Invadopodia direct cell migration into and through surrounding extraceilular matches and tissues and this is accomplished by their ability to extend outward from the cell and adhere to and degrade the matrix. A novel role for cortactin is proposed in which this actin-binding, c-Src substrate participates in targeted vesicle delivery, docking and retrieval at invadopodia and that c-Src is required for the formation of functional invadopodial complexes containing cortactin. Further, it is proposed that the spleen tyrosine kinase, Syk, that we have shown to be a tumor suppressor, alters cellular motility and invasion via its effect upon Src activity. The interaction of loss of Syk with increased expression and activation of Src and cortactin may promote breast cancer progression by collectively affecting major signal transduction pathways. We propose four specific aims.
Aim1, Determine the requirement for Src/cortactin for targeted membrane transport to and from invadopodia.
Aim2, Determine regulation of MT1-MMP transport to and from invadopodia regulated by Src/cortactin.
Aim3, Determine regulation of invadopodia by Syk via negative regulation of Src.
Aim4, Determine relevance of Src, cortactin, and Syk interaction for tumor cell invasion in vivo, and their potential for therapeutic targeting, risk assessment or diagnosis. Assays for membrane and molecular :lynamics at invadopodia include confocal imaging of live cells expressing green or red fluorescent chimeras. Sites of matrix degradation will be co-localized with invadopodia-associated molecules. Immuno-electron microscopy will be used to determine the ultrastructure of cortactin-associated vesicles and membranes at invadopodia. Mutants, inhibitors, or RNAi knockdown will be used to assess the molecular requirements for Src, cortactin and Syk. Finally, in situ hybridization and immunohistochemistry will be used to determine the levels of Src, EMSI/cortactin, and Syk in human breast tissues. Our long term goal is to develop strategies to interfere with Src-driven metastasis and to study risk assessment strategies for patients.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA112673-13
Application #
7437427
Study Section
Tumor Progression and Metastasis Study Section (TPM)
Program Officer
Woodhouse, Elizabeth
Project Start
1994-09-30
Project End
2010-06-30
Budget Start
2008-07-01
Budget End
2009-06-30
Support Year
13
Fiscal Year
2008
Total Cost
$250,168
Indirect Cost
Name
Georgetown University
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
049515844
City
Washington
State
DC
Country
United States
Zip Code
20057
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Polackwich, Robert J; Koch, Daniel; Arevalo, Richard et al. (2013) A novel 3D fibril force assay implicates src in tumor cell force generation in collagen networks. PLoS One 8:e58138
Johnson, Michael D; Mueller, Susette C (2013) Three dimensional multiphoton imaging of fresh and whole mount developing mouse mammary glands. BMC Cancer 13:373
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Sung, You Me; Xu, Xuehua; Sun, Junfeng et al. (2009) Tumor suppressor function of Syk in human MCF10A in vitro and normal mouse mammary epithelium in vivo. PLoS One 4:e7445
Artym, Vira V; Yamada, Kenneth M; Mueller, Susette C (2009) ECM degradation assays for analyzing local cell invasion. Methods Mol Biol 522:211-9