Dataset Information

Therapeutic depletion of CCR8⁺ tumor-infiltrating regulatory T cells elicits antitumor immunity and synergizes with anti-PD-1 therapy.

ABSTRACT:

Background

Modulation and depletion strategies of regulatory T cells (Tregs) constitute valid approaches in antitumor immunotherapy but suffer from severe adverse effects due to their lack of selectivity for the tumor-infiltrating (ti-)Treg population, indicating the need for a ti-Treg specific biomarker.

Methods

We employed single-cell RNA-sequencing in a mouse model of non-small cell lung carcinoma (NSCLC) to obtain a comprehensive overview of the tumor-infiltrating T-cell compartment, with a focus on ti-Treg subpopulations. These findings were validated by flow cytometric analysis of both mouse (LLC-OVA, MC38 and B16-OVA) and human (NSCLC and melanoma) tumor samples. We generated two CCR8-specific nanobodies (Nbs) that recognize distinct epitopes on the CCR8 extracellular domain. These Nbs were formulated as tetravalent Nb-Fc fusion proteins for optimal CCR8 binding and blocking, containing either an antibody-dependent cell-mediated cytotoxicity (ADCC)-deficient or an ADCC-prone Fc region. The therapeutic use of these Nb-Fc fusion proteins was evaluated, either as monotherapy or as combination therapy with anti-programmed cell death protein-1 (anti-PD-1), in both the LLC-OVA and MC38 mouse models.

Results

We were able to discern two ti-Treg populations, one of which is characterized by the unique expression of Ccr8 in conjunction with Treg activation markers. Ccr8 is also expressed by dysfunctional CD4⁺ and CD8⁺ T cells, but the CCR8 protein was only prominent on the highly activated and strongly T-cell suppressive ti-Treg subpopulation of mouse and human tumors, with no major CCR8-positivity found on peripheral Tregs. CCR8 expression resulted from TCR-mediated Treg triggering in an NF-?B-dependent fashion, but was not essential for the recruitment, activation nor suppressive capacity of these cells. While treatment of tumor-bearing mice with a blocking ADCC-deficient Nb-Fc did not influence tumor growth, ADCC-prone Nb-Fc elicited antitumor immunity and reduced tumor growth in synergy with anti-PD-1 therapy. Importantly, ADCC-prone Nb-Fc specifically depleted ti-Tregs in a natural killer (NK) cell-dependent fashion without affecting peripheral Tregs.

Conclusions

Collectively, our findings highlight the efficacy and safety of targeting CCR8 for the depletion of tumor-promoting ti-Tregs in combination with anti-PD-1 therapy.

SUBMITTER: Van Damme H

PROVIDER: S-EPMC7887378 | biostudies-literature | 2021 Feb

REPOSITORIES: biostudies-literature

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Publications

Therapeutic depletion of CCR8<sup>+</sup> tumor-infiltrating regulatory T cells elicits antitumor immunity and synergizes with anti-PD-1 therapy.

Van Damme Helena H Dombrecht Bruno B Kiss Máté M Roose Heleen H Allen Elizabeth E Van Overmeire Eva E Kancheva Daliya D Martens Liesbet L Murgaski Aleksandar A Bardet Pauline Madeleine Rachel PMR Blancke Gillian G Jans Maude M Bolli Evangelia E Martins Maria Solange MS Elkrim Yvon Y Dooley James J Boon Louis L Schwarze Julia Katharina JK Tacke Frank F Movahedi Kiavash K Vandamme Niels N Neyns Bart B Ocak Sebahat S Scheyltjens Isabelle I Vereecke Lars L Nana Frank Aboubakar FA Merchiers Pascal P Laoui Damya D Van Ginderachter Jo Agnes JA

Journal for immunotherapy of cancer 20210201 2

<h4>Background</h4>Modulation and depletion strategies of regulatory T cells (Tregs) constitute valid approaches in antitumor immunotherapy but suffer from severe adverse effects due to their lack of selectivity for the tumor-infiltrating (ti-)Treg population, indicating the need for a ti-Treg specific biomarker.<h4>Methods</h4>We employed single-cell RNA-sequencing in a mouse model of non-small cell lung carcinoma (NSCLC) to obtain a comprehensive overview of the tumor-infiltrating T-cell compa ...[more]

PMID: 33589525

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Project description:Chemokine (C-C motif) receptor 8 (CCR8) is a chemokine receptor selectively expressed on tumor-infiltrating regulatory T cells (Tregs). Strong immunosuppression mediated by CCR8+ Tregs observed in breast and lung malignancies suggest for their functional significance in cancer therapy. To date, detailed characterization of tumor-infiltrating CCR8+ Tregs cells in colorectal cancer (CRC) is limited. To study the presence and functional involvement of CCR8+ Tregs in CRC, we analyzed the proportions of CCR8-expressing T cells in different T cell subsets in tumor and adjacent normal tissues and peripheral blood mononuclear cells (PBMCs) from CRC patients by Flow cytometry. Also, we compared the distribution of CCR8+ T cells in malignant tissues and peripheral lymphoid organs from a subcutaneous CRC murine model. Bioinformatic analysis was performed to address the significance of CCR8 expression levels in CRC prognosis, immune regulatory gene expression profiles and potential molecular mechanisms associated with CCR8+ Tregs in CRC tumors. Further, we administrated an anti-CCR8 monoclonal antibody to CT26 tumor-bearing mice and examined the antitumor activity of CCR8-targeted therapy both in vivo and in an ex vivo confirmative model. Here, we showed that Tregs was predominantly presented in the tumors of CRC patients (13.4 ± 5.8, p < 0.0001) and the CRC subcutaneous murine model (35.0 ± 2.6, p < 0.0001). CCR8 was found to be preferentially expressed on these tumor-infiltrating Tregs (CRC patients: 63.6 ± 16.0, p < 0.0001; CRC murine model: 65.3 ± 9.5, p < 0.0001), which correlated with poor survival. We found that majority of the CCR8+ Tregs expressed activation markers and exhibited strong suppressive functions. Treatment with anti-CCR8 antibody hampered the growth of subcutaneous CRC tumor through effectively restoring the anti-tumor immunity of CD4+ conventional T cells (CD4+ Tconvs) and CD8+ T cells, which was confirmed in the ex vivo examinations. Collectively, these findings illustrate the importance of CCR8+ Tregs for an immunosuppressive microenvironment in CRC tumors by functional inhibition of CD4+ Tconvs and CD8+ T cells, and suggest for the applicable value of CCR8-targeted therapy for CRC.

Project description:BACKGROUND:Programmed death-1 (PD-1) immune checkpoint blockade has achieved clinical successes in cancer therapy. However, the response rate of anti-PD-1 agents remains low. Additionally, a subpopulation of patients developed hyperprogressive disease upon PD-1 blockade therapy. Combination therapy with targeted agents may improve immunotherapy. Recent studies show that p53 activation in the myeloid linage suppresses alternative (M2) macrophage polarization, and attenuates tumor development and invasion, leading to the hypothesis that p53 activation may augment antitumor immunity elicited by anti-PD-1 therapy. METHOD:Using APG-115 that is a MDM2 antagonist in clinical development as a pharmacological p53 activator, we investigated the role of p53 in immune modulation and combination therapy with PD-1 blockade. RESULTS:In vitro treatment of bone marrow-derived macrophages with APG-115 resulted in activation of p53 and p21, and a decrease in immunosuppressive M2 macrophage population through downregulation of c-Myc and c-Maf. Increased proinflammatory M1 macrophage polarization was observed in the spleen from mice treated with APG-115. Additionally, APG-115 has co-stimulatory activity in T cells and increases PD-L1 expression in tumor cells. In vivo, APG-115 plus anti-PD-1 combination therapy resulted in enhanced antitumor activity in Trp53wt, Trp53mut, and Trp53-deficient (Trp53-/-) syngeneic tumor models. Importantly, such enhanced activity was abolished in a syngeneic tumor model established in Trp53 knockout mice. Despite differential changes in tumor-infiltrating leukocytes (TILs), including the increases in infiltrated cytotoxic CD8+ T cells in Trp53wt tumors and M1 macrophages in Trp53mut tumors, a decrease in the proportion of M2 macrophages consistently occurred in both Trp53wt and Trp53mut tumors upon combination treatment. CONCLUSION:Our results demonstrate that p53 activation mediated by APG-115 promotes antitumor immunity in the tumor microenvironment (TME) regardless of the Trp53 status of tumors per se. Instead, such an effect depends on p53 activation in Trp53 wild-type immune cells in the TME. Based on the data, a phase 1b clinical trial has been launched for the evaluation of APG-115 in combination with pembrolizumab in solid tumor patients including those with TP53mut tumors.

Dataset Information

Therapeutic depletion of CCR8⁺ tumor-infiltrating regulatory T cells elicits antitumor immunity and synergizes with anti-PD-1 therapy.

Background

Methods

Results

Conclusions

Publications

Therapeutic depletion of CCR8<sup>+</sup> tumor-infiltrating regulatory T cells elicits antitumor immunity and synergizes with anti-PD-1 therapy.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets

Dataset Information

Therapeutic depletion of CCR8+ tumor-infiltrating regulatory T cells elicits antitumor immunity and synergizes with anti-PD-1 therapy.

Background

Methods

Results

Conclusions

Publications

Therapeutic depletion of CCR8<sup>+</sup> tumor-infiltrating regulatory T cells elicits antitumor immunity and synergizes with anti-PD-1 therapy.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets

Therapeutic depletion of CCR8⁺ tumor-infiltrating regulatory T cells elicits antitumor immunity and synergizes with anti-PD-1 therapy.