StealTHY: enabling CRISPR-Cas9 screens in immunocompetent hosts to expose concealed metastatic regulators [single-end]

CRISPR screens have become standard gene discovery platforms in various contexts, including cancer. Yet, commonly available CRISPR-Cas9 tools are increasingly recognized as unfit for in vivo investigations in immunocompetent contexts, due to the broad immunogenicity of bacterial nucleases and reporters. Here, we show how CRISPR screens with tumor grafts are systematically jeopardized by immunoediting of Cas9-expressing cells in immunocompetent hosts, resulting in iatrogenic clonal dropouts and ultimately compromising target identification. Overall design: To learn more about how T-cells are recruited in Cas9-expressing tumors, we carried out RNA-sequencing of tumors at the earliest time point of immune rejection, when Cas9-expressing cells are still predominant, namely between seven and 10 days post-transplantation