Abstract 3426: Combining cell barcoding and CRISPR sgRNA libraries with targeted gene expression for single-cell genetic analysis of tumor metastasis

Pooled lentiviral libraries of CRISPR sgRNAs to mediate genome-wide gene knockout have become an invaluable tool for uncovering the functional genetic drivers required for a biological response. Another type of pooled lentiviral library designed with unique DNA sequence tags have also been used to label large populations of cells with unique cell-specific barcodes which allows monitoring changes in sub-populations of cells with distinct phenotypes over time. We have combined cell barcodes with CRISPR sgRNA to construct libraries that enable the identification of multiple occurrences of a common phenotypic response from independent transductions of the same sgRNA effector. Specifically, we demonstrate how this sort of library can be used to identify genes whose activation promotes metastasis of tumors derived from MDA-MB-231 cells engrafted into mice after transduction with a barcoded CRISPR-activation (CRISPRa) sgRNA library. By incorporating multiple barcodes with each sgRNA effector, it is possible to see that, not only are cells in metastatic tumors more likely to have a particular sgRNA targeted to a certain gene, but also that independent transductions of that sgRNA sequence lead to multiple independent metastatic events. With multiple independent clones producing the same phenotype, it is possible to confidently isolate the sgRNA, and by implication, the increased activation of its gene target, as the primary cause of the metastatic phenotype. Citation Format: Alex Chenchik, Paul Diehl, Mikhail Makhanov. Combining cell barcoding and CRISPR sgRNA libraries with targeted gene expression for single-cell genetic analysis of tumor metastasis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3426.