Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:O76050 (neu)
 3,969 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The neu protooncogene encodes a tyrosine kinase receptor that is involved in the regulation of normal growth and malignant transformation. To circumvent the use of the incompletely characterized ligand of Neu, we constructed a chimeric protein composed of the ligand-binding domain of the epidermal growth factor receptor and the transmembrane and cytoplasmic portions of Neu. By expressing this Neu-epidermal growth factor receptor chimera (termed NEC), we found that following stimulation by the heterologous ligand, the tyrosine kinase of Neu became associated with a phosphatidylinositol (PI) kinase activity. The association was dependent on the concentration of the ligand and was almost maximal within 30 s after ligand binding. The lipid kinase was identified as a type I PI 3'-kinase on the basis of its inhibition by Nonidet P-40 and high pressure liquid chromatography of the phosphorylated product. To confirm the identification of PI 3'-kinase as an effector of Neu, we raised antibodies to the alpha-isoform of the regulatory subunit of PI 3'-kinase (p85). Using these antibodies, it was possible to directly demonstrate ligand-dependent formation of a tyrosine-phosphorylated complex of NEC and PI 3'-kinase. Apparently, both PI 3'-kinase and phospholipase C gamma, another substrate of the Neu kinase, simultaneously associated with the same activated NEC molecule. Nevertheless, immunofluorescence localization of PI 3'-kinase revealed no significant cellular redistribution of the enzyme after activation of the Neu kinase. Interestingly, PI 3'-kinase was localized primarily to the cell nucleus and to confined regions of the plasma membrane. Analysis of mutants of the Neu protein indicated that the oncogenic point-mutated Neu (Glu664) was permanently coupled to PI 3'-kinase; but two nontransforming versions of the oncoprotein, a kinase-defective protein and a carboxyl-terminally deleted Neu, were devoid of the constitutive association with PI 3'-kinase. Hence, we concluded that phosphatidylinositol 3'-kinase is a physiological substrate of the Neu receptor, but the regulation of this coupling is released upon oncogenic activation.
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PMID:Regulated coupling of the Neu receptor to phosphatidylinositol 3'-kinase and its release by oncogenic activation. 135 Oct 56

The neu/HER2 proto-oncogene encodes a transmembrane tyrosine kinase homologous to receptors for polypeptide growth factors. The oncogenic potential for the presumed receptor is released through multiple genetic mechanisms including a specific point mutation, truncation at the extracellular domain and overexpression of the protooncogene. Here we show that all these modes of oncogenic activation result in a constitutively phosphorylated neu protein and an increase in tyrosine phosphorylation of a phosphatidylinositol-specific phospholipase (PLC gamma). The examined transforming neu/HER2 proteins, unlike the normal gene product, also co-immunoprecipitated with PLC gamma molecules. A kinase-defective mutant of a transforming neu failed to mediate both tyrosine phosphorylation and association with PLC gamma, suggesting direct interaction of the neu kinase with PLC gamma. This possibility was examined by employing a chimeric protein composed of the extracellular ligand-binding domain of the epidermal growth factor receptor and the neu cytoplasmic portion. The chimeric receptor mediated rapid ligand-dependent modification of PLC gamma on tyrosine residues. It also physically associated, in a ligand-dependent manner, with the phosphoinositidase. Based on the presented results we suggest that the mechanism of cellular transformation by the neu/HER2 receptor involves tyrosine phosphorylation and activation of PLC gamma.
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PMID:Oncogenic forms of the neu/HER2 tyrosine kinase are permanently coupled to phospholipase C gamma. 167 73

Activation of T cells by professional APCs that present peptide epitopes of tumor-associated Ags is critical for the induction of cell-mediated immunity against tumors. To facilitate targeted delivery of the ErbB2 (HER2, neu) tumor Ag to APCs in vivo, we have generated chimeric proteins that contain the extracellular domain of CTLA-4 for binding to B7 molecules on the APC surface, which is genetically fused to a human ErbB2 fragment as an antigenic determinant. Bacterially expressed CTLA-4-ErbB2 fusion protein and a similar molecule harboring in addition the translocation domain of Pseudomonas exotoxin A as an endosome escape function displayed specific binding to B7-expressing cells, followed by protein internalization and intracellular degradation. Vaccination of BALB/c mice with the fusion proteins resulted in the induction of ErbB2-specific CD8(+) T cells and CTL-dependent protection from subsequent challenge with ErbB2-expressing but not ErbB2-negative murine renal carcinoma cells. In a therapeutic setting, injection of CTLA-4-ErbB2 protein vaccines caused rejection of established ErbB2-expressing tumors. Thereby, immunological memory was induced, leading to long-term systemic immunity and protection against rechallenge several months later. Our results demonstrate that these chimeric protein vaccines are effective tools for the induction of ErbB2-specific, T cell-mediated immunity.
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PMID:Targeted delivery of the ErbB2/HER2 tumor antigen to professional APCs results in effective antitumor immunity. 1584 46

To induce Her2-specific cell immune response, we used xenogeneic antigen rat neu L2-S2 domains as the vaccine antigen. The antigenic protein was engineered as a chimeric protein with human IgG1 Fc region (neu-Fc). Neu-Fc could stimulate the cell proliferation in mixed lymphocyte reaction effectively. Simultaneous neu-Fc and IFN-gamma stimulation dramatically elevated IL-12 secretion and reduced IL-10 production in PBMC. To further augment the activating effects on Th1-type response, Bacille Calmette-Guerin (BCG) was utilized as a non-specific stimulus. Neu-Fc, IFN-gamma and BCG costimulation exhibited the most conspicuous effects on the reversal of the Th1-type inhibitory effects by MCF-7 cell supernatant compared with neu-Fc alone or IFN-gamma and BCG costimulation. The lytic activity of effector cells to Her2 overexpressing cells was greatly promoted by neu-Fc, IFN-gamma and BCG stimulation simultaneously. Neu-Fc led to considerable retardation in EMT6/Her2 tumour growth in Balb/c mice. IFN-gamma and BCG efficiently enhanced the antitumour activity. A large amount of inflammatory cells were found to be accumulated in the tumour tissues or surrounded tumours in mice treated with neu-Fc, IFN-gamma and BCG but no inflammatory cell infiltration was observed in control tumours, indicating that the strategy is potent enough to support the initiation and propagation of tumour-specific immune response in an established tumour and generate a proinflammatory environment.
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PMID:A new strategy to induce effective antitumour response in vitro and in vivo. 1878 57

This study was aimed to investigate the effects of xenogeneic antigen neu-Fc in combination with the recombinant human granulocyte-macrophage colony stimulating factor (GM-CSF) and Bacillus Calmette-Guerin (BCG) on the regulation of Th1 and Th2 immune response in vitro. The rat neu L2-S2 domain was engineered as a chimeric protein with human IgG Fc. The eukaryotic expression vector was constructed. The recombinant protein was stably expressed in CHO cells and purified by rProtein A Sepharose Fast Flow column. The recombinant protein was identified by SDS-PAGE and Western blot. Peripheral blood mononuclear cells (PBMNCs) were obtained by means of standard Ficoll separation from the blood of healthy donors. Neu-Fc-induced PBMNC proliferation was tested by MTT. The production of IL-12 and IL-10 was measured by ELISA. The results showed that the level of IL-12 decreased and IL-10 increased after PBMNCs were incubated with MCF-7 cultural supernatant. 10 nmol/L neu-Fc strongly induced the cell proliferation. Compared with neu-Fc or GM-CSF or BCG treatment alone, neu-Fc in combination with GM-CSF and BCG significantly stimulated IL-12 production and inhibited IL-10 production (p < 0.01). It is concluded that the neu-Fc can stimulate the proliferation activity of PBMNCs. neu-Fc, GM-CSF and BCG costimulation efficiently induces Th1 immune response.
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PMID:[Immunoregulation effects in vitro of the xenoprotein in combination with recombinant human granulocyte-macrophage colony stimulating factor and bacillus Calmette-Guerin]. 1909 54

Immune cells become increasingly attractive as delivery system for immunotoxins in cancer therapy to reduce the intrinsic toxicity and severe side effects of chimeric protein toxins. In this study, we investigated the potential of human primary T cells to deliver a secreted immunotoxin through transient messenger RNA (mRNA) transfection. The chimeric protein toxin was directed toward the neovasculature of cancer cells by fusing a truncated version of Pseudomonas exotoxin A (PE38) to human vascular endothelial growth factor (VEGF) and to the single chain variable fragment (scFv) of anti-Her2/neu. Protocols for the transient transfection of human embryonic kidney cells (HEK293) as well as activated primary human T cells were established. Transient transfection with mRNA coding for the immunotoxins e23-PE38, VEGF-PE38 and its attenuated variant VEGF-PE38D yielded efficient expression and secretion. Mass spectrometry analysis endorsed that a fraction of VEGF-PE38D was properly translocated into the endoplasmic reticulum. Furthermore, cytotoxic activity of immunotoxin secreting T cells toward cancer cells was confirmed in co-culture with ovarian adenocarcinoma cells in the presence of a bispecific antibody (bsAb), highlighting the potential of primary T cells for mRNA-mediated immunotoxin delivery.
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PMID:Primary T cells for mRNA-mediated immunotoxin delivery. 2893 81