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 murine retroviral oncogene v-cbl induces pre-B cell lymphomas and myelogenous leukemias. The protein product of the mammalian c-cbl proto-oncogene is a widely expressed cytoplasmic 120-kDa protein (p120cbl) whose normal cellular function has not been determined. Here we show that upon stimulation of human epidermal growth factor (EGF) receptor, p12ocbl becomes strongly tyrosine-phosphorylated and associates with activated EGF receptor in vivo. A GST fusion protein containing amino acids 1-486 of p120cbl, including a region highly conserved in nematodes, binds directly to the autophosphorylated carboxyl-terminal tail of the EGF receptor. Platelet-derived growth factor (PDGF), fibroblast growth factor (FGF), or nerve growth factor (NGF) stimulation also results in tyrosine phosphorylation of p120cbl. Recent genetic studies in Caenorhabditis elegans indicate that Sli-1, a p120cbl homologue, plays a negative regulatory role in control of the Ras signaling pathway initiated by the C. elegans EGF receptor homologue. Our results indicate that p120cbl is involved in an early step in the EGF signaling pathway that is conserved from nematodes to mammals.
J Biol Chem 1995 Sep 01
PMID:Tyrosine phosphorylation of the c-cbl proto-oncogene protein product and association with epidermal growth factor (EGF) receptor upon EGF stimulation. 765 91

We have examined the selective cytotoxicity of immunoliposomes containing doxorubicin (chemoimmunoliposomes, CILs) targeting the c-erbB-2 gene product (gp185) or gp125. Anti-gp185 and anti-gp125 CILs were prepared by conjugation of doxorubicin-containing liposomes with monoclonal antibodies SER4 (IgG) and HBJ127 (IgG) respectively. Both CILs bound to human SKBr-3 breast cancer cells and MKN-7 human gastric cancer cells, which express both antigens in high density. The IC50 of anti-gp185 CILs on protein synthesis by SKBr-3 cells was respectively 2- and 25-fold lower than that of anti-gp125 CILs and unmodified liposomes. Furthermore, anti-gp185 CILs significantly inhibited neither the phytohaemagglutin response of normal lymphocytes nor protein synthesis of gp185-negative T24 bladder cancer. Quantitative analysis of cell-associated doxorubicin revealed that, compared with anti-gp125 CILs, anti-gp185 CILs required, respectively 4.5 and 4.3 times less doxorubicin association in SKBR-3 and MKN-7 cells, for 50% cytotoxicity. In addition, flow cytometric analysis showed that both SKBr-3 and MKN-7 internalised more anti-gp185 CILs and processed them more efficiently than anti-gp125 CILs. These results suggest that anti-gp185 CILs act selectively against gp185-expressing cancer cells and that gp185 is a more sensitive antigen for CIL cytotoxicity associated with endocytosis activity.
Br J Cancer 1995 Sep
PMID:Cytotoxicity of anti-c-erbB-2 immunoliposomes containing doxorubicin on human cancer cells. 766 78

The issue of whether multifocal breast cancer represents intramammary spread from a single primary tumor or multiple synchronous tumors remains unresolved. We have used a series of immunocytochemical markers, B72.3, DF3, c-erbB-2, SP-1, CEA, and p53, to attempt to answer this question. Of 24 cases with separate discrete synchronous tumors in the same breast, 10 were histologically and immunocytochemically identical, five were histologically similar but immunocytochemically different, two were histologically different but immunocytochemically identical, and in seven cases the tumors were different both histologically and immunocytochemically. In seven of the 24 cases lymph nodes containing metastatic tumor were also available; in each instance, the immunoreactivity of the metastasis was similar to one or other of the tumors in the breast. This study indicates that multifocal breast cancer may result from either intramammary spread from a single primary tumor or multiple synchronous primary tumors.
Hum Pathol 1995 Sep
PMID:Mechanisms of multifocal breast cancer: an immunocytochemical study. 767 96

Frequent recurrences and multicentricity of bladder cancer suggest that alterations of the urothelium distant from the tumor may be relevant to prognosis. In this study immunohistochemistry and fluorescence in situ hybridization (FISH) were used to examine expression of p53, erbB-2, and epidermal growth factor receptor (EGF-r), genomic aberrations, and tumor cell proliferation (Ki67 LI) in normal and dysplastic urothelium. Biopsy specimens examined included normal urothelium (n = 40), mild dysplasia (n = 34), moderate dysplasia (n = 18) and carcinoma in situ (CIS; n = 20). Several different oncogene expression patterns were found, only some of which were associated with dysplasia. EGF-r expression was equally frequent in normal and dysplastic urothelium and showed a strong association with Ki67 LI (P < .0001). A purely superficial erbB-2 positivity was present in both normal and dysplastic biopsies. However, diffuse erbB-2 positivity and p53 overexpression were both associated with advanced dysplasia (P < .0001 each). FISH analysis showed erbB-2 gene amplification and p53 deletions in selected CIS, as well as a marked chromosome 17 copy number heterogeneity in all six CIS examined. These findings indicate a considerable genomic instability in bladder CIS. They show that both erbB-2 and p53 are altered during malignant transformation. Detectable oncogene expression alone, however, is not diagnostic of malignancy in bladder urothelium.
Hum Pathol 1995 Sep
PMID:Patterns of p53, erbB-2, and EGF-r expression in premalignant lesions of the urinary bladder. 767 97

The SH2 domain protein tyrosine phosphatases (PTPases) PTP1C and PTP1D were found associated with epidermal growth factor (EGF) receptor which was purified from A431 cell membranes by several steps of chromatography. Both PTPases also associated with the EGF receptor upon exposure of immunoprecipitated receptor to lysates of MCF7 mammary carcinoma cells. The associated PTPases had little activity toward the bound receptor when it was autophosphorylated in vitro. Receptor dephosphorylation could, however, be initiated by treatment of the receptor-PTPase complex with phosphatidic acid (PA). When autophosphorylated EGF receptor was exposed to lysates of PTP1C or PTP1D overexpressing 293 cells, the association of PTP1C but not of PTP1D was enhanced in the presence of PA. In intact A431 cells, an association of PTP1C and PTP1D with the EGF receptor was detectable by coimmunoprecipitation experiments. PA treatment reduced the phosphorylation state of ligand activated EGF receptors in A431 cells and in 293 cells overexpressing EGF receptors together with PTP1C but not in 293 cells overexpressing EGF receptors alone or together with PTP1D. We conclude that PTP1C but not PTP1D participates in dephosphorylation of activated EGF receptors. A possible role of PA for physiological modulation of EGF receptor signaling is discussed.
J Biol Chem 1995 Sep 08
PMID:Association of SH2 domain protein tyrosine phosphatases with the epidermal growth factor receptor in human tumor cells. Phosphatidic acid activates receptor dephosphorylation by PTP1C. 767 63

HER2, the erbB-2/neu proto-oncogene product, is a 185-kDa transmembrane glycoprotein related to the epidermal growth factor receptor. Overexpression of HER2 was reported in several human adenocarcinomas, including mammary and ovarian carcinomas. A family of glycoproteins, the heregulin/neu differentiation factors, was characterized and implicated as the ligands for HER2. Recently, it has been shown that HER2 alone is not sufficient to reconstitute high affinity heregulin receptors and that HER3 or HER4 may be the required components of the heregulin receptors on mammary carcinoma cells (Sliwkowski, M.X., Schaefer, G., Akita, R.W., Lofgren, J.A., Fitzpatrick, V.D., Nuijens, A., Fendly, B.M., Cerione, R.A., Vandlen, R.L., and Carraway, K.L., III (1994) J. Biol. Chem. 269, 14661-14665; Plowman, G.D., Green, J.M., Culouscou, J.-M., Carlton, G.W., Rothwell, V.M., and Buckley, W. (1993) Nature 366, 473-475). Using the Cytosensor to measure the extracellular acidification rate, we have examined the effects of recombinant human heregulin-alpha on three mammary carcinoma cell lines expressing HER2 (MDA-MB-453, SK-BR-3, and MCF-7), an ovarian carcinoma cell line expressing HER2 (SK-OV-3), and CHO-K1 and 293-EBNA cells stably transfected with HER2. By reverse transcription polymerase chain reaction and Western blotting, we found that the breast cells also express HER3 and that the ovarian line co-expresses the HER4 message. A dramatic increase in the acidification rate was observed for the mammary carcinoma cells co-expressing high levels of HER2 and HER3. In contrast, the ovarian cells expressing high levels of HER2 and low levels of HER4 or CHO-K1 and 293-EBNA cells expressing HER2 alone were not responsive to heregulin. When these same transfected cells were exposed to monoclonal anti-HER2 antibody followed by anti-IgG to cause aggregation of the HER2 molecules, an increase in the acidification rate was observed, indicating coupling of transfected HER2 to the signal transduction pathway. Transfection of HER2 into MCF-7 cells, on the other hand, gave 4-fold enhanced acidification responses. These data, together with the previously reported high affinity heregulin binding and activation of tyrosine phosphorylation in HER2 and HER3 co-transfected cells support the role of HER2 and HER3 as components of the heregulin receptor in breast cells.
J Biol Chem 1995 Sep 22
PMID:Heregulin activation of extracellular acidification in mammary carcinoma cells is associated with expression of HER2 and HER3. 767 53

The Shc gene encodes three overlapping proteins which all contain a carboxy-terminal SH2 domain. Shc proteins are ubiquitously expressed and are downstream targets and effectors of activated tyrosine kinases (TK). We investigated tyrosine-phosphorylation of Shc proteins in normal and transformed cells. In tumor cells with known TK gene alterations Shc proteins were constitutively phosphorylated and complexed with the activated TK. No constitutive Shc phosphorylation was found in primary cell cultures and normal tissues. In 14 of 27 tumor cell lines with no reported TK alterations, Shc proteins were constitutively phosphorylated and formed stable complexes with novel tyrosine-phosphorylated polypeptides. Ten distinct Shc-associated phosphoproteins were identified with molecular weights ranging from 30 to 200 kDa. In a subset of carcinoma cell lines, phosphorylated Shc proteins complexed with a p175 phosphoprotein that was identified as the constitutively activated EGFR. In one glioblastoma cell line, a Shc-associated p190 was identified as the activated PDGFR. In 13 of 14 acute leukemia samples phosphorylated Shc proteins were constitutively complexed with a p140 phosphoprotein. Some of the Shc-associated phosphoproteins (EGFR, PDGFR, erbB-2, Met, bcr-abl, H4-ret) bound both the Shc- and Grb2-SH2 domains in vitro; others (p175; p70-p80) only the Shc-SH2 domain and yet others (p140) only the Grb2-SH3 domains. These results indicate that Shc proteins are common substrates of constitutively activated TKs and that the analysis of Shc phosphorylation allow the identification of tumors with constitutive TK activation.
Oncogene 1995 Sep 07
PMID:Constitutive phosphorylation of Shc proteins in human tumors. 767 49

An expression cloning method which allows direct isolation of cDNAs encoding substrates for tyrosine kinases was applied to the study of the epidermal growth factor (EGF) receptor (EGFR) signaling pathway. A previously undescribed cDNA was isolated and designated eps15. The structural features of the predicted eps15 gene product allow its subdivision into three domains. Domain I contains signatures of a regulatory domain, including a candidate tyrosine phosphorylation site and EF-hand-type calcium-binding domains. Domain II presents the characteristic heptad repeats of coiled-coil rod-like proteins, and domain III displays a repeated aspartic acid-proline-phenylalanine motif similar to a consensus sequence of several methylases. Antibodies specific for the eps15 gene product recognize two proteins: a major species of 142 kDa and a minor component of 155 kDa, both of which are phosphorylated on tyrosine following EGFR activation by EGF in vivo. EGFR is also able to directly phosphorylate the eps15 product in vitro. In addition, phosphorylation of the eps15 gene product in vivo is relatively receptor specific, since the erbB-2 kinase phosphorylates it very inefficiently. Finally, overexpression of eps15 is sufficient to transform NIH 3T3 cells, thus suggesting that the eps15 gene product is involved in the regulation of mitogenic signals.
Mol Cell Biol 1993 Sep
PMID:eps15, a novel tyrosine kinase substrate, exhibits transforming activity. 768 53

The in vivo properties of monovalent and divalent single-chain Fv (sFv)-based molecules with the specificity of the anti-c-erbB-2 monoclonal antibody 741F8 were examined in scid mice bearing SK-OV-3 tumor xenografts. 741F8 sFv monomers exhibited rapid, biphasic clearance from blood, while a slightly slower clearance was observed with the divalent 741F8 (sFv')2 comprising a pair of 741F8 sFv' with a C-terminal Gly4Cys joined by a disulfide bond. Following i.v. injection, the 741F8 sFv monomer was selectively retained in c-erbB-2-overexpressing SK-OV-3 tumor, with excellent tumor:normal organ ratios uniformly exceeding 10:1 by 24 h. The specificity of this effect was demonstrated by the lack of retention of the anti-digoxin 26-10 sFv monomer, as evaluated by biodistribution studies, gamma camera imaging, and cryomacroautoradiography studies. The specificity index (741F8 sFv retention/26-10 sFv retention) of 741F8 monomer binding, measured by the percentage of injected dose per g of tissue, was 13.2:1 for tumor, and 0.8 to 2.1 for all tested normal organs, with specificity indices for tumor:organ ratios ranging from 7.0 (kidneys) to 16.7 (intestines). Comparing divalent 741F8 (sFv')2 with the 26-10 (sFv')2, similar patterns emerged, with specificity indices for retention in tumor of 16.9 for the Gly4Cys-linked (sFv')2. These data demonstrate that, following their i.v. administration, both monovalent and divalent forms of 741F8 sFv are specifically retained by SK-OV-3 tumors. This antigen-specific binding, in conjunction with the 26-10 sFv controls, precludes the possibility that passive diffusion and pooling in the tumor interstitium contributes significantly to long-term tumor localization. 741F8 (sFv')2 species with peptide spacers exhibited divalent binding and increased retention in tumors as compared with 741F8 sFv monomers. Since the blood retention of the (sFv')2 is slightly more prolonged than that of the monomer, it was necessary to demonstrate that the increased tumor localization of the peptide-linked (sFv')2 was due to its divalent nature. The significantly greater localization of the divalent bismalimidohexane-linked 741F8 (sFv')2 as compared with a monovalent 741F8 Fab fragment of approximately the same size suggests that the increased avidity of the (sFv')2 is a factor in its improved tumor retention. This is the first report of successful specific in vivo targeting of tumors by divalent forms of sFv molecules. The improved retention of specific divalent (sFv')2 by tumors may have important consequences for targeted diagnostic or therapeutic strategies.
Cancer Res 1993 Sep 01
PMID:Highly specific in vivo tumor targeting by monovalent and divalent forms of 741F8 anti-c-erbB-2 single-chain Fv. 768 21

We recently reported the molecular cloning of HER4/p180erbB4, a new member of the epidermal growth factor receptor family, as well as its activation by a partially purified ligand (Plowman, G. D., Culouscou, J.-M., Whitney, G. S., Green, J. M., Carlton, G. W., Foy, L., Neubauer, M. G., and Shoyab, M. (1993) Proc. Natl. Acad. Sci. U. S. A. 90, 1746-1750). In this report we describe the purification to homogeneity of a 45-kDa protein (p45) that induces the differentiation of MDA-MB-453 human breast cancer cells and stimulates the tyrosine phosphorylation of p180erbB4, the HER4-encoded protein. Hydrophobic interaction, ion-exchange, heparin, and size exclusion chromatographies were used to purify this p180erbB4 activator to homogeneity. N-terminal amino acid sequencing suggests that p45 is related to heregulin, a recently reported ligand for p185erbB2. Binding and cross-linking experiments demonstrated that p45 specifically binds to cells expressing recombinant p180erbB4 and not cells expressing recombinant p185erbB2.
J Biol Chem 1993 Sep 05
PMID:Characterization of a breast cancer cell differentiation factor that specifically activates the HER4/p180erbB4 receptor. 768 52


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