Self-associated molecular patterns mediate cancer immune evasion by engaging Siglecs on T cells
Michal A. Stanczak, … , Alfred Zippelius, Heinz Läubli
Michal A. Stanczak, … , Alfred Zippelius, Heinz Läubli
Published August 21, 2018
Citation Information: J Clin Invest. 2018;128(11):4912-4923. https://doi.org/10.1172/JCI120612.
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Research Article Immunology Oncology

Self-associated molecular patterns mediate cancer immune evasion by engaging Siglecs on T cells

Abstract

First-generation immune checkpoint inhibitors, including anti–CTLA-4 and anti–programmed death 1 (anti–PD-1) antibodies, have led to major clinical progress, yet resistance frequently leads to treatment failure. Thus, new targets acting on T cells are needed. CD33-related sialic acid–binding immunoglobulin-like lectins (Siglecs) are pattern-recognition immune receptors binding to a range of sialoglycan ligands, which appear to function as self-associated molecular patterns (SAMPs) that suppress autoimmune responses. Siglecs are expressed at very low levels on normal T cells, and these receptors were not until recently considered as interesting targets on T cells for cancer immunotherapy. Here, we show an upregulation of Siglecs, including Siglec-9, on tumor-infiltrating T cells from non–small cell lung cancer (NSCLC), colorectal, and ovarian cancer patients. Siglec-9–expressing T cells coexpressed several inhibitory receptors, including PD-1. Targeting of the sialoglycan-SAMP/Siglec pathway in vitro and in vivo resulted in increased anticancer immunity. T cell expression of Siglec-9 in NSCLC patients correlated with reduced survival, and Siglec-9 polymorphisms showed association with the risk of developing lung and colorectal cancer. Our data identify the sialoglycan-SAMP/Siglec pathway as a potential target for improving T cell activation for immunotherapy.

Authors

Michal A. Stanczak, Shoib S. Siddiqui, Marcel P. Trefny, Daniela S. Thommen, Kayluz Frias Boligan, Stephan von Gunten, Alexandar Tzankov, Lothar Tietze, Didier Lardinois, Viola Heinzelmann-Schwarz, Michael von Bergwelt-Baildon, Wu Zhang, Heinz-Josef Lenz, Younghun Han, Christopher I. Amos, Mohammedyaseen Syedbasha, Adrian Egli, Frank Stenner, Daniel E. Speiser, Ajit Varki, Alfred Zippelius, Heinz Läubli

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Figure 4

Sia-SAMPs inhibit T cell–mediated tumor cell killing in vitro.

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Sia-SAMPs inhibit T cell–mediated tumor cell killing in vitro. (A) Inhib...
(A) Inhibition of T cell activation by LGALS3BP in a dose-dependent manner measured by intracellular IFN-γ by flow cytometry. CD8+ T cells from healthy donors were activated with anti-CD3 and anti-CD28 antibodies in the presence of increasing amounts of LGALS3BP (μg/ml, n = 3). (B) Representative histograms of binding of Sig9-Fc to A549 WT cells, enzymatically desialylated A549 cells (desia), GNE-deficient A549 cells (GNE-KO), and GNE-KO A549 cells refed with 10 mM Neu5Ac. (C) Percentage of cleaved caspase-3–positive (clCasp3+) WT A549 cells, desialylated A549 cells, GNE-KO A549 cells, or GNE-KO A549 cells fed with Neu5Ac (refed) after incubation with CD8+ T cells and catumaxomab (n = 10). (D) Apoptosis of WT, desialylated, GNE-KO, and refed GNE-KO HT-29 cells measured by upregulation of cleaved caspase-3 in tumor cells (n = 6). (E and F) clCaps3+ A549 (E, n = 11) or HT-29 (F, n = 11) tumor cells after coincubation with TILs from NSCLC or CRC samples. (G) CD8+ T cells were sorted according to their Siglec-9 expression and incubated with either WT or GNE-KO A549 cells (n = 4). (H) CD19+ RAMOS cells were incubated with CD8+ T cells from healthy donors in the presence of CD3 and CD19 bispecific antibody blinatumomab (n = 7). (I) GNE-KO RAMOS cells incubated with CD8+ T cells from patients with chronic lymphocytic leukemia (n = 3). (J) Activation measured by CD25 on CD8+ T cells treated with anti-CD3 and anti-CD28 antibodies in the presence of anti–Siglec-9 antibody (clone 191240, g/ml, n = 4). (K) Relative IL-2 production of NSCLC primary tumor samples incubated with SEB and Siglec-9–blocking antibody and the Fab fragments (clone 191240, n = 5). (L) Measurement of CD69 upregulation on CD8+ TILs from NSCLC patients upon incubation with SEB in the presence of antibodies or Fab fragments (n = 5). Statistical analyses in this figure were performed by 1-way ANOVA. Data are presented as mean ± SD. *P < 0.05; **P < 0.01; ***P < 0.001.