Use of signal specific receptor tyrosine kinase oncoproteins reveals that pathways downstream from Grb2 or Shc are sufficient for cell transformation and metastasis.
Many human cancers have been associated with the deregulation of receptor tyrosine kinases (RTK). However, the individual contribution of receptor-associated signaling proteins in cellular transformation and metastasis is poorly understood. To examine the role of RTK activated signal transduction pathways to processes involved in cell transformation, we have exploited the oncogenic derivative of the Met RTK (Tpr-Met). Unlike other RTKs, twin tyrosine residues in the carboxy-terminal tail of the Met oncoprotein and receptor are required for all biological and transforming activities, and a mutant lacking these tyrosines is catalytically active but non transforming. Using this mutant we have inserted oligonucleotide cassettes, each encoding a binding site for a specific signaling protein derived from other RTKs. We have generated variant forms of the Tpr-Met oncoprotein with the ability to bind individually to the p85 subunit of PI3'K, PLCgamma, or to the Grb2 or Shc adaptor proteins. Variants that recruit the Shc or Grb2 adaptor proteins generated foci of morphologically transformed fibroblast cells and induced anchorage-independent growth, scattering of epithelial cells and experimental metastasis. In contrast, variants that bind and activate PI3'K or PLCgamma failed to generate readily detectable foci. Although cell lines expressing the PI3'K variant grew in soft-agar, these cells were non metastatic. Using this unique RTK oncoprotein model, we have established that Grb2 or Shc dependent signaling pathways are sufficient for cell transformation and metastatic spread.
Saucier
Caroline
C
Molecular Oncology Group, McGill University Hospital Center, Montreal, Quebec, Canada H3A 1A1.
Papavasiliou
Vasilios
V
Palazzo
Alexander
A
Naujokas
Monica A
MA
Kremer
Richard
R
Park
Morag
M
D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D015153:Blotting, Western; D002448:Cell Adhesion / Q000502:physiology; D002460:Cell Line; D002471:Cell Transformation, Neoplastic / Q000378:metabolism*; D003114:Colony-Forming Units Assay; D006224:Cricetinae; D017931:DNA Primers; D004789:Enzyme Activation; D004847:Epithelial Cells / Q000378:metabolism; D051380:GRB2 Adaptor Protein; D006801:Humans; D019751:Intramolecular Transferases / Q000235:genetics / Q000378:metabolism*; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D016297:Mutagenesis, Site-Directed; D009362:Neoplasm Metastasis; D015514:Oncogene Proteins, Fusion / Q000235:genetics / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics / Q000378:metabolism*; D051966:Phospholipase C gamma; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation; D011233:Precipitin Tests; D011485:Protein Binding; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D011916:Rats, Inbred F344; D015398:Signal Transduction / Q000502:physiology*; D010738:Type C Phospholipases / Q000235:genetics / Q000378:metabolism*
D048868:Adaptor Proteins, Signal Transducing; D017931:DNA Primers; C098587:GAB1 protein, human; D051380:GRB2 Adaptor Protein; C495948:GRB2 protein, human; C490897:Gab1 protein, mouse; C490896:Gab1 protein, rat; C495949:Grb2 protein, mouse; C495950:Grb2 protein, rat; D007527:Isoenzymes; D015514:Oncogene Proteins, Fusion; D010750:Phosphoproteins; D011506:Proteins; D019869:Phosphatidylinositol 3-Kinases; D010738:Type C Phospholipases; D051966:Phospholipase C gamma; D019751:Intramolecular Transferases; C066630:squalene-hopene cyclase