TMOD-17. A SWINE MODEL OF GLIOBLASTOMA INDUCED BY SOMATIC GENE MODIFICATION

Abstract

Abstract Glioblastoma (GBM) is the most common and malignant primary brain tumor. New, effective treatments for GBM are needed since the standard of care universally fails to cure patients. A major hurdle for GBM therapeutic development is the lack of relevant large animal models with high translational value for preclinical studies. To overcome this, we are developing a model of GBM in outbred, immune-proficient swine which have comparable brain size and anatomy to humans. GBM tumors will be driven by somatic alterations to major signaling pathways frequently altered in human GBM and will express a secreted reporter for tumor growth detectable in the peripheral blood. These alterations and reporter expression cassettes will be induced by delivering transposons and CRISPR/Cas9 gene-editing tools to the subventricular brain cells of live swine by stereotactic injections. We have developed and deployed these gene-editing tools, demonstrating their efficacy in swine cells. We have identified stereotactic coordinates to reproducibly target the lateral ventricles of neonatal swine brains and have demonstrated successful plasmid delivery to cells at these coordinates. Stable, persistent transposon integration and clonal expansion of modified cells has been confirmed by sequencing transposon-genomic DNA junctions in brain tissue six-months post-injection. To induce GBM-like tumors, we have introduced gene delivery and gene editing reagents to alter six major human GBM-associated signaling pathways in a cohort of swine. Resulting tumors will be examined molecularly to detect the pathway-associated transposons and CRISPR/Cas9-induced mutations in tumor tissue and determine the resemblance to human GBM. This somatic cell gene-modification platform will be adaptable, allowing on-demand inclusion of preclinical study-relevant alterations in GBM tumors, and will allow the rapid development tumors histologically and genetically similar to human GBM, which will be valuable for use in pre-clinical therapeutic studies, imaging studies using human clinical grade equipment, and surgical technique development.