Abstract LB-078: RNAi and CRISPR/Cas9-based in vivo models for drug discovery

Abstract

Abstract Genetically engineered mouse models (GEMMs) are a powerful platform that enable the study of disease initiation and maintenance, the microenvironment and the responsiveness of disease to known or novel therapeutics; however, the long lead times and high costs required to develop, intercross and maintain models with various disease predisposing gene combinations have limited their practical utility in the drug discovery process. RNA interference (RNAi), a mechanism that controls gene expression, is a rapid and cost-effective alternative to gene deletion that can be exploited experimentally to reversibly silence nearly any gene target not only in vitro but also in live mice. By using our “Sensor assay” to biologically identify short hairpin RNAs (shRNAs) that induce potent gene suppression in combination with a new miRNA scaffold, miR-E, we have engineered a reliable system for in vivo gene suppression. Furthermore, by utilizing tetracycline-regulated miR-E based shRNAs with high efficiency ES cell targeting, we have developed a fast, scalable pipeline for the production of shRNA transgenic mice with reversible gene silencing. Recently, with the advent of new genome editing techniques, such as CRISPR/Cas9 technology, we are able to introduce additional sensitizing lesions to induce disease pathogenesis. In synergy with RNAi technology, complex multi-allelic ESC based GEMMs can be generated without extensive intercrossing. Using this combination of CRISPR/Cas9 and RNAi technologies, we are able to not only model disease pathogenesis, but also mimic drug therapy in mice, giving us unprecedented capabilities to perform preclinical studies in vivo. Here, we demonstrate that RNAi in combination with CRISPR/Cas9 genome editing enables us to recapitulate the phenotypes of knockout mice and further explore potential therapeutic approaches within the same model. Using our robust system, we have created a a cost-effective and scalable platform for the production of complex GEMMs with RNAi silencing of nearly any gene - mice with enormous predictive power that will shape our development of better tolerated therapies. Citation Format: Prem K. Premsrirut, Christof Fellmann. RNAi and CRISPR/Cas9-based in vivo models for drug discovery. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr LB-078. doi:10.1158/1538-7445.AM2015-LB-078