PDL1 Signals through Conserved Sequence Motifs to Overcome Interferon-Mediated Cytotoxicity

Publication date: 22 August 2017
Source:Cell Reports, Volume 20, Issue 8
Author(s): Maria Gato-Cañas, Miren Zuazo, Hugo Arasanz, Maria Ibañez-Vea, Laura Lorenzo, Gonzalo Fernandez-Hinojal, Ruth Vera, Cristian Smerdou, Eva Martisova, Imanol Arozarena, Claudia Wellbrock, Diana Llopiz, Marta Ruiz, Pablo Sarobe, Karine Breckpot, Grazyna Kochan, David Escors
PDL1 blockade produces remarkable clinical responses, thought to occur by T cell reactivation through prevention of PDL1-PD1 T cell inhibitory interactions. Here, we find that PDL1 cell-intrinsic signaling protects cancer cells from interferon (IFN) cytotoxicity and accelerates tumor progression. PDL1 inhibited IFN signal transduction through a conserved class of sequence motifs that mediate crosstalk with IFN signaling. Abrogation of PDL1 expression or antibody-mediated PDL1 blockade strongly sensitized cancer cells to IFN cytotoxicity through a STAT3/caspase-7-dependent pathway. Moreover, somatic mutations found in human carcinomas within these PDL1 sequence motifs disrupted motif regulation, resulting in PDL1 molecules with enhanced protective activities from type I and type II IFN cytotoxicity. Overall, our results reveal a mode of action of PDL1 in cancer cells as a first line of defense against IFN cytotoxicity.

Graphical abstract

Teaser

Gato-Cañas et al. find that PDL1 protects cancer cells from interferon toxicity by counteracting interferon signaling through the activities of two non-classical conserved motifs. Human cancers acquire somatic mutations within these motifs that enhance PDL1 anti-interferon activities, favoring tumor progression.


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