In vivo CRISPR screens reveals SerpinB9 and Adam2 as regulators of immune therapy in lung cancer

We established a direct in vivo CRISPR/Cas9 gene editing methodology that allowed us to assess the immune-modulatory capabilities of 573 putative cancer genes associated with altered activity in mouse model of lung cancer. Using mouse models of of KrasG12D- and BrafV600E-driven lung cancer, we identified Serpinb9 as our top suppressive and Adam2 as our top enhancing gene. RNA seq analysis from tumors overexpressing Adam2 revealed that Adam2's oncogenic function is dependent on modulating the tumor immune microenvironment by restraining productive type I and type II interferon responses as well as cytokine signaling, reducing presentation of tumor associated antigen, and modulating surface expression of several immunoregulatory receptors within Kras-driven lung tumors. Adam2 overexpression also led to reduction in expression of immune checkpoint inhibitors such as PD-L1, Lag3, Tigit, and Tim3.This less exhausted tumor microenvironment further induced enhanced cytotoxic efficacy against Adam2 overexpressing lung tumors, in vitro and in vivo. Together, our study highlights the power of integrating cancer genomic with in vivo CRISPR/Cas9 screens to uncover how cancer-associated genetic alterations control responses to immunotherapies. Overall design: Profiling of Adam2, LLC-CTLR-OVA or LLC-Adam2-OVA cells transplanted in immunocompetent C57BL/6 mice followed by adoptive transfer of antigen primed OT-I cells at day 14 (=two days after tumor onset).