Research findings related to UNITE work package B01
Intrinsic malignant brain tumors, such as glioblastomas are frequently resistant to immune checkpoint blockade (ICB) with few hypermutated glioblastomas showing response. Modeling patient-individual resistance is challenging due to the lack of predictive biomarkers and limited accessibility of tissue for serial biopsies. Here, Michael Platten et al. investigate resistance mechanisms to anti-PD-1 and anti-CTLA-4 therapy in syngeneic hypermutated experimental gliomas and show a clear dichotomy and acquired immune heterogeneity in ICB-responder and non-responder tumors. They made use of this dichotomy to establish a radiomic signature predicting tumor regression after pseudoprogression induced by ICB therapy based on serial magnetic resonance imaging. They provide evidence that macrophage-driven ICB resistance is established by CD4 T cell suppression and Treg expansion in the tumor microenvironment via the PD-L1/PD-1/CD80 axis. These findings uncover an unexpected heterogeneity of response to ICB in strictly syngeneic tumors and provide a rationale for targeting PD-L1-expressing tumor-associated macrophages to overcome resistance to ICB.
Aslan K, Turco V, Blobner J, Sonner JK, Liuzzi AR, Núñez NG, De Feo D, Kickingereder P*, Fischer M, Green E, Sadik A, Friedrich M, Sanghvi K, Kilian M, Cichon F, Wolf L, Jähne K, von Landenberg A, Bunse L*, Sahm F*, Schrimpf D, Meyer J, Alexander A, Brugnara G, Röth R, Pfleiderer K, Niesler B, von Deimling A, Opitz C, Breckwoldt MO, Heiland S, Bendszus M*, Wick W*, Becher B, Platten M*. Heterogeneity of response to immune checkpoint blockade in hypermutated experimental gliomas. Nat Commun. 2020 Feb 18;11(1):931. *UNITE Principle Investigators