Inactivation of Fbxw7 Impairs Dsrna Sensing and Confers Resistance to PD-1 Blockade
Published OnlineFirst May 5, 2020; DOI: 10.1158/2159-8290.CD-19-1416 RESEARCH ARTICLE Inactivation of Fbxw7 Impairs dsRNA Sensing and Confers Resistance to PD-1 Blockade Cécile Gstalder1,2, David Liu1,3, Diana Miao1, Bart Lutterbach1,2, Alexander L. DeVine1,2, Chenyu Lin4, Megha Shettigar1,2, Priya Pancholi1,2, Elizabeth I. Buchbinder1, Scott L. Carter5,6, Michael P. Manos1, Vanesa Rojas-Rudilla7, Ryan Brennick1, Evisa Gjini8, Pei-Hsuan Chen8, Ana Lako8, Scott Rodig8,9, Charles H. Yoon10, Gordon J. Freeman1, David A. Barbie1, F. Stephen Hodi1, Wayne Miles4, Eliezer M. Van Allen1, and Rizwan Haq1,2 Downloaded from cancerdiscovery.aacrjournals.org on September 26, 2021. © 2020 American Association for Cancer Research. Published OnlineFirst May 5, 2020; DOI: 10.1158/2159-8290.CD-19-1416 ABSTRACT The molecular mechanisms leading to resistance to PD-1 blockade are largely unknown. Here, we characterize tumor biopsies from a patient with melanoma who displayed heterogeneous responses to anti–PD-1 therapy. We observe that a resistant tumor exhibited a loss-of-function mutation in the tumor suppressor gene FBXW7, whereas a sensitive tumor from the same patient did not. Consistent with a functional role in immunotherapy response, inactivation of Fbxw7 in murine tumor cell lines caused resistance to anti–PD-1 in immunocompetent animals. Loss of Fbxw7 was associated with altered immune microenvironment, decreased tumor-intrinsic expression of the double-stranded RNA (dsRNA) sensors MDA5 and RIG1, and diminished induction of type I IFN and MHC-I expression. In contrast, restoration of dsRNA sensing in Fbxw7-deficient cells was suffi- cient to sensitize them to anti–PD-1.
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