Defining and overcoming Bcl2L12-driven therapy resistance in GBM

High-grade Malignant glioma are characterized by extreme resistance to all extant therapeutic modalities, including late-generation targeted therapies, and a neurologically debilitating course culminating in death often within 14 months of diagnosis. With this dismal prognosis and a near 100% failure rate of glioma drug development, the critical challenges facing the glioma field are (a) to identify novel drug targets to overcome the notorious therapy (apoptosis) resistance of GBM, and (b) to functionally characterize and preclinically validate these targets in physiologically relevant cell and animal models that recapitulate phenotypic and genotypic hallmarks of the human disease, and (c) to devise therapeutic strategies to target these aberrations. In our studies aimed at addressing these currently unmet needs in the development of effective glioma therapies, we identified Bcl2L12 (for Bcl2-Like-12) as a first-in-class glioma oncogene that is over-expressed in virtually all GBM samples, yet is low or absent in low-grade disease and normal tissue. Extensive biochemical studies have established that Bcl2L12 functions as a mitogenic and anti-apoptotic protein by inhibiting effector caspase and p53 function. These studies pointed to Bcl2L12 up-regulation as a key progression event and molecular determinant for therapy refractoriness in high-grade gliomas. The objective of this proposal is to define the role of Bcl2L12 for the genesis of malignant gliomas in vivo, to molecularly understand the mechanism of action, by which Bcl2L12 promoter glioma progression, and to targeted Bcl2L12 in established gliomas using a novel RNAi-based nanotechnological platform. In Aim 1, we will characterize the role of Bcl2L12 for glioma pathogenesis and therapy resistance in genetically engineered human and murine models harboring a conditional Bcl2L12 knockout allele. We will determine the impact of Bcl2L12 ablation for glioma progression. We will assess the role of Bcl2L12 phosphorylation on glioma progression and responses toward anti-glioma therapies. In Aim 2, we will preclincially characterize a novel nanotechnological platform, i.e., RNAi-based, Bcl2L12-targeting Spherical nucleic acids (H-SNAs). SNAs contain gold nanoparticles (Au-NPs, size 13 nm) functionalized with Bcl2L12-specific siRNA oligonucleotides and a monoclonal anti-uPAR antibody to specifically deliver SNAs to glioma tumor elements. We propose a multi-leveled, proof-of-principle pre-clinical validation of SNAs in mouse and cell culture models. The results of this proposal could pave the way to successfully implementing Bcl2L12-based therapies into neuro-oncological practice.