CD200 ectodomain shedding into the tumor microenvironment leads to NK cell dysfunction and apoptosis
Huw J. Morgan, Elise Rees, Simone Lanfredini, Kate A. Powell, Jasmine Gore, Alex Gibbs, Charlotte Lovatt, Gemma E. Davies, Carlotta Olivero, Boris Y. Shorning, Giusy Tornillo, Alex Tonks, Richard Darley, Eddie C.Y. Wang, Girish K. Patel
Huw J. Morgan, Elise Rees, Simone Lanfredini, Kate A. Powell, Jasmine Gore, Alex Gibbs, Charlotte Lovatt, Gemma E. Davies, Carlotta Olivero, Boris Y. Shorning, Giusy Tornillo, Alex Tonks, Richard Darley, Eddie C.Y. Wang, Girish K. Patel
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Research Article Oncology

CD200 ectodomain shedding into the tumor microenvironment leads to NK cell dysfunction and apoptosis

Abstract

The basis of immune evasion, a hallmark of cancer, can differ even when cancers arise from one cell type such as in the human skin keratinocyte carcinomas: basal and squamous cell carcinoma. Here we showed that the basal cell carcinoma tumor–initiating cell surface protein CD200, through ectodomain shedding, was responsible for the near absence of NK cells within the basal cell carcinoma tumor microenvironment. In situ, CD200 underwent ectodomain shedding by metalloproteinases MMP3 and MMP11, which released biologically active soluble CD200 into the basal cell carcinoma microenvironment. CD200 bound its cognate receptor on NK cells to suppress MAPK pathway signaling that in turn blocked indirect (IFN-γ release) and direct cell killing. In addition, reduced ERK phosphorylation relinquished negative regulation of PPARγ-regulated gene transcription and led to membrane accumulation of the Fas/FADD death receptor and its ligand, FasL, which resulted in activation-induced apoptosis. Blocking CD200 inhibition of MAPK or PPARγ signaling restored NK cell survival and tumor cell killing, with relevance to many cancer types. Our results thus uncover a paradigm for CD200 as a potentially novel and targetable NK cell–specific immune checkpoint, which is responsible for NK cell–associated poor outcomes in many cancers.

Authors

Huw J. Morgan, Elise Rees, Simone Lanfredini, Kate A. Powell, Jasmine Gore, Alex Gibbs, Charlotte Lovatt, Gemma E. Davies, Carlotta Olivero, Boris Y. Shorning, Giusy Tornillo, Alex Tonks, Richard Darley, Eddie C.Y. Wang, Girish K. Patel

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Figure 3

CD200 blocks NK cell activation, degranulation, and cytokine release.

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CD200 blocks NK cell activation, degranulation, and cytokine release. (A...
(A) Flow cytometric analysis histogram of CD107a expression levels on CD56+ NKPOS cells cocultured with HeLaPOS or HeLaNEG at an E:T ratio of 5:1 for 4 hours. (B and C) CCL4 ELISA of culture supernatant from NKPOS cells cocultured with HeLaPOS or HeLaNEG at an E:T ratio of 1:1 and 2:1 for 4 hours (B), and together with CD200-blocking antibody (C). (D) ELISpot IFN-γ determination from NKPOS cells cocultured with HeLaPOS or HeLaNEG at an E:T ratio of 1:10 for 4 hours, together with either CD200 peptide or CD200-blocking antibody. (E and F) Day 5 tumors from nude mice were grafted with 1 × 106 HeLaPOS or HeLaNEG (n = 5 each). Histological analysis of tumor cellularity, necrosis and inflammatory cell infiltration (E), and paraffin-embedded sections labeled with anti-NK1.1, anti–cleaved caspase 3, and anti-CD200R antibodies by immunohistochemistry to determine NK cell infiltrate, using spleen sections as positive control, and frequency of cleaved caspase 3–positive and CD200R-positive cells (F). Asterisks show necrotic tissue area. (G) BCC colonies were established in primary culture (n = 3) over a period of 2 weeks using an irradiated NIH/3T3 mouse fibroblast layer. Colonies were coincubated with NKPOS cells and treated with either a CD200-blocking antibody or an isotype antibody control for 4 hours and then enumerated. Data are presented as mean ± SD of 3 independent experiments. *P < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001 by 2-tailed Student’s t test (A–D) or 2-way ANOVA with Bonferroni’s post hoc test (E–G).