Journal Articles

Enhancement of ferroptosis in escape variant tumor cells by IFN-γ derived from antigen-specific T cells controls tumor with heterogeneity

Spotlight 

To enhance immunotherapy efficacy against escape variant clones, Ehara et al. combined MART-1 TCR-T cells with the ferroptosis inducer RSL3. IFNγ secreted by the TCR-T cells enhanced the susceptibility of melanoma cells to ferroptosis. In mice injected with an equal mix of 526MEL and β2mKO cells, the combination treatment inhibited tumor growth, including reduction of the HLA-negative tumor mass, and significantly increased T cell infiltration compared to controls. In patients with melanoma, high expression of IFNγ signature genes STAT1 and IRF1 and low expression of SLC2A2 (counteracting ferroptosis) predicted better outcomes.

Contributed by Ute Burkhardt

To enhance immunotherapy efficacy against escape variant clones, Ehara et al. combined MART-1 TCR-T cells with the ferroptosis inducer RSL3. IFNγ secreted by the TCR-T cells enhanced the susceptibility of melanoma cells to ferroptosis. In mice injected with an equal mix of 526MEL and β2mKO cells, the combination treatment inhibited tumor growth, including reduction of the HLA-negative tumor mass, and significantly increased T cell infiltration compared to controls. In patients with melanoma, high expression of IFNγ signature genes STAT1 and IRF1 and low expression of SLC2A2 (counteracting ferroptosis) predicted better outcomes.

Contributed by Ute Burkhardt

ABSTRACT: Tumor masses often exhibit heterogeneity, including escape variant clones that lack antigen-presenting machinery and/or tumor antigens, which poses a major challenge to immunotherapy. Ferroptosis, a form of regulated cell death driven by iron-dependent lipid peroxidation, has been shown to effectively induce cell death in various tumor cells. Recent studies have reported that IFN-γ suppresses the expression of System Xc-, thereby enhancing the induction of ferroptosis. Based on this, we hypothesized that combining immunotherapy with ferroptosis inducers could enhance antitumor effects against both antigen-positive and antigen-negative tumor cells. We found that combining RSL3, a ferroptosis inducer, with MART-1-specific TCR-T cells eradicates a heterogeneous tumor model consisting of human melanoma cells and their β2 microglobulin knockout counterparts. In NOG mice, this combination therapy demonstrates a significant antitumor effect against tumors with heterogeneity. These findings suggest that integrating ferroptosis inducers with immunotherapy could overcome the limitations imposed by escape variant tumor clones, offering a promising strategy for cancer treatment.

Author Info: (1) Nagasaki University Nagasaki Japan. ROR: https://ror.org/058h74p94 (2) Nagasaki University Nagasaki Japan. ROR: https://ror.org/058h74p94 (3) Nagasaki University Nagasaki Japan

Author Info: (1) Nagasaki University Nagasaki Japan. ROR: https://ror.org/058h74p94 (2) Nagasaki University Nagasaki Japan. ROR: https://ror.org/058h74p94 (3) Nagasaki University Nagasaki Japan. ROR: https://ror.org/058h74p94 (4) Aichi Cancer Center Research Institute Chikusa-ku, Nagoya, Aichi Japan. (5) Nagasaki University Nagasaki Japan. ROR: https://ror.org/058h74p94 (6) Nagasaki University Nagasaki Japan. ROR: https://ror.org/058h74p94 (7) Nagasaki University Nagasaki Japan. ROR: https://ror.org/058h74p94 (8) Nagasaki University Nagasaki Japan. ROR: https://ror.org/058h74p94 (9) Takara Bio Inc. Kusatsu, Shiga Japan. (10) Takara Bio Inc. Otsu, Shiga Japan. (11) Nagasaki University Nagasaki Japan. ROR: https://ror.org/058h74p94 (12) Nagasaki University Nagasaki, Nagasaki Japan. ROR: https://ror.org/058h74p94

Single-cell transcriptomic analysis reveals tumor-immune determinants of lymph node colonization and progression in thyroid cancer Spotlight 

Nguyen et al. used single-cell RNAseq and multiplex IHC on paired primary thyroid carcinomas and metastatic lymph nodes (LNs) to define immune determinants of nodal colonization. In metastatic LNs, thyrocytes and TAMs downregulated inflammatory cytokine receptors. including TNFRSF12A and CX3CR1, and were enriched for Tregs relative to matched primary tumors, which suggests suppression of T cell-mediated cytotoxicity. Tumor-infiltrating lymphocytes in metastatic LNs showed increased IL7R expression, and high IL7R levels within nodal metastases correlated with enhanced immune activation and improved progression-free survival in a validation cohort.

Contributed by Shishir Pant

Nguyen et al. used single-cell RNAseq and multiplex IHC on paired primary thyroid carcinomas and metastatic lymph nodes (LNs) to define immune determinants of nodal colonization. In metastatic LNs, thyrocytes and TAMs downregulated inflammatory cytokine receptors. including TNFRSF12A and CX3CR1, and were enriched for Tregs relative to matched primary tumors, which suggests suppression of T cell-mediated cytotoxicity. Tumor-infiltrating lymphocytes in metastatic LNs showed increased IL7R expression, and high IL7R levels within nodal metastases correlated with enhanced immune activation and improved progression-free survival in a validation cohort.

Contributed by Shishir Pant

ABSTRACT: Lymph node (LN) metastases are a major driver of mortality across solid cancers, including thyroid carcinomas, which are known for high rates of nodal colonization. To elucidate the determinants of nodal spread, we isolated tumor-infiltrating leukocytes from primary thyroid tumors and matched metastatic LNs for single-cell RNA sequencing with validation by multiplex immunohistochemistry. Comparing the microenvironmental alterations between primary tumors and their LNs, we found that thyrocytes and tumor-associated macrophages down-regulate the expression of multiple inflammatory cytokine receptors, including TNFRSF12A and CX3CR1, upon LN colonization. LNs were associated with the induction of regulatory T cells to suppress T cell-mediated cytotoxicity compared to matched primary tumors. Notably, tumor-infiltrating lymphocytes within LNs demonstrated increased expression of activation markers, including interleukin-7 receptor (IL7R). High LN expression of IL7R was significantly correlated with improved outcomes and can serve as a biomarker in this heterogeneous disease. Our findings on the dynamic equilibrium within LN metastases may offer conserved mechanisms for nodal colonization across solid tumors.

Author Info: (1) Department of Radiation Oncology, Cedars-Sinai Medical Center, Los Angeles, CA, USA. Samuel Oschin Comprehensive Cancer Institute, Cedars-Sinai Medical Center, Los Angeles, CA,

Author Info: (1) Department of Radiation Oncology, Cedars-Sinai Medical Center, Los Angeles, CA, USA. Samuel Oschin Comprehensive Cancer Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA. Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA. (2) Department of Radiation Oncology, Cedars-Sinai Medical Center, Los Angeles, CA, USA. (3) Department of Radiation Oncology, Cedars-Sinai Medical Center, Los Angeles, CA, USA. (4) Department of Radiation Oncology, Cedars-Sinai Medical Center, Los Angeles, CA, USA. (5) Department of Radiation Oncology, Cedars-Sinai Medical Center, Los Angeles, CA, USA. (6) Department of Radiation Oncology, Cedars-Sinai Medical Center, Los Angeles, CA, USA. (7) Division of Endocrinology, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, USA. (8) Samuel Oschin Comprehensive Cancer Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA. Division of Otolaryngology-Head and Neck Surgery, Department of Surgery, Cedars-Sinai Medical Center, Los Angeles, CA, USA. (9) Department of Surgery, Cedars-Sinai Medical Center, Los Angeles, CA, USA. (10) Samuel Oschin Comprehensive Cancer Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA. Division of Otolaryngology-Head and Neck Surgery, Department of Surgery, Cedars-Sinai Medical Center, Los Angeles, CA, USA. (11) Division of Medical Oncology, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, USA. (12) Division of Medical Oncology, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, USA. (13) Department of Radiation Oncology, Cedars-Sinai Medical Center, Los Angeles, CA, USA. Samuel Oschin Comprehensive Cancer Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA. (14) Department of Radiation Oncology, Cedars-Sinai Medical Center, Los Angeles, CA, USA. Samuel Oschin Comprehensive Cancer Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA. (15) Department of Radiation Oncology, Cedars-Sinai Medical Center, Los Angeles, CA, USA. Samuel Oschin Comprehensive Cancer Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA. (16) Department of Pathology and Laboratory Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, USA. (17) Department of Radiation Oncology, Cedars-Sinai Medical Center, Los Angeles, CA, USA. Samuel Oschin Comprehensive Cancer Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA. Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA. (18) Samuel Oschin Comprehensive Cancer Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA. Division of Otolaryngology-Head and Neck Surgery, Department of Surgery, Cedars-Sinai Medical Center, Los Angeles, CA, USA.

Sustained A2AR expression and loss paradoxically promote CD8+ T cell exhaustion

Spotlight 

Using single-cell multiomics and genetic models, Song and Kharel et al. showed that, paradoxically, both sustained A2AR expression under chronic antigen exposure and hypoxia, and complete loss of A2AR drive the transition of TCFhi memory-like progenitor (Tpro) cells to exhausted T cells. A2AR expression was rapidly induced upon TCR stimulation and was required to sustain CD8+ T cell functions. Persistent A2AR expression promoted continuous TCR engagement and CD8+ T cell exhaustion via activation of the GαS-cAMP-PKA pathway. A2AR depletion led to epigenetic remodeling and activation of CD122 (IL-2Rβ)-dependent signaling, driving exhaustion.

Contributed by Ute Burkhardt

Using single-cell multiomics and genetic models, Song and Kharel et al. showed that, paradoxically, both sustained A2AR expression under chronic antigen exposure and hypoxia, and complete loss of A2AR drive the transition of TCFhi memory-like progenitor (Tpro) cells to exhausted T cells. A2AR expression was rapidly induced upon TCR stimulation and was required to sustain CD8+ T cell functions. Persistent A2AR expression promoted continuous TCR engagement and CD8+ T cell exhaustion via activation of the GαS-cAMP-PKA pathway. A2AR depletion led to epigenetic remodeling and activation of CD122 (IL-2Rβ)-dependent signaling, driving exhaustion.

Contributed by Ute Burkhardt

ABSTRACT: Although A2AR is a key immunoregulatory receptor that suppresses CD8(+) T cell activation in response to elevated extracellular adenosine in inflamed or hypoxic microenvironments, its role in CD8(+) T cell differentiation and cell-fate decisions during chronic viral infection and cancer remains poorly understood. Using A2AR-eGFP reporter mice, we show that A2AR expression is rapidly induced by TCR stimulation and persists under chronic antigen exposure and hypoxia, with sustained expression strongly associated with terminal exhaustion via the canonical G_(s)-cAMP-PKA pathway. Paradoxically, A2AR loss does not alleviate exhaustion but instead accelerates differentiation toward the terminally exhausted state. Single-cell multiomics profiling revealed that A2AR deficiency activates CD122 (IL-2R_)-dependent signaling, driving T cell exhaustion. Genetic deletion of CD122 in A2AR-deficient CD8(+) T cells reduced terminal exhaustion, identifying CD122 signaling as a key mediator of A2AR loss-driven exhaustion. Intriguingly, both sustained A2AR expression and A2AR loss converge to promote T cell exhaustion differentiation through distinct mechanisms. These findings uncover a paradoxical role of A2AR in shaping CD8(+) T cell fate choices during chronic infection and cancer.

Author Info: (1) Department of Medicine and Hematology and Oncology Division, Robert H. Lurie Comprehensive Cancer Center, Northwestern University Feinberg School of Medicine Chicago, IL 60611.

Author Info: (1) Department of Medicine and Hematology and Oncology Division, Robert H. Lurie Comprehensive Cancer Center, Northwestern University Feinberg School of Medicine Chicago, IL 60611. ROR: https://ror.org/02p4far57 (2) Department of Pathology, Northwestern University, Feinberg School of Medicine, Chicago, IL 60611. (3) Department of Medicine and Hematology and Oncology Division, Robert H. Lurie Comprehensive Cancer Center, Northwestern University Feinberg School of Medicine Chicago, IL 60611. ROR: https://ror.org/02p4far57 (4) Department of Medicine and Hematology and Oncology Division, Robert H. Lurie Comprehensive Cancer Center, Northwestern University Feinberg School of Medicine Chicago, IL 60611. ROR: https://ror.org/02p4far57 (5) Department of Medicine and Hematology and Oncology Division, Robert H. Lurie Comprehensive Cancer Center, Northwestern University Feinberg School of Medicine Chicago, IL 60611. ROR: https://ror.org/02p4far57 (6) Department of Pathology, Northwestern University, Feinberg School of Medicine, Chicago, IL 60611. (7) Biotherapy Center, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, China. ROR: https://ror.org/056swr059 (8) Department of Pathology, Northwestern University, Feinberg School of Medicine, Chicago, IL 60611. (9) Department of Medicine and Hematology and Oncology Division, Robert H. Lurie Comprehensive Cancer Center, Northwestern University Feinberg School of Medicine Chicago, IL 60611. ROR: https://ror.org/02p4far57

RIG-I-targeted immunotherapy synergizes with immune checkpoint inhibition in a hepatocellular carcinoma model Spotlight 

Marx, Teppert, and Marisch et al. showed retinoic acid-inducible gene-I (RIG-I), the cytoplasmic sensor of short dsRNA with uncapped 5’-triphosphate (3p-RNA), was expressed in human HCC samples and induced by IFN-I on cell lines. 3p-RNA treatment given i.v. reduced tumor burden in murine orthotopic tumor models and induced immune memory. Therapeutic effects depended on CD4+ and CD8+ T, but not NK cells, and on tumor-intrinsic Fas expression, but not systemic intracellular RIG-I pathway signaling. Treatment with 3p-RNA upregulated PD-L1 expression on HCC cells and synergized with anti-PD-1 to improve efficacy in HCC mouse models.

Contributed by Paula Hochman

Marx, Teppert, and Marisch et al. showed retinoic acid-inducible gene-I (RIG-I), the cytoplasmic sensor of short dsRNA with uncapped 5’-triphosphate (3p-RNA), was expressed in human HCC samples and induced by IFN-I on cell lines. 3p-RNA treatment given i.v. reduced tumor burden in murine orthotopic tumor models and induced immune memory. Therapeutic effects depended on CD4+ and CD8+ T, but not NK cells, and on tumor-intrinsic Fas expression, but not systemic intracellular RIG-I pathway signaling. Treatment with 3p-RNA upregulated PD-L1 expression on HCC cells and synergized with anti-PD-1 to improve efficacy in HCC mouse models.

Contributed by Paula Hochman

ABSTRACT: Retinoic acid-inducible gene-I (RIG-I) is a cytoplasmic pattern recognition receptor that senses short double-stranded RNA with uncapped 5'-triphosphate (3p-RNA). Upon activation, RIG-I induces type I interferons and proinflammatory cytokines, thereby promoting adaptive immunity. Thus, RIG-I activation is a promising approach for creating a proinflammatory tumor microenvironment. In this study, we investigated its therapeutic potential in hepatocellular carcinoma (HCC). We explored and confirmed RIG-I expression and signaling in human HCC samples and cell lines. The therapeutic potential of RIG-I activation by 3p-RNA for the treatment of HCC was investigated in vitro and in syngeneic murine orthotopic tumor models. In vivo, 3p-RNA treatment significantly reduced the tumor burden, delayed disease progression, and achieved partial complete remission of RIL-175 tumors with durable immune memory. However, no therapeutic effects were observed in the Hep-55.1C model. Tumor clearance depended on CD4⁺ and CD8⁺ T cells, but not NK cells. Additionally, 3p-RNA induced PD-L1 expression on HCC cells, enhancing their sensitivity to anti-PD-1 immune checkpoint therapy in vivo. RIG-I activation via 3p-RNA therapy shows promise as an immunotherapeutic strategy for hepatocellular carcinoma (HCC). Future investigations need to focus on tumor-intrinsic factors to understand heterogeneity between tumors and to overcome resistance mechanisms.

Author Info: (1) LMU Klinikum Munich Germany. ROR: https://ror.org/02jet3w32 (2) LMU Klinikum Munich Germany. ROR: https://ror.org/02jet3w32 (3) LMU Klinikum Munich Germany. ROR: https://ror.or

Author Info: (1) LMU Klinikum Munich Germany. ROR: https://ror.org/02jet3w32 (2) LMU Klinikum Munich Germany. ROR: https://ror.org/02jet3w32 (3) LMU Klinikum Munich Germany. ROR: https://ror.org/02jet3w32 (4) LMU Klinikum Munich Germany. ROR: https://ror.org/02jet3w32 (5) LMU Klinikum Munich Germany. ROR: https://ror.org/02jet3w32 (6) LMU Klinikum Munich Germany. ROR: https://ror.org/02jet3w32 (7) LMU Klinikum Munich Germany. ROR: https://ror.org/02jet3w32 (8) LMU Klinikum Munich Germany. ROR: https://ror.org/02jet3w32 (9) LMU Klinikum Munich Germany. ROR: https://ror.org/02jet3w32 (10) LMU Klinikum Munich Germany. ROR: https://ror.org/02jet3w32 (11) LMU Klinikum Munich Germany. ROR: https://ror.org/02jet3w32 (12) Ludwig-Maximilians-UniversitŠt MŸnchen Munich, Bavaria Germany. ROR: https://ror.org/05591te55 (13) LMU Klinikum Munich Germany. ROR: https://ror.org/02jet3w32 (14) Sanofi (Germany) Frankfurt Germany. ROR: https://ror.org/03ytdtb31 (15) Sanofi (Germany) Frankfurt Germany. ROR: https://ror.org/03ytdtb31 (16) LMU Klinikum Munich Germany. ROR: https://ror.org/02jet3w32 (17) LMU Klinikum Munich Germany. ROR: https://ror.org/02jet3w32 (18) LMU Klinikum Munich Germany. ROR: https://ror.org/02jet3w32 (19) LMU Klinikum Munich Germany. ROR: https://ror.org/02jet3w32 (20) LMU Klinikum Munich Germany. ROR: https://ror.org/02jet3w32

FLT3L-secreting cDC1 in situ vaccination enhances antitumor immunity and synergizes with PD-1 blockade in murine non-small cell lung cancer Spotlight 

Abascal et al. engineered FLT3L-secreting mouse cDC1s that retained APC and phagocytic ability in vitro. In situ vaccination (ISV) with the cDC1s inhibited s.c. tumor growth in multiple syngeneic murine models, including those with driver mutations common in human NSCLC, and increased trafficking of the autologous cDC1s to TdLN and tumor infiltration of T cells. TCGA analysis showed that FLT3L expression in human NSCLC correlated with profiles of B and T cells, activated DCs and HEV-enriched TLS. ISV increased immature TLS formation in the murine TIME and synergized with anti-PD-1 in a NSCLC model to enhance efficacy and induce immune memory.

Contributed by Paula Hochman

Abascal et al. engineered FLT3L-secreting mouse cDC1s that retained APC and phagocytic ability in vitro. In situ vaccination (ISV) with the cDC1s inhibited s.c. tumor growth in multiple syngeneic murine models, including those with driver mutations common in human NSCLC, and increased trafficking of the autologous cDC1s to TdLN and tumor infiltration of T cells. TCGA analysis showed that FLT3L expression in human NSCLC correlated with profiles of B and T cells, activated DCs and HEV-enriched TLS. ISV increased immature TLS formation in the murine TIME and synergized with anti-PD-1 in a NSCLC model to enhance efficacy and induce immune memory.

Contributed by Paula Hochman

BACKGROUND: Non-small cell lung cancer (NSCLC) frequently evades immune surveillance through defective antigen presentation and a suppressive tumor microenvironment (TME), limiting the efficacy of immune checkpoint blockade (ICB). Conventional type 1 dendritic cells (cDC1s) are essential for initiating antitumor CD8(+) T-cell responses; however, their abundance and function are often diminished in NSCLC, contributing to poor outcomes and resistance to immunotherapy. We hypothesized that in situ vaccination (ISV) using gene-modified cDC1s engineered to secrete FMS-like tyrosine kinase 3 ligand (FLT3L) would enhance cDC1 function within the TME, promote antitumor immunity, and improve responses to ICB. METHODS: Syngeneic murine models of NSCLC (Kras(G12D)/P53(-/-)/Lkb1(-/-); Kras(G12D)/P53(-/-) ; and Kras(G12D) ) with varying tumor mutational burden, along with the MC38 model, were used to assess the therapeutic efficacy of FLT3L-cDC1 ISV. Flow cytometry and multiplex immunofluorescence were used to evaluate immune mechanisms of response. To assess translational relevance, immune and tertiary lymphoid structure (TLS) signatures were analyzed in The Cancer Genome Atlas (TCGA) NSCLC datasets, with TLS signatures refined using a retrained xCell2 framework incorporating curated TLS and high endothelial venule (HEV) microdissection datasets. RESULTS: FLT3L-cDC1 ISV remodeled the TME across multiple NSCLC models, inducing T lymphocyte infiltration and expanding cytolytic CD8(+) T cells. FLT3L-cDC1 ISV was associated with increased formation of immature TLS with primary follicle-like features within the TME. TCGA analyses revealed that FLT3L expression correlates with activated DC, T cell, and B cell signatures, as well as HEV-enriched TLS-associated programs. Combination with PD-1 blockade further enhanced the antitumor immunity of FLT3L-cDC1 ISV, resulting in robust local and systemic T-cell activation and the expansion of activated CCR7(+)PD-L1(+) cDC1s and stem-like TCF1(+)PD-1(+) CD8(+) progenitors within the TME. In an LKB1-deficient NSCLC model, FLT3L-cDC1 ISV plus PD-1 blockade induced complete and durable regression in 85% of tumors, leading to long-lasting systemic tumor-specific immune memory, consistent with effective tumor vaccination. CONCLUSIONS: FLT3L-cDC1 ISV represents a rational cytokine-enhanced cellular immunotherapy designed to overcome immunosuppression and restore DC function within the TME, thereby promoting tumor-specific adaptive immune responses and enhancing responsiveness to ICB.

Author Info: (1) Department of Medicine, David Geffen School of Medicine, Los Angeles, California, USA. (2) Department of Medicine, David Geffen School of Medicine, Los Angeles, California, USA

Author Info: (1) Department of Medicine, David Geffen School of Medicine, Los Angeles, California, USA. (2) Department of Medicine, David Geffen School of Medicine, Los Angeles, California, USA. (3) Department of Medicine, David Geffen School of Medicine, Los Angeles, California, USA. VA Greater Los Angeles Healthcare System, Los Angeles, California, USA. (4) Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, Los Angeles, California, USA. (5) Department of Medicine, David Geffen School of Medicine, Los Angeles, California, USA. (6) Department of Medicine, David Geffen School of Medicine, Los Angeles, California, USA. VA Greater Los Angeles Healthcare System, Los Angeles, California, USA. (7) Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, Los Angeles, California, USA. (8) Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, Los Angeles, California, USA. (9) Department of Medicine, David Geffen School of Medicine, Los Angeles, California, USA. (10) UCLA, Los Angeles, California, USA. (11) Department of Medicine, David Geffen School of Medicine, Los Angeles, California, USA. (12) Department of Medicine, David Geffen School of Medicine, Los Angeles, California, USA. (13) Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, Los Angeles, California, USA. (14) Department of Medicine, David Geffen School of Medicine, Los Angeles, California, USA. (15) Department of Medicine, David Geffen School of Medicine, Los Angeles, California, USA. VA Greater Los Angeles Healthcare System, Los Angeles, California, USA. Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, Los Angeles, California, USA. (16) Department of Medicine, David Geffen School of Medicine, Los Angeles, California, USA rsalehirad@mednet.ucla.edu bliu@mednet.ucla.edu. (17) Department of Medicine, David Geffen School of Medicine, Los Angeles, California, USA rsalehirad@mednet.ucla.edu bliu@mednet.ucla.edu. VA Greater Los Angeles Healthcare System, Los Angeles, California, USA.

B cell-derived type I interferon sustains T cell functionality upon strong TCR stimulation during chronic infection Spotlight 

Graça et al. show that B cells are essential for CD8+ T cell effector response during chronic, but not acute, LCMV infection. In chronic infection, splenic B cells sense viruses via TLR7/8-STING pathways and produce IFN-I, which promotes exhausted T cell differentiation and sustain effector function in the spleen, whereas CD8+ T cells in the LN or responding to low antigen load were B cell independent. Loss of B cells or IFN-I signaling impaired exhausted T cell cytokine production (‘tolerized-like’). IRF1 integrates IFN-I signals to promote T cell expansion. Chronic human HBV showed a similar antigen-load-dependent effect observed in the murine LCMV model.

Contributed by Shishir Pant

Graça et al. show that B cells are essential for CD8+ T cell effector response during chronic, but not acute, LCMV infection. In chronic infection, splenic B cells sense viruses via TLR7/8-STING pathways and produce IFN-I, which promotes exhausted T cell differentiation and sustain effector function in the spleen, whereas CD8+ T cells in the LN or responding to low antigen load were B cell independent. Loss of B cells or IFN-I signaling impaired exhausted T cell cytokine production (‘tolerized-like’). IRF1 integrates IFN-I signals to promote T cell expansion. Chronic human HBV showed a similar antigen-load-dependent effect observed in the murine LCMV model.

Contributed by Shishir Pant

ABSTRACT: B cells are highly abundant lymphocytes and central players in humoral immunity. Although T cells are well known to support humoral responses, how B cells influence T cell responses is less understood. Here, we show that B cells are critical for CD8(+) T cell responses to chronic, but not acute, viral infections. In the absence of B cells, T cells responding to chronic infection exhibited severely impaired effector differentiation. This dependency on B cell help was dictated by high antigen loads and strong T cell receptor (TCR) stimulation. Loss of either B cells or interferon-I (IFN-I) signaling led to severe functional deficits in exhausted T cells, implicating B cells as key producers of IFN-I. The IFN-I-dependent T cell response to strong TCR stimulation is mediated, in part, by the transcription factor IRF1. Therefore, during chronic infection, we uncover an important role for B cell-derived IFN-I in modulating T cell responses to strong TCR stimulation.

Author Info: (1) Department of Microbiology and Immunology, the Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, Australia. (2) Department of Microbi

Author Info: (1) Department of Microbiology and Immunology, the Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, Australia. (2) Department of Microbiology and Immunology, the Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, Australia. (3) Department of Microbiology and Immunology, the Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, Australia. (4) Institute of Molecular Medicine and Experimental Immunology, University Hospital Bonn, University of Bonn, Venusberg-Campus 1, 53127 Bonn, Germany. (5) Department of Microbiology and Immunology, the Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, Australia; Institute of Molecular Medicine and Experimental Immunology, University Hospital Bonn, University of Bonn, Venusberg-Campus 1, 53127 Bonn, Germany. (6) Department of Microbiology and Immunology, the Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, Australia. (7) Department of Microbiology and Immunology, the Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, Australia. (8) Department of Microbiology and Immunology, the Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, Australia. (9) Department of Microbiology and Immunology, the Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, Australia. (10) Institute for Immunology, University Hospital Heidelberg, Heidelberg, Germany. (11) Department of Microbiology and Immunology, the Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, Australia. (12) Department of Microbiology and Immunology, the Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, Australia. (13) Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, VIC, Australia; Department of Molecular and Translational Science, Monash University, Clayton, VIC, Australia. (14) Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, VIC, Australia; Department of Molecular and Translational Science, Monash University, Clayton, VIC, Australia. (15) Institute for Immunology, University Hospital Heidelberg, Heidelberg, Germany. (16) Department of Medicine II (Gastroenterology, Hepatology, Endocrinology, and Infectious Diseases), Medical Center, University of Freiburg, Baden-WŸrttemberg, Germany. (17) Department of Medicine II (Gastroenterology, Hepatology, Endocrinology, and Infectious Diseases), Medical Center, University of Freiburg, Baden-WŸrttemberg, Germany. (18) Department of Microbiology and Immunology, the Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, Australia. (19) Institute of Molecular Medicine and Experimental Immunology, University Hospital Bonn, University of Bonn, Venusberg-Campus 1, 53127 Bonn, Germany. (20) Computational Sciences Initiative (CSI), the Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, Australia. (21) Department of Microbiology and Immunology, the Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, Australia. (22) Department of Microbiology and Immunology, the Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, Australia. Electronic address: yannick.alexandre@unimelb.edu.au. (23) Department of Microbiology and Immunology, the Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, Australia. Electronic address: daniel.utzschneider@unimelb.edu.au.

IL-2 mutein promotes antigen-specific transplant acceptance in mice through expansion of ST2(+) regulatory T cells Spotlight 

Focused on improving transplantation tolerance, Ganchiku et al. evaluated a long-lived, high-affinity receptor binding IL-2 mutein (mIL-2) in multiple solid organ transplantation models. mIL-2 therapy (with transient co-stimulation blockade) significantly improved long-term allograft survival in an Ag-specific manner, which persisted after cessation of treatment. Allograft survival was accompanied by Treg activation, decreased effector T cell activation, and reduced donor specific antibody levels. mIL-2-mediated allograft survival depended on expansion of highly active and suppressive tissue ST2+ Tregs and was abrogated in Treg-specific ST2 KO graft recipients.

Contributed by Katherine Turner

Focused on improving transplantation tolerance, Ganchiku et al. evaluated a long-lived, high-affinity receptor binding IL-2 mutein (mIL-2) in multiple solid organ transplantation models. mIL-2 therapy (with transient co-stimulation blockade) significantly improved long-term allograft survival in an Ag-specific manner, which persisted after cessation of treatment. Allograft survival was accompanied by Treg activation, decreased effector T cell activation, and reduced donor specific antibody levels. mIL-2-mediated allograft survival depended on expansion of highly active and suppressive tissue ST2+ Tregs and was abrogated in Treg-specific ST2 KO graft recipients.

Contributed by Katherine Turner

ABSTRACT: Although transplantation is the preferred treatment for end-stage organ disease, long-term outcomes are limited by immunosuppressive drug toxicity and immune-mediated injury. Selective in vivo expansion of regulatory T cells (Tregs) using interleukin-2 (IL-2) analogs has emerged as a strategy to induce antigen-specific transplant tolerance with fewer side effects. Herein, we investigate the therapeutic efficacy of an IL-2 mutein molecule (mIL-2) with enhanced receptor specificity and extended half-life in murine models of solid organ transplantation. mIL-2 therapy significantly improves allograft survival in an antigen-specific manner, accompanied by increased Treg activation, decreased effector T cell activation and reduced donor-specific antibody production. Transcriptional profiling reveals expansion of Tregs expressing the suppression of tumorigenicity 2 (ST2) Tregs with heightened activation status and suppressive function. Accordingly, the mIL-2-induced long-term allograft survival is abrogated in Treg-specific ST2 knockout graft recipients, underscoring the critical role of ST2(+) Tregs. These findings identify mIL-2 as an approach to promote long-term transplant tolerance while reducing reliance on conventional immunosuppression.

Author Info: (1) Center for Transplantation Sciences, Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA. Department of Gastroenterological Surg

Author Info: (1) Center for Transplantation Sciences, Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA. Department of Gastroenterological Surgery I, Graduate School of Medicine, Hokkaido University, Hokkaido, Japan. (2) Center for Transplantation Sciences, Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA. (3) Center for Transplantation Sciences, Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA. (4) Center for Transplantation Sciences, Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA. (5) Center for Transplantation Sciences, Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA. (6) Center for Transplantation Sciences, Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA. (7) Center for Immunology & Inflammatory Diseases, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA. Division of Pulmonary and Critical Care Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA. (8) Center for Immunology & Inflammatory Diseases, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA. Division of Rheumatology, Allergy & Immunology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA. (9) Visterra, Inc., Waltham, MA, USA. (10) Visterra, Inc., Waltham, MA, USA. (11) Center for Transplantation Sciences, Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA. (12) Center for Transplantation Sciences, Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA. (13) Center for Transplantation Sciences, Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA. (14) Center for Transplantation Sciences, Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA. LRIELLA@mgh.harvard.edu. Nephrology Division, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA. LRIELLA@mgh.harvard.edu.

Treg cells promote immunotherapy-induced immune evasion by restraining CD4 T cell control of MHC-I-deficient metastatic pancreatic cancer

Featured  

Schmiechen et al. found that variants of PDA that escaped following PD-L1 blockade showed epigenetic silencing of Tap1 expression, which induced loss of IFNγ-inducible MHC-I and reduced tumor cell killing mediated by CD8+ T cell. Escape variants also had an increased capacity for metastasis, which was promoted by Tregs and their suppressive effect on conventional CD4+ T cells. Combination strategies involving restoring IFNγ-inducible MHC-I, targeting Tregs, and enhancing Tconv enabled more effective cancer immunotherapy, suggesting potentially targetable mechanisms to enhance immunotherapy in PDA.

Schmiechen et al. found that variants of PDA that escaped following PD-L1 blockade showed epigenetic silencing of Tap1 expression, which induced loss of IFNγ-inducible MHC-I and reduced tumor cell killing mediated by CD8+ T cell. Escape variants also had an increased capacity for metastasis, which was promoted by Tregs and their suppressive effect on conventional CD4+ T cells. Combination strategies involving restoring IFNγ-inducible MHC-I, targeting Tregs, and enhancing Tconv enabled more effective cancer immunotherapy, suggesting potentially targetable mechanisms to enhance immunotherapy in PDA.

ABSTRACT: Mechanisms driving immunotherapy resistance in pancreatic cancer are poorly defined. We demonstrate that programmed death-ligand 1 immune checkpoint blockade promoted immune evasion by epigenetic Tap1 (transporter associated with antigen processing 1) silencing, increasing selection of metastatic tumor variants with defective interferon-_ (IFN-_)-inducible class I major histocompatibility complex (MHC-I) expression. Unleashing CD4 conventional T cells by regulatory T cell (T(reg) cell) depletion, transfer of tumor-reactive CD4 T cells, or anti-CTLA-4 prevented metastasis. Tumor-specific CD4 T cells adopted a TCF-1(+)SLAMF6(+) progenitor state in lymph nodes and differentiated in tumors. Anti-CTLA-4 increased intratumoral accumulation of CD4 T cells with stemness and tissue residency features, reduced metastasis, and induced gene signatures correlated with improved patient outcomes. MHC-I restoration with anti-CTLA-4 prolonged survival in murine models. In patient tumors, T(reg) cells and CD4 T cells colocalized, and abundance correlated with survival. These findings identify targetable mechanisms of immune evasion and metastasis in immunotherapy-resistant cancer.

Author Info: (1) Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, MN, USA. Center for Immunology, University of Minnesota Medical School, Minneapo

Author Info: (1) Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, MN, USA. Center for Immunology, University of Minnesota Medical School, Minneapolis, MN, USA. (2) Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, MN, USA. Center for Immunology, University of Minnesota Medical School, Minneapolis, MN, USA. (3) Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, MN, USA. Center for Immunology, University of Minnesota Medical School, Minneapolis, MN, USA. (4) Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, MN, USA. Center for Immunology, University of Minnesota Medical School, Minneapolis, MN, USA. (5) Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, MN, USA. Center for Immunology, University of Minnesota Medical School, Minneapolis, MN, USA. (6) Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA. (7) Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA. (8) Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, ON, Canada. Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada. (9) Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, MN, USA. Center for Immunology, University of Minnesota Medical School, Minneapolis, MN, USA. (10) Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, MN, USA. Center for Immunology, University of Minnesota Medical School, Minneapolis, MN, USA. (11) Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, MN, USA. Center for Immunology, University of Minnesota Medical School, Minneapolis, MN, USA. (12) Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, MN, USA. Center for Immunology, University of Minnesota Medical School, Minneapolis, MN, USA. (13) Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, MN, USA. Center for Immunology, University of Minnesota Medical School, Minneapolis, MN, USA. (14) Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, MN, USA. Center for Immunology, University of Minnesota Medical School, Minneapolis, MN, USA. (15) Institute for Health Informatics, University of Minnesota Medical School, Minneapolis, MN, USA. Clinical Translational Science Institute, University of Minnesota Medical School, Minneapolis, MN, USA. (16) Institute for Health Informatics, University of Minnesota Medical School, Minneapolis, MN, USA. Clinical Translational Science Institute, University of Minnesota Medical School, Minneapolis, MN, USA. (17) Institute for Health Informatics, University of Minnesota Medical School, Minneapolis, MN, USA. Clinical Translational Science Institute, University of Minnesota Medical School, Minneapolis, MN, USA. (18) Caris Life Sciences, Phoenix, AZ, USA. (19) Caris Life Sciences, Phoenix, AZ, USA. (20) Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, MN, USA. Center for Immunology, University of Minnesota Medical School, Minneapolis, MN, USA. (21) Institute for Health Informatics, University of Minnesota Medical School, Minneapolis, MN, USA. Clinical Translational Science Institute, University of Minnesota Medical School, Minneapolis, MN, USA. (22) Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, ON, Canada. Division of Oncology, Department of Statistical Sciences, University of Toronto, Toronto, ON, Canada. Ontario Institute for Cancer Research, Toronto, ON, Canada. Vector Institute, Toronto, ON, Canada. (23) Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA. (24) Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, MN, USA. Center for Immunology, University of Minnesota Medical School, Minneapolis, MN, USA. Masonic Cancer Center, University of Minnesota Medical School, Minneapolis, MN, USA.

Metabolic determinants of cancer immunotherapy outcomes identified by plasma profiling Spotlight 

Suissa and Fidelle et al. performed targeted metabolomics to 4,336 plasma samples from 1,714 ICI-treated patients across 16 cohorts and trained an ML model that predicted 12‑month PFS, with histidine as a favorable marker and long-chain fatty acids and succinate associated with poor outcome. Histidine supplementation promoted mitochondrial FAO and regulated T cell exhaustion, enhancing ICI-induced antitumor immunity in fibrosarcoma and melanoma models. Histidine-rich diet was associated with favorable PFS in patients without dysbiosis-associated histidine catabolism, and fecal histidine levels inversely correlated with severe irAEs.

Contributed by Shishir Pant

Suissa and Fidelle et al. performed targeted metabolomics to 4,336 plasma samples from 1,714 ICI-treated patients across 16 cohorts and trained an ML model that predicted 12‑month PFS, with histidine as a favorable marker and long-chain fatty acids and succinate associated with poor outcome. Histidine supplementation promoted mitochondrial FAO and regulated T cell exhaustion, enhancing ICI-induced antitumor immunity in fibrosarcoma and melanoma models. Histidine-rich diet was associated with favorable PFS in patients without dysbiosis-associated histidine catabolism, and fecal histidine levels inversely correlated with severe irAEs.

Contributed by Shishir Pant

ABSTRACT: Immune-checkpoint inhibitors benefit a subset of patients with advanced cancer, and the metabolic determinants of response remain unclear. Here, using targeted metabolomics and metagenomics, we profiled 4,336 plasma samples from 1,714 patients across five tumor types and 16 cohorts spanning Europe and North America, longitudinally sampled during five immune-checkpoint inhibitor-based treatment modalities, including fecal microbiota transplantation. A multimodal machine-learning framework integrating 154 metabolites with clinical variables identified five metabolites, age, body mass index and renal function as predictors of 12-month progression-free survival. The model achieved areas under the curve of 0.88 in training and 0.73 in validation cohorts of 105 and 30 patients, respectively and generalized across seven external cohorts. Histidine was a favorable prognostic feature of survival, whereas long-chain fatty acids and succinate were negatively associated with outcome. Histidine supplementation enhanced antitumor immunity in mice. Histidine-rich diets improved progression-free survival in patients lacking dysbiotic microbiome signatures associated with histidine catabolism.

Author Info: (1) UniversitŽ Paris-Saclay, Gustave Roussy, ClinicObiome, Inserm UMR1367, Microbiota and Mucosal Immunity for Cancer Immunotherapy, Villejuif, France. (2) UniversitŽ Paris-Saclay,

Author Info: (1) UniversitŽ Paris-Saclay, Gustave Roussy, ClinicObiome, Inserm UMR1367, Microbiota and Mucosal Immunity for Cancer Immunotherapy, Villejuif, France. (2) UniversitŽ Paris-Saclay, Gustave Roussy, ClinicObiome, Inserm UMR1367, Microbiota and Mucosal Immunity for Cancer Immunotherapy, Villejuif, France. (3) UniversitŽ Paris-Saclay, Gustave Roussy, ClinicObiome, Inserm UMR1367, Microbiota and Mucosal Immunity for Cancer Immunotherapy, Villejuif, France. (4) UniversitŽ Paris-Saclay, Gustave Roussy, ClinicObiome, Inserm UMR1367, Microbiota and Mucosal Immunity for Cancer Immunotherapy, Villejuif, France. (5) UniversitŽ Paris-Saclay, Gustave Roussy, ClinicObiome, Inserm UMR1367, Microbiota and Mucosal Immunity for Cancer Immunotherapy, Villejuif, France. (6) Department of Gastroenterology and Hepatology, University of Groningen and University Medical Center Groningen, Groningen, The Netherlands. Department of Medical Oncology, University of Groningen and University Medical Center Groningen, Groningen, The Netherlands. (7) INSERM U1138 - Metabolism, Cancer & Immunity, ƒquipe LabellisŽe par la Ligue Contre le Cancer, Centre de Recherche des Cordeliers, UniversitŽ Paris CitŽ, Sorbonne UniversitŽ, Paris, France. UniversitŽ Paris-Saclay, INSERM US23 AMMICa, Metabolomic Platform, Gustave Roussy, Villejuif, France. (8) INSERM U1138 - Metabolism, Cancer & Immunity, ƒquipe LabellisŽe par la Ligue Contre le Cancer, Centre de Recherche des Cordeliers, UniversitŽ Paris CitŽ, Sorbonne UniversitŽ, Paris, France. UniversitŽ Paris-Saclay, INSERM US23 AMMICa, Metabolomic Platform, Gustave Roussy, Villejuif, France. (9) Department of Immunology and Genomic Medicine, Center for Cancer Immunotherapy and Immunobiology (CCII), Graduate School of Medicine, Kyoto University, Kyoto, Japan. (10) UniversitŽ Paris-Saclay, Gustave Roussy, ClinicObiome, Inserm UMR1367, Microbiota and Mucosal Immunity for Cancer Immunotherapy, Villejuif, France. (11) UniversitŽ Paris-Saclay, Gustave Roussy, ClinicObiome, Inserm UMR1367, Microbiota and Mucosal Immunity for Cancer Immunotherapy, Villejuif, France. (12) UniversitŽ Paris-Saclay, Gustave Roussy, ClinicObiome, Inserm UMR1367, Microbiota and Mucosal Immunity for Cancer Immunotherapy, Villejuif, France. (13) UniversitŽ Paris-Saclay, Gustave Roussy, ClinicObiome, Inserm UMR1367, Microbiota and Mucosal Immunity for Cancer Immunotherapy, Villejuif, France. (14) UniversitŽ Paris-Saclay, Gustave Roussy, ClinicObiome, Inserm UMR1367, Microbiota and Mucosal Immunity for Cancer Immunotherapy, Villejuif, France. Oncoclinicas&Co - Medica Scientia Innovation Research (MEDSIR), Sao Paulo, Brazil. Gonalo Moniz Institute, Fiocruz, Salvador, Brazil. Federal University of Bahia, Salvador, Brazil. (15) Department of Radiation Oncology, Gustave Roussy, UniversitŽ Paris-Saclay, INSERM U1355, RHU LySAIRI, Villejuif, France. (16) Department of Therapeutic Innovation and Early Trials (DITEP), INSERM U981, Gustave Roussy, Villejuif, France. (17) Department of Computational, Cellular and Integrative Biology, University of Trento, Trento, Italy. (18) Department of Computational, Cellular and Integrative Biology, University of Trento, Trento, Italy. (19) Department of Medical Oncology, University of Groningen and University Medical Center Groningen, Groningen, The Netherlands. (20) Verspeeten Family Cancer Centre, London Health Sciences Research Institute, London, Ontario, Canada. Department of Pathology and Laboratory Medicine, Western University, London, Ontario, Canada. Department of Oncology, Division of Experimental Oncology, Schulich School of Medicine & Dentistry, Western University, London, Ontario, Canada. (21) Lawson Health Research Institute, London, Ontario, Canada. Department of Microbiology & Immunology, Western University, London, Ontario, Canada. Department of Medicine, Division of Infectious Diseases, Western University, London, Ontario, Canada. Division of Infectious Diseases, St Joseph's Health Care, London, Ontario, Canada. (22) Verspeeten Family Cancer Centre, London Health Sciences Research Institute, London, Ontario, Canada. Department of Oncology, Western University, London, Ontario, Canada. (23) Department of Twin Research and Genetic Epidemiology, King's College London, London, UK. Department of Dermatology, Mount Vernon Cancer Centre, Northwood, UK. Department of Dermatology, Hemel Hempstead Hospital, West Hertfordshire NHS Trust, Hemel Hempstead, UK. (24) Department of Thoracic Surgery, H™pital-Nord-APHM, Aix-Marseille University, Marseille, France. H™pital Marie Lannelongue, GHPSJ, Le Plessis-Robinson, France. (25) Research Unit Hypertension and Cardiovascular Epidemiology, KU Leuven Department of Cardiovascular Sciences, University of Leuven, Leuven, Belgium. (26) Department of Gastroenterology and Hepatology, University of Groningen and University Medical Center Groningen, Groningen, The Netherlands. (27) Centre de Recherche du Centre Hospitalier de l'UniversitŽ de MontrŽal (CRCHUM), Axe Cancer, Montreal, Quebec, Canada. (28) INSERM U1138 - Metabolism, Cancer & Immunity, ƒquipe LabellisŽe par la Ligue Contre le Cancer, Centre de Recherche des Cordeliers, UniversitŽ Paris CitŽ, Sorbonne UniversitŽ, Paris, France. UniversitŽ Paris-Saclay, INSERM US23 AMMICa, Metabolomic Platform, Gustave Roussy, Villejuif, France. (29) Department of Public Health, Erasmus Medical Centre - University Medical Centre Rotterdam, Rotterdam, The Netherlands. (30) Department of Public Health, Erasmus Medical Centre - University Medical Centre Rotterdam, Rotterdam, The Netherlands. (31) Department of Dermatology, Friedrich-Alexander-UniversitŠt Erlangen-NŸrnberg (FAU), UniversitŠtsklinikum Erlangen, Erlangen, Germany. Bavarian Cancer Research Center (BZKF), Erlangen, Germany. (32) Medical BioSciences, Radboud University Medical Center, Nijmegen, The Netherlands. (33) Centre de Recherche du Centre Hospitalier de l'UniversitŽ de MontrŽal (CRCHUM), Axe Cancer, Montreal, Quebec, Canada. Hemato-Oncology Division, Centre Hospitalier de l'UniversitŽ de MontrŽal (CHUM), Montreal, Quebec, Canada. (34) Dana-Farber Cancer Institute, Boston, MA, USA. Yale School of Medicine, New Haven, CT, USA. (35) Dana-Farber Cancer Institute, Boston, MA, USA. (36) Bavarian Cancer Research Center (BZKF), Erlangen, Germany. Department of Dermatology, University Hospital Regensburg, Regensburg, Germany. (37) Department of Dermatology, Goethe University Frankfurt, University Hospital, Frankfurt am Main, Germany. (38) Department of Translational Medicine and Surgery, Universitˆ Cattolica del Sacro Cuore, Facoltˆ di Medicina e Chirurgia, Rome, Italy. Department of Medical and Surgical Sciences, UOC CEMAD Centro Malattie dell'Apparato Digerente, Medicina Interna e Gastroenterologia, Fondazione Policlinico Universitario Gemelli IRCCS, Rome, Italy. (39) Department of Translational Medicine and Surgery, Universitˆ Cattolica del Sacro Cuore, Facoltˆ di Medicina e Chirurgia, Rome, Italy. Department of Medical and Surgical Sciences, UOC Oncologia Medica, Comprehensive Cancer Center, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome, Italy. (40) Department of Translational Medicine and Surgery, Universitˆ Cattolica del Sacro Cuore, Facoltˆ di Medicina e Chirurgia, Rome, Italy. Department of Medical and Surgical Sciences, UOC Oncologia Medica, Comprehensive Cancer Center, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome, Italy. (41) Unit of Medical Oncology 2, University Hospital of Pisa, Pisa, Italy. Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy. (42) Dana-Farber Cancer Institute, Boston, MA, USA. Harvard Medical School, Boston, MA, USA. (43) Centre de Recherche du Centre Hospitalier de l'UniversitŽ de MontrŽal (CRCHUM), Axe Cancer, Montreal, Quebec, Canada. Hemato-Oncology Division, Centre Hospitalier de l'UniversitŽ de MontrŽal (CHUM), Montreal, Quebec, Canada. (44) INSERM U1138 - Metabolism, Cancer & Immunity, ƒquipe LabellisŽe par la Ligue Contre le Cancer, Centre de Recherche des Cordeliers, UniversitŽ Paris CitŽ, Sorbonne UniversitŽ, Paris, France. UniversitŽ Paris-Saclay, INSERM US23 AMMICa, Metabolomic Platform, Gustave Roussy, Villejuif, France. Institut du Cancer Paris CARPEM, Department of Biology, H™pital EuropŽen Georges Pompidou, AP-HP, Paris, France. (45) Department of Dermatology, Friedrich-Alexander-UniversitŠt Erlangen-NŸrnberg (FAU), UniversitŠtsklinikum Erlangen, Erlangen, Germany. Bavarian Cancer Research Center (BZKF), Erlangen, Germany. Department of Dermatology and Allergy, LMU University Hospital LMU Munich, Munich, Germany. (46) Department of Immunology and Genomic Medicine, Center for Cancer Immunotherapy and Immunobiology (CCII), Graduate School of Medicine, Kyoto University, Kyoto, Japan. Division of Cancer Immune Regulation, Center for Cancer Immunotherapy and Immunobiology (CCII), Graduate School of Medicine, Kyoto University, Kyoto, Japan. (47) Department of Translational Medicine and Surgery, Universitˆ Cattolica del Sacro Cuore, Facoltˆ di Medicina e Chirurgia, Rome, Italy. Department of Medical and Surgical Sciences, UOC CEMAD Centro Malattie dell'Apparato Digerente, Medicina Interna e Gastroenterologia, Fondazione Policlinico Universitario Gemelli IRCCS, Rome, Italy. (48) Centre de Recherche du Centre Hospitalier de l'UniversitŽ de MontrŽal (CRCHUM), Axe Cancer, Montreal, Quebec, Canada. Hemato-Oncology Division, Centre Hospitalier de l'UniversitŽ de MontrŽal (CHUM), Montreal, Quebec, Canada. (49) UniversitŽ Paris-Saclay, Gustave Roussy, ClinicObiome, Inserm UMR1367, Microbiota and Mucosal Immunity for Cancer Immunotherapy, Villejuif, France. Department of Medical Oncology, Gustave Roussy, Villejuif, France. (50) MICS Laboratory, CentraleSupŽlec, UniversitŽ Paris-Saclay, Gif-sur-Yvette, France. nikos.paragios@centralesupelec.fr. TheraPanacea, Paris, France. nikos.paragios@centralesupelec.fr. (51) UniversitŽ Paris-Saclay, Gustave Roussy, ClinicObiome, Inserm UMR1367, Microbiota and Mucosal Immunity for Cancer Immunotherapy, Villejuif, France. Laurence.zitvogel@gustaveroussy.fr.

Case of complete response to immunotherapy in MMR-deficient prostate cancer associated with NK-like and CD4+CD8+ T cells

Spotlight 

In a patient with advanced prostate cancer, pembrolizumab resulted in CR and, followed by a radical prostatectomy, prevented recurrence out to 18mo. Tumor whole-exome NGS indicated dMMR/MSI-H and an extremely high TMB. Among PBMCs, CD56+ NK-like CD8+ T cells and CD4+CD8+ double-positive (DP) T cells were observed at high frequency relative to healthy donors, expressed cytotoxic/effector gene signatures and TEMRA phenotype, and clonally expanded after ICB. In other trials (prostate and dMMR/MSI-H cancers), CD56+CD8+ and DP T cells were found among TILs in ICB-treated patients, and DP T cell expansion was positively associated with patient response.

Contributed by Alex Najibi

In a patient with advanced prostate cancer, pembrolizumab resulted in CR and, followed by a radical prostatectomy, prevented recurrence out to 18mo. Tumor whole-exome NGS indicated dMMR/MSI-H and an extremely high TMB. Among PBMCs, CD56+ NK-like CD8+ T cells and CD4+CD8+ double-positive (DP) T cells were observed at high frequency relative to healthy donors, expressed cytotoxic/effector gene signatures and TEMRA phenotype, and clonally expanded after ICB. In other trials (prostate and dMMR/MSI-H cancers), CD56+CD8+ and DP T cells were found among TILs in ICB-treated patients, and DP T cell expansion was positively associated with patient response.

Contributed by Alex Najibi

ABSTRACT: Mismatch repair deficiency (dMMR) and microsatellite instability (MSI-H) are rare in prostate cancer, occurring in 2%-4% of cases. These defects result in increased genomic instability and elevated tumor mutational burden (TMB), which can support responses to immune checkpoint inhibitors (ICIs). Here, we report a patient with locally advanced Gleason 5 + 5 = 10 prostatic adenocarcinoma harboring MSH2 and MSH6 genomic deletions with ultrahigh TMB (>250 mutations/megabase) in whom pembrolizumab resulted in a striking complete radiographic, pathologic, and molecular response. Using digital-spatial microscopy, single-cell RNA/T cell receptor (TCR) sequencing, and multiplex cytometry, we identify atypical tumor-infiltrating T cells with natural killer-like phenotypes and CD4(+)CD8(+) (double-positive) lymphocytes. These clonal T cell populations expand preferentially following ICI and adopt terminally differentiated and cytotoxic profiles that may drive clinical response. Similar T cells are also present in diverse cancers and expand exclusively in ICI-responsive patients. These findings inform on the cellular mechanisms by which immunotherapies may mediate profound responses in patients with dMMR solid tumors.

Author Info: (1) Division of Hematology, Oncology and Transplantation, Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA; Masonic Cancer Center, University of Minnesot

Author Info: (1) Division of Hematology, Oncology and Transplantation, Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA; Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA; Center for Immunology, University of Minnesota, Minneapolis, MN 55455, USA. (2) Division of Hematology, Oncology and Transplantation, Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA; Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA. (3) Division of Hematology, Oncology and Transplantation, Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA; Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA. (4) Division of Hematology, Oncology and Transplantation, Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA; Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA. (5) Institute for Health Informatics, University of Minnesota, Minneapolis, MN 55455, USA; Clinical Translational Science Institute, University of Minnesota, Minneapolis, MN 55415, USA. (6) Division of Hematology, Oncology and Transplantation, Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA; Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA. (7) Division of Hematology, Oncology and Transplantation, Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA; Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA. (8) Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA. (9) Department of Pharmacology, University of Minnesota, Minneapolis, MN 55455, USA. (10) Division of Hematology, Oncology and Transplantation, Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA; Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA. (11) Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA. (12) Division of Infectious Diseases, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA. (13) Genitourinary Oncology Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA. (14) Genitourinary Oncology Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA. (15) Caris Life Sciences, Phoenix, AZ 85040, USA. (16) Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN 55455, USA. (17) Division of Hematology, Oncology and Transplantation, Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA; Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA. (18) Division of Hematology, Oncology and Transplantation, Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA; Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA. (19) Allina Health Cancer Institute, Minneapolis, MN 55407, USA. (20) Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA; Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN 55455, USA. (21) Division of Hematology, Oncology and Transplantation, Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA; Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA. (22) Institute for Health Informatics, University of Minnesota, Minneapolis, MN 55455, USA; Clinical Translational Science Institute, University of Minnesota, Minneapolis, MN 55415, USA. (23) Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA. (24) Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA. (25) Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA. (26) Division of Hematology, Oncology and Transplantation, Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA; Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA. (27) Division of Hematology, Oncology and Transplantation, Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA; Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA. Electronic address: anton401@umn.edu.

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