Manguso et al. used an in vivo loss-of-function CRISPR-Cas9 genetic screen to confirm known immune evasion targets (PD-L1, CD47, IFN-γ signaling) and identify new genes in multiple biological pathways that were critical to immunotherapy, including the kinase PTPN2 which impacts IFN-γ sensing and antigen presentation.
Immunotherapy with PD-1 checkpoint blockade is effective in only a minority of patients with cancer, suggesting that additional treatment strategies are needed. Here we use a pooled in vivo genetic screening approach using CRISPR-Cas9 genome editing in transplantable tumours in mice treated with immunotherapy to discover previously undescribed immunotherapy targets. We tested 2,368 genes expressed by melanoma cells to identify those that synergize with or cause resistance to checkpoint blockade. We recovered the known immune evasion molecules PD-L1 and CD47, and confirmed that defects in interferon-gamma signalling caused resistance to immunotherapy. Tumours were sensitized to immunotherapy by deletion of genes involved in several diverse pathways, including NF-kappaB signalling, antigen presentation and the unfolded protein response. In addition, deletion of the protein tyrosine phosphatase PTPN2 in tumour cells increased the efficacy of immunotherapy by enhancing interferon-gamma-mediated effects on antigen presentation and growth suppression. In vivo genetic screens in tumour models can identify new immunotherapy targets in unanticipated pathways.
Author Info: (1) Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA. Division of Medical Sciences, Harvard Medical School, Boston, Massachusetts 02
Author Info: (1) Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA. Division of Medical Sciences, Harvard Medical School, Boston, Massachusetts 02115, USA. Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA. (2) Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA. Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA. (3) Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA. Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA. (4) Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA. Division of Medical Sciences, Harvard Medical School, Boston, Massachusetts 02115, USA. (5) Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA. Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA. (6) Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA. Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA. Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA. (7) Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA. Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA. Division of Pediatric Hematology and Oncology, Children's Hospital, Boston, Massachusetts 02115, USA. (8) Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA. Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA. (9) Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA. Division of Medical Sciences, Harvard Medical School, Boston, Massachusetts 02115, USA. (10) Department of Microbiology and Immunology, Harvard Medical School, Boston, Massachusetts 02115, USA. (11) Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA. (12) Cutaneous Biology Research Center, Massachusetts General Hospital and Harvard Medical School, Building 149, 13th Street, Charlestown, Massachusetts 02129, USA. (13) Cutaneous Biology Research Center, Massachusetts General Hospital and Harvard Medical School, Building 149, 13th Street, Charlestown, Massachusetts 02129, USA. (14) Division of Medical Sciences, Harvard Medical School, Boston, Massachusetts 02115, USA. Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA. (15) Division of Medical Sciences, Harvard Medical School, Boston, Massachusetts 02115, USA. Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA. (16) Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA. (17) Division of Pediatric Hematology and Oncology, Children's Hospital, Boston, Massachusetts 02115, USA. Evergrande Center for Immunologic Diseases, Harvard Medical School, Boston, Massachusetts 02115, USA. (18) Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA. (19) Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA. Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA. Division of Pediatric Hematology and Oncology, Children's Hospital, Boston, Massachusetts 02115, USA.
