Development Of A 3-Dimensional Synthetic Lethality Screening Approach Targeting Krasmut Cells

Proceedings: AACR 104th Annual Meeting 2013; Apr 6-10, 2013; Washington, DC Three-dimensional (3D) in vitro models have been used in cancer research to overcome limitations of 2D systems. 3D in vitro models recapitulate many aspects of actual tumors including hypoxia, metabolism, proliferation gradients, cell-cell and cell-matrix interactions and closer clinical gene expression profiles than those seen in 2D. Importantly, some cancer drugs showed high potency only in the 3D environment compared to 2D (Muranen, et al, Cancer Cell, 2012). In order to identify improved cancer drugs, we established a simple and versatile 3D spheroid culture approach for high-throughput screening for compounds that selectively kill cancer cells with certain genetic backgrounds. We used HCT116 (parental: HCT116/KRas-mut) and an isogenic counterpart that expresses a genetically modified KRas gene (HCT116/KRas-wt) for 3D cell culture. To validate this approach, HCT116/KRas-mut and HCT116/KRas-wt were cultured separately, treated with 15 selected tool compounds and viability was measured using a caspase 3/7 assay. We found 4 compounds that induced caspase 3/7 activity only in 3D culture of HCT116/KRas-mut and not in 2D. Furthermore, 5 compounds were predominantly sensitive to HCT116/KRas-wt cells in 3D culture, but not in HCT116/KRas-mut 3D culture. These results indicate that the more physiological relevant 3D synthetic lethal screen is an attractive approach to cancer drug discovery and may identify compounds missed in conventional 2D culture model screens. Citation Format: Toshiya Tsuji, Lisa M. Sapinoso, I-Lin Lin, Shuichan Xu, John F. Boylan. Development of a 3-dimensional synthetic lethality screening approach targeting KRas-mut cells. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3839. doi:10.1158/1538-7445.AM2013-3839