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Query: UNIPROT:O76050 (neu)
 3,969 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Incidence rates have risen rapidly for esophageal and gastric cardia adenocarcinomas. These cancers, arising at and around the gastroesophageal junction (GEJ), share a poor prognosis. In contrast, there is no consensus with respect to clinical staging resulting in possible adverse effects on treatment and survival. The goal of this study was to provide more insight into the genetic changes underlying esophageal and gastric cardia adenocarcinomas. We have used comparative genomic hybridization for a genetic analysis of 28 adenocarcinomas of the GEJ. Eleven tumors were localized in the distal esophagus and related to Barrett's esophagus, and 10 tumors were situated in the gastric cardia. The remaining seven tumors were located at the junction and could not be classified as either Barrett-related, or gastric cardia. We found alterations in all 28 neoplasms. Gains and losses were distinguished in comparable numbers. Frequent loss (> or = 25% of all tumors) was detected, in decreasing order of frequency, on 4pq (54%), 14q (46%), 18q (43%), 5q (36%), 16q (36%), 9p (29%), 17p (29%), and 21q (29%). Frequent gain (> or = 25% of all tumors) was observed, in decreasing order of frequency, on 20pq (86%), 8q (79%), 7p (61%), 13q (46%), 12q (39%), 15q (39%), 1q (36%), 3q (32%), 5p (32%), 6p (32%), 19q (32%), Xpq (32%), 17q (29%), and 18p (25%). Nearly all patients were male, and loss of chromosome Y was frequently noted (64%). Recurrent high-level amplifications (> 10% of all tumors) were seen at 8q23-24.1, 15q25, 17q12-21, and 19q13.1. Minimal overlapping regions could be determined at multiple locations (candidate genes are in parentheses): minimal regions of overlap for deletions were assigned to 3p14 (FHIT, RCA1), 5q14-21 (APC, MCC), 9p21 (MTS1/CDKN2), 14q31-32.1 (TSHR), 16q23, 18q21 (DCC, P15) and 21q21. Minimal overlapping amplified sites could be seen at 5p14 (MLVI2), 6p12-21.1 (NRASL3), 7p12 (EGFR), 8q23-24.1 (MYC), 12q21.1, 15q25 (IGF1R), 17q12-21 (ERBB2/HER2-neu), 19q13.1 (TGFB1, BCL3, AKT2), 20p12 (PCNA), 20q12-13 (MYBL2, PTPN1), and Xq25. The distribution of the imbalances revealed similar genetic patterns in the three GEJ tumor groups. However, loss of 14q31-32.1 occurred significantly more frequent in Barrett-related adenocarcinomas of the distal esophagus, than in gastric cardia cancers (P = 0.02). The unclassified, "pure junction" group displayed an intermediate position, suggesting that these may be in part gastric cardia tumors, whereas the others may be related to (short-segment) Barrett's esophagus. In conclusion, this study has, fist, provided a detailed comparative genomic hybridization-map of GEJ adenocarcinomas documenting new genetic changes, as well as candidate genes involved. Second, genetic divergence was revealed in this poorly understood group of cancers.
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PMID:Comparative genomic hybridization of cancer of the gastroesophageal junction: deletion of 14Q31-32.1 discriminates between esophageal (Barrett's) and gastric cardia adenocarcinomas. 997 27

A novel series of N-(phenylalkyl)cinnamides related to N-(4-phenylbutyl)-3,4-dihydroxy-beta-cyanocinnamide (6, an EGFR-K inhibitor with high antiproliferative activity) was synthesized and tested for antagonism at N-methyl-D-aspartate (NMDA) receptor subtypes. Potency and subunit selectivity were assayed by electrical recordings in Xenopus oocytes expressing three binary combinations of cloned rat NMDA receptor subunits: NR1A expressed in combination with either NR2A, NR2B, or NR2C. The N-(phenylalkyl)cinnamides are selective antagonists of NR1A/2B receptors. Assayed under steady-state conditions, N-(4-phenylbutyl)-4-hydroxycinnamide (16) has an IC(50) value of 77 nM and >1000-fold selectivity with respect to NR1A/2A and NR1A/2C receptors. Potency at alpha(1) adrenergic receptors is low for the four cinnamides tested. Inhibition of NR1A/2B receptors does not correlate with EGFR and ErbB2/neu tyrosine kinase inhibitor activity. The N-(phenylalkyl)cinnamide series we describe provides a novel and structurally diverse framework for designing new NR2B-selective NMDA antagonists as potential CNS therapeutics.
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PMID:Structure-activity relationship of N-(phenylalkyl)cinnamides as novel NR2B subtype-selective NMDA receptor antagonists. 1046 27

We used a genetic approach to characterize features of mitogen-activated protein kinase (MAPK) activation occurring as a consequence of expression of distinct erbB receptor combinations in transformed human cells. Kinase-deficient erbB proteins reduced epidermal growth factor (EGF)-induced tyrosine phosphorylation of endogenous Shc proteins and also reduced immediate and sustained EGF-induced ERK MAPK activities in human glioblastoma cells, although basal ERK MAPK activities were unaffected. Basal and EGF-induced JNK and p38 MAPK kinase activities were equivalent in parental cancer cells and EGFR-inhibited subclones. When ectopically overexpressed in murine fibroblasts and human glioblastoma cells, a constitutively activated human EGF receptor oncoprotein (deltaEGFR) induced EGF-independent elevation of basal ERK MAPK activity. Basal JNK MAPK kinase activity was also specifically induced by deltaEGFR, which correlated with increased phosphorylation of a 54-kDa JNK2 protein observed in deltaEGFR-containing cells. The JNK activities in response to DNA damage were comparably increased in cells containing wildtype EGFR or deltaEGFR. Consistent with the notion that transforming erbB complexes induce sustained and unregulated MAPK activities, coexpression of p185(neu) and EGFR proteins to levels sufficient to transform murine fibroblasts also resulted in prolonged EGF-induced ERK in vitro kinase activation. Transforming erbB complexes, including EGFR homodimers, deltaEGFR homodimers, and p185(neu)/EGFR heterodimers, appear to induce sustained, unattenuated activation of MAPK activities that may contribute to increased transformation and resistance to apoptosis in primary human glioblastoma cells.
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PMID:Sustained mitogen-activated protein kinase activation is induced by transforming erbB receptor complexes. 1054 32

Selection of surrogate endpoint biomarkers (SEBs) and appropriate study design are two of the main challenges in evaluating potential chemopreventive agents. In a prospective random fine-needle aspiration (FNA) study of women at high risk of development of breast cancer, we previously demonstrated that cytologic evidence of epithelial hyperplasia with or without atypia, as well as abnormalities of several cellular biomarkers (DNA ploidy; immunocytochemical expression of p53, EGFR, ER, and/or Her-2/neu), were more prevalent in high-risk women than in low-risk controls. We also demonstrated that the subsequent development of breast cancer was best predicted by an initial presentation of hyperplasia with atypia, as well as by multiple biomarker abnormalities. These findings indicate that FNA cytology and biomarkers can be used to identify women who are appropriate subjects for chemoprevention trials, and can then be used as surrogate endpoint biomarkers to monitor efficacy of potential agents. An example of this use in an ongoing single-agent phase II trial is provided. Several options for study design of possible multi-agent breast cancer chemoprevention trials are discussed, depending upon the existing preclinical and clinical data, the questions being asked, and the number of eligible subjects available.
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PMID:Breast cancer chemoprevention trials using the fine-needle aspiration model. 1076 8

The neu differentiation factors/heregulins (HRGs) comprise a family of polypeptide growth factors that activate p185(erbB-2) through direct binding to either erbB-3 or erbB-4 receptor tyrosine kinases. We have previously shown that HRG-beta is mitogenic for various human mammary epithelial cell lines that coexpress c-erbB-2 and c-erbB-3. Phosphatidylinositol 3-kinase (PI3K) is activated by p185(erbB-2) /erbB-3 heterodimers in cells stimulated by HRG, and PI3K is constitutively activated by p185(erbB-2) /erbB-3 in breast carcinoma cells that overexpress c-erbB-2. To better understand the relative abilities of HRGs, epidermal growth factor (EGF), or insulin to activate PI3K under normal physiological conditions, we compared the levels of recruitment of the 85-kDa regulatory subunit of PI3K when activated by the type I (erbB) or type II [insulin-like growth factor (IGF)] receptor tyrosine kinases in two different nontransformed human mammary epithelial cell lines. The nontransformed H16N-2 cells isolated from normal tissue express EGFR, p185(erbB-2), and erbB-3, and are highly responsive to the mitogenic effects of HRG-beta as well as to the combination of EGF and insulin in serum-free culture. We measured the stoichiometry of p85 recruited by tyrosine-phosphorylated proteins induced in H16N-2 cells by either the alpha or the beta isoform of HRG. HRG-beta was greater than 10-fold more potent in inducing p85 recruitment than was the less biologically active HRG-alpha isoform. HRG-beta was also a more potent inducer of p85 recruited by tyrosine-phosphorylated proteins than was either EGF, insulin, or EGF and insulin combined. Furthermore, erbB-3 principally mediated the direct recruitment of p85 in cells stimulated by HRG or EGF, indicating that, in addition to the high-level activation of PI3K by p185(erbB-2) / erbB-3, EGFR/erbB-3 heterodimer interaction is essential for the weak but significant level of PI3K activated by EGF in cells that express normal EGFR levels. Studies using the PI3K inhibitor wortmannin also indicated that PI3K activation was required for the proliferation of H16N-2 cells induced by either HRG-beta or EGF and insulin in serum-free culture. Finally, HRG-beta was also an especially potent inducer of PI3K in the nontransformed MCF-10A cells, which were derived spontaneously from normal reduction mammoplasty tissue. These data show, for the first time, a side-by-side quantitative comparison of the relative degree of PI3K activated by different growth factors in nontransformed growth factor-dependent cells under precisely defined conditions in culture.
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PMID:Heregulin-beta is especially potent in activating phosphatidylinositol 3-kinase in nontransformed human mammary epithelial cells. 1079 4

The transcriptional regulation of the human EGFR3 and ERBB2 genes has been extensively studied, particularly in the context of their overexpression in breast cancer. Here we summarize published work detailing the transcription factors which interact with the promoters of these and the rat ERBB2 homologue, neu, genes and discuss their possible relevance to gene activation in cancer. In addition we review the biologically significant molecules which modulate expression of these genes and discuss the nuclear factors involved in mediating these responses. We also describe novel therapies which may result from these studies and highlight directions for future research into the control of expression of the EGFR and ERBB2 genes in the normal mammary gland and in breast cancer.
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PMID:Transcriptional regulation of type I receptor tyrosine kinases in the mammary gland. 1088 1

The erbB family of receptor tyrosine kinase enzymes, and particularly EGFR and HER2/neu, have become important targets for potential anticancer drugs. The substrate protein binding site theoretically is the more attractive intracellular target on these enzymes, possessing lower homology than the ATP site between different receptor kinases. However, a major breakthrough in this field was the discovery that 4-anilinoquinazolines are potent and selective inhibitors, despite binding at the ATP site. The very tight structure-activity relationships shown by these compounds suggested a clearly-defined binding mode, where the quinazoline ring binds in the adenine pocket and the anilino ring binds in an adjacent, unique lipophilic pocket. A unique cysteine (Cys-773) adjacent to the quinazoline binding site has prompted the development of irreversible inhibitors that target this residue. Three 4-anilinoquinazoline analogues (two reversible and one irreversible inhibitor) have been evaluated clinically as anticancer drugs. Data from the most advanced, the reversible inhibitor Iressa, suggest that this class of compounds may be of value in cancer chemotherapy.
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PMID:The 4-anilinoquinazoline class of inhibitors of the erbB family of receptor tyrosine kinases. 1134 67

Regional metastasis is an important factor in the prognosis and treatment of head and neck squamous cell carcinoma (HNSCC). The results of earlier studies suggested the possibility of predicting nodal metastasis in HNSCC using biological markers. To identify which factors may be relevant in the metastatic behaviour of these tumours, the expression of several markers involved in tumour progression was studied in both nodal metastases and their corresponding primary tumours. Expression of p53, Rb, cyclin D1, myc, bcl-2, EGFR, neu, E-cadherin, epithelial cell adhesion molecule (Ep-CAM), and nm23 was studied in 54 primary tumours and their corresponding metastases in patients with HNSCC. The expression of most genes involved in tumourigenesis (p53, Rb, cyclin D1, myc, bcl-2, EGFR, neu, and E-cadherin) was similar in primary tumours and metastases. The expression of nm23 and Ep-CAM was found to be more frequently lower than higher in metastases, compared with their primary tumours. Whereas most genetic alterations of primary tumours remain unchanged in metastases, expression of the cell adhesion molecule Ep-CAM and of nm23 is more frequently reduced than increased in metastases, compared with their primary tumours, suggesting relevance to the process of metastasis. This also implies differences in the regulation of markers involved in tumourigenesis and the process of metastasis.
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PMID:Expression of genetic markers in lymph node metastases compared with their primary tumours in head and neck cancer. 1143 61

Dramatic progress has been made over recent years toward the elucidation of the mechanisms regulating lineage determination and cell survival in the developing peripheral nervous system. However, our understanding of Schwann cell development is limited. This is partly due to the difficulties in culturing primary Schwann cell precursor cells, the earliest developmental stage of the Schwann cell lineage defined to date. Both the inability to maintain cultured Schwann cell precursor cells in an undifferentiated state and the technical difficulties involved in their isolation have hampered progress. We have conditionally immortalized rat Schwann cell precursor cells using a retrovirally encoded EGFR/neu fusion protein to circumvent these problems and to generate a source of homogeneous cells. The resulting SpL201 cell line expresses p75 and nestin, two proteins expressed by neural crest-derived cells, as well as peripheral myelin protein 22, protein zero, and Oct-6 as markers of the Schwann cell lineage. When cultured in EGF-containing medium, the SpL201 cells proliferate and maintain an undifferentiated, Schwann cell precursor cell-like state. The cell line is dependent on EGF for survival but can differentiate into early Schwann cell-like cells in response to exogenous factors. Like primary rat Schwann cells, SpL201 cells upregulate Oct-6 and myelin gene expression in response to forskolin treatment. Furthermore, the SpL201 cell line can form myelin in the presence of axons in vitro and is capable of extensively remyelinating a CNS white matter lesion in vivo. Thus, this cell line provides a valuable and unique tool to study the Schwann cell lineage, including differentiation from the Schwann cell precursor cell stage through to myelination.
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PMID:SpL201: a conditionally immortalized Schwann cell precursor line that generates myelin. 1157 82

Aberrrant signaling by the epidermal growth factor receptor [EGFR (HER1, erbB1)] and/or HER2/neu tyrosine kinases is present in a cohort of breast carcinomas. Because HER2 is constitutively phosphorylated in some breast tumors, we speculated that, in these cancers, transmodulation of HER2 may occur via EGFR signaling. To test this possibility, we examined the effect of EGFR-specific kinase inhibitors against the HER2-overexpressing human breast tumor lines BT-474, SKBR-3, MDA-361, and MDA-453. ZD1839 (Iressa) is an ATP-mimetic that inhibits the purified EGFR and HER2 kinases in vitro with an IC(50) of 0.033 and >3.7 microM, respectively. The specificity of ZD1839 against EGFR was confirmed in Rat1 fibroblasts transfected with EGFR or HER2 chimeric receptors activated by synthetic ligands without the interference of endogenous receptors. Treatment of all breast cancer cell lines (except MDA-453) with 1 microM ZD1839 almost completely eliminated HER2 phosphorylation. In contrast, the incorporation of [gamma-(32)P]ATP in vitro onto HER2 receptors isolated from BT-474 cells was unaffected by 1 microM ZD1839. EGFR is expressed by BT-474, SKBR-3, and MDA-361 but not by MDA-453 cells, suggesting that ZD1839-mediated inhibition of the EGFR kinase explained the inhibition of HER2 phosphorylation in vivo. In SKBR-3 cells, ZD1839 exhibited a greater growth-inhibitory effect than Herceptin, a monoclonal antibody against the HER2 ectodomain. In both SKBR-3 and BT-474 cells, treatment with ZD1839 plus Herceptin induced a greater apoptotic effect than either inhibitor alone. Finally, ZD1839 completely prevented growth of BT-474 xenografts established in nude mice and enhanced the antitumor effect of Herceptin. These data imply that EGFR tyrosine kinase inhibitors will be effective against HER2-overexpressing breast tumor cells that also express EGFR and support their use in combination with HER2 antibodies, such as Herceptin, against mammary carcinomas with high levels of the HER2 proto-oncogene.
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PMID:Epidermal growth factor receptor (HER1) tyrosine kinase inhibitor ZD1839 (Iressa) inhibits HER2/neu (erbB2)-overexpressing breast cancer cells in vitro and in vivo. 1175 13


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