title: Accelerated mammary tumor development in mutant polyomavirus middle T transgenic mice expressing elevated levels of either the Shc or Grb2 adapter protein.
abstract: The Grb2 and Shc adapter proteins play critical roles in coupling activated growth factor receptors to several cellular signaling pathways. To assess the role of these molecules in mammary epithelial development and tumorigenesis, we have generated transgenic mice which individually express the Grb2 and Shc proteins in the mammary epithelium. Although mammary epithelial cell-specific expression of Grb2 or Shc accelerated ductal morphogenesis, mammary tumors were rarely observed in these strains. To explore the potential role of these adapter proteins in mammary tumorigenesis, mice coexpressing either Shc or Grb2 and a mutant form of polyomavirus middle T (PyV mT) antigen in the mammary epithelium were generated. Coexpression of either Shc or Grb2 with the mutant PyV mT antigen resulted in a dramatic acceleration of mammary tumorigenesis compared to parental mutant PyV mT strain. The increased rate of tumor formation observed in these mice was correlated with activation of the epidermal growth factor receptor family and mitogen-activated protein kinase pathway. These observations suggest that elevated levels of the Grb2 or Shc adapter protein can accelerate mammary tumor progression by sensitizing the mammary epithelial cell to growth factor receptor signaling.
authors.affiliation: Institute for Molecular Biology and Biotechnology, McMaster University, Hamilton, Ontario, Canada L8S 4K1.
authors.forename: M J
authors.initials: MJ
authors.lastname: Rauh
authors.forename: V
authors.initials: V
authors.lastname: Blackmore
authors.forename: E R
authors.initials: ER
authors.lastname: Andrechek
authors.forename: C G
authors.initials: CG
authors.lastname: Tortorice
authors.forename: R
authors.initials: R
authors.lastname: Daly
authors.forename: V K
authors.initials: VK
authors.lastname: Lai
authors.forename: T
authors.initials: T
authors.lastname: Pawson
authors.forename: R D
authors.initials: RD
authors.lastname: Cardiff
authors.forename: P M
authors.initials: PM
authors.lastname: Siegel
authors.forename: W J
authors.initials: WJ
authors.lastname: Muller
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D000818:Animals; D000952:Antigens, Polyomavirus Transforming / Q000235:genetics / Q000502:physiology*; D005260:Female; D051380:GRB2 Adaptor Protein; D015870:Gene Expression; D005822:Genetic Vectors; D006801:Humans; D008325:Mammary Neoplasms, Experimental / Q000473:pathology*; D008324:Mammary Tumor Virus, Mouse; D051379:Mice; D008822:Mice, Transgenic; D009024:Morphogenesis; D014176:Protein Biosynthesis; D011506:Proteins / Q000235:genetics / Q000502:physiology*; D011817:Rabbits; D055765:Shc Signaling Adaptor Proteins; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D000952:Antigens, Polyomavirus Transforming; D051380:GRB2 Adaptor Protein; C495948:GRB2 protein, human; C495949:Grb2 protein, mouse; D011506:Proteins; C528024:SHC1 protein, human; D055765:Shc Signaling Adaptor Proteins; C528034:Shc1 protein, mouse; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1