The overall goals of this project are to elucidate regulatory mechanisms of ErbB signaling components and to explore these molecules as molecular targets for cancer therapy. SHP2 protein tyrosine phosphatase (PTPase) mediates ErbB-induced Erk mitogen-activated protein (MAP) kinase activation and is involved in cytoskeletal reorganization and cell motility. However, how SHP2 mediates these responses is not well understood. It has been shown that Gab1 is a key SHP2 regulator in epidermal growth factor (EGF)-stimulated cells and that Src and Ras are activated by SHP2, but the mechanisms by which SHP2 activates Src and Ras have not been defined. Two models for SHP2-mediated Src activation are postulated and will be evaluated in Specific Aim I. The involvement of Src in EGF-induced Ras and Erk activation also will be analyzed.
In Specific Aim II, the novel small interfering RNA (siRNA) technique for gene knockdown will be developed and used to analyze the role of Gab1, Gab2, and SHP2 in EGF-induced cellular responses. These include Src and Akt/PKB activation, temporal regulation of Ras-MAP kinase activation, gene expression, paxillin dephosphorylation, and cell growth and metastatic properties. Based on our preliminary observations, we postulate that Gab1 and related pleckstrin-homology (PH) domains are novel molecular targets for antagonizing ErbB signaling and PTEN mutation in human cancers. This hypothesis will be evaluated in Specific Aim III using doxycycline-inducible decoy constructs in stable cancer cell lines in vitro and in tumor xenografts. These studies will define a major ErbB and SHP2 signaling mechanism, greatly advance our understanding of the function of Gab proteins, uncover novel targets for molecular intervention of malignant signaling, and stimulate further development of new inhibitors targeting these signaling components for cancer treatment. ? ? ?

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA077467-08
Application #
6914376
Study Section
Metabolic Pathology Study Section (MEP)
Program Officer
Perry, Mary Ellen
Project Start
1999-01-01
Project End
2008-04-30
Budget Start
2005-07-01
Budget End
2006-04-30
Support Year
8
Fiscal Year
2005
Total Cost
$290,140
Indirect Cost
Name
H. Lee Moffitt Cancer Center & Research Institute
Department
Type
DUNS #
139301956
City
Tampa
State
FL
Country
United States
Zip Code
33612
Shen, Zheng; Zhang, Xiaohui; Tang, Jinfu et al. (2011) The coupling of epidermal growth factor receptor down regulation by 1alpha,25-dihydroxyvitamin D3 to the hormone-induced cell cycle arrest at the G1-S checkpoint in ovarian cancer cells. Mol Cell Endocrinol 338:58-67
Scott, Latanya M; Chen, Liwei; Daniel, Kenyon G et al. (2011) Shp2 protein tyrosine phosphatase inhibitor activity of estramustine phosphate and its triterpenoid analogs. Bioorg Med Chem Lett 21:730-3
Chen, Liwei; Pernazza, Daniele; Scott, Latanya M et al. (2010) Inhibition of cellular Shp2 activity by a methyl ester analog of SPI-112. Biochem Pharmacol 80:801-10
Ren, Yuan; Chen, Zhengming; Chen, Liwei et al. (2010) Critical role of Shp2 in tumor growth involving regulation of c-Myc. Genes Cancer 1:994-1007
Scott, Latanya M; Lawrence, Harshani R; Sebti, Saïd M et al. (2010) Targeting protein tyrosine phosphatases for anticancer drug discovery. Curr Pharm Des 16:1843-62
Meng, Songshu; Gui, Qiu; Xu, Qing et al. (2010) Association of Shp2 with phosphorylated IL-22R1 is required for interleukin-22-induced MAP kinase activation. J Mol Cell Biol 2:223-30
Lawrence, Harshani R; Pireddu, Roberta; Chen, Liwei et al. (2008) Inhibitors of Src homology-2 domain containing protein tyrosine phosphatase-2 (Shp2) based on oxindole scaffolds. J Med Chem 51:4948-56
Ren, Yuan; Chen, Zhengming; Chen, Liwei et al. (2007) Shp2E76K mutant confers cytokine-independent survival of TF-1 myeloid cells by up-regulating Bcl-XL. J Biol Chem 282:36463-73