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 effect of tyrosine kinase inhibitor, erbstatin, on cell growth and mRNA expression of growth-factor/receptor system was examined in 6 human gastric-carcinoma cell lines. Erbstatin inhibited both EGF-induced and serum-stimulated cell growth of all 6 cell lines (TMK-1, MKN-1, -7, -28, -45, -74) in a dose-dependent manner. 3H-thymidine incorporation by TMK-1 cells was also suppressed by erbstatin. Erbstatin inhibited protein kinase activity of EGF receptor, p185ERBB2 and pp60c-src in TMK-1 cells. The expression of mRNA of EGF receptor gene and ERBB-2 by TMK-1 cells was not changed by erbstatin treatment, whereas that of c-src was slightly decreased. Interestingly, erbstatin decreased membrane-bound TGF-alpha precursor as measured by anti-TGF-alpha antibody-binding assay, although mRNA expression for TGF-alpha was not altered by erbstatin. Our findings suggest that erbstatin may act as a growth inhibitor for human gastric-carcinoma cells and may not only inhibit tyrosine kinase activities but also negatively modulate the post-transcriptional step of TGF-alpha expression.
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PMID:Effects of tyrosine kinase inhibitor, erbstatin, on cell growth and growth-factor/receptor gene expression in human gastric carcinoma cells. 184 25

The product of the erbB-2 gene is a 185-kD receptor-like glycoprotein. erbB-2 gp185 displays constitutive tyrosine kinase activity and transforms NIH 3T3 cells when expressed 100-fold over the normal levels. We have analyzed the role of tyrosine kinase function and of receptor autophosphorylation in the regulation of erbB-2 biological activity. Abolition of erbB-2 gp185 tyrosine kinase function resulted in complete loss of its transforming activity and the absence of in vivo tyrosine phosphorylation. The steady-state content of phosphotyrosine in erbB-2 gp185 was found to be solely dependent on receptor autophosphorylation and to be dependent on the specific enzymatic activity of the erbB-2 protein. The major sites of erbB-2 autophosphorylation were shown to be in its COOH-terminal domain. Biological analysis of erbB-2 mutants containing either individual or multiple Tyr----Phe substitutions at the potential sites of autophosphorylation revealed that autophosphorylation upregulates erbB-2 gp185 transforming activity. Autophosphorylation did not modulate receptor turnover. A Tyr----Phe substitution of erbB-2 Tyr-877 homologous to pp60c-src Tyr-416 did not alter erbB-2 biological and biochemical properties, thus excluding the possibility that phosphorylation of this residue, located in the kinase domain, modulates erbB-2 gp185 catalytic function. Hence, autophosphorylation of tyrosine residues localized in its COOH terminus appears to be required for optimal coupling of erbB-2 gp185 with its mitogenic pathway.
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PMID:The role of autophosphorylation in modulation of erbB-2 transforming function. 198 72

Inhibition by seven synthetic 4-hydroxycinnamamide derivatives, ST 271, ST 280, ST 458, ST 494, ST 633, ST 638, and ST 642, of tyrosine-specific protein kinases (tyrosine kinase) of oncogene or proto-oncogene products (p130gag-v-fps, p70gag-actin-v-fgr, pp60v-src, pp60c-src) and epidermal growth factor (EGF) receptor kinase were investigated. ST 638 (alpha-cyano-3-ethoxy-4-hydroxy-5-phenylthiomethylcinnamamide) strongly inhibited more of the tyrosine kinases than any of the other compounds. The susceptibilities of these tyrosine kinases to ST 638 increased in the following order: EGF receptor greater than p70gag-actin-v-fgr greater than pp60c-src greater than p130gag-v-fps, pp60v-src, with 50% inhibitory concentration values of 1.1, 4.2, 18, 70, and 87 microM, respectively. The phosphorylation of the tyrosine residues in particulate fractions from RR1022 cells expressing pp60v-src was inhibited by ST 638 in a dose-dependent way, while it had a negligible effect on the phosphorylations of threonine and serine residues. Kinetic analysis showed that ST 638 competitively inhibited the phosphorylation of an exogenous substrate by the EGF receptor kinase with a Ki of 2.1 microM. ST 638 noncompetitively inhibited autophosphorylation by EGF receptor kinase. These results indicate that ST 638 is a potent and specific inhibitor of tyrosine kinases in vitro, and that its inhibitory activity is caused by competing with the substrate protein for the tyrosine kinase binding site.
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PMID:Specific inhibitors of tyrosine-specific protein kinases: properties of 4-hydroxycinnamamide derivatives in vitro. 270 25

Overexpression and amplification of the erbB-2 (neu) is thought to play a major role in mammary cancer. Although studies suggest that Neu is directly involved in the genesis of mammary tumors, the molecular mechanism by which Neu induces tumors is not well understood. Recently, we have demonstrated that the activity of c-Src tyrosine kinase is elevated in Neu-induced mammary tumors and this elevated activity correlates with its capacity to physically associate with Neu. To explore whether other members of the c-Src family are activated in these mammary tumors, we measured the in vitro kinase activity of the c-Yes and Fyn kinases in protein extracts derived from mammary tumor tissue and morphological normal adjacent tissue. These analyses revealed that c-Yes kinase activity was elevated in Neu-induced tumors by comparison to the adjacent tissue. By contrast, no significant activation of the Fyn kinase was noted in these tumors. Activation of c-Yes tyrosine kinase correlated with the capacity of c-Yes to associate with Neu in vivo in lysates derived from primary tumor samples. Studies with Rat.2 fibroblasts overexpressing activated Neu revealed that c-Src requires the presence of tyrosine phosphorylated Neu for its ability to interact with Neu in vivo. Moreover, analyses using radiolabeled c-Yes SH2 fusion protein revealed that this interaction is likely occurring in a direct fashion. Although both c-Src and c-Yes kinase associate with Neu in vivo, a tyrosine phosphorylated protein of 89 kd (p89) was found associated with c-Src but not with c-Yes in cell lysates derived from mammary epithelial cells transformed by either Neu or PyV middle T antigen. Furthermore, this tyrosine phosphorylated protein was not detected in c-Src complexes derived from fibroblasts transformed by either Neu or PyV middle T. These observations suggest that p89 associates with c-Src only in mammary epithelial cells and not in fibroblasts.
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PMID:Activation of Src family kinases in Neu-induced mammary tumors correlates with their association with distinct sets of tyrosine phosphorylated proteins in vivo. 747 8

In the previous study [Sato et al. (1995) Biochem. Biophys. Res. Commun. 210, 844-851], we found that c-Src was associated with epidermal growth factor (EGF) receptor and activated upon EGF treatment in A431 cells. In the present study, we investigated the phosphorylation of EGF receptor by c-Src in the c-Src-EGF receptor complex. We have focused our attention to tyrosine residue 845 (Y845) of EGF receptor as a candidate for the phosphorylation site. A synthetic peptide containing Y845, named Y845 peptide, which corresponds to residue 837 to 856 of EGF receptor, was found to be phosphorylated by c-Src and used to provide the standard phosphopeptide. In addition to the autophosphorylated peptide of 25 kDa, a phosphopeptide of 7 kDa was detected in the cyanogen bromide-digested fragments of the c-Src-associated EGF receptor phosphorylated in vitro in an EGF-dependent manner. In phosphopeptide mapping, tryptic digest of the 7-kDa phosphopeptide was shown to co-migrate with that of the phosphorylated Y845 peptide. The 7-kDa phosphopeptide was found to be phosphorylated exclusively on tyrosine. These results suggest that c-Src can phosphorylate EGF receptor on Y845 in an EGF-dependent manner. Furthermore, we confirmed that the same site of the c-Src-associated EGF receptor was phosphorylated in EGF-treated A431 cells.
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PMID:c-Src phosphorylates epidermal growth factor receptor on tyrosine 845. 748 34

We have examined the interaction between c-Src and epidermal growth factor (EGF) receptor in A431 cells. c-Src was found exclusively in the Triton X-100-solubilized particulate fraction and activated up to 3-fold within 1 min after EGF treatment of the cells. Association between c-Src and EGF receptor was detected by immunoprecipitation of c-Src followed by immunoblotting with anti-EGF receptor antibody. The c-Src-EGF receptor complex was found in both EGF-treated and untreated cells, but an augmented complex formation was observed in EGF-treated cells. We have isolated the complex by DEAE-cellulose column chromatography and found that a site-specific anti-c-Src antibody, which was raised against a synthetic peptide corresponding to residues 413 to 431 of human c-Src, did not recognize the c-Src protein in the complex, while other c-Src-specific antibodies tested did. Incubation of the complex with this synthetic peptide resulted in a partial dissociation of the complex. These results suggest that the specific region of c-Src is involved in the association with EGF receptor.
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PMID:Site-specific association of c-Src with epidermal growth factor receptor in A431 cells. 753 62

The Src family protein-tyrosine kinases are required for mitogenic signaling from the platelet-derived growth factor (PDGF), colony stimulating factor-1, and epidermal growth factor (EGF) receptor protein-tyrosine kinases (RPTK) (Twamley-Stein, G. M., Pepperkok, R., Ansorge, W., and Courtneidge, S. A. (1993) Proc. Natl. Acad. Sci. U. S. A. 90, 7696-7700; Roche, S., Koegl, M., Barone, M. V., Roussel, M. F., and Courtneidge, S. A.(1995) Mol. Cell. Biol. 15, 1102-1109). In NIH3T3 fibroblasts, c-Src, Fyn, and c-Yes associate with the activated PDGF receptor, are substrates for receptor phosphorylation, and are themselves activated. Src family catalytic function is required for RPTK mitogenic signaling as evidenced by the SH2-dependent dominant negative phenotype exhibited by kinase-inactive Src and Fyn mutants (Twamley-Stein, G. M., Pepperkok, R., Ansorge, W., and Courtneidge, S. A.(1993) Proc. Natl. Acad. Sci. U. S. A. 90, 7696-7700). Here, we have generated clonal Src- murine fibroblast cell lines overexpressing various murine c-Src mutants and studied the effect of these mutant Src proteins on PDGF- and EGF-induced mitogenesis. Two c-Src SH3 domain mutants, Y133F and Y138F, each inhibited PDGF BB- and EGF-induced DNA synthesis in quiescent cells. This demonstrates an involvement of the Src SH3 domain in PDGFbeta and EGF receptor mitogenic signaling. Since both Tyr-133 and Tyr-138 are located on the ligand binding surface of the SH3 domain, these results suggest that the c-Src SH3 domain is required for PDGF and EGF mitogenic signaling. The dominant negative effect of either single mutant on PDGF receptor signaling was reversed by a second SH2-inactivating mutation. We conclude that the c-Src SH3 domain function requires the SH2 domain in the case of the PDGF receptor, presumably because binding of c-Src to the receptor via its SH2 domain is a prerequisite for the SH3 domain function. In contrast, SH2 function is apparently not essential for the SH3 function in EGF receptor signaling.
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PMID:Requirement for c-Src catalytic activity and the SH3 domain in platelet-derived growth factor BB and epidermal growth factor mitogenic signaling. 866 29

We have examined the function of the epidermal growth factor (EGF) receptor, c-Src and focal adhesion kinase (FAK) in the progression of colon cancer using an in vitro progression model. A non-tumorigenic cell line was derived from a premalignant colonic adenoma (PC/AA) from which a clonogenic variant was established (AA/C1). Following sequential treatment with sodium butyrate and the carcinogen N-methyl-N'-nitro-N-nitro-soguanidine an anchorage-independent line was isolated which, with time in culture, became tumorigenic when injected into athymic nude mice (AA/C1/SB10). We have shown that both EGF receptor and FAK protein levels were elevated in the carcinoma cells as compared to the adenoma cells, while the expression and activity of c-Src were unaltered during the adenoma to carcinoma transition. EGF induced the movement of the carcinoma cells into a reconstituted basement membrane which was not seen with the premalignant adenoma cells. This increased motility was accompanied by an EGF-induced increase in c-Src kinase activity, relocalisation of c-Src to the cell periphery and phosphorylation of FAK in the carcinoma cells but not in the adenoma cells. This suggests that c-Src plays a role in the biological behaviour of colonic carcinoma cells induced by migratory factors such as EGF, perhaps acting in conjunction with FAK to regulate focal adhesion turnover and tumour cell motility. Furthermore, although c-Src has been implicated in colonic tumour progression, we demonstrate here that in the adenoma to carcinoma in vitro model c-Src is not the driving force for this progression but co-operates with other molecules in carcinoma development.
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PMID:A role for epidermal growth factor receptor, c-Src and focal adhesion kinase in an in vitro model for the progression of colon cancer. 901 14

In many cells, stimulation of mitogen-activated protein kinases by both receptor tyrosine kinases and receptors that couple to pertussis toxin-sensitive heterotrimeric G proteins proceed via convergent signaling pathways. Both signals are sensitive to inhibitors of tyrosine protein kinases and require Ras activation via phosphotyrosine-dependent recruitment of Ras guanine nucleotide exchange factors. Receptor tyrosine kinase stimulation mediates ligand-induced receptor autophosphorylation, which creates the initial binding sites for SH2 domain-containing docking proteins. However, the mechanism whereby G protein-coupled receptors mediate the phosphotyrosine-dependent assembly of a mitogenic signaling complex is poorly understood. We have studied the role of Src family nonreceptor tyrosine kinases in G protein-coupled receptor-mediated tyrosine phosphorylation in a transiently transfected COS-7 cell system. Stimulation of Gi-coupled lysophosphatidic acid and alpha2A adrenergic receptors or overexpression of Gbeta1gamma2 subunits leads to tyrosine phosphorylation of the Shc adapter protein, which then associates with tyrosine phosphoproteins of approximately 130 and 180 kDa, as well as Grb2. The 180-kDa Shc-associated tyrosine phosphoprotein band contains both epidermal growth factor (EGF) receptor and p185(neu). 3-5-fold increases in EGF receptor but not p185(neu) tyrosine phosphorylation occur following Gi-coupled receptor stimulation. Inhibition of endogenous Src family kinase activity by cellular expression of a dominant negative kinase-inactive mutant of c-Src inhibits Gbeta1gamma2 subunit-mediated and Gi-coupled receptor-mediated phosphorylation of both EGF receptor and Shc. Expression of Csk, which inactivates Src family kinases by phosphorylating the regulatory carboxyl-terminal tyrosine residue, has the same effect. The Gi-coupled receptor-mediated increase in EGF receptor phosphorylation does not reflect increased EGF receptor autophosphorylation, assayed using an autophosphorylation-specific EGF receptor monoclonal antibody. Lysophosphatidic acid stimulates binding of EGF receptor to a GST fusion protein containing the c-Src SH2 domain, and this too is blocked by Csk expression. These data suggest that Gbetagamma subunit-mediated activation of Src family nonreceptor tyrosine kinases can account for the Gi-coupled receptor-mediated tyrosine phosphorylation events that direct recruitment of the Shc and Grb2 adapter proteins to the membrane.
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PMID:Gbetagamma subunits mediate Src-dependent phosphorylation of the epidermal growth factor receptor. A scaffold for G protein-coupled receptor-mediated Ras activation. 902 Jan 93

PD 089828, a novel protein tyrosine kinase inhibitor of a new structural class, the 6-aryl-pyrido-[2,3-d]pyrimidines, was identified by screening a compound library with assays that measured protein tyrosine kinase activity. PD 089828 was found to inhibit human full-length fibroblast growth factor (FGF) receptor-1 (FGFR-1), platelet-derived growth factor (PDGF) receptor beta subunit (PDGFR-beta), Src nonreceptor tyrosine kinase (c-Src) and epidermal growth factor (EGF) receptor (EGFR) tyrosine kinases with half-maximal inhibitory potencies (IC50 values) of 0.15 +/- 0.02 (n = 4), 0.18 +/- 0.04 (n = 3), 1.76 +/- 0.28 (n = 4) and 5.47 +/- 0.78 (n = 6) microM, respectively. PD 089828 was further characterized as an ATP competitive inhibitor of the growth factor receptor tyrosine kinases (FGFR-1, PDGFR-beta and EGFR) but a noncompetitive inhibitor of c-Src tyrosine kinase with respect to ATP. In addition, PD 089828 inhibited PDGF- and EGF-stimulated receptor autophosphorylation in vascular SMC (VSMC) and basic FGF-mediated tyrosine phosphorylation in A121 cells with IC50 values similar to the potencies observed for inhibition of receptor tyrosine kinase activity. The inhibition of PDGF receptor autophosphorylation in VSMC by PD 089828 occurred rapidly, with maximal effects reached within 5 min of drug exposure. Inhibition after single exposure was long lasting but also rapidly reversible, occurring within 5 min after drug removal. The PDGF-induced association of downstream signaling proteins, including phosphoinositide-3-kinase (PI-3K), growth factor receptor binding protein-2 (GRB2), SH-2 domain and collagen like (Shc) and phospholipase Cgamma (PLCgamma), with VSMC PDGF receptors was also blocked as a result of the inhibition of PDGF-stimulated receptor autophosphorylation by PD 089828. PD 089828 also inhibited the PDGF-induced tyrosine phosphorylation of the 44- and 42-kDa mitogen-activated protein kinase isoforms. Moreover, the effects of PD 089828 were demonstrated in functional assays in which PDGF-stimulated DNA synthesis, PDGF-directed migration and serum-stimulated growth of VSMC were all inhibited to the same extent as PDGF receptor autophosphorylation (IC50 = 0.8, 4.5 and 1.8 microM, respectively). These results highlight the biological characteristics of PD 089828 as a novel, broadly active protein tyrosine kinase inhibitor with long-lasting but reversible cellular effects. The potential therapeutic use of these broadly acting, nonselective inhibitors as antiproliferative and antimigratory agents could extend to such diseases as cancer, atherosclerosis and restenosis in which redundancies in growth-signaling pathways are known to exist.
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PMID:Inhibition of growth factor-mediated tyrosine phosphorylation in vascular smooth muscle by PD 089828, a new synthetic protein tyrosine kinase inhibitor. 919 Aug 82


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