Forward genetic screens using CRISPR (clustered regularly interspaced short palindromic repeats)–associated nucleases like Cas9 are a powerful tool to pinpoint genes involved in disease. Initial screens capitalized on genome-scale libraries to perturb nearly all protein-coding genes in the human genome to examine therapeutic resistance and gene essentiality in cancer cell lines.
We have further developed the CRISPR screening toolbox in several new directions, including in vivo screens to understand drivers of lung metastasis, saturation mutagenesis of noncoding regions to identify functional elements that drive chemotherapeutic resistance in melanoma, and screens that dissect complex interactions between tumor cells and primary immune cells in cancer immunotherapy. Recently, we developed the first RNA-targeting CRISPR screens in melanoma and combined CRISPR perturbations of chromatin modifiers with single-cell measurements of chromatin accessibility. Taken together, these new frontiers expand the potential of CRISPR screens for fundamental genomic discovery, gene regulation, and therapeutic development to overcome drug resistance.