Loss-of-function genetic screens in cancer cell lines permit the systematic interrogation of genes and pathways involved in cell proliferation and viability. The CRISPR-Cas9 system enables effective genome editing for perturbation of gene function. To identify genes that are essential for cancer cell proliferation and survival, we have optimized an approach for efficient genome-scale CRISPR-Cas9 pooled screening and performed negative-selection knock-out screens in 43 human cancer cell lines with diverse genetic and phenotypic features, including 8 pancreatic cancer cell lines. We report that CRISPR-Cas9 efficacy varies depending on the cell context and propose methods to effectively identify differential cancer dependencies across cell lines. Additionally, we identify a strong correlation between genomic copy number and perceived gene dependency, and further elucidate a gene-independent effect of CRISPR-Cas9 cutting. Using these screening data, we performed a detailed interrogation of gene and pathway dependencies in pancreatic cancer. Through integrative analysis of CRISPR-Cas9 screening results with RNA-interference and small molecule screening data, as well as DNA and RNA sequencing, we identified a high-confidence set of recurrently essential genes in pancreatic cancer, including several with associated biomarkers. Moreover, through pathway analyses of CRISPR-Cas9 screening data, we have identified a number of essential biologic processes including key metabolic and cell signaling pathways that may represent potential therapeutic avenues. In particular, we characterize the sterol regulatory element binding protein (SREBP) signaling pathway as a recurrent vulnerability in pancreatic cancer and credential this pathway as a potential therapeutic target.

This abstract is also being presented as Poster A13

Citation Format: Andrew J. Aguirre, Wei Shao, Han Xu, Barbara Weir, Francisca Vazquez, Robin Meyers, Cheng-Zhong Zhang, Mihir Doshi, Glenn S. Cowley, Theodore Ewachiw, Zeshaan Rasheed, Todd R. Golub, Kimberly Stegmaier, Charles W. Roberts, Levi A. Garraway, Matthew Meyerson, Aviad Tsherniak, David E. Root, Peter J. Espenshade, William C. Hahn.{Authors}. Genome-scale CRISPR-Cas9 screening to identify essential genes and pathways in pancreatic cancer. [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Advances in Science and Clinical Care; 2016 May 12-15; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2016;76(24 Suppl):Abstract nr PR05.