Using genetically engineered conditional mouse models and lentiviral-mediated somatic gene inactivation, Adler and Xu et al. developed models that allowed them to quantify immunoediting by evaluating fixed neoantigen expression against genotypic tumor backgrounds defined by common driver mutations and different tumor suppressor genes. While genetic features promoting tumor proliferation generally correlated with increased sensitivity to immunosurveillance, different genotypes differentially affected immune cell recruitment, selection of tumor cells with neoantigen silencing, tumor growth, and mechanisms of immune evasion.
Contributed by Lauren Hitchings
ABSTRACT: The impact of cancer driving mutations on immunosurveillance throughout tumor development remains poorly understood. To better understand the contribution of tumor genotype to immunosurveillance, we generated and validated lentiviral-based vectors that create increasingly immunogenic neoantigens. This vector system is compatible with autochthonous Cre-regulated cancer models, CRISPR/Cas9-mediated somatic genome editing, and tumor barcoding. Here, we show that in the context of oncogenic KRAS-driven lung cancer and strong neoantigen expression, tumor suppressor genotype dictates the degree of immune cell recruitment, positive selection of tumors with neoantigen silencing, and tumor outgrowth. By quantifying the impact of 11 commonly inactivated tumor suppressor genes on tumor growth across neoantigenic contexts, we show that the growth-promoting effects of tumor suppressor gene inactivation correlate with increasing sensitivity to immunosurveillance. Importantly, some genotypes also dramatically changed sensitivity to immunosurveillance independently of their growth-promoting effects. We propose a model of immunoediting in which tumor suppressor gene inactivation works in tandem with neoantigen expression to shape tumor immunosurveillance and immunoediting such that the same neoantigens uniquely modulate tumor immunoediting depending on the genetic context.
