Transformation of epithelial cells is marked by a loss of the classic polarized epithelial phenotype and the acquisition of a migratory, invasive phenotype. Associated with this switch in cellular phenotype are changes in cellular interactions with the extracellular matrix. In particular, the alpha2beta1 integrin, a receptor for collagens and laminin, is an important regulator of breast cell phenotype. Members of the Ras family of small GTPases are also important regulators of cell phenotype and transformation. Activation of a specific family member, R-Ras, disrupts epithefial polarization of human breast cells, and instead promotes cell migration and invasion. Activated R-Ras specifically promotes breast cell adhesion, migration, and focal adhesion formation on collagen through the alpha5beta1 integrin, but not on fibronectin through the alpha2beta1 integrin. Activated R-Ras enhances the phosphorylation of FAK (focal adhesion kinase), p130Cas, and PI3-kinase downstream of the alpha2beta1 integrin, in a manner that differs from, but requires, the alpha2beta1 integrin. The long-term goal of this proposal is to understand signaling pathways related to R-Ras and integrins, and how they affect the choice of a cell to polarize or migrate. As our working hypothesis, we propose that R-Ras plays a normal physiologically relevant role in outside-in and inside-out signaling events related to the alpha2beta1 integrin in a controlled spatial and temporal manner, and that dysregulation of R-Ras disrupts epithelial polarization and alters cell migration. This hypothesis will be tested in the following Specific Aims: 1) Define R-Ras and alpha2beta1 integrin regulation of the epithelial vs. migratory phenotype of cells; 2) Determine the molecular basis for R-Ras participation in alpha2beta1 integrin signaling pathways; 3) Investigate molecular mechanisms by which R-Ras promotes tumor formation. This work should enhance our understanding of the molecular mechanisms regulating epithelial phenotype, migration, and tumorigenesis.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA076537-10
Application #
7022193
Study Section
Pathology B Study Section (PTHB)
Program Officer
Jhappan, Chamelli
Project Start
1997-12-11
Project End
2008-03-31
Budget Start
2006-04-01
Budget End
2007-03-31
Support Year
10
Fiscal Year
2006
Total Cost
$295,938
Indirect Cost
Name
University of Wisconsin Madison
Department
Pathology
Type
Schools of Medicine
DUNS #
161202122
City
Madison
State
WI
Country
United States
Zip Code
53715
Conklin, Matthew W; Ada-Nguema, Aude; Parsons, Maddy et al. (2010) R-Ras regulates beta1-integrin trafficking via effects on membrane ruffling and endocytosis. BMC Cell Biol 11:14
Gehler, Scott; Baldassarre, Massimiliano; Lad, Yatish et al. (2009) Filamin A-beta1 integrin complex tunes epithelial cell response to matrix tension. Mol Biol Cell 20:3224-38
Provenzano, Paolo P; Eliceiri, Kevin W; Keely, Patricia J (2009) Shining new light on 3D cell motility and the metastatic process. Trends Cell Biol 19:638-48
Conklin, Matthew W; Provenzano, Paolo P; Eliceiri, Kevin W et al. (2009) Fluorescence lifetime imaging of endogenous fluorophores in histopathology sections reveals differences between normal and tumor epithelium in carcinoma in situ of the breast. Cell Biochem Biophys 53:145-57
Provenzano, P P; Inman, D R; Eliceiri, K W et al. (2009) Matrix density-induced mechanoregulation of breast cell phenotype, signaling and gene expression through a FAK-ERK linkage. Oncogene 28:4326-43
Provenzano, Paolo P; Keely, Patricia J (2009) The role of focal adhesion kinase in tumor initiation and progression. Cell Adh Migr 3:347-50
Provenzano, Paolo P; Eliceiri, Kevin W; Keely, Patricia J (2009) Multiphoton microscopy and fluorescence lifetime imaging microscopy (FLIM) to monitor metastasis and the tumor microenvironment. Clin Exp Metastasis 26:357-70
Rueden, Curtis T; Conklin, Matthew W; Provenzano, Paolo P et al. (2009) Nonlinear optical microscopy and computational analysis of intrinsic signatures in breast cancer. Conf Proc IEEE Eng Med Biol Soc 2009:4077-80
Provenzano, Paolo P; Inman, David R; Eliceiri, Kevin W et al. (2008) Contact guidance mediated three-dimensional cell migration is regulated by Rho/ROCK-dependent matrix reorganization. Biophys J 95:5374-84
Provenzano, Paolo P; Rueden, Curtis T; Trier, Steve M et al. (2008) Nonlinear optical imaging and spectral-lifetime computational analysis of endogenous and exogenous fluorophores in breast cancer. J Biomed Opt 13:031220

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