Our growth regulation research has been concerned with oncogenes and tumor suppressor genes as positive and negative regulators of normal and neoplastic growth. We have studied the Ras-specific guanine nucleotide exchange factors (Ras-GNEFs), which play a key role in signal transduction, and in activation of the ras proto-oncogene. Most recently, we have begun to investigate E-cadherin, a key cell surface adhesion protein that is a tumor suppressor that is frequently silenced in many epithelial cancers and melanoma. We have found that E-cadherin specifically inhibits the activation of a variety of receptor tyrosine kinases (RTKs) by their physiologic ligands. The inhibition probably results from the formation of a complex between E-cadherin and the RTKs, which restricts the ability of the ligands to bind their cognate RTK with high affinity. This inhibitory activity of E-cadherin is abrogated when it is silenced in tumors, permitting more robust responses to RTKs by their ligands, a widespread phenomemon implicated in the pathogenesis of many tumors. Future studies will examine other mechanisms by which E-cadherin regulates cell growth and the possibility of using E-cadherin as a potential cancer treatment target.

Agency
National Institute of Health (NIH)
Institute
Division of Basic Sciences - NCI (NCI)
Type
Intramural Research (Z01)
Project #
1Z01BC008905-23
Application #
7048786
Study Section
(LMB)
Project Start
Project End
Budget Start
Budget End
Support Year
23
Fiscal Year
2004
Total Cost
Indirect Cost
Name
Basic Sciences
Department
Type
DUNS #
City
State
Country
United States
Zip Code
Park, Yeong-Gwan; Zhao, Xiaohong; Lesueur, Fabienne et al. (2005) Sipa1 is a candidate for underlying the metastasis efficiency modifier locus Mtes1. Nat Genet 37:1055-62
Qian, Xiaolan; Karpova, Tatiana; Sheppard, Allan M et al. (2004) E-cadherin-mediated adhesion inhibits ligand-dependent activation of diverse receptor tyrosine kinases. EMBO J 23:1739-48
Zhang, Shuling; Qian, Xiaolan; Redman, Chanelle et al. (2003) p16 INK4a gene promoter variation and differential binding of a repressor, the ras-responsive zinc-finger transcription factor, RREB. Oncogene 22:2285-95
Li, Shaowei; Braverman, Richard; Li, Hongzhen et al. (2003) Regulation of cell morphology and adhesion by the tuberous sclerosis complex (TSC1/2) gene products in human kidney epithelial cells through increased E-cadherin/beta-catenin activity. Mol Carcinog 37:98-109
Bliskovsky, Valery; Ramsay, Edward S; Scott, John et al. (2003) Frap, FKBP12 rapamycin-associated protein, is a candidate gene for the plasmacytoma resistance locus Pctr2 and can act as a tumor suppressor gene. Proc Natl Acad Sci U S A 100:14982-7