Maltez et al. reported that in combination with anti-PD-1 and anti-CTLA-4, treatment with agonist anti-CD40 induced spatial reorganization of Tregs within PDAC tumor microenvironments, and supported the conversion of conventional Tregs into “ExTregs”. These effects were dependent on cDC1s through Cxcl9/Cxcr3-mediated recruitment, IFNγ and IL-12 stimulation, and direct TCR–MHC-II interactions with Tregs in the tumor periphery. In Tregs, these interactions activated nuclear translocation of NFAT1, leading to Foxp3 loss and acquisition of Th1-like features, including Tbet and IFNγ expression. Observations in patient samples were consistent with this pattern, and loss of Tregs was associated with longer disease-free survival.
ABSTRACT: In pancreatic ductal adenocarcinoma (PDAC), agonistic anti-CD40 (αCD40) reduces frequencies of intratumoral regulatory T (Treg) cells despite a lack of CD40 expression on Treg cells. Here, we leveraged spatiotemporal imaging and lineage tracing approaches to examine intratumoral Treg cell fate in a mouse model of PDAC, where immune checkpoint blockade (ICB) (αPD-1 + αCTLA-4) combined with αCD40 controls tumor growth. Intratumoral Foxp3+ Treg cell numbers collapsed upon treatment, dependent on CD40-activated dendritic cells (DCs) and induction of interleukin (IL)-12 and interferon (IFN)-γ. This reduction corresponded with cellular alterations; Treg cells acquired an "ExTreg" phenotype characterized by loss of Foxp3 expression and acquisition of T helper 1 (Th1)-like features (Tbet+IFN-γ+). αCD40 promoted a spatially reorganized tumor microenvironment (TME), with Cxcr3⁺ Treg and ExTreg cells localized to the tumor periphery with Cxcl9-expressing DCs. Through in situ analyses of T cell receptor (TCR) signaling, we found that ExTreg cells had the highest antigen-driven activation among tumor-infiltrating T cells. Reprogramming of intratumoral Treg cells into Th1-like effectors reveals plasticity and an anti-tumor capacity of these cells.
Author Info: (1) Postdoctoral Research Associate Training (PRAT) Program Fellow, NIGMS, NIH, Bethesda, MD, USA; Lymphocyte Biology Section, Laboratory of Immune System Biology, NIAID, NIH, Beth
Author Info: (1) Postdoctoral Research Associate Training (PRAT) Program Fellow, NIGMS, NIH, Bethesda, MD, USA; Lymphocyte Biology Section, Laboratory of Immune System Biology, NIAID, NIH, Bethesda, MD, USA. (2) Abramson Cancer Center, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. (3) Department of Cell, Developmental and Cancer Biology, Oregon Health and Science University, Portland, OR, USA. (4) Department of Cell, Developmental and Cancer Biology, Oregon Health and Science University, Portland, OR, USA. (5) Department of Cell, Developmental and Cancer Biology, Oregon Health and Science University, Portland, OR, USA; Graduate Program in Biomedical Sciences, Oregon Health and Science University, Portland, OR, USA. (6) Abramson Cancer Center, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. (7) Lymphocyte Biology Section, Laboratory of Immune System Biology, NIAID, NIH, Bethesda, MD, USA. (8) Department of Biomedical Engineering, Oregon Health and Science University, Portland, OR, USA; The Knight Cancer Institute, Oregon Health and Science University, Portland, OR, USA. (9) Department of Cell, Developmental and Cancer Biology, Oregon Health and Science University, Portland, OR, USA; The Knight Cancer Institute, Oregon Health and Science University, Portland, OR, USA. (10) The Knight Cancer Institute, Oregon Health and Science University, Portland, OR, USA; Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, OR, USA; Brenden-Colson Center for Pancreatic Care, Oregon Health and Science University, Portland, OR, USA. (11) Department of Cell, Developmental and Cancer Biology, Oregon Health and Science University, Portland, OR, USA; The Knight Cancer Institute, Oregon Health and Science University, Portland, OR, USA. (12) Abramson Cancer Center, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA; Parker Institute for Cancer Immunotherapy, University of Pennsylvania, Philadelphia, PA, USA. (13) Lymphocyte Biology Section, Laboratory of Immune System Biology, NIAID, NIH, Bethesda, MD, USA; Center for Advanced Tissue Imaging (CAT-I), NIAID and NCI, NIH, Bethesda, MD, USA. Electronic address: rgermain@niaid.nih.gov. (14) Department of Cell, Developmental and Cancer Biology, Oregon Health and Science University, Portland, OR, USA; The Knight Cancer Institute, Oregon Health and Science University, Portland, OR, USA; Brenden-Colson Center for Pancreatic Care, Oregon Health and Science University, Portland, OR, USA; Parker Institute for Cancer Immunotherapy, University of Pennsylvania, Philadelphia, PA, USA. Electronic address: byrneka@ohsu.edu.
