Grantee: Henry Ford Hospital, Detriot, MI, USA
Researcher: Sandra A. Rempel, Ph.D.
Grant Title: Characterization of the SPARC-Induced Changes in Glioblastoma Adhesion, Migration, and Signaling Pathways
Program Area: Researching Brain Cancer
Grant Type: Research Award
Amount: $227,709
Year Awarded: 1998
We have identified SPARC, a gene implicated in the modulation of matrix degradation and cellmatrix interactions (biological processes necessary for fetal tissue development and vascular morphogenesis), as a gene that is overexpressed in astrocytomas. We now have considerable evidence to hypothesize that the inappropriate expression of SPARC contributes to brain tumor cell migration. The hypothesis to be tested in this proposal is that increased SPARC expression decreases glioblastoma cell adhesion and promotes tumor cell migration, in an extracellular matrix (ECM)specific manner, through a signaling mechanism that alters gene and/or protein expression. To test this hypothesis, we propose the following specific aims.
SPECIFIC AIM 1: To determine whether SPARC expression alters tumor cell adhesion in an ECM-specific manner using in vitro adhesion assays of the control U87T2 clone transfected with the tetracycline-controlled transcriptional activator and tetracycline-regulatable sense SPARC transfectants.
SPECIFIC AIM 2: To determine whether SPARC expression alters tumor cell migration in an ECM-specific manner using in vitro migration assays of the control U87T2 clone and tetracycline-regulatable sense SPARC transfectants.
SPECIFIC AIM 3: To identify the transcriptionally-regulated downstream genes modulated by SPARC expression using cDNA microarray hybridization analysis of control U87T2 clone and tetracycline-regulatable sense SPARC transfectants.
SPECIFIC AIM 4: To identify the translationallyregulated downstream proteins that are modulated by SPARC expression using 2-dimensional gel electrophoresis coupled with Edman amino-terminal sequencing, mass spectrometry and amino acid analysis of the control U87T2 clone and tetracycline-regulatable SPARC transfectants.
SPECIFIC AIM 5: To identify the post-translationally-regulated downstream proteins that are changed in phosphorylation status by SPARC expression using 2-dimensional gel electrophoresis coupled with Edman amino-terminal sequencing, mass spectrometry, and amino acid analysis of the control U87T2 clone and tetracycline-regulatable SPARC transfectants.
This proposal represents a comprehensive analysis to identify and characterize the genes involved in the ECM-specific, SPARC-induced signal transduction pathway at the transcriptional, translational, and post-translational levels. By characterizing the mechanism by which SPARC mediates cell adhesion and migration, development of anti-invasion-specific therapeutic interventions to target the most disabling phenotype of these tumors may be possible.