101
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Dankort D, Maslikowski B, Warner N, Kanno N, Kim H, Wang Z, Moran MF, Oshima RG, Cardiff RD, Muller WJ. Grb2 and Shc adapter proteins play distinct roles in Neu (ErbB-2)-induced mammary tumorigenesis: implications for human breast cancer. Mol Cell Biol 2001; 21:1540-51. [PMID: 11238891 PMCID: PMC86700 DOI: 10.1128/mcb.21.5.1540-1551.2001] [Citation(s) in RCA: 134] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Amplification of the Neu (ErbB-2 or HER-2) receptor tyrosine kinase occurs in 20 to 30% of human mammary carcinomas, correlating with a poor clinical prognosis. We have previously demonstrated that four (Y1144 Y1201, Y1227 and Y1253) of the five known Neu autophosphorylation sites can independently mediate transforming signals. The transforming potential of two of these mutants correlates with their capacity to recruit Grb2 directly to Y1144 (YB) or indirectly through Shc to Y1227 (YD). Here, we demonstrate that these transformation-competent neu mutants activate extracellular signal-regulated kinases and stimulate Ets-2-dependent transcription. Although the transforming potential of three of these mutants (YB, YD, and YE) was susceptible to inhibition by Rap1A, a genetic antagonist of Ras, the transforming potential of YC was resistant to inhibition by Rap1A. To further address the significance of these ErbB-2-coupled signaling molecules in induction of mammary cancers, transgenic mice expressing mutant Neu receptors lacking the known autophosphorylation sites (NYPD) or those coupled directly to either Grb2 (YB) or Shc (YD) adapter molecules were derived. In contrast to the NYPD strains, which developed focal mammary tumors after a long latency period with low penetrance, all female mice derived from YB and YD strains rapidly developed mammary tumors. Although female mice from several independent YB or YD lines developed mammary tumors, the YB strains developed lung metastases at substantially higher rates than the YD strains. These observations argue that Grb2 and Shc play important and distinct roles in ErbB-2/Neu-induced mammary tumorigenesis and metastasis.
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MESH Headings
- Adaptor Proteins, Signal Transducing
- Adaptor Proteins, Vesicular Transport
- Alleles
- Animals
- Binding Sites
- Breast Neoplasms/etiology
- Breast Neoplasms/metabolism
- Cell Line
- Chromatography, Affinity
- DNA-Binding Proteins
- Female
- GRB2 Adaptor Protein
- Glutathione Transferase/metabolism
- Humans
- Immunoblotting
- Kinetics
- Mammary Neoplasms, Animal/etiology
- Mammary Neoplasms, Animal/metabolism
- Mice
- Mice, Transgenic
- Mitogen-Activated Protein Kinases/metabolism
- Neoplasm Metastasis
- Phosphorylation
- Precipitin Tests
- Protein Structure, Tertiary
- Proteins/physiology
- Proto-Oncogene Protein c-ets-2
- Proto-Oncogene Proteins/metabolism
- Rats
- Receptor, ErbB-2/metabolism
- Recombinant Fusion Proteins/metabolism
- Repressor Proteins
- Shc Signaling Adaptor Proteins
- Signal Transduction
- Src Homology 2 Domain-Containing, Transforming Protein 1
- Terminal Repeat Sequences
- Time Factors
- Trans-Activators/metabolism
- Transcription Factors
- Transcription, Genetic
- Transcriptional Activation
- Transfection
- rap1 GTP-Binding Proteins/metabolism
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Affiliation(s)
- D Dankort
- Department of Biology, Institute for Molecular Biology and Biotechnology, McMaster University, Hamilton, Ontario, Canada L8S 4K1
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102
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Siegel PM, Dankort DL, Muller WJ. Oncogene mediated signal transduction in transgenic mouse models of human breast cancer. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2001; 480:185-94. [PMID: 10959426 DOI: 10.1007/0-306-46832-8_23] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Affiliation(s)
- P M Siegel
- Institute for Molecular Biology & Biotechnology, McMaster University, Hamilton, Ontario
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103
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Bjorge JD, Pang A, Fujita DJ. Identification of protein-tyrosine phosphatase 1B as the major tyrosine phosphatase activity capable of dephosphorylating and activating c-Src in several human breast cancer cell lines. J Biol Chem 2000; 275:41439-46. [PMID: 11007774 DOI: 10.1074/jbc.m004852200] [Citation(s) in RCA: 242] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
c-Src tyrosine kinase activity is elevated in several types of human cancer, and this has been attributed to elevated c-Src expression levels, increased c-Src specific activity, and activating mutations in c-Src. We have found a number of human breast cancer cell lines with elevated c-Src specific activity that also possess elevated phosphatase activity directed against the carboxyl-terminal negative regulatory domain of Src family kinases. To identify this phosphatase, cell extracts from MDA-MB-435S cells were chromatographed and the fractions were assayed for phosphatase activity. Four peaks of phosphatase activity directed against the nonspecific substrate poly(Glu/Tyr) were detected. One peak also dephosphorylated a peptide modeled against the c-Src carboxyl-terminal negative regulatory domain and intact human c-Src. Immunoblotting and immunodepletion experiments identified the phosphatase as protein-tyrosine phosphatase 1B (PTP1B). Examination of several human breast cancer cell lines with increased c-Src activity showed elevated levels of PTP1B protein relative to normal control breast cells. In vitro c-Src reactivation experiments confirmed the ability of PTP1B to dephosphorylate and activate c-Src. In vivo overexpression of PTP1B in 293 cells caused a 2-fold increase of endogenous c-Src kinase activity. Our findings indicate that PTP1B is the primary protein-tyrosine phosphatase capable of dephosphorylating c-Src in several human breast cancer cell lines and suggests a regulatory role for PTP1B in the control of c-Src kinase activity.
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Affiliation(s)
- J D Bjorge
- Cancer Biology Research Group, Department of Biochemistry and Molecular Biology, University of Calgary Health Sciences Centre, Calgary, Alberta T2N 4N1, Canada
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104
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Chan PM, Nestler HP, Miller WT. Investigating the substrate specificity of the HER2/Neu tyrosine kinase using peptide libraries. Cancer Lett 2000; 160:159-69. [PMID: 11053645 DOI: 10.1016/s0304-3835(00)00581-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The product of the HER2/Neu oncogene is a receptor tyrosine kinase that is amplified in 25-30% of human primary breast tumors. In this project, we have isolated the HER2/Neu kinase from Sf9 cells infected with a baculovirus expression vector. We probed the substrate specificity of the HER2/Neu kinase using two peptide libraries: (1) a soluble peptide library containing three degenerate positions N-terminal to tyrosine; and (2) a bead-supported combinatorial library possessing six degenerate positions at P-1, P-2, P-3, P+1, P+2, and P+3. We identified four novel substrate sequences for HER2/Neu from the two peptide libraries. We synthesized these peptides as individual sequences and measured steady-state kinetic properties for phosphorylation by HER2/Neu. One of the peptides, AAEEIYAARRG, is the best synthetic peptide substrate reported to date for HER2/Neu. All of the sequences bear a resemblance to sites of autophosphorylation on HER2/Neu and related epidermal growth factor (EGF) receptor family tyrosine kinases.
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Affiliation(s)
- P M Chan
- The Department of Physiology and Biophysics, Basic Science Tower, T-6, School of Medicine, State University of New York at Stony Brook, Stony Brook, NY 11794-8661, USA
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105
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Abstract
Since the original identification of a transmissible agent responsible for the development of tumors in chickens, now known to be a retrovirus encoding the v-src gene, significant progress has been made in defining the potential functions of its human homolog, SRC. The product of the human SRC gene, c-Src, is found to be over-expressed and highly activated in a wide variety of human cancers. The relationship between Src activation and cancer progression appears to be significant. Moreover, Src may have an influence on the development of the metastatic phenotype. This review discusses the data supporting a role for c-Src as a critical component of the signal transduction pathways that control cancer cell development and growth, and provides the rationale for targeting Src in drug discovery efforts.
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Affiliation(s)
- R B Irby
- Department of Surgery, H. Lee Moffitt Cancer Center and Research Institute, University of South Florida, 12902 Magnolia Drive, Tampa, Florida, FL 33612, USA
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106
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Levkowitz G, Oved S, Klapper LN, Harari D, Lavi S, Sela M, Yarden Y. c-Cbl is a suppressor of the neu oncogene. J Biol Chem 2000; 275:35532-9. [PMID: 10940298 DOI: 10.1074/jbc.m002661200] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A rodent oncogenic mutant of the Neu receptor tyrosine kinase is a useful experimental model because overexpression of the respective receptor, namely HER2/ErbB-2, in human malignancies is associated with relatively aggressive diseases. Here we show that the oncogenic form of Neu is constitutively associated with the product of the c-cbl proto-oncogene and is part of a large complex that includes the phosphoinositide 3-kinase and Shc. Ectopic expression of c-Cbl, a ubiquitin-protein isopeptide ligase specific to activated tyrosine kinases, causes rapid removal of Neu from the cell surface and severely reduces signaling downstream of oncogenic Neu. c-Cbl-induced down-regulation of Neu involves covalent attachment of ubiquitin molecules and requires the carboxyl-terminal domain of Neu. The negative effect of c-Cbl is antagonized by v-Cbl, a virus-encoded oncogenic truncated form of c-Cbl. In an in vivo model, infection of a Neu-transformed neuroblastoma with a c-Cbl-encoding retrovirus caused enhanced down-regulation of Neu and correlated with tumor retardation. Our results implicate c-Cbl in negative regulation of Neu and offer a potential target for treatment of HER2/ErbB-2-positive human malignancies.
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MESH Headings
- 3T3 Cells
- Adaptor Proteins, Signal Transducing
- Adaptor Proteins, Vesicular Transport
- Animals
- Antibodies, Monoclonal/metabolism
- Biotinylation
- CHO Cells
- Cell Line
- Cricetinae
- DNA, Complementary/metabolism
- DNA-Binding Proteins/metabolism
- Down-Regulation
- Electrophoresis, Polyacrylamide Gel
- Fibroblasts/metabolism
- Humans
- Immunoblotting
- Ligases/metabolism
- Male
- Mice
- Mice, Nude
- Neoplasm Transplantation
- Neuroblastoma/metabolism
- Nuclear Proteins/metabolism
- Phosphatidylinositol 3-Kinases/metabolism
- Phosphorylation
- Precipitin Tests
- Protein Structure, Tertiary
- Proteins/metabolism
- Proto-Oncogene Mas
- Proto-Oncogene Proteins/genetics
- Proto-Oncogene Proteins/metabolism
- Proto-Oncogene Proteins/physiology
- Proto-Oncogene Proteins c-cbl
- Rats
- Receptor, ErbB-2/genetics
- Receptor, ErbB-2/metabolism
- Retroviridae/genetics
- Serum Response Factor
- Shc Signaling Adaptor Proteins
- Signal Transduction
- Src Homology 2 Domain-Containing, Transforming Protein 1
- Time Factors
- Transfection
- Ubiquitin-Protein Ligases
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Affiliation(s)
- G Levkowitz
- Departments of Biological Regulation and Immunology, The Weizmann Institute of Science, Rehovot 76100, Israel
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107
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Henriques DA, Ladbury JE, Jackson RM. Comparison of binding energies of SrcSH2-phosphotyrosyl peptides with structure-based prediction using surface area based empirical parameterization. Protein Sci 2000; 9:1975-85. [PMID: 11106171 PMCID: PMC2144457 DOI: 10.1110/ps.9.10.1975] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The prediction of binding energies from the three-dimensional (3D) structure of a protein-ligand complex is an important goal of biophysics and structural biology. Here, we critically assess the use of empirical, solvent-accessible surface area-based calculations for the prediction of the binding of Src-SH2 domain with a series of tyrosyl phosphopeptides based on the high-affinity ligand from the hamster middle T antigen (hmT), where the residue in the pY+ 3 position has been changed. Two other peptides based on the C-terminal regulatory site of the Src protein and the platelet-derived growth factor receptor (PDGFR) are also investigated. Here, we take into account the effects of proton linkage on binding, and test five different surface area-based models that include different treatments for the contributions to conformational change and protein solvation. These differences relate to the treatment of conformational flexibility in the peptide ligand and the inclusion of proximal ordered solvent molecules in the surface area calculations. This allowed the calculation of a range of thermodynamic state functions (deltaCp, deltaS, deltaH, and deltaG) directly from structure. Comparison with the experimentally derived data shows little agreement for the interaction of SrcSH2 domain and the range of tyrosyl phosphopeptides. Furthermore, the adoption of the different models to treat conformational change and solvation has a dramatic effect on the calculated thermodynamic functions, making the predicted binding energies highly model dependent. While empirical, solvent-accessible surface area based calculations are becoming widely adopted to interpret thermodynamic data, this study highlights potential problems with application and interpretation of this type of approach. There is undoubtedly some agreement between predicted and experimentally determined thermodynamic parameters: however, the tolerance of this approach is not sufficient to make it ubiquitously applicable.
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Affiliation(s)
- D A Henriques
- Department of Biochemistry and Molecular Biology, University College, London, United Kingdom
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108
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Thor AD, Liu S, Edgerton S, Moore D, Kasowitz KM, Benz CC, Stern DF, DiGiovanna MP. Activation (tyrosine phosphorylation) of ErbB-2 (HER-2/neu): a study of incidence and correlation with outcome in breast cancer. J Clin Oncol 2000; 18:3230-9. [PMID: 10986055 DOI: 10.1200/jco.2000.18.18.3230] [Citation(s) in RCA: 123] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
PURPOSE We hypothesize that phosphorylated ErbB-2 (P-ErbB-2, identified by a novel antibody PN2A) may provide either more significant or additional prognostic marker data for breast cancer patients. This study was designed to compare the incidence and prognostic value of ErbB-2 (HER-2/neu) and P-ErbB-2 immunoexpression in archival breast cancer samples. MATERIALS AND METHODS Eight hundred sixteen invasive breast cancers with a median of 16.3 years of follow-up were immunostained for ErbB-2 (using antibody CB11) and P-ErbB-2 (using antibody PN2A). ErbB-2 and P-ErbB-2 data were compared with clinical, histologic, immunohistochemical, and outcome variables. RESULTS Of 816 primary breast cancers, 307 (38%) were positive for ErbB-2 and 37 (12% of ErbB-2 positive and 5% of the study population) expressed P-ErbB-2. P-ErbB-2 was not detected in ErbB-2-negative cases (n = 509). ErbB-2 immunohistochemical data were bimodal; patients with > or = 80% cellular expression had the shortest disease-free and disease-specific survival. P-ErbB-2 was associated with a higher percentage of ErbB-2-positive cells, a higher number of positive lymph nodes, and cellular proliferation. ErbB-2 and P-ErbB-2 were indicators of poor prognosis in node-positive patients in both univariate and multivariate analyses. We found that either P-ErbB-2 expression or high (> or = 80%) ErbB-2 expression provided the most significant prognostic value in node-positive cases by multivariate analyses. There were too few P-ErbB-2-positive cases and events in the node-negative patient group to allow statistical analysis of P-ErbB-2 in that subgroup. CONCLUSION PN2A immunostaining identified a subset (approximately 12% of ErbB-2-positive breast cancers) with activation (phosphorylation) of the receptor ErbB-2. P-ErbB-2 expression was strongly associated with higher levels of ErbB-2 expression (> or = 80%), although it was not a surrogate. Identification of cases with a high percentage of invasive breast cancer cells expressing ErbB-2 or determination of receptor activation via P-ErbB-2 may provide additional prognostic value in node-positive breast cancers.
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Affiliation(s)
- A D Thor
- Department of Pathology, Evanston Hospital/Northwestern University, Evanston, IL 60201, USA.
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109
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Rajala RV, Dehm S, Bi X, Bonham K, Sharma RK. Expression of N-myristoyltransferase inhibitor protein and its relationship to c-Src levels in human colon cancer cell lines. Biochem Biophys Res Commun 2000; 273:1116-20. [PMID: 10891381 DOI: 10.1006/bbrc.2000.3066] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Earlier, we have reported that N-myristoyltransferase (NMT) activity is higher in colonic epithelial neoplasms than in normal appearing colonic tissue and that increase in NMT activity appears at an early stage in colonic carcinogenesis [Magnuson, B., Raju, R. V. S., Moyana, T. N., and Sharma, R. K. (1995) J. Natl. Cancer Inst. 87, 1630-1635]. In this study, we demonstrate increased NMT mRNA in well-differentiated adenocarcinomas. NMT and c-Src mRNA levels were generally elevated in a subset of human colon cancer cell lines. Western blotting analysis employing N-myristoyltransferase inhibitory protein (NIP(71)) antibody demonstrated low levels of NIP(71) in high-expressing c-Src cell lines and high levels of NIP(71) in low-expressing c-Src cell lines. Interestingly, down regulation of c-Src by antisense expression in the HT-29 cell line resulted in increased expression of NIP(71), suggesting c-Src may negatively regulate NIP(71) expression. Furthermore, this is the first study demonstrating the expression of NIP(71) in human colon cancer cell lines and a possible relationship to colon carcinogenesis.
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Affiliation(s)
- R V Rajala
- Department of Pathology, Saskatchewan Cancer Agency, Saskatoon, Saskatchewan, S7N 4H4, Canada
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110
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Bénistant C, Chapuis H, Mottet N, Noletti J, Crapez E, Bali JP, Roche S. Deregulation of the cytoplasmic tyrosine kinase cSrc in the absence of a truncating mutation at codon 531 in human bladder carcinoma. Biochem Biophys Res Commun 2000; 273:425-30. [PMID: 10873622 DOI: 10.1006/bbrc.2000.2948] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The involvement of the cytoplasmic tyrosine kinase cSrc was investigated in human bladder carcinogenesis. Kinase activity was determined in tissue lysates from bladder transitional cell carcinoma (TCC) relative to normal epithelia. Strong kinase activation was observed at all stages of carcinogenesis with a peak at the stage pT1, where tumor cells disrupt the basement membrane and invade the submucosa. In agreement with a role for cSrc in cell invasion, immunocytochemistry analysis showed a strong staining of invading cells. An increase in cSrc protein level were also found in most tumor samples, however, it did not correlate with an increase in activity (r = 0.44) suggesting that cSrc is deregulated in these tumors. Indeed, high Src activity was affinity-purified from a column (IRSVSSDGHE(p)YIYVDP-Affigel 10) that specifically retains active Src. Enzymatic regulation involves the C-terminus, recently found mutated at codon 531 in a subset of advanced human colon cancers. However, no such mutations were detected in TCC, suggesting the existence of other mechanisms for kinase activation.
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111
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Abstract
Protein tyrosine kinases (PTKs) play a crucial role in many cell regulatory processes. It is therefore not surprising to see that functional perturbation of PTKs results in many diseases. Despite the diverse primary structure organization of various PTKs, the catalytic or kinase domains of various PTKs as well as that of Ser/Thr kinases are generally conserved. The high resolution crystal structure of a few PTKs has been solved in the last few years. In contrast to the well-defined linear peptide substrate motifs recognized by specific Ser/Thr kinases, the identification of specific substrate motifs for PTK has been slow. It is not until recently that through the use of combinatorial peptide library methods that specific recognition motifs for specific PTKs have begun to emerge. Efficient and specific peptide substrates for some PTKs with Km at the mid microM range have been identified. Based on these peptide substrates, relatively potent (IC50 at the low microM range) and highly selective pseudosubstrate-based peptide inhibitors have been developed. There has been enormous effort in the development of PTK inhibitors for diseases such as cancer, psoriasis, and osteoporosis. Several new high-throughput PTK assay technologies have recently been described. Small molecules against specific PTK have been developed. Most of them are competitive inhibitors at the ATP binding site. Some of these inhibitors have already been in clinical trial.
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Affiliation(s)
- F A al-Obeidi
- Selectide Corporation, A Subsidiary of Hoechst Marion Roussel, Inc., Tucson, AZ 85737, USA
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112
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Allgayer H, Babic R, Gruetzner KU, Tarabichi A, Schildberg FW, Heiss MM. c-erbB-2 is of independent prognostic relevance in gastric cancer and is associated with the expression of tumor-associated protease systems. J Clin Oncol 2000; 18:2201-9. [PMID: 10829039 DOI: 10.1200/jco.2000.18.11.2201] [Citation(s) in RCA: 189] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
PURPOSE The c-erbB-2 gene (encoding the protein p185) is overexpressed in diverse human cancers and has been implicated to be of prognostic value in gastric cancer. Recent studies suggest a role of p185 in tumor progression by specifically promoting the invasive capacity of tumor cells. Therefore, the present study was conducted with the following three objectives: (1) to support the prognostic value of c-erbB-2 in gastric cancer in a large prospective series using a monoclonal antibody and a highly sensitive immunohistochemical method; (2) to determine the association of c-erbB-2 expression with the expression of invasion-related genes; and (3) to perform the first overall multivariate analysis including c-erbB-2 and the invasion-related tumor-associated protease systems. PATIENTS AND METHODS In a consecutive prospective series of 203 gastric cancer patients (median follow-up, 42 months), expression of c-erbB-2 and a panel of tumor-associated proteases and inhibitors by tumor cells were evaluated semiquantitatively (score 0 to 3) and analyzed for correlation (chi(2) test, Bonferroni-corrected). Kaplan-Meier survival analysis and multivariate Cox analysis were performed to determine the relative prognostic impact of c-erbB-2 and the invasion-related parameters. RESULTS Kaplan-Meier analysis (log-rank statistics) revealed a significant association of increasing expression of c-erbB-2 with shorter disease-free (P =. 0023) and overall survival (P =.0160). High amounts of p185 were significantly associated with a high expression of urokinase-type plasminogen activator (uPA) (P <.010), uPA-receptor (P =.030), type-1 plasminogen activator inhibitor (PAI) (P <.010), type-2 PAI (P =.021), cathepsin D (P =.036), matrix metalloproteinase-2 (P =. 024), alpha-1-antichymotrypsin (P =.025), and alpha-2-macroglobulin (P =.017). Multivariate analysis considering these proteases/protease inhibitors, in addition to alpha-1-antitrypsin, tissue plasminogen activator, plasminogen, alpha-2-antiplasmin, and antithrombin III, and established prognostic parameters revealed that, in addition to surgical curability, pT stage, pN stage, and PAI-1, c-erbB-2 is an independent prognostic factor for overall survival of curatively resected patients (n = 139; P =.049; relative risk, 1.54; 95% confidence interval, 1.08 to 1.67) and all patients (P =.028; relative risk 1.33; 95% CI, 1.28 to 1.38). CONCLUSION c-erbB-2 is confirmed as a new independent, functional prognostic parameter for overall survival in gastric cancer, even when a panel of invasion-related factors, including the strong prognostic parameter PAI-1, are considered. The significant correlation of p185 with several tumor-associated proteases supports the hypothesis that c-erbB-2 is a promoter of invasion and metastasis. This strongly suggests that c-erbB-2 may be a promising target for anti-invasive therapy in gastric cancer.
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Affiliation(s)
- H Allgayer
- Department of Surgery, Klinikum Grosshadern, Ludwig Maximilians University of Munich, Germany
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113
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Arcaro A, Zvelebil MJ, Wallasch C, Ullrich A, Waterfield MD, Domin J. Class II phosphoinositide 3-kinases are downstream targets of activated polypeptide growth factor receptors. Mol Cell Biol 2000; 20:3817-30. [PMID: 10805725 PMCID: PMC85707 DOI: 10.1128/mcb.20.11.3817-3830.2000] [Citation(s) in RCA: 125] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/1999] [Accepted: 02/15/2000] [Indexed: 11/20/2022] Open
Abstract
The class II phosphoinositide 3-kinases (PI3K) PI3K-C2alpha and PI3K-C2beta are two recently identified members of the large PI3K family. Both enzymes are characterized by the presence of a C2 domain at the carboxy terminus and, in vitro, preferentially utilize phosphatidylinositol and phosphatidylinositol 4-monophosphate as lipid substrates. Little is understood about how the catalytic activity of either enzyme is regulated in vivo. In this study, we demonstrate that PI3K-C2alpha and PI3K-C2beta represent two downstream targets of the activated epidermal growth factor (EGF) receptor in human carcinoma-derived A431 cells. Stimulation of quiescent cultures with EGF resulted in the rapid recruitment of both enzymes to a phosphotyrosine signaling complex that contained the EGF receptor and Erb-B2. Ligand addition also induced the appearance of a second, more slowly migrating band of PI3K-C2alpha and PI3K-C2beta immunoreactivity on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Since both PI3K enzymes can utilize Ca(2+) as an essential divalent cation in lipid kinase assays and since the catalytic activity of PI3K-C2alpha is refractory to the inhibitor wortmannin, these properties were used to confirm the recruitment of each PI3K isozyme to the activated EGF receptor complex. To examine this interaction in greater detail, PI3K-C2beta was chosen for further investigation. EGF and platelet-derived growth factor also stimulated the association of PI3K-C2beta with their respective receptors in other cells, including epithelial cells and fibroblasts. The use of EGF receptor mutants and phosphopeptides derived from the EGF receptor and Erb-B2 demonstrated that the interaction with recombinant PI3K-C2beta occurs through E(p)YL/I phosphotyrosine motifs. The N-terminal region of PI3K-C2beta was found to selectively interact with the EGF receptor in vitro, suggesting that it mediates the association of this PI3K with the receptor. However, the mechanism of this interaction remains unclear. We conclude that class II PI3K enzymes may contribute to the generation of 3' phosphoinositides following the activation of polypeptide growth factor receptors in vivo and thus mediate certain aspects of their biological activity.
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Affiliation(s)
- A Arcaro
- Ludwig Institute for Cancer Research, University College, London W1P 8BT, United Kingdom
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114
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Olufunmilayo I, Olopade MD, Fackenthal JD. Breast cancer genetics. Implications of clinical practice. Hematol Oncol Clin North Am 2000; 14:705-25. [PMID: 11203330 DOI: 10.1016/s0889-8588(05)70304-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- I Olufunmilayo
- Department of Medicine, Pritzker School of Medicine, University of Chicago, Illinois
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115
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Abstract
Since their discovery as key mediators of cytokine signaling, considerable progress has been made in defining the structure-function relationships of Signal Transducers and Activators of Transcription (STATs). In addition to their central roles in normal cell signaling, recent studies have demonstrated that diverse oncoproteins can activate specific STATs (particularly Stat3 and Stat5) and that constitutively-activated STAT signaling directly contributes to oncogenesis. Furthermore, extensive surveys of primary tumors and cell lines derived from tumors indicate that inappropriate activation of specific STATs occurs with surprisingly high frequency in a wide variety of human cancers. Together, these findings provide compelling evidence that aberrant STAT activation associated with oncogenesis is not merely adventitious but instead contributes to the process of malignant transformation. These studies are beginning to reveal the molecular mechanisms leading to STAT activation in the context of oncogenesis, and candidate genes regulated by STATs that may contribute to oncogenesis are being identified. Recent studies suggest that activated STAT signaling participates in oncogenesis by stimulating cell proliferation and preventing apoptosis. This review presents the evidence for critical roles of STATs in oncogenesis and discusses the potential for development of novel cancer therapies based on mechanistic understanding of STAT signaling. Oncogene (2000).
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Affiliation(s)
- T Bowman
- Molecular Oncology Program, H. Lee Moffitt Cancer Center and Research Institute, 12902 Magnolia Drive, Tampa, Florida, FL 33612, USA
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116
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Wang W, Ramdas L, Sun G, Ke S, Obeyesekere NU, Budde RJ, McMurray JS. Cyclic peptides incorporating 4-carboxyphenylalanine and phosphotyrosine are potent inhibitors of pp60(c-)(src). Biochemistry 2000; 39:5221-8. [PMID: 10819990 DOI: 10.1021/bi992994f] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The protein tyrosine kinase, pp60(c-)(src), is involved in cellular signaling and is activated during mitosis and in various tumors. We have been employing cyclic decapeptides to identify the determinants for substrate binding and phosphorylation to develop inhibitors competitive with protein substrates of Src. A structure-activity study [McMurray, J. S., Budde, R. J. A., Ke, S., Obeyesekere, O. U., Wang, W., Ramdas, L., and Lewis, C. A. (1998) Arch. Biochem. Biophys. 355, 124] revealed that, at the position 3 residues C-terminal to the phosphorylated tyrosine (Y + 3), both glutamic acid and phenylalanine gave identical K(i), K(m), and V(max) values. We hypothesized that the area of Src that binds the Y + 3 residue contains either a positively charged lysine or an arginine, capable of ionic interactions with glutamic acid or cation-pi interactions with phenylalanine. To test this hypothesis, a series of phenylalanine analogues were substituted at position 7 (the Y + 3 residue) in cyclo(Asp(1)-Asn(2)-Glu(3)-Tyr(4)-Ala(5)-Phe(6)-Phe(7)-Gln(8)-D-Phe(9 )-Pro(10)). Of these, 4-carboxyphenylalanine (4-Cpa) and phosphotyrosine resulted in high affinity peptides exhibiting K(i) values of 0.85 and 1.1 microM, respectively, 180- and 130-fold increases in potency over the parent cyclic peptide (K(i) = 150 microM). These peptides were noncompetitive with respect to ATP and competitive against the phosphate-accepting substrate, polyGlu(4)Tyr. The truncated cyclic peptide, cyclo(Phe-4-Cpa-Gln-D-Phe-Pro-Asp-Aca) (Aca = epsilon-aminocaproic acid), which did not contain tyrosine, was also a competitive inhibitor with a K(i) value of 24 microM. We conclude that these cyclic peptides bind to a positively charged area that is near the phosphate transfer region of the active site of Src but does not necessarily include the tyrosine-binding pocket. Furthermore, the 4-Cpa-containing cyclic decapeptide shows remarkable selectivity in the inhibition of Src versus the src family members Yes and Lck, as well as other protein tyrosine kinases, Ser/Thr kinases, and other ATP-utilizing enzymes.
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Affiliation(s)
- W Wang
- The University of Texas M. D. Anderson Cancer Center, Department of Neuro-Oncology, P. O. Box 316, 1515 Holcombe Boulevard, Houston, Texas 77030, USA
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117
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Jope RS, Zhang L, Song L. Peroxynitrite modulates the activation of p38 and extracellular regulated kinases in PC12 cells. Arch Biochem Biophys 2000; 376:365-70. [PMID: 10775424 DOI: 10.1006/abbi.2000.1728] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Although peroxynitrite appears to contribute to neuronal dysfunction in several neurodegenerative disorders, little is known about how peroxynitrite affects cellular signaling processes. This study investigated if peroxynitrite affects the mitogen-activated protein kinases, extracellular-regulated kinases 1 and 2 (ERK1/2) and p38. Exposure of PC12 cells to 500 microM peroxynitrite activated ERK1/2 and p38 within 5 min and this was followed by gradual decreases in activation over the next 25 min. Activation of ERK1/2 by peroxynitrite was mediated by activation of the epidermal growth factor (EGF) receptor in a calcium/calmodulin-dependent kinase II- and src family tyrosine kinase-dependent manner, as it was blocked by the selective EGF receptor inhibitor AG1478, by KN62, an inhibitor of calcium/calmodulin-dependent kinase II, and by PP1, a src family tyrosine kinase inhibitor. Activation of p38 by peroxynitrite was independent of the EGF receptor, required activation of calcium/calmodulin-dependent kinase II and src family tyrosine kinases, and was modulated by nerve growth factor (NGF) in a time-dependent manner. Pretreatment with NGF (2 h) attenuated, whereas cotreatment with NGF potentiated, peroxynitrite-induced activation of p38. Thus, peroxynitrite activates ERK1/2 and p38, activation of EGF receptors, calcium/calmodulin-dependent kinase II, and src family tyrosine kinases participate in these signaling responses to peroxynitrite, and peroxynitrite- and NGF-induced signaling activities converge on p38.
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Affiliation(s)
- R S Jope
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, Alabama 35294-0017, USA
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118
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Biscardi JS, Ishizawar RC, Silva CM, Parsons SJ. Tyrosine kinase signalling in breast cancer: epidermal growth factor receptor and c-Src interactions in breast cancer. Breast Cancer Res 2000; 2:203-10. [PMID: 11250711 PMCID: PMC138776 DOI: 10.1186/bcr55] [Citation(s) in RCA: 243] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/1999] [Accepted: 02/21/2000] [Indexed: 01/12/2023] Open
Abstract
Both the non-receptor tyrosine kinase, c-Src, and members of the epidermal growth factor (EGF) receptor family are overexpressed in high percentages of human breast cancers. Because these molecules are plasma membrane-associated and involved in mitogenesis, it has been speculated that they function in concert with one another to promote breast cancer development and progression. Evidence to date supports a model wherein c-Src potentiates the survival, proliferation and tumorigenesis of EGF receptor family members, in part by associating with them. Phosphorylation of the EGF receptor by c-SRC is also critical for mitogenic signaling initiated by the EGF receptor itself, as well as by several G-protein coupled receptors (GPCRs), a cytokine receptor, and the estrogen receptor. Thus, c-Src appears to have pleiotropic effects on cancer cells by modulating the action of multiple growth-promoting receptors.
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Affiliation(s)
| | - Rumey C Ishizawar
- University of Virginia Health Sciences Center, Charlottesville, Virginia, USA
| | - Corinne M Silva
- University of Virginia Health Sciences Center, Charlottesville, Virginia, USA
| | - Sarah J Parsons
- University of Virginia Health Sciences Center, Charlottesville, Virginia, USA
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119
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Abstract
The most essential kinases involved in cell membrane receptor activation, signal transduction and cell cycle control or programmed cell death and their interconnections are reviewed. In tumours, the genes of many of those kinases are mutated or amplified or the proteins are overexpressed. The use of key kinases offers the possibility to screen in vitro for synthetic small molecule kinase inhibitors. In view of the many interconnections of cellular kinases, their role in preventing or inducing programmed cell death and the possibility that a considerable number of signal transducing proteins are still unknown, cellular test systems are recommended in which the respective key kinase or one of its main partner molecules are overexpressed.
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Affiliation(s)
- H H Sedlacek
- Aventis Pharma Deutschland GmbH, Central Biotechnology, Marburg, Germany.
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120
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Abstract
A number of genes have been implicated in breast cancer development, yet few have been demonstrated to play causative roles in mammary tumor formation. The advent of transgenic mouse and embryonic stem cell technologies now permits manipulation of the mouse genome in such a way as to temporally and spatially control a gene product's expression. Thus, the basic researcher now can directly assess the involvement of particular genes in tumorigenesis and disease progression and, in the process, to develop mouse models of human genetic disease. The utility of such technologies is emphasized in transgenic mice expressing genes thought to play important roles in the initiation and progression of mammary carcinomas. As these transgenic strains have been the subject of several reviews, here we focus on two mouse mammary tumor models, Polyomavirus middle T antigen and the Neu/ErbB-2 receptor tyrosine kinase, which are most amenable to study specific signaling pathways in process of mammary tumorigenesis.
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Affiliation(s)
- D L Dankort
- Department of Biology, Institute for Molecular Biology and Biotechnology, McMaster University, 1280 Main St. West, Hamilton, Ontario, Canada, L8S 4K1
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121
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Spencer KS, Graus-Porta D, Leng J, Hynes NE, Klemke RL. ErbB2 is necessary for induction of carcinoma cell invasion by ErbB family receptor tyrosine kinases. J Cell Biol 2000; 148:385-97. [PMID: 10648571 PMCID: PMC2174273 DOI: 10.1083/jcb.148.2.385] [Citation(s) in RCA: 134] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The epidermal growth factor (EGF) family of tyrosine kinase receptors (ErbB1, -2, -3, and -4) and their ligands are involved in cell differentiation, proliferation, migration, and carcinogenesis. However, it has proven difficult to link a given ErbB receptor to a specific biological process since most cells express multiple ErbB members that heterodimerize, leading to receptor cross-activation. In this study, we utilize carcinoma cells depleted of ErbB2, but not other ErbB receptor members, to specifically examine the role of ErbB2 in carcinoma cell migration and invasion. Cells stimulated with EGF-related peptides show increased invasion of the extracellular matrix, whereas cells devoid of functional ErbB2 receptors do not. ErbB2 facilitates cell invasion through extracellular regulated kinase (ERK) activation and coupling of the adaptor proteins, p130CAS and c-CrkII, which regulate the actin-myosin cytoskeleton of migratory cells. Overexpression of ErbB2 in cells devoid of other ErbB receptor members is sufficient to promote ERK activation and CAS/Crk coupling, leading to cell migration. Thus, ErbB2 serves as a critical component that couples ErbB receptor tyrosine kinases to the migration/invasion machinery of carcinoma cells.
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Affiliation(s)
- Kathryn S.R. Spencer
- Department of Immunology, The Scripps Research Institute, La Jolla, California 92037
| | | | - Jie Leng
- Department of Immunology, The Scripps Research Institute, La Jolla, California 92037
| | - Nancy E. Hynes
- Friedrich Miescher Institute, CH-4002 Basel, Switzerland
| | - Richard L. Klemke
- Department of Immunology, The Scripps Research Institute, La Jolla, California 92037
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122
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Andrechek ER, Muller WJ. Tyrosine kinase signalling in breast cancer: tyrosine kinase-mediated signal transduction in transgenic mouse models of human breast cancer. Breast Cancer Res 2000; 2:211-6. [PMID: 11250712 PMCID: PMC138777 DOI: 10.1186/bcr56] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/1999] [Accepted: 02/21/2000] [Indexed: 11/10/2022] Open
Abstract
The ability of growth factors and their cognate receptors to induce mammary epithelial proliferation and differentiation is dependent on their ability to activate a number of specific signal transduction pathways. Aberrant expression of specific receptor tyrosine kinases (RTKs) has been implicated in the genesis of a significant proportion of sporadic human breast cancers. Indeed, mammary epithelial expression of activated RTKs such as ErbB2/neu in transgenic mice has resulted in the efficient induction of metastatic mammary tumours. Although it is clear from these studies that activation these growth factor receptor signalling cascades are directly involved in mammary tumour progression, the precise interaction of each of these signalling pathways in mammary tumourigenesis and metastasis remains to be elucidated. The present review focuses on the role of several specific signalling pathways that have been implicated as important components in RTK-mediated signal transduction. In particular, it focuses on two well characterized transgenic breast cancer models that carry the polyomavirus middle T(PyV mT) and neu oncogenes.
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Affiliation(s)
- E R Andrechek
- Institute for Molecular Biology and Biotechnology, Department of Biology, McMaster University, Hamilton, Ontario, Canada
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123
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Nakagawa T, Tanaka S, Suzuki H, Takayanagi H, Miyazaki T, Nakamura K, Tsuruo T. Overexpression of thecsk gene suppresses tumor metastasisin vivo. Int J Cancer 2000. [DOI: 10.1002/1097-0215(20001101)88:3<384::aid-ijc10>3.0.co;2-b] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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124
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Prenzel N, Zwick E, Leserer M, Ullrich A. Tyrosine kinase signalling in breast cancer. Epidermal growth factor receptor: convergence point for signal integration and diversification. Breast Cancer Res 2000; 2:184-90. [PMID: 11250708 PMCID: PMC138773 DOI: 10.1186/bcr52] [Citation(s) in RCA: 115] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/1999] [Accepted: 02/21/2000] [Indexed: 12/16/2022] Open
Abstract
Cross-communication between different signalling systems is critical for the integration of multiple and changing environmental influences on individual cells. The epidermal growth factor receptor (EGFR) has been identified as a key element in the complex signalling network that is utilized by various classes of cell-surface receptors. This nonclassical mode of signalling system cross-talk, in distinction to receptor activation induced by cognate ligands, has been termed 'signal transactivation'. With the EGFR as the convergence point and distribution focus, this scenario may involve signals emitted by other members of the tyrosine kinase family, cytokine receptors, ion channels, G-protein-coupled receptors and integrins.
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Affiliation(s)
| | - Esther Zwick
- Max-Planck Institut für Biochemie, Martinsried, Germany
| | | | - Axel Ullrich
- Max-Planck Institut für Biochemie, Martinsried, Germany
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125
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Sherman L, Sleeman JP, Hennigan RF, Herrlich P, Ratner N. Overexpression of activated neu/erbB2 initiates immortalization and malignant transformation of immature Schwann cells in vitro. Oncogene 1999; 18:6692-9. [PMID: 10597275 DOI: 10.1038/sj.onc.1203055] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The neu/erbB2 protooncogene is overexpressed in numerous human cancers and is mutationally activated in N-ethyl-N-nitrosourea (ENU)-induced rodent tumors of the Schwann cell lineage. We investigated whether expression of activated neu in Schwann cells is sufficient to initiate their immortalization and transformation. Clones of embryonic dorsal root ganglia cells infected with a retrovirus bearing activated neu (NID cells) were selected based on their expression of Schwann cell-specific markers. Compared to embryonic Schwann cells infected with a virus encoding empty vector, we found that NID cells have altered shapes and disorganized cytoskeletons, grow in the absence of growth factors required for normal Schwann cell survival and proliferation, and can be repeatedly passaged. Furthermore, NID cells are invasive in an in vitro matrix invasion assay and form metastatic tumors when injected into syngeneic animals. The neu-induced growth and invasive phenotypes could be reversed by drugs that inhibit Ras and Src activity. Interestingly, later stage Schwann cells infected with activated neu failed to become immortalized. These findings indicate that constitutive activation of erbB2 is sufficient to initiate the immortalization and transformation of immature Schwann cells, and support the notion that Schwann cells have particular developmental stages during which they are susceptible to immortalizing and transforming events.
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Affiliation(s)
- L Sherman
- Department of Cell Biology, Neurobiology and Anatomy, University of Cincinnati College of Medicine, OH 45267-0521, USA
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126
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Hornia A, Lu Z, Sukezane T, Zhong M, Joseph T, Frankel P, Foster DA. Antagonistic effects of protein kinase C alpha and delta on both transformation and phospholipase D activity mediated by the epidermal growth factor receptor. Mol Cell Biol 1999; 19:7672-80. [PMID: 10523655 PMCID: PMC84804 DOI: 10.1128/mcb.19.11.7672] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Downregulation of protein kinase C delta (PKC delta) by treatment with the tumor-promoting phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) transforms cells that overexpress the non-receptor class tyrosine kinase c-Src (Z. Lu et al., Mol. Cell. Biol. 17:3418-3428, 1997). We extended these studies to cells overexpressing a receptor class tyrosine kinase, the epidermal growth factor (EGF) receptor (EGFR cells); like c-Src, the EGF receptor is overexpressed in several human tumors. In contrast with expectations, downregulation of PKC isoforms with TPA did not transform the EGFR cells; however, treatment with EGF did transform these cells. Since TPA downregulates all phorbol ester-responsive PKC isoforms, we examined the effects of PKC delta- and PKC alpha-specific inhibitors and the expression of dominant negative mutants for both PKC delta and alpha. Consistent with a tumor-suppressing function for PKC delta, the PKC delta-specific inhibitor rottlerin and a dominant negative PKC delta mutant transformed the EGFR cells in the absence of EGF. In contrast, the PKC alpha-specific inhibitor Go6976 and expression of a dominant negative PKC alpha mutant blocked the transformed phenotype induced by both EGF and PKC delta inhibition. Interestingly, both rottlerin and EGF induced substantial increases in phospholipase D (PLD) activity, which is commonly elevated in response to mitogenic stimuli. The elevation of PLD activity in response to inhibiting PKC delta, like transformation, was dependent upon PKC alpha and restricted to the EGFR cells. These data demonstrate that PKC isoforms alpha and delta have antagonistic effects on both transformation and PLD activity and further support a tumor suppressor role for PKC delta that may be mediated by suppression of tyrosine kinase-dependent increases in PLD activity.
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Affiliation(s)
- A Hornia
- Department of Biological Sciences, Hunter College of The City University of New York, New York, New York 10021, USA
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127
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Esposti MD, Hatzinisiriou I, McLennan H, Ralph S. Bcl-2 and mitochondrial oxygen radicals. New approaches with reactive oxygen species-sensitive probes. J Biol Chem 1999; 274:29831-7. [PMID: 10514462 DOI: 10.1074/jbc.274.42.29831] [Citation(s) in RCA: 143] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Investigations into the capacity of the Bcl-2 protein to prevent apoptosis have targeted mitochondria as key sites of the preventative action accorded by Bcl-2 to cells. Using novel approaches with fluorescence probes and autofluorescence detection of endogenous NAD(P)H, we have examined the effects of expressing Bcl-2 in the Bcl-2 negative Burkitt's lymphoma cell line Daudi. We evaluated for the first time the effect of Bcl-2 expression on the intracellular distribution and production of hydrogen peroxide, under basal conditions and after treatment with apoptosis inducing agents, ceramide analogs and tumor necrosis factor (TNF)-alpha. Increased availability of mitochondrial NAD(P)H was detected in Bcl-2-expressing cells and was correlated with an increased constitutive mitochondrial production of hydrogen peroxide. Although production of hydrogen peroxide was increased by either C(6)-ceramide or TNF-alpha in Bcl-2 negative Daudi cells commensurate with the early phases of apoptosis, this increase did not occur in Bcl-2-expressing cells. Thus, Bcl-2 appears to allow cells to adapt to an increased state of oxidative stress, fortifying the cellular anti-oxidant defenses and counteracting the radical overproduction imposed by different cell death stimuli. Furthermore, we report altered cytological features of mitochondria during the early phases of apoptosis induced by C(6)-ceramide and TNF-alpha. In particular, mitochondria changed in appearance, clustering in the perinuclear region and Bcl-2 expression prevented these changes from occurring.
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Affiliation(s)
- M D Esposti
- Department of Biochemistry, Monash University, Clayton 3168 Victoria, Australia.
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128
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Wang Y, Ripperger J, Fey GH, Samols D, Kordula T, Wetzler M, Van Etten RA, Baumann H. Modulation of hepatic acute phase gene expression by epidermal growth factor and Src protein tyrosine kinases in murine and human hepatic cells. Hepatology 1999; 30:682-97. [PMID: 10462375 DOI: 10.1002/hep.510300318] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
As part of systemic inflammatory reactions, interleukin 6 (IL-6) induces acute phase protein (APP) genes through the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway. Epidermal growth factor (EGF), which contributes to the regenerative process after liver injury and also activates STATs, does not induce but attenuates IL-6-stimulated expression of several APP genes in primary mouse hepatocytes. The APP-modifying action of EGF receptor (EGFR) was characterized in HepG2 cells. Although EGF less effectively engages STAT proteins in these cells, it reduces expression of fibrinogen and haptoglobin, but stimulates production of alpha(1)-antichymotrypsin and induces transcription through the alpha(1)-antichymotrypsin and C-reactive protein promoter. The stimulatory EGFR signal is insensitive to inhibition of JAKs and appears to involve Src kinases and STAT proteins as shown by inhibition through overexpression of C-terminal Src kinase (Csk) and transdominant negative STAT3, respectively. A mediator role of Src is supported by the ability of c-Src and v-Src to activate STATs and induce transcription through APP promoters. Src kinases have been observed in association with the IL-6 receptor; however, inhibition of Src kinases by Csk enhances IL-6-induced transcription. The Csk effect is attributed to prevention of Src kinases from phosphorylating gp130 at the docking site for the signal-moderating protein tyrosine phosphatase SHP-2. The inhibitory EGFR signal on APP expression correlates with the activation of Erk1 and Erk2. The study shows a dual signaling function for EGFR and suggests that the ratio of receptor-activated STATs and Erks influence the level of stimulated or inhibited expression of individual APPs.
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Affiliation(s)
- Y Wang
- Roswell Park Cancer Institute, Department of Molecular and Cellular Biiology, Buffalo, NY 14263, USA
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129
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Holbrook MR, O'Donnell JB, Slakey LL, Gross DJ. Epidermal growth factor receptor internalization rate is regulated by negative charges near the SH2 binding site Tyr992. Biochemistry 1999; 38:9348-56. [PMID: 10413509 DOI: 10.1021/bi990195r] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This study examines the effects of mutations at and in the vicinity of tyrosine 992 of the epidermal growth factor receptor (EGFr) on epidermal growth factor- (EGF-) stimulated internalization of the receptor. Two regions of the EGFr adjacent to this domain have been defined previously as internalization domains. The present work shows that the mutation of negatively charged amino acid residues near Tyr992 to their uncharged analogues increases the rate of EGF receptor internalization. In addition, the conversion of Tyr992, which is an EGFr ligand-induced autophosphorylation site, to phenylalanine also increases the rate of receptor internalization. However, the mutation of Tyr992 to a glutamate residue does not alter the receptor internalization rate. In addition, the truncation of the EGFr at glutamate 996 reduces the internalization rate by half. This result confirms previous reports that residues immediately C-terminal to Glu996 are necessary to allow the normal rate of ligand-induced receptor endocytosis. The data suggest that negative charge in the vicinity of Tyr992, and potentially the phosphorylation of the EGFr at Tyr992, reduces the rate of ligand-induced receptor endocytosis. This reduction in internalization rate increases the lifetime of the activated EGFr in the plasma membrane by about 70%, thus suggesting that phosphorylation of Tyr992 acts to increase the signaling capacity of the EGF receptor even as it directly acts as an SH2 binding site.
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Affiliation(s)
- M R Holbrook
- Program in Molecular and Cellular Biology, Department of Biochemistry, University of Massachusetts at Amherst 01003, USA
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130
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Olayioye MA, Beuvink I, Horsch K, Daly JM, Hynes NE. ErbB receptor-induced activation of stat transcription factors is mediated by Src tyrosine kinases. J Biol Chem 1999; 274:17209-18. [PMID: 10358079 DOI: 10.1074/jbc.274.24.17209] [Citation(s) in RCA: 269] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Epidermal growth factor (EGF) binding to its receptor, ErbB1, triggers various signal transduction pathways, one of which leads to the activation of signal transducer and activator of transcription (Stat) factors. The mechanism underlying ErbB1-induced Stat activation and whether Stats are downstream targets of other ErbB receptors have not been explored. In this report we show that ErbB2, ErbB3, and ErbB4 do not potentiate Stat5 phosphorylation by EGF. However, neu differentiation factor-induced heterodimers of ErbB2 and ErbB4 activated Stat5. In A431 cells, Stat1, Stat3, and Stat5, were constitutively complexed with ErbB1 and rapidly phosphorylated on tyrosine in response to EGF. Neither mutation of the conserved tyrosine residue (Tyr694) nor inactivation of the Stat5a SH2 domain disrupted this association. However, an intact SH2 domain was necessary for EGF-induced Stat5a phosphorylation. In contrast to prolactin, which induced only Tyr694 phosphorylation of Stat5a, EGF promoted phosphorylation on Tyr694 and additional tyrosine residue(s). Janus kinases (Jaks) were also constitutively associated with ErbB receptors and were phosphorylated in response to EGF-related ligands. However, we provide evidence that EGF- and neu differentiation factor-induced Stat activation are dependent on Src but not Jak kinases. Upon EGF stimulation, c-Src was rapidly recruited to Stat/ErbB receptor complexes. Pharmacological Src kinase inhibitors and a dominant negative c-Src ablated both Stat and Jak tyrosine phosphorylation. However, dominant negative Jaks did not affect EGF-induced Stat phosphorylation. Taken together, the experiments establish two independent roles for Src kinases: (i) key molecules in ErbB receptor-mediated Stat signaling and (ii) potential upstream regulators of Jak kinases.
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Affiliation(s)
- M A Olayioye
- Friedrich Miescher Institute, P.O. Box 2543, CH-4002 Basel, Switzerland
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131
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Daly JM, Olayioye MA, Wong AM, Neve R, Lane HA, Maurer FG, Hynes NE. NDF/heregulin-induced cell cycle changes and apoptosis in breast tumour cells: role of PI3 kinase and p38 MAP kinase pathways. Oncogene 1999; 18:3440-51. [PMID: 10376522 DOI: 10.1038/sj.onc.1202700] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Neu differentiation factor (NDF)/heregulin activates ErbB2 via heterodimerization with the NDF receptors ErbB3 and ErbB4. Cells which express normal levels of these receptors are often growth stimulated by NDF, whereas SKBR3, and other ErbB2-overexpressing breast tumour cells are growth inhibited. We demonstrate here that in SKBR3 cells, NDF induces G1 progression but also causes a G2 delay from day 1 and apoptosis from days 2-3. G1 progression was associated with ErbB2 transactivation of ErbB3 and subsequent stimulation of the phosphatidylinositol 3-kinase (PI3K) pathway whereas apoptosis was dependent on p38 MAPK. Inhibition of ERK1/ERK2 had no effect on cell cycle progression or apoptosis. Activation of ErbB3 and PI3K was also seen with betacellulin (BTC) but not epidermal growth factor (EGF) and correlated with the growth effects of these ligands. All three ligands induced short-term activation of p38 MAPK in a c-Src-dependent manner. However, only NDF caused a second, c-Src-independent increase in p38 MAPK activity which was required for apoptosis.
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Affiliation(s)
- J M Daly
- Friedrich Miescher Institute, Basel, Switzerland
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132
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Fry DW. Inhibition of the epidermal growth factor receptor family of tyrosine kinases as an approach to cancer chemotherapy: progression from reversible to irreversible inhibitors. Pharmacol Ther 1999; 82:207-18. [PMID: 10454198 DOI: 10.1016/s0163-7258(98)00050-3] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
The rationale to inhibit the epidermal growth factor receptor (EGFR) tyrosine kinase family as an approach to cancer chemotherapy has continued to grow stronger over the last 10 years. Both preclinical and clinical data strongly support the involvement of these receptors in the formation and progression of human cancers, as well as establish a high correlation in cancer patients between receptor/ ligand expression and poor prognosis. During the past 4 years, significant progress has been made in the area of EGFR tyrosine kinase inhibitors, and new structural classes have emerged that exhibit enormous improvements with regard to potency, specificity, and in vitro and in vivo activity. Very recently, further advancements in this field have been made whereby very specific, irreversible inhibitors of the EGFR family have been synthesized that provide unique pharmacological properties and exceptional efficacy. The in vivo performance of these modern kinase inhibitors has improved to the point where several compounds are either in clinical trials or very near to that point in their development. This review will briefly address the justification for targeting the EGFR family for cancer therapeutics, and then will highlight some of the more promising kinase inhibitors that are in development.
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Affiliation(s)
- D W Fry
- Department of Cancer Research, Parke-Davis Pharmaceutical Research, Division of Warner-Lambert Co., Ann Arbor, MI 48106, USA
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133
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Verbeek BS, Vroom TM, Rijksen G. Overexpression of c-Src enhances cell-matrix adhesion and cell migration in PDGF-stimulated NIH3T3 fibroblasts. Exp Cell Res 1999; 248:531-7. [PMID: 10222144 DOI: 10.1006/excr.1999.4416] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
c-Src is normally associated with the plasma membrane, but upon activation by tyrosine kinase receptors it translocates to the cytoskeleton. Activation of c-Src alters its conformation and induces the association of c-Src with cytoskeletal proteins. c-Src is implicated in tyrosine phosphorylation of cytoskeletal proteins, which might affect the cytoskeletal architecture. Rearrangements of the cytoskeleton affect cell-matrix adhesion and cell migration. In this study NIH3T3 fibroblasts, that overexpress c-Src, were used to analyze the effect of c-Src on both cell-matrix adhesion and cell migration. Upon PDGF stimulation translocation of c-Src to the cytoskeleton was detected. PDGF treatment also increased cell-matrix adhesion and cell migration. The cell line with the highest c-Src expression showed the largest increases in both phenomena. These findings suggest that translocation of c-Src to the cytoskeleton results in enhanced cell-matrix adhesion and cell migration.
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Affiliation(s)
- B S Verbeek
- Department of Hematology, University Hospital Utrecht, Utrecht, 3508 GA, The Netherlands.
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134
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Affiliation(s)
- J S Biscardi
- Department of Microbiology and Cancer Center, University of Virginia Health Sciences Center, Charlottesville 22908, USA
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135
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Biscardi JS, Maa MC, Tice DA, Cox ME, Leu TH, Parsons SJ. c-Src-mediated phosphorylation of the epidermal growth factor receptor on Tyr845 and Tyr1101 is associated with modulation of receptor function. J Biol Chem 1999; 274:8335-43. [PMID: 10075741 DOI: 10.1074/jbc.274.12.8335] [Citation(s) in RCA: 518] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Accumulating evidence indicates that interactions between the epidermal growth factor receptor (EGFR) and the nonreceptor tyrosine kinase c-Src may contribute to an aggressive phenotype in multiple human tumors. Previous work from our laboratory demonstrated that murine fibroblasts which overexpress both these tyrosine kinases display synergistic increases in DNA synthesis, soft agar growth, and tumor formation in nude mice, and increased phosphorylation of the receptor substrates Shc and phospholipase gamma as compared with single overexpressors. These parameters correlated with the ability of c-Src and EGFR to form an EGF-dependent heterocomplex in vivo. Here we provide evidence that association between c-Src and EGFR can occur directly, as shown by receptor overlay experiments, and that it results in the appearance of two novel tyrosine phosphorylations on the receptor that are seen both in vitro and in vivo following EGF stimulation. Edman degradation analyses and co-migration of synthetic peptides with EGFR-derived tryptic phosphopeptides identify these sites as Tyr845 and Tyr1101. Tyr1101 lies within the carboxyl-terminal region of the EGFR among sites of receptor autophosphorylation, while Tyr845 resides in the catalytic domain, in a position analogous to Tyr416 of c-Src. Phosphorylation of Tyr416 and homologous residues in other tyrosine kinase receptors has been shown to be required for or to increase catalytic activity, suggesting that c-Src can influence EGFR activity by mediating phosphorylation of Tyr845. Indeed, EGF-induced phosphorylation of Tyr845 was increased in MDA468 human breast cancer cells engineered to overexpress c-Src as compared with parental MDA 468 cells. Furthermore, transient expression of a Y845F variant EGFR in murine fibroblasts resulted in an ablation of EGF-induced DNA synthesis to nonstimulated levels. Together, these data support the hypothesis that c-Src-mediated phosphorylation of EGFR Tyr845 is involved in regulation of receptor function, as well as in tumor progression.
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Affiliation(s)
- J S Biscardi
- Department of Microbiology and Cancer Center, Box 441, University of Virginia Health Sciences Center, Charlottesville, Virginia 22908, USA
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136
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Tice DA, Biscardi JS, Nickles AL, Parsons SJ. Mechanism of biological synergy between cellular Src and epidermal growth factor receptor. Proc Natl Acad Sci U S A 1999; 96:1415-20. [PMID: 9990038 PMCID: PMC15477 DOI: 10.1073/pnas.96.4.1415] [Citation(s) in RCA: 361] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/1998] [Indexed: 11/18/2022] Open
Abstract
Overexpression of both cellular Src (c-Src) and the epidermal growth factor receptor (EGFR) occurs in many of the same human tumors, suggesting that they may functionally interact and contribute to the progression of cancer. Indeed, in murine fibroblasts, overexpression of c-Src has been shown to potentiate the mitogenic and tumorigenic capacity of the overexpressed EGFR. Potentiation correlated with the ability of c-Src to physically associate with the activated EGFR and the appearance of two unique in vivo phosphorylations on the receptor (Tyr-845 and Tyr-1101). Using stable cell lines of C3H10T1/2 murine fibroblasts that contain kinase-deficient (K-) c-Src and overexpressed wild-type EGFR, we show that the kinase activity of c-Src is required for both the biological synergy with the receptor and the phosphorylations on the receptor, but not for the association of c-Src with the receptor. In transient transfection assays, not only epidermal growth factor but also serum- and lysophosphatidic acid-induced DNA synthesis was ablated in a dominant-negative fashion by a Y845F mutant of the EGFR, indicating that c-Src-induced phosphorylation of Y845 is critical for the mitogenic response to both the EGFR and a G protein-coupled receptor (lysophosphatidic acid receptor). Unexpectedly, the Y845F mutant EGFR was found to retain its full kinase activity and its ability to activate the adapter protein SHC and extracellular signal-regulated kinase ERK2 in response to EGF, demonstrating that the mitogenic pathway involving phosphorylation of Y845 is independent of ERK2-activation. The application of these findings to the development of novel therapeutics for human cancers that overexpress c-Src and EGFR is discussed.
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Affiliation(s)
- D A Tice
- Box 441, Department of Microbiology and Cancer Center, University of Virginia Health Sciences Center, Charlottesville, VA 22908, USA
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137
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Egan C, Pang A, Durda D, Cheng HC, Wang JH, Fujita DJ. Activation of Src in human breast tumor cell lines: elevated levels of phosphotyrosine phosphatase activity that preferentially recognizes the Src carboxy terminal negative regulatory tyrosine 530. Oncogene 1999; 18:1227-37. [PMID: 10022129 DOI: 10.1038/sj.onc.1202233] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Elevated levels of Src kinase activity have been reported in a number of human cancers, including colon and breast cancer. We have analysed four human breast tumor cell lines that exhibit high levels of Src kinase activity, and have determined that these cell lines also exhibit a high level of a phosphotyrosine phosphatase activity that recognizes the Src carboxy-terminal P-Tyr530 negative regulatory site. Total Src kinase activity in these cell lines is elevated as much as 30-fold over activity in normal control cells and specific activity is elevated as much as 5.6-fold. When the breast tumor cells were grown in the presence of the tyrosine phosphatase inhibitor vanadate, Src kinase activity was reduced in all four breast tumor cell lines, suggesting that Src was being activated by a phosphatase which could recognize the Tyr530 negative regulatory site. In fractionated cell extracts from the breast tumor cells, we found elevated levels of a membrane associated tyrosine phosphatase activity that preferentially dephosphorylated a Src family carboxy-terminal phosphopeptide containing the regulatory tyrosine 530 site. Src was hypophosphorylated in vivo at tyrosine 530 in at least two of the tumor cell lines, further suggesting that Src was being activated by a phosphatase in these cells. In preliminary immunoprecipitation and antibody depletion experiments, we were unable to correlate the major portion of this phosphatase activity with several known phosphatases.
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Affiliation(s)
- C Egan
- Department of Medical Biochemistry, University of Calgary Medical Centre, Alberta, Canada
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138
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Shahabi NA, Daaka Y, McAllen K, Sharp BM. Delta opioid receptors expressed by stably transfected jurkat cells signal through the map kinase pathway in a ras-independent manner. J Neuroimmunol 1999; 94:48-57. [PMID: 10376935 DOI: 10.1016/s0165-5728(98)00211-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Delta opioid receptors (DOR) are G-protein coupled 7-transmembrane receptors (GPCR), expressed by thymic and splenic T cells, that modulate interleukin (IL)-2 production and proliferation in response to concanavalin A or crosslinking the TCR. Mitogen-activated protein kinases (MAPKs) are involved in mediating intracellular responses to TCR crosslinking. In addition, MAPKs can be activated by signaling cascades that are initiated by the release of G-proteins from GPCRs. To determine whether DORs expressed by T cells signal through the MAPKs, extracellular-regulated kinases (ERKs) 1 and 2, two delta opioid peptides, deltorphin and [D-Ala2,D-Leu5]-enkephalin (DADLE), were studied in Jurkat cells that had been stably transfected with DOR (DOR-Ju.1). These peptides rapidly and dose-dependently induced ERK phosphorylation; pretreatment with naltrindole (NTI), a selective DOR antagonist, abolished this. Pertussis toxin (PTX) also inhibited phosphorylation, indicating the involvement of the Gi/o proteins. Herbimycin A, a protein tyrosine kinase (PTK) inhibitor, reduced the DADLE-induced ERK phosphorylation by 68%. ERK phosphorylation was inhibited by Bisindolylmaleimide 1 (GF109203X), an inhibitor of PKC, and by pretreatment with PMA prior to DADLE. A GTP/GDP exchange assay was used to assess the potential role of Ras in the pathway leading to ERK phosphorylation; DADLE failed to stimulate GTP/GDP exchange in comparison to PMA. Additional studies showed that DADLE stimulated an increase in cfos mRNA; this was reduced by the inhibitor of MAPK/ERK kinase (MEK), PD98059. Therefore, in DOR-Ju.1 cells, DOR agonists stimulate ERK phosphorylation in a Ras independent and PKC-dependent manner; PTKs appear to be involved. MAPKs mediate the increase in cfos mRNA induced by DOR agonists.
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MESH Headings
- Adjuvants, Immunologic/metabolism
- Animals
- Benzoquinones
- Calcium Signaling/drug effects
- Calcium Signaling/immunology
- Calcium-Calmodulin-Dependent Protein Kinases/metabolism
- Carcinogens/pharmacology
- Enkephalin, Leucine-2-Alanine/pharmacology
- Enzyme Activation/immunology
- Enzyme Inhibitors/pharmacology
- Flavonoids/pharmacology
- GTPase-Activating Proteins
- Gene Expression Regulation, Enzymologic/drug effects
- Gene Expression Regulation, Enzymologic/immunology
- Humans
- Jurkat Cells/chemistry
- Jurkat Cells/enzymology
- Jurkat Cells/immunology
- Lactams, Macrocyclic
- Mice
- Mice, Inbred BALB C
- Mitogen-Activated Protein Kinase 1
- Mitogen-Activated Protein Kinase 3
- Mitogen-Activated Protein Kinases
- Oligopeptides/pharmacology
- Pertussis Toxin
- Phosphorylation
- Proteins/metabolism
- Proto-Oncogene Proteins c-fos/genetics
- Quinones/pharmacology
- RNA, Messenger/analysis
- Receptors, Opioid, delta/genetics
- Receptors, Opioid, delta/immunology
- Reverse Transcriptase Polymerase Chain Reaction
- Rifabutin/analogs & derivatives
- Tetradecanoylphorbol Acetate/pharmacology
- Virulence Factors, Bordetella/pharmacology
- ras GTPase-Activating Proteins
- ras Proteins/metabolism
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Affiliation(s)
- N A Shahabi
- Endocrine-Neuroscience and Neuroimmunomodulation Research Laboratories, Minneapolis Medical Research Foundation, Hennepin County Medical Center and University of Minnesota, 55404, USA
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139
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Wellbrock C, Schartl M. Multiple binding sites in the growth factor receptor Xmrk mediate binding to p59fyn, GRB2 and Shc. EUROPEAN JOURNAL OF BIOCHEMISTRY 1999; 260:275-83. [PMID: 10091608 DOI: 10.1046/j.1432-1327.1999.00180.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Melanoma formation in Xiphoporus is initiated by overexpression of the EGFR-related receptor tyrosine kinase Xmrk (Xiphoporus melanoma receptor kinase). This receptor is activated in fish melanoma as well as in a melanoma-derived cell line (PSM) resulting in constitutive Xmrk-mediated mitogenic signaling. In order to define the underlying signaling pathway(s), triggered by the activated Xmrk receptor, we attempted to identify its physiological substrates. Examination of the Xmrk carboxyterminus for putative tyrosine autophosphorylation sites revealed the presence of potential binding motifs for GRB2 as well as for Shc. Binding of these adaptor proteins to the Xmrk receptor was detected in vitro and in cells expressing the mrk kinase. The GRB2 and Shc interactions with the receptor could be disrupted individually by phosphotyrosine peptides containing putative Xmrk autophosphorylation sites, indicating direct binding of both proteins. Recruitment of GRB2 by the constitutively activated Xmrk receptor led to strong MAP kinase activation in Xiphoporus melanoma cells. We also identified a high-affinity binding site for src-kinases (pYEDL) in the Xmrk carboxyterminus. Competition experiments with phosphopeptides comprising this site confirmed that it is used for high-affinity binding of Xiphoporus fyn (Xfyn) to Xmrk in melanoma cells. Thus, Xmrk can initiate different signaling pathways by using multiple substrate-binding sites to trigger proliferation of pigment cells.
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Affiliation(s)
- C Wellbrock
- Department of Physiological Chemistry I, University of Würzburg, Germany.
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140
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Daly RJ. Take your partners, please--signal diversification by the erbB family of receptor tyrosine kinases. Growth Factors 1999; 16:255-63. [PMID: 10427500 DOI: 10.3109/08977199909069144] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- R J Daly
- Cancer Research Program, Garvan Institute of Medical Research, St Vincent's Hospital, Sydney, Australia.
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141
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Klapper LN, Kirschbaum MH, Seta M, Yarden Y. Biochemical and Clinical Implications of the ErbB/HER Signaling Network of Growth Factor Receptors. Adv Cancer Res 1999. [DOI: 10.1016/s0065-230x(08)60784-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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142
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143
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Epidermal growth factor receptors in breast cancer: from experiment to clinical practice. Bull Exp Biol Med 1998. [DOI: 10.1007/bf02447238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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144
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Ritchie S, Bonham K. The human c-Src proto-oncogene promoter contains multiple targets for triplex-forming oligonucleotides. ANTISENSE & NUCLEIC ACID DRUG DEVELOPMENT 1998; 8:391-400. [PMID: 9826266 DOI: 10.1089/oli.1.1998.8.391] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The overexpression and activation of the human c-Src proto-oncogene is closely associated with cancer of the colon and breast. Characterization of the 5' region of the c-Src gene revealed that the promoter is very GC rich, regulated by the Sp family of transcription factors, and contains four perfect homopolypurine/homopolypyrimidine tracts (Pu:Py tracts). These Pu:Py tracts (TC1, TC1.1, TC2, and TC3) are located near or overlap critical Spl binding sites required for full activation of the gene. Triplex-forming oligonucleotides (TFOs) can be targeted to such sequences with high affinity to form intermolecular triple-helical DNA and modulate transcriptional activity. We therefore designed a series of antiparallel purine-based TFOs and measured their ability to form triplexes with the c-Src promoter Pu:Py tracts using comigration, bandshift, and chemical footprint techniques. With one interesting exception, all of the TFOs were found to bind with specificity and high affinity (67 nM-28 nM) to their target sequences at physiologic pH. These results indicate that the c-Src gene can successfully form stable triplexes under physiologic conditions and is, therefore, an excellent candidate for triplex-mediated transcriptional downregulation.
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Affiliation(s)
- S Ritchie
- Department of Biochemistry, University of Saskatchewan, Saskatoon, Canada
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145
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Olayioye MA, Graus-Porta D, Beerli RR, Rohrer J, Gay B, Hynes NE. ErbB-1 and ErbB-2 acquire distinct signaling properties dependent upon their dimerization partner. Mol Cell Biol 1998; 18:5042-51. [PMID: 9710588 PMCID: PMC109089 DOI: 10.1128/mcb.18.9.5042] [Citation(s) in RCA: 196] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/1998] [Accepted: 06/12/1998] [Indexed: 12/31/2022] Open
Abstract
The different epidermal growth factor (EGF)-related peptides elicit a diverse array of biological responses as the result of their ability to activate distinct subsets of ErbB receptor dimers, leading to the recruitment of different intracellular signaling networks. To specifically examine dimerization-dependent modulation of receptor signaling, we constructed NIH 3T3 cell lines expressing ErbB-1 and ErbB-2 singly and in pairwise combinations with each other ErbB family member. This model system allowed the comparison of EGF-activated ErbB-1 with ErbB-1 activated by Neu differentiation factor (NDF)-induced heterodimerization with ErbB-4. In both cases, ErbB-1 coupled to the adaptor protein Shc, but only when activated by EGF was it able to interact with Grb2. Compared to the rapid internalization of EGF-activated ErbB-1, NDF-activated ErbB-1 showed delayed internalization characteristics. Furthermore, the p85 subunit of phosphatidylinositol kinase (PI3-K) associated with EGF-activated ErbB-1 in a biphasic manner, whereas association with ErbB-1 transactivated by ErbB-4 was monophasic. The signaling properties of ErbB-2 following heterodimerization with the other ErbB receptors or homodimerization induced by point mutation or monoclonal antibody treatment were also analyzed. ErbB-2 binding to peptides containing the Src homology 2 domain of Grb2 or p85 and the phosphotyrosine binding domain of Shc varied according to the mode of receptor activation. Finally, tryptic phosphopeptide mapping of both ErbB-1 and ErbB-2 revealed that receptor phosphorylation is dependent on the dimerization partner. Differential receptor phosphorylation may, therefore, be the basis for the differences in the signaling properties observed.
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Affiliation(s)
- M A Olayioye
- Friedrich Miescher Institute, CH-4002 Basel, Switzerland
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146
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Abstract
We have recently found and characterized EAST, a novel EGF receptor-associated protein with SH3 and TAM domains. In this study we show that EAST becomes phosphorylated by Src kinase. This, in conjunction with our earlier observations on the close association between EAST and the endocytic machinery, suggests that EAST could be involved in Src-dependent effects on EGF receptor endocytosis.
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Affiliation(s)
- O Lohi
- Department of Pathology, University of Oulu, Finland
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147
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Herrlich A, Daub H, Knebel A, Herrlich P, Ullrich A, Schultz G, Gudermann T. Ligand-independent activation of platelet-derived growth factor receptor is a necessary intermediate in lysophosphatidic, acid-stimulated mitogenic activity in L cells. Proc Natl Acad Sci U S A 1998; 95:8985-90. [PMID: 9671791 PMCID: PMC21189 DOI: 10.1073/pnas.95.15.8985] [Citation(s) in RCA: 116] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Growth factor-derived mitogenic signals from the cell surface are transmitted to the nucleus via receptor tyrosine kinases (RTKs), the adaptor proteins Shc and Grb2, and a Ras-dependent protein kinase cascade that activates the extracellular signal regulated kinase (ERK) subfamily of mitogen-activated protein kinases. ERKs also are activated by hormones that stimulate G protein-coupled receptors (GPCRs). We report here that, in agreement with previous data, the epidermal growth factor receptor (EGFR) is a signaling intermediate in ERK activation by GPCRs. Of import, we show that cross-talk between two classes of surface receptors, RTKs and GPCRs, is a general feature. Lysophosphatidic acid not only induces ligand-independent tyrosine autophosphorylation of EGFR but also of platelet-derived growth factor beta receptor (PDGF-beta-R) as shown by detection of tyrosine phosphorylation and by the use of specific inhibitors of RTKs. The cross-talk appears to be cell type-specific: In L cells that lack EGFR, lysophosphatidic acid-induced Shc and ERK activation is prevented completely by specific inhibition of PDGFR, whereas in COS-7 cells expressing only EGFR, the pathway via EGFR is chosen. In Rat-1 cells, however, that express both EGFR and PDGFR, the EGFR pathway dominates.
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Affiliation(s)
- A Herrlich
- Institut für Pharmakologie, Freie Universität Berlin, Thielallee 67-73, 14195 Berlin, Germany.
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148
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Wong LH, Hatzinisiriou I, Devenish RJ, Ralph SJ. IFN-γ Priming Up-Regulates IFN-Stimulated Gene Factor 3 (ISGF3) Components, Augmenting Responsiveness of IFN-Resistant Melanoma Cells to Type I IFNs. THE JOURNAL OF IMMUNOLOGY 1998. [DOI: 10.4049/jimmunol.160.11.5475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
IFN-stimulated gene factor 3 (ISGF3) mediates transcriptional activation of IFN-sensitive genes (ISGs). The component subunits of ISGF3, STAT1αβ, STAT2, and p48-ISGF3γ, are tyrosine phosphorylated before their assembly into a complex. Subsequently, the ISGF3 complex is translocated to the nucleus. We have recently established that the responsiveness of human melanoma cell lines to type I IFNs correlates directly with their intracellular levels of ISGF3 components, particularly STAT1. In the present study, we show that pretreating IFN-resistant melanoma cell lines with IFN-γ (IFN-γ priming) before stimulation with type I IFN also results in increased levels of ISGF3 components and enhanced DNA-binding activation of ISGF3. In addition, IFN-γ priming of IFN-resistant melanoma cell lines increased expression of type I IFN-induced ISG products, including ISG54, 2′-5′-oligoadenylate synthase, HLA class I, B7-1, and ICAM-1 Ags. Furthermore, IFN-γ priming enhanced the antiviral effect of IFN-β on the IFN-resistant melanoma cell line, MM96. These results support a role for IFN-γ priming in up-regulating ISGF3, thereby augmenting the responsiveness of IFN-resistant melanoma cell lines to type I IFN and providing a molecular basis and justification for using sequential IFN therapy, as proposed by others, to enhance the use of IFNs in the treatment of melanoma.
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Affiliation(s)
- Lee H. Wong
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Irene Hatzinisiriou
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Rodney J. Devenish
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Stephen J. Ralph
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
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149
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Pacofsky GJ, Lackey K, Alligood KJ, Berman J, Charifson PS, Crosby RM, Dorsey GF, Feldman PL, Gilmer TM, Hummel CW, Jordan SR, Mohr C, Shewchuk LM, Sternbach DD, Rodriguez M. Potent dipeptide inhibitors of the pp60c-src SH2 domain. J Med Chem 1998; 41:1894-908. [PMID: 9599239 DOI: 10.1021/jm970853a] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The design, synthesis, and evaluation of dipeptide analogues as ligands for the pp60c-src SH2 domain are described. The critical binding interactions between Ac-Tyr-Glu-N(n-C5H11)2 (2) and the protein are established and form the basis for our structure-based drug design efforts. The effects of changes in both the C-terminal (11-27) and N-terminal (51-69) portions of the dipeptide are explored. Analogues with reduced overall charge (92-95) are also investigated. We demonstrate the feasibility of pairing structurally diverse subunits in a modest dipeptide framework with the goal of increasing the druglike attributes without sacrificing binding affinity.
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Affiliation(s)
- G J Pacofsky
- Department of Medicinal Chemistry, Glaxo Wellcome Inc., 5 Moore Drive, Research Triangle Park, North Carolina 27709, USA
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150
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Enan E, El-Sabeawy F, Overstreet J, Matsumura F, Lasley B. Mechanisms of gender-specific TCDD-induced toxicity in guinea pig adipose tissue. Reprod Toxicol 1998; 12:357-69. [PMID: 9628558 DOI: 10.1016/s0890-6238(98)00017-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
After treatment with TCDD, the activities of cytosolic AhR-associated c-Src kinase, microsomal protein kinase C (nPKC epsilon), microsomal c-Src kinase, nuclear p44/42 MAPK, c-Jun N terminus kinase, and the amount of microsomal pan-Ras protein were different in males and females. TCDD did not decrease body or adipose tissue weights in transgenic src-deficient male mice as compared to their wild-type littermates, and the activity of AhR-associated c-Src kinase was not increased by TCDD in src-deficient male mice. Similar results were obtained when TCDD was given to male guinea pigs treated with the Src-kinase inhibitor, geldanamycin. Treatment with estradiol protected male guinea pigs from TCDD-induced wasting. TCDD induced similar changes in protein tyrosine kinase activity in adipose tissues of castrated male and intact female guinea pigs. The gender-specific mechanisms of TCDD-induced toxicity appear to involve c-Src kinase, nPKC epsilon, and pan-Ras, as well as overlap in the cytosolic signal transduction pathways of TCDD and sex steroids.
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Affiliation(s)
- E Enan
- Department of Environmental Toxicology and Institute of Toxicology and Environmental Health, University of California, Davis 95616, USA.
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