The poor prognosis of glioma patients is largely due to the highly invasive nature of these tumors. We have demonstrated that SPARC is highly expressed in gliomas and that it functionally contributes to invasion in vitro. Importantly, our Preliminary Data show that SPARC promotes invasion in vivo. The focus of this proposal is to determine the mechanisms by which SPARC expression promotes brain tumor invasion.
In Specific Aim 1. we will determine the extent to which SPARC functionally promotes glioma invasion by: la) Characterizing the effects of SPARC expression on tumor cell invasion during the course of tumor development in viva. We will use doxycycline (dox)-regulatable SPARC-transfected U87 glioma clones in a nude rat xenograft model to evaluate the effects of increased SPARC expression on the extent of tumor cell invasion, angiogenesis. necrosis, proliferation, and overall tumor growth during the course of tumor progression. ib) Determining whether tumor-expressed SPARC is sufficient for tumor invasion in vitro. We will assess tumor invasion into normal and Sparc knockout fetal aggregates in the in vitro spheroid confrontation assay. ic) Determining the extent to which loss ol SPARC expression inhibits brain tumor invasion in viva. We will use a SPARC-targeting construct and homologous recombination to create a SPARC knockout in the C6 glioma cell line that will be assessed as in Specific Aim 1a.
In Specific Aim 2, we will determine the biological mechanism(s) by which SPARC promotes tumor invasion. We will use our U87T2 parental clone and SPARC-transfected clones (+/- dox), serum-free C6 (+/- SPARC), and Sparc (-/-) and (+7+/-) fetal astrocytes to: 2a) Analyze how SPARC promotes the critical intermediate stage of adhesion. We will use the three cell models in timed studies using different concentrations of brain ECM molecules. We will assess the effect of SPARC on 1) attachment, 2) spreading, 3) or formation of focal adhesions and stress fibers via its affects on integrins and focal adhesion-associated proteins. 2b) Determine whether SPARC promotes migration in a concentration-dependent, ECM-specific manner. We will use the three cell models to perform migration assays using different concentrations of ECMs. Migration will be assessed using the cell sedimentation assay, the wounding assay, and Boyden chambers. 2c) Determine whether SPARC promotes invasion by reducing the proliferation rate of tumors. We will assess SPARC's effect on proliferation by performing 1) growth curves for the three cell models on specific brain ECM molecules, as well as perform 2) anchorage-independent growth assays, and 3) FACS analyses under the same conditions. Direct effects of SPARC on cell cycle progression will be monitored for changes in cyclin A, tk, and p107 expression and/or phosphorylation.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA086997-03
Application #
6633766
Study Section
Pathology B Study Section (PTHB)
Program Officer
Macleod, Carol L
Project Start
2001-04-16
Project End
2004-03-31
Budget Start
2003-04-01
Budget End
2004-03-31
Support Year
3
Fiscal Year
2003
Total Cost
$238,166
Indirect Cost
Name
Henry Ford Health System
Department
Neurosurgery
Type
Schools of Medicine
DUNS #
073134603
City
Detroit
State
MI
Country
United States
Zip Code
48202
Thomas, Stacey L; Schultz, Chad R; Mouzon, Ezekiell et al. (2015) Loss of Sparc in p53-null Astrocytes Promotes Macrophage Activation and Phagocytosis Resulting in Decreased Tumor Size and Tumor Cell Survival. Brain Pathol 25:391-400
Alam, Ridwan; Schultz, Chad R; Golembieski, William A et al. (2013) PTEN suppresses SPARC-induced pMAPKAPK2 and inhibits SPARC-induced Ser78 HSP27 phosphorylation in glioma. Neuro Oncol 15:451-61
Schultz, Chad R; Golembieski, William A; King, Daniel A et al. (2012) Inhibition of HSP27 alone or in combination with pAKT inhibition as therapeutic approaches to target SPARC-induced glioma cell survival. Mol Cancer 11:20
McClung, Heather M; Golembieski, William A; Schultz, Chad R et al. (2012) Deletion of the SPARC acidic domain or EGF-like module reduces SPARC-induced migration and signaling through p38 MAPK/HSP27 in glioma. Carcinogenesis 33:275-84
Weaver, Matt; Workman, Gail; Schultz, Chad R et al. (2011) Proteolysis of the matricellular protein hevin by matrix metalloproteinase-3 produces a SPARC-like fragment (SLF) associated with neovasculature in a murine glioma model. J Cell Biochem 112:3093-102
Thomas, Stacey L; Alam, Ridwan; Lemke, Nancy et al. (2010) PTEN augments SPARC suppression of proliferation and inhibits SPARC-induced migration by suppressing SHC-RAF-ERK and AKT signaling. Neuro Oncol 12:941-55
Martino, Mikaƫl M; Mochizuki, Mayumi; Rothenfluh, Dominique A et al. (2009) Controlling integrin specificity and stem cell differentiation in 2D and 3D environments through regulation of fibronectin domain stability. Biomaterials 30:1089-97
Golembieski, William A; Thomas, Stacey L; Schultz, Chad R et al. (2008) HSP27 mediates SPARC-induced changes in glioma morphology, migration, and invasion. Glia 56:1061-75
Yunker, Christopher K; Golembieski, William; Lemke, Nancy et al. (2008) SPARC-induced increase in glioma matrix and decrease in vascularity are associated with reduced VEGF expression and secretion. Int J Cancer 122:2735-43
Lee, Hae Kyung; Xiang, Cunli; Cazacu, Simona et al. (2008) GRP78 is overexpressed in glioblastomas and regulates glioma cell growth and apoptosis. Neuro Oncol 10:236-43

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