CHARACTERIZATION OF THE NOTCH MOLECULAR NETWORK IN BRAIN TUMORS
Notch defines a fundamental cell signaling mechanism controlling biological development. Consistent with its key roles in CNS development as well as its broad contribution to oncogenesis across tissues, Notch has emerged recently as an essential contributor to both glioblastoma and medulloblastoma. Notch-directed therapies based on the use of inhibitors of the gamma-secretase protease complex, which is essential for proteolytic cleavage of Notch and subsequent signaling, have been tested in several clinical trials for brain tumor patients. However, their use leads to substantial side effects associated with the ubiquitous knock down a pathway as pleiotropic as Notch. Modulation of Notch signals is context-dependent and involves a complex network of proteins. We hypothesize that the use of a context-specific, Notch-directed therapeutic approach should provide the desired healing benefit with minimum side-effects to treat Notch-related brain tumors. Our objective is to discover which brain-specific Notch pathway proteins and associated protein interactions are essential in brain tumor cells to maintain tumorigenic potential. We propose to combine proteomic and genetic tools to discover context-specific modulators of aberrant Notch signal in brain tumors.
The Rual Lab is in the process of generating a comprehensive map of the Notch molecular network by taking advantage of a unique protein-protein interaction mapping platform that combines the use of two complementary technologies for high-throughput protein interaction mapping, i.e., the yeast two-hybrid system (Y2H; Rual et al., Nature, 2005) and co-affinity purification coupled to mass spectrometry analysis (coAP-MS; Guruharsha, Rual et al, Cell, 2011). This “interactome” approach will define novel proteins and protein-protein interactions involved in modulating the activity of Notch signal in brain cells. The Rual Lab has already identified interesting hits in this context.
The Lee Lab has extensive expertise in the use of genetic tools in the Drosophila melanogster model organism to study larval brain development upon modulation of Notch signals (Weng et al., Developmental Neurobiology, 2012). Dr. Lee proposes to use his fly genetic platform to systematically investigate in vivo the biological relevance of the candidate genes identified in the Rual Lab. In collaboration with the Rual Lab, Dr. Lee has already contributed interesting genetic observations linking the Drosophila ortholog a human Polycomb protein (identified previously by Dr. Rual as a Notch pathway biophysical interactor) to Notch signal modulation in the larval fly brain, thus corroborating the hypothesis that the potential tumor suppressor role of this Polycomb gene in brain tumor is mediated through Notch signal modulation.
Dr. Camelo is a clinical neuropathologist with extensive expertise in the histopathology-based diagnosis of brain tumor specimens, in both human and mouse. As a Co-Investigator on this project, Dr. Camelo will investigate in primary brain tumor tissues the genetic and molecular features, e.g., genomic alteration or aberrant protein overexpression, associated with candidate genes identified by Dr. Rual. Dr. Camelo will also provide expert support for the characterization of candidate genes in mouse model of brain tumorigenesis.
$600,000 grant from the Children's Brain Tumor Foundation
$30,000 grant from the Association for Research Childhood Cancer (AROCC)
Published in Neoplasia Journal, 2017
$120,000 grant from the CONCERN Foundations