Abstract B001: Chromatin engineering using a dCas9-based inducible dimerization system

Abstract

Abstract Epigenetic cancers lead to tumor progression via oncogene activation, tumor suppressor silencing, cell fate transitions, and genomic instability. Approximately 50% of tumors have alterations in Chromatin regulators. One group of Chromatin regulators, the mSWI/SNF complexes, are mutated in 20% of tumors making them one of the most mutated chromatin regulator complexes in cancer. In the past, the mechanism of action of ATP-dependent chromatin regulators, such as mSWI/SNF was largely explored using in vitro methods based on measurements of nucleosome mobility. These studies were limited by the fact that these assays were not sensitive to tissue-specific chromatin modifications, topology, long-range interactions, and complex patterns of histone modifications as well as patterns of DNA methylation and human disease mutational backgrounds. To circumvent these problems, we developed the FIRE-Cas9 system that allows one to recruit a specific chromatin regulator and follow the consequences with minute-by-minute kinetics on physiologic chromatin. I can examine any locus of biological or medical importance in virtually any cell type using this technique. We can recruit endogenous proteins or protein complexes such as different mSWI/SNF complexes, histone methyltransferases, or histone demethylases and assay changes in chromatin state and transcriptional state. Because chromatin regulator complexes have alterations in many human cancers, it is imperative to understand the mechanism of action of these complexes with unparalleled precision as a basis for therapeutic development. The FIRE-Cas9 system allows one to do this for the first time. Citation Format: Mary Bergwell, JinYoung Park, Laura Pistoni, Jacob G. Kirkland. Chromatin engineering using a dCas9-based inducible dimerization system. [abstract]. In: Proceedings of the AACR Special Conference: Cancer Epigenomics; 2022 Oct 6-8; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2022;82(23 Suppl_2):Abstract nr B001.