Abstract A21: Modeling of oncogenic chromosomal translocations of aggressive fusion-positive sarcomas by CRISPR-Cas9 genomic engineering

Abstract

Abstract A prominent challenge in fusion-positive sarcoma research is that the oncogenic driver is typically a chimeric transcription factor. Although considered the disease-specific molecular drivers, these chimeric transcription factors remain challenging to target pharmacologically. An alternative approach is the elucidation of molecular pathways controlled by the oncogenic transcription factor, with the aim of identifying druggable targets. However, many fusion-driven sarcomas have a paucity of suitable genetic models, with some lacking any patient-derived cell lines. In the situations where patient-derived cell lines are available, most have been passaged for decades, potentially adding further complexity and bias. Therefore, development of faithful model systems of oncogenic chromosomal translocations is of principal importance for these aggressive translocation-driven pediatric sarcomas. Here, we describe a novel approach that combines CRISPR-Cas9 genomic editing technology, with homology-directed repair (HDR) to engineer, capture, and modulate the expression of chromosomal translocation products in a human cell line. We have applied this approach to the genetic modeling of t(11;22)(q24;q12) and t(11;22)(p13;q12), translocation products of the EWSR1 gene and its 3 fusion partners FLI1 and WT1, present in Ewing's sarcoma and desmoplastic small round cell tumor, respectively. Our approach establishes an innovative platform for constructing isogenic and conditionally inducible biologically relevant models for a variety of sarcomas driven by chromosomal translocations. Citation Format: Lee Spraggon, Luciano Martelotto, Julija Hmeljak, Tyler Hitchman, Jiang Wang, Lu Wang, Emily Slotkin, Pang-Dian Fan, Jorge Reis-Filho, Marc Ladanyi. Modeling of oncogenic chromosomal translocations of aggressive fusion-positive sarcomas by CRISPR-Cas9 genomic engineering [abstract]. In: Proceedings of the AACR Conference on Advances in Sarcomas: From Basic Science to Clinical Translation; May 16-19, 2017; Philadelphia, PA. Philadelphia (PA): AACR; Clin Cancer Res 2018;24(2_Suppl):Abstract nr A21.