 patients followed for a median of 23 months (range, 1-97 months). The mRNA content of four ligands and their isoforms (HRG1alpha, HRG1beta, HRG2alpha, HRG2beta, HRG3 and HRG4) and two receptors (HER3 and HER4) was quantified by real-time PCR. A significantly lower mRNA expression level of HER3 (P=0.0003), HRG2alpha (P=0.0159), HRG2beta (P=0.0007) and HRG4 (P<0.0001) was observed in muscle-invasive (T2-T4) tumours as compared to superficial (Ta) tumours. The expression of HER3 mRNA correlated strongly to overall survival (P=0.0042); increased expression of HER4 (P=0.0261) and HRG4 (P=0.0245) was also associated with better prognosis. Interestingly, patients with coexpression of HER3 (P=0.0034) or HER4 (P=0.0080) together with their stimulating ligand HRG4 showed even better survival than for HER3 or HER4 alone. Our results together with previous data suggest a dual face for the EGF system. While it is well established that an increased signalling through HER1 and HER2 is related to a poor prognosis, our data suggest that signalling through HER3 and HER4 is related to a favourable outcome in bladder cancer patients.
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PMID:Expression of HER3, HER4 and their ligand heregulin-4 is associated with better survival in bladder cancer patients. 1558 96

The human epidermal growth factor (EGF) receptor (HER) family of receptor tyrosine kinases has frequently been implicated in cancer. Apart from overexpression or mutation of these receptors, also the aberrant autocrine or paracrine activation of HERs by EGF-like ligands may be important in cancer progression. Neuregulins constitute a family of EGF-like ligands that bind to HER3 or HER4, preferably forming heterodimers with the orphan receptor HER2. Mesenchymal neuregulin typically serves as a pro-survival and pro-differentiation signal for adjacent epithelia. Disruption of the balance between proliferation and differentiation, because of autocrine production by the epithelial cells, increased sensitivity to paracrine signals or disruption of the spatial organization, may lead to constitutive receptor activation, in the absence of receptor overexpression. Consequently, the analysis of ligand expression and/or activated receptors in tumor samples may broaden the group of patients that can benefit from targeted therapies.
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PMID:Roles for neuregulins in human cancer. 1603 12

The assessment of ERa, PgR and HER2 status is routinely performed today to determine the endocrine responsiveness of breast cancer samples. Such determination is usually accomplished by means of immunohistochemistry and in case of HER2 amplification by means of fluorescent in situ hybridization (FISH). The analysis of these markers can be improved by simultaneous measurements using quantitative real-time PCR (Qrt-PCR). In this study we compared Qrt-PCR results for the assessment of mRNA levels of ERa, PgR, and the members of the human epidermal growth factor receptor family, HER1, HER2, HER3 and HER4. The results were obtained in two independent laboratories using two different methods, SYBR Green I and TaqMan probes, and different primers. By linear regression we demonstrated a good concordance for all six markers. The quantitative mRNA expression levels of ERa, PgR and HER2 also strongly correlated with the respective quantitative protein expression levels prospectively detected by EIA in both laboratories. In addition, HER2 mRNA expression levels correlated well with gene amplification detected by FISH in the same biopsies. Our results indicate that both Qrt-PCR methods were robust and sensitive tools for routine diagnostics and consistent with standard methodologies. The developed simultaneous assessment of several biomarkers is fast and labor effective and allows optimization of the clinical decision-making process in breast cancer tissue and/or core biopsies.
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PMID:Simultaneous quantitative detection of relevant biomarkers in breast cancer by quantitative real-time PCR. 1671 11

The aim of the study was to evaluate the prognostic ability of the transcriptional profiling of the HER family genes in early breast cancer, as well as to investigate the predictive value of HER2 mRNA expression for adjuvant treatment with paclitaxel. RNA was extracted from 268 formalin-fixed paraffin-embedded (FFPE) tumour tissue samples of high-risk breast cancer patients enrolled in the randomised HE10/97 trial, evaluating the effect of dose-dense anthracycline-based sequential adjuvant chemotherapy with or without paclitaxel. The mRNA expression of all four HER family members was assessed by kinetic reverse transcription-polymerase chain reaction (kRT-PCR). The overall concordance between kRT-PCR and IHC/FISH for HER2 status determination was 74%. At a median follow-up of 8 years, multivariate analysis showed that EGFR and HER2 mRNA expression was associated with reduced overall survival (OS). HER3 and HER4 mRNA level had a favourable prognostic value in terms of OS and disease-free survival (DFS), respectively. Adjusting for HER2 mRNA expression, OS and DFS did not differ between treatment groups. These data indicate that EGFR as well as HER2 are prognostic factors of worse clinical outcomes, whereas HER3 and HER4 gene transcription is associated with better prognosis in high-risk early breast cancer. However, HER2 mRNA expression did not predict clinical benefit from paclitaxel. Kinetic RT-PCR represents an alternative method for evaluating the expression of HER family members in FFPE breast carcinomas.
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PMID:Evaluation of the prognostic and predictive value of HER family mRNA expression in high-risk early breast cancer: a Hellenic Cooperative Oncology Group (HeCOG) study. 1898 33


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