Protein tyrosine kinase Syk modulates EGFR signalling in human mammary epithelial cells.

Signalling through protein tyrosine kinases (PTKs) is critical in the regulation of important cellular processes and its deregulation is associated with pathophysiological disorders such as cancer. We investigated the function of the PTK spleen tyrosine kinase (Syk) in the regulation of growth factor signalling pathways in human mammary epithelial cells. Our results show that downregulation of endogenous Syk expression enhances the ligand-induced activity of the epidermal growth factor receptor (EGFR) but not that of the closely related human epidermal growth factor receptor 2 (HER2) and human epidermal growth factor receptor 3 (HER3) receptors. Moreover, Syk function interfered with EGFR-mediated cell responses such as proliferation and survival of mammary epithelial cells. A mechanistic link between Syk and EGFR is further supported by the colocalisation of the two PTKs in membrane fractions as well as the regulatory feedback effects of the EGFR kinase on Syk activity. Our findings demonstrate that Syk acts a negative control element of EGFR signalling.

[1]  G L Johnson,et al.  Organization and regulation of mitogen-activated protein kinase signaling pathways. , 1999, Current opinion in cell biology.

[2]  A. Ostman,et al.  Regulation of receptor tyrosine kinase signaling by protein tyrosine phosphatases. , 2001, Trends in cell biology.

[3]  J. D. Di Santo,et al.  Tyrosine kinase SYK: essential functions for immunoreceptor signalling. , 2000, Immunology today.

[4]  Joseph Schlessinger,et al.  Signal transduction by receptors with tyrosine kinase activity , 1990, Cell.

[5]  A. Ullrich,et al.  The epidermal growth factor receptor family as a central element for cellular signal transduction and diversification. , 2001, Endocrine-related cancer.

[6]  T. Tiganis.  Protein Tyrosine Phosphatases: Dephosphorylating the Epidermal Growth Factor Receptor , 2002, IUBMB life.

[7]  A. Andres,et al.  Molecular characterization of the murine syk protein tyrosine kinase cDNA, transcripts and protein. , 1995, Biochemical and biophysical research communications.

[8]  A. Sahin,et al.  Hypermethylation leads to silencing of the SYK gene in human breast cancer. , 2001, Cancer research.

[9]  U. Rodeck,et al.  The EGF receptor - an essential regulator of multiple epidermal functions. , 2000, European journal of dermatology : EJD.

[10]  A. Ullrich,et al.  HER2 cytoplasmic domain generates normal mitogenic and transforming signals in a chimeric receptor. , 1989, The EMBO journal.

[11]  S. McLeskey,et al.  The Syk tyrosine kinase suppresses malignant growth of human breast cancer cells , 2000, Nature.

[12]  H. Jansen,et al.  c-Cbl ubiquitinates the EGF receptor at the plasma membrane and remains receptor associated throughout the endocytic route. , 2001, Journal of cell science.

[13]  P. Cohen,et al.  EGF triggers neuronal differentiation of PC12 cells that overexpress the EGF receptor , 1994, Current Biology.

[14]  S. Ethier,et al.  Mitogenic activity of neu differentiation factor/heregulin mimics that of epidermal growth factor and insulin‐like growth factor‐I in human mammary epithelial cells , 1995, Journal of cellular physiology.

[15]  G. G. Stokes.  "J." , 1890, The New Yale Book of Quotations.

[16]  A. Ullrich,et al.  Receptor tyrosine kinases as targets for anticancer drugs. , 2002, Trends in molecular medicine.

[17]  M. Siegel,et al.  Inhibition of Protein Synthesis in vitro by Cycloheximide , 1963, Nature.

[18]  M. Israel,et al.  Anthracycline drug targeting: cytoplasmic versus nuclear--a fork in the road. , 2001, Drug resistance updates : reviews and commentaries in antimicrobial and anticancer chemotherapy.

[19]  A. Godzik,et al.  Tyrosine phosphorylation of VHR phosphatase by ZAP-70 , 2003, Nature Immunology.

[20]  T. Tuschl,et al.  Duplexes of 21-nucleotide RNAs mediate RNA interference in cultured mammalian cells , 2001, Nature.

[21]  Z. Kam,et al.  c-Cbl/Sli-1 regulates endocytic sorting and ubiquitination of the epidermal growth factor receptor. , 1998, Genes & development.

[22]  Hiroko Yamashita,et al.  Reduced expression of the Syk gene is correlated with poor prognosis in human breast cancer. , 2003, Cancer letters.

[23]  Pier Paolo Pandolfi,et al.  The p66shc adaptor protein controls oxidative stress response and life span in mammals , 1999, Nature.

[24]  A. Ullrich,et al.  Functional analysis of the ligand binding site of EGF‐receptor utilizing chimeric chicken/human receptor molecules. , 1989, The EMBO journal.

[25]  A. Levitzki,et al.  Tyrosine kinase inhibition: an approach to drug development. , 1995, Science.

[26]  A. Godwin,et al.  A Grb2-associated docking protein in EGF- and insulin-receptor signalling , 1996, Nature.

[27]  O. Segatto,et al.  Negative regulation of receptor tyrosine kinase signals , 2001, FEBS letters.

[28]  Kodi S Ravichandran,et al.  Signaling via Shc family adapter proteins , 2001, Oncogene.

[29]  P G Pelicci,et al.  Not all Shc's roads lead to Ras. , 1996, Trends in biochemical sciences.

[30]  Juan Zhang,et al.  A unique insert in the linker domain of Syk is necessary for its function in immunoreceptor signalling , 1998, The EMBO journal.

[31]  N. Normanno,et al.  Epidermal growth factor-related peptides and their receptors in human malignancies. , 1995, Critical reviews in oncology/hematology.

[32]  A. Ullrich,et al.  Mig-6 Is a Negative Regulator of the Epidermal Growth Factor Receptor Signal , 2001, Biological chemistry.

[33]  H. Steven Wiley,et al.  Regulation of Receptor Tyrosine Kinase Signaling by Endocytic Trafficking , 2001, Traffic.

[34]  Antony W Burgess,et al.  Epidermal growth factor receptor: mechanisms of activation and signalling. , 2003, Experimental cell research.

[35]  A. Ullrich,et al.  Dynamin binds to SH3 domains of phospholipase C gamma and GRB-2. , 1994, The Journal of biological chemistry.

[36]  H. Varmus,et al.  Function, location, and regulation of the src protein-tyrosine kinase. , 1989, Princess Takamatsu symposia.

[37]  J. Kinet,et al.  Syk-dependent Phosphorylation of Shc , 1996, The Journal of Biological Chemistry.

[38]  J. Fargnoli,et al.  Molecular Cloning of Rodent p72Syk. , 1995, The Journal of Biological Chemistry.

[39]  Sheila M. Thomas,et al.  Association of the Shc and Grb2/Sem5 SH2-containing proteins is implicated in activation of the Ras pathway by tyrosine kinases , 1992, Nature.

[40]  W. Symmans,et al.  Alternative splicing disrupts a nuclear localization signal in spleen tyrosine kinase that is required for invasion suppression in breast cancer. , 2003, Cancer research.

[41]  A. Ullrich,et al.  Signal characteristics of G protein‐transactivated EGF receptor , 1997, The EMBO journal.

[42]  A. Ullrich,et al.  Epidermal growth factor receptors: critical mediators of multiple receptor pathways. , 1999, Current opinion in cell biology.

[43]  Joseph Schlessinger,et al.  A Novel Positive Feedback Loop Mediated by the Docking Protein Gab1 and Phosphatidylinositol 3-Kinase in Epidermal Growth Factor Receptor Signaling , 2000, Molecular and Cellular Biology.

[44]  J. Herman,et al.  Hypermethylation of tumor suppressor genes in cancer. , 1999, Seminars in cancer biology.

[45]  G. Kundu,et al.  Syk, a Protein-tyrosine Kinase, Suppresses the Cell Motility and Nuclear Factor κB-mediated Secretion of Urokinase Type Plasminogen Activator by Inhibiting the Phosphatidylinositol 3′-Kinase Activity in Breast Cancer Cells* , 2003, The Journal of Biological Chemistry.

[46]  G. Nolan,et al.  Episomal vectors rapidly and stably produce high-titer recombinant retrovirus. , 1996, Human gene therapy.

[47]  S. R. Datta,et al.  Akt Phosphorylation of BAD Couples Survival Signals to the Cell-Intrinsic Death Machinery , 1997, Cell.