Journal Articles

Targeting MDA5 induces immunogenic cell death and promotes anti-tumor immunity

Niu and Cheng et al. found that the RNA sensor MDA5 promoted tumor immune evasion by suppressing the unfolded protein response and the release of DAMPs associated with immunogenic cell death (ICD). Targeting MDA5 in murine tumors enhanced ICD as well as DC antigen uptake and cross-talk with T cells, resulting in increased T cell activation, tumor infiltration, effector functions, and memory. MDA5 depletion also primed the ASK1-JNK/P38 pathway in tumors, increasing vulnerability to TNFα and IFNγ. In patient data, MDA5 was upregulated in cancer, and high pre-treatment MDA5 predicted poor survival and resistance to ICB across multiple cancers.

Contributed by Lauren Hitchings

Niu and Cheng et al. found that the RNA sensor MDA5 promoted tumor immune evasion by suppressing the unfolded protein response and the release of DAMPs associated with immunogenic cell death (ICD). Targeting MDA5 in murine tumors enhanced ICD as well as DC antigen uptake and cross-talk with T cells, resulting in increased T cell activation, tumor infiltration, effector functions, and memory. MDA5 depletion also primed the ASK1-JNK/P38 pathway in tumors, increasing vulnerability to TNFα and IFNγ. In patient data, MDA5 was upregulated in cancer, and high pre-treatment MDA5 predicted poor survival and resistance to ICB across multiple cancers.

Contributed by Lauren Hitchings

ABSTRACT: Identifying targets to enhance tumor immunity is an urgent need. Although nucleic acid sensors play critical roles in promoting tumor immune clearance, their exceptionally low mutation rate in cancers suggests potential unexplored roles in tumor progression. Here, we demonstrate that the RNA sensor melanoma differentiation-associated protein 5 (MDA5) promotes immune evasion, and its high expression is strongly predictive of poor survival and resistance to immune checkpoint blockade (ICB) therapy in patients. Targeting MDA5 reshapes the tumor microenvironment, strengthening immune memory responses and enhancing effector CD8⁺ T cell activity in preclinical models in female mice. Mechanistically, MDA5 deficiency triggers unfolded protein response driven immunogenic cell death through induction of damage-associated molecular patterns, leading to enhanced dendritic cell-mediated antigen engulfment and T cell activation. Additionally, MDA5 loss primes the ASK1-JNK/P38 signaling pathway, sensitizing tumor cells to TNF-α/IFN-γ, further amplifying this process. Consequently, targeting MDA5 enhances the efficacy of ICB therapy across multiple cancer types, positioning it as a promising therapeutic target.

Author Info: Guangdong Provincial Key laboratory of Colorectal and Pelvic Floor Disease, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, 510655, China Zhitong Niu, Bing Cheng,

Author Info: Guangdong Provincial Key laboratory of Colorectal and Pelvic Floor Disease, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, 510655, China Zhitong Niu, Bing Cheng, Yue Jiang, Yingzhen Weng, Qian Xiao, Chaoying Wei, Qiufeng Liu, Jinxin Chen, Xiaojian Wu & Wenyu WangGuangdong Institute of Gastroenterology, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, 510655, China Zhitong Niu, Bing Cheng, Yue Jiang, Yingzhen Weng, Qian Xiao, Chaoying Wei, Qiufeng Liu, Jinxin Chen, Xiaojian Wu & Wenyu WangBiomedical Innovation Center, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, 510655, China Zhitong Niu, Bing Cheng, Yue Jiang, Yingzhen Weng, Qian Xiao, Guojie Long, Chaoying Wei, Qiufeng Liu, Jinxin Chen, Xiaofeng Wen, Yufeng Chen, Yan Huang, Weidong Pan, Xiaojian Wu & Wenyu WangDepartment of General Surgery, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, 510655, China Guojie Long, Xiaofeng Wen, Yufeng Chen, Weidong Pan & Xiaojian WuThe First Affiliated Hospital of Jinan University, Guangzhou, 510630, China Panpan WangDepartment of Pathology, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, 510655, China Yan HuangState Key Laboratory of Oncology in South China, Guangdong Provincial Clinical Research Center for Cancer, Sun Yat-sen University Cancer Center, Guangzhou, 510060, China Jing TanLaboratory of Cancer Epigenome, Division of Medical Sciences, National Cancer Centre Singapore, Singapore, 168583, Singapore Jing TanHainan Academy of Medical Science, Hainan Medical University, Haikou, 571199, China Jing TanPharmacy college, Jinan University, Guangzhou, 510632, China Ronghua ZhangCancer research institute, Jinan University, Guangzhou, 510632, China Ronghua ZhangGenome Institute of Singapore, Agency for Science, Technology and Research (A*STAR), Biopolis, 138672, Singapore Qiang YuDepartment of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117597, Singapore Qiang YuCancer and Stem Cell Biology, Duke-NUS Medical School, Singapore, 169857, Singapore Qiang Yu

In vivo engineering of CAR natural killer cells for immunotherapy using ligand-directed lipid nanoparticles

Chen, Monkovic, and Mughal et al. used NK cell receptor-specific scFvs to generate NK cell-targeted LNPs (NtLNPs) that transfected up to 80% of circulating and tissue NK cells, with minimal off-target effects. NtLNP delivery of CAR mRNAs generated NK cells that specifically depleted B cells in healthy mice, restored AST/ALT to baseline levels in an autoimmune hepatitis model, and cleared antigen+ melanoma cells in a solid tumor model. NtLNPs targeting NKG2a boosted efficacy in solid tumor models by mitigating Qa-1b mediated immunosuppression. In vivo and ex vivo, NtLNP-generated human CAR NK cells induced regression in humanized lymphoma and T cell leukemia mouse models.

Contributed by Paula Hochman

Chen, Monkovic, and Mughal et al. used NK cell receptor-specific scFvs to generate NK cell-targeted LNPs (NtLNPs) that transfected up to 80% of circulating and tissue NK cells, with minimal off-target effects. NtLNP delivery of CAR mRNAs generated NK cells that specifically depleted B cells in healthy mice, restored AST/ALT to baseline levels in an autoimmune hepatitis model, and cleared antigen+ melanoma cells in a solid tumor model. NtLNPs targeting NKG2a boosted efficacy in solid tumor models by mitigating Qa-1b mediated immunosuppression. In vivo and ex vivo, NtLNP-generated human CAR NK cells induced regression in humanized lymphoma and T cell leukemia mouse models.

Contributed by Paula Hochman

ABSTRACT: Targeted lipid nanoparticles (LNPs) offer a nonviral approach for in vivo cell engineering but efficient programming of natural killer (NK) cells remains underexplored. Here we develop NK cell-targeted LNPs (NtLNPs) using engineered biparatopic NK cell ligands to drive receptor-specific uptake and mRNA delivery. Lead NtLNPs achieve up to ~80% NK cell transfection with minimal off-target effects in mice. Systemic delivery of chimeric antigen receptor (CAR) mRNA using NtLNPs generates CAR NK cells in vivo. CD19-targeted CAR NKs completely deplete circulating B cells in healthy mice and CD3-targeted CAR NKs eliminate nearly all autoreactive T cells in an autoimmune hepatitis model, highlighting a potential advantage over CAR T therapies for T cell-driven disease. In solid tumors, NtLNPs targeting the inhibitory checkpoint NKG2A enhance antitumor efficacy by relieving Qa-1(b)-mediated immunosuppression. Lastly, we optimized NtLNPs for in vivo engineering of human CAR NK cells, enabling regression of two humanized hematologic malignancy models and establishing NtLNPs as a modular immunotherapy system.

Author Info: (1) David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA. Department of Chemical Engineering, Massachusetts Institute

Author Info: (1) David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA. Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA. (2) David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA. Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA. (3) David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA. Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA. (4) David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA. Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA. (5) David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA. Harvard and MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, USA. (6) David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA. Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA. Department of Anesthesiology, Critical Care and Pain Medicine, Boston Children's Hospital, Boston, MA, USA. (7) David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA. Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA. (8) David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA. Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA. (9) David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA. Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA. (10) David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA. Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA. (11) David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA. Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA. (12) David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA. Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA. (13) David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA. Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA. (14) David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA. (15) David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA. Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA. Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA. Harvard and MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, USA. Department of Anesthesiology, Critical Care and Pain Medicine, Boston Children's Hospital, Boston, MA, USA. Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA. Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA. (16) David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA. dgander@mit.edu. Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA. dgander@mit.edu. Harvard and MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, USA. dgander@mit.edu. Department of Anesthesiology, Critical Care and Pain Medicine, Boston Children's Hospital, Boston, MA, USA. dgander@mit.edu. Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA. dgander@mit.edu.

Cullin-5 RING E3 ligase limits CD8⁺ T-cell persistence and effector responses during chronic antigen stimulation

Two recent back-to-back publications by Bachl et al. and Saco et al. used CRISPR-Cas9 knockout screens in primary human T cells exposed to repetitive antigen challenge and uncovered the enrichment of Cullin-RING Ligase 5 (CRL5) complex members over time with chronic antigen exposure. Knockouts of CRL5 components resulted in maintenance of antitumor effector function and delayed dysfunction. KO of these components in CAR-T or TCR-T cells improved tumor control in mice.

Two recent back-to-back publications by Bachl et al. and Saco et al. used CRISPR-Cas9 knockout screens in primary human T cells exposed to repetitive antigen challenge and uncovered the enrichment of Cullin-RING Ligase 5 (CRL5) complex members over time with chronic antigen exposure. Knockouts of CRL5 components resulted in maintenance of antitumor effector function and delayed dysfunction. KO of these components in CAR-T or TCR-T cells improved tumor control in mice.

ABSTRACT: T-cell exhaustion limits durable antitumor responses and remains a barrier to adoptive cell therapies (ACT) in solid tumors. To identify regulators of T-cell persistence, we performed genome-wide CRISPR knockout screens in primary human CD8_ T cells expressing an NY-ESO-1-specific T-cell receptor and subjected them to repeated tumor cell rechallenge. These screens revealed enrichment of single-guide RNAs targeting components of Cullin-RING E3 ligases, particularly Cullin-5 (CRL5) assemblies comprising CUL5, RNF7, and ARIH2. Disruption of CRL5 genes in T cells preserved cytotoxic activity and enhanced cytokine production while sustaining effector-associated transcriptional programs and suppressing exhaustion-related signatures. Pharmacologic inhibition of cullin neddylation with the NEDD8-activating enzyme inhibitor MLN4924 recapitulated CRL5 loss and enhanced T-cell effector function in vitro. In a human melanoma xenograft model, ACT with CRL5-deficient T cells improved tumor control. Together, these findings identify CRL5 as a negative regulator of T-cell fitness and a potential therapeutic target to enhance ACT durability in solid tumors.

Author Info: (1) University of California, Los Angeles Los Angeles, CA United States. ROR: https://ror.org/046rm7j60 (2) University of California, Los Angeles LA, CA United States. ROR: https:/

Author Info: (1) University of California, Los Angeles Los Angeles, CA United States. ROR: https://ror.org/046rm7j60 (2) University of California, Los Angeles LA, CA United States. ROR: https://ror.org/046rm7j60 (3) University of California, Los Angeles Los Angeles, CA United States. ROR: https://ror.org/046rm7j60 (4) Gladstone Institutes San Francisco, California United States. ROR: https://ror.org/038321296 (5) Gladstone Institutes San Francisco, California United States. ROR: https://ror.org/038321296 (6) University of California, San Francisco San Francisco, CA United States. ROR: https://ror.org/043mz5j54 (7) University of California, Los Angeles Los Angeles, CA United States. ROR: https://ror.org/046rm7j60 (8) University of California, Los Angeles Los Angeles, CA United States. ROR: https://ror.org/046rm7j60 (9) University of California, Los Angeles Los Angeles, CA United States. ROR: https://ror.org/046rm7j60 (10) University of California, Los Angeles Los Angeles, CA United States. ROR: https://ror.org/046rm7j60 (11) Dana-Farber Cancer Institute Boston United States. ROR: https://ror.org/02jzgtq86 (12) Max Planck Institute of Biochemistry Martinsried Germany. ROR: https://ror.org/04py35477 (13) University of California, Los Angeles Los Angeles, CA United States. ROR: https://ror.org/046rm7j60 (14) University of California, San Francisco San Francisco, CA United States. ROR: https://ror.org/043mz5j54 (15) University of California, Los Angeles Los Angeles, CA United States. ROR: https://ror.org/046rm7j60 (16) University of California, Los Angeles Los Angeles, CA United States. ROR: https://ror.org/046rm7j60

Disruption of the CRL5 ubiquitin ligase complex enhances engineered T-cell persistence under chronic tumor antigen exposure

Two recent back-to-back publications by Bachl et al. and Saco et al. used CRISPR-Cas9 knockout screens in primary human T cells exposed to repetitive antigen challenge and uncovered the enrichment of Cullin-RING Ligase 5 (CRL5) complex members over time with chronic antigen exposure. Knockouts of CRL5 components resulted in maintenance of antitumor effector function and delayed dysfunction. KO of these components in CAR-T or TCR-T cells improved tumor control in mice.

Two recent back-to-back publications by Bachl et al. and Saco et al. used CRISPR-Cas9 knockout screens in primary human T cells exposed to repetitive antigen challenge and uncovered the enrichment of Cullin-RING Ligase 5 (CRL5) complex members over time with chronic antigen exposure. Knockouts of CRL5 components resulted in maintenance of antitumor effector function and delayed dysfunction. KO of these components in CAR-T or TCR-T cells improved tumor control in mice.

ABSTRACT: Engineered T-cell therapies are limited by progressive dysfunction under chronic tumor antigen exposure, and genetic perturbation of negative regulators has emerged as a promising strategy to sustain effector activity. We reanalyzed a genome-wide CRISPR knockout screen in primary human T cells under repetitive tumor stimulation; protein-protein interaction mapping revealed seven members of the Cullin-RING Ligase 5 (CRL5) complex as an enriched hit cluster. Knockout of any of these members (CUL5, ARIH2, RNF7, UBE2F, UBE2L3, CISH, DCUN1D3) enhanced tumor serial killing, and CUL5, the complex scaffold, emerged as the strongest target. CUL5 knockout T cells exhibited sustained cytotoxicity, elevated effector cytokine production, and fewer exhaustion marker-positive cells while retaining antigen specificity and cytokine dependence. Quantitative ubiquitylation proteomics in resting, and acutely and chronically stimulated T cells mapped CRL5-dependent candidate substrates beyond the canonical JAK/STAT axis, including nutrient transporters, receptor trafficking proteins, and TCR signaling components. The benefit of CUL5 knockout extended across CARs targeting CD19, BCMA, and HER2 with different costimulatory domains, and to 1XX-modified CAR and HLA-independent TCR architectures. Combining CUL5 ablation with a tumor-induced IL-2 circuit produced tumor control across nine rounds of repetitive stimulation, whereas either modification alone eventually failed. In vivo, CUL5 knockout BCMA CAR T cells were enriched in the bone marrow following repeated tumor rechallenge and exhibited enhanced ex vivo cytotoxicity after nearly 90 days in tumor-bearing mice. These findings position CUL5 perturbation as a strategy to improve T-cell persistence and the efficacy of adoptive cell therapies, potentially with engineered cytokine support.

Author Info: (1) Gladstone Institutes San Francisco, California United States. ROR: https://ror.org/038321296 (2) Gladstone Institutes San Francisco, California United States. ROR: https://ror.

Author Info: (1) Gladstone Institutes San Francisco, California United States. ROR: https://ror.org/038321296 (2) Gladstone Institutes San Francisco, California United States. ROR: https://ror.org/038321296 (3) H™pital Saint-Louis Paris France. ROR: https://ror.org/049am9t04 (4) University of California San Francisco Medical Center United States. ROR: https://ror.org/01t8svj65 (5) University of California, San Francisco San Francisco, CA United States. ROR: https://ror.org/043mz5j54 (6) University of California, San Francisco San Francisco, CA United States. ROR: https://ror.org/043mz5j54 (7) University of California, San Francisco San Francisco, CA United States. ROR: https://ror.org/043mz5j54 (8) Gladstone Institutes United States. ROR: https://ror.org/038321296 (9) University of California, San Francisco San Francisco, CA United States. ROR: https://ror.org/043mz5j54 (10) University of California, San Francisco San Francisco, CA United States. ROR: https://ror.org/043mz5j54 (11) University of California, San Francisco San Francisco, CA United States. ROR: https://ror.org/043mz5j54 (12) University of California, San Francisco San Francisco, CA United States. ROR: https://ror.org/043mz5j54 (13) UCSF San Francisco, CA United States. (14) Tango Therapeutics (United States) Boston, Massachusetts United States. ROR: https://ror.org/003x6t567 (15) University of California, San Francisco San Francisco, California United States. ROR: https://ror.org/043mz5j54 (16) University of California, San Francisco San Francisco, California United States. ROR: https://ror.org/043mz5j54 (17) University of California, San Francisco San Francisco, CA United States. ROR: https://ror.org/043mz5j54 (18) University of California, San Francisco United States. ROR: https://ror.org/043mz5j54 (19) Gladstone Institutes San Francisco, California United States. ROR: https://ror.org/038321296 (20) UCSF San Francisco, CA United States. (21) University of California, San Francisco San Francisco, CA United States. ROR: https://ror.org/043mz5j54

Systemic antitumor responses to hypofractionated radiotherapy plus Poly(I:C) in advanced hepatocellular carcinoma: A phase 2 trial

In a phase 2 clinical trial in 37 patients with advanced HCC, Qiu et al. observed that adding s.c. Poly(I:C) to hypofractionated radiotherapy (HFRT) was well tolerated, and evaluable patients had better overall responses (54.5% vs. 21.2% with HRFT alone), abscopal responses, 6-month disease control, PFS, and OS, with even more pronounced benefits in subset of patients treated with a TKI (mostly lenvatinib, but also soratenib). Systemic responses were associated with increases in circulating CD28+CD8+ T cells. In mice, CD8+ T cells and CD28 co-stimulation were required for abscopal effects, and lenvatinib enhanced T cell infiltration by normalizing the tumor vasculature.

Contributed by Lauren Hitchings

In a phase 2 clinical trial in 37 patients with advanced HCC, Qiu et al. observed that adding s.c. Poly(I:C) to hypofractionated radiotherapy (HFRT) was well tolerated, and evaluable patients had better overall responses (54.5% vs. 21.2% with HRFT alone), abscopal responses, 6-month disease control, PFS, and OS, with even more pronounced benefits in subset of patients treated with a TKI (mostly lenvatinib, but also soratenib). Systemic responses were associated with increases in circulating CD28+CD8+ T cells. In mice, CD8+ T cells and CD28 co-stimulation were required for abscopal effects, and lenvatinib enhanced T cell infiltration by normalizing the tumor vasculature.

Contributed by Lauren Hitchings

BACKGROUND: The abscopal effect, regression of unirradiated tumors after localized radiotherapy, is rare. Whether hypofractionated radiotherapy (HFRT) plus the innate immune agonist polyinosinic-polycytidylic acid [Poly(I:C)] amplifies systemic antitumor immunity in advanced hepatocellular carcinoma is unclear. METHODS: In this single-arm, phase 2 trial (ChiCTR2100053441), 37 patients received HFRT plus subcutaneous Poly(I:C); 33 were response evaluable. Outcomes were compared with 33 propensity score-matched patients treated with HFRT alone. The primary endpoint was the objective response rate per RECIST v.1.1; secondary endpoints included progression-free survival, overall survival, and safety; and abscopal response was prespecified. Mechanisms were explored by single-cell RNA sequencing and flow cytometry in patients and by CD8 depletion and CD28 blockade in mice. FINDINGS: HFRT plus Poly(I:C) was well tolerated; it was associated with a higher objective response rate (54.5% vs. 21.2%; p = 0.011) and abscopal response rate (45.0% vs. 10.5%; p = 0.042) as well as longer progression-free survival (8.4 vs. 4.6 months; adjusted hazard ratio = 0.542; p = 0.042) and overall survival (not reached vs. 13.6 months; adjusted hazard ratio = 0.386; p = 0.011) vs. HFRT alone. The progression-free survival benefit was also higher in patients concurrently receiving tyrosine kinase inhibitors (p for interaction = 0.013). Peripheral CD8(+)CD28(+) T cell expansion correlated with abscopal tumor control; in mice, CD8(+) T cells and CD28 co-stimulation were required for this effect. CONCLUSIONS: HFRT plus Poly(I:C) showed promising systemic antitumor activity with manageable safety in advanced hepatocellular carcinoma, with CD8(+)CD28(+) T cells as an immune correlate of response. These exploratory findings warrant confirmation in randomized trials. FUNDING: The National Natural Science Foundation of China.

Author Info: (1) The United Innovation of Mengchao Hepatobiliary Technology Key Laboratory of Fujian Province, Mengchao Hepatobiliary Hospital of Fujian Medical University, Fuzhou, Fujian 35002

Author Info: (1) The United Innovation of Mengchao Hepatobiliary Technology Key Laboratory of Fujian Province, Mengchao Hepatobiliary Hospital of Fujian Medical University, Fuzhou, Fujian 350025, China; The Liver Center of Fujian Province, Fujian Medical University, Fuzhou, Fujian 350025, China. (2) Department of Radiotherapy, Mengchao Hepatobiliary Hospital of Fujian Medical University, Fuzhou, Fujian 350025, China. (3) The United Innovation of Mengchao Hepatobiliary Technology Key Laboratory of Fujian Province, Mengchao Hepatobiliary Hospital of Fujian Medical University, Fuzhou, Fujian 350025, China; The Liver Center of Fujian Province, Fujian Medical University, Fuzhou, Fujian 350025, China. (4) The United Innovation of Mengchao Hepatobiliary Technology Key Laboratory of Fujian Province, Mengchao Hepatobiliary Hospital of Fujian Medical University, Fuzhou, Fujian 350025, China; The Liver Center of Fujian Province, Fujian Medical University, Fuzhou, Fujian 350025, China. (5) Department of Radiotherapy, Mengchao Hepatobiliary Hospital of Fujian Medical University, Fuzhou, Fujian 350025, China. (6) Department of Radiotherapy, Mengchao Hepatobiliary Hospital of Fujian Medical University, Fuzhou, Fujian 350025, China. (7) The United Innovation of Mengchao Hepatobiliary Technology Key Laboratory of Fujian Province, Mengchao Hepatobiliary Hospital of Fujian Medical University, Fuzhou, Fujian 350025, China; The Liver Center of Fujian Province, Fujian Medical University, Fuzhou, Fujian 350025, China. (8) The United Innovation of Mengchao Hepatobiliary Technology Key Laboratory of Fujian Province, Mengchao Hepatobiliary Hospital of Fujian Medical University, Fuzhou, Fujian 350025, China; The Liver Center of Fujian Province, Fujian Medical University, Fuzhou, Fujian 350025, China. (9) The United Innovation of Mengchao Hepatobiliary Technology Key Laboratory of Fujian Province, Mengchao Hepatobiliary Hospital of Fujian Medical University, Fuzhou, Fujian 350025, China; The Liver Center of Fujian Province, Fujian Medical University, Fuzhou, Fujian 350025, China. (10) The United Innovation of Mengchao Hepatobiliary Technology Key Laboratory of Fujian Province, Mengchao Hepatobiliary Hospital of Fujian Medical University, Fuzhou, Fujian 350025, China; The Liver Center of Fujian Province, Fujian Medical University, Fuzhou, Fujian 350025, China. (11) The United Innovation of Mengchao Hepatobiliary Technology Key Laboratory of Fujian Province, Mengchao Hepatobiliary Hospital of Fujian Medical University, Fuzhou, Fujian 350025, China; The Liver Center of Fujian Province, Fujian Medical University, Fuzhou, Fujian 350025, China. (12) The United Innovation of Mengchao Hepatobiliary Technology Key Laboratory of Fujian Province, Mengchao Hepatobiliary Hospital of Fujian Medical University, Fuzhou, Fujian 350025, China; The Liver Center of Fujian Province, Fujian Medical University, Fuzhou, Fujian 350025, China. (13) Department of Radiotherapy, Mengchao Hepatobiliary Hospital of Fujian Medical University, Fuzhou, Fujian 350025, China. Electronic address: fjjhb8@sina.com. (14) The United Innovation of Mengchao Hepatobiliary Technology Key Laboratory of Fujian Province, Mengchao Hepatobiliary Hospital of Fujian Medical University, Fuzhou, Fujian 350025, China; The Liver Center of Fujian Province, Fujian Medical University, Fuzhou, Fujian 350025, China. Electronic address: caizhixiong1985@163.com. (15) The United Innovation of Mengchao Hepatobiliary Technology Key Laboratory of Fujian Province, Mengchao Hepatobiliary Hospital of Fujian Medical University, Fuzhou, Fujian 350025, China; The Liver Center of Fujian Province, Fujian Medical University, Fuzhou, Fujian 350025, China. Electronic address: xiaoloong.liu@gmail.com.

Propionate promotes MHC class I antigen presentation and anti-tumor immunity

Li et al. found that dietary supplementation with the short-chain fatty acid propionate could be used to stabilize and maintain expression of MHC-I in tumor cells by binding to the E3 ligase STUB1, blocking the K30 and N34 residues, and thus the direct interactions that would lead to STUB1-mediated polyubiquitination and lysosomal degradation of MHC-I. In mice, dietary propionate increased MHC-I on tumor cells, resulting in enhanced CD8+ T cell-mediated antitumor immunity and IFNγ production, which further increased tumor MHC-I. Propionate also improved the efficacy of anti-PD-1, as did the propionate-producing probiotic A. muciniphila.

Contributed by Lauren Hitchings

Li et al. found that dietary supplementation with the short-chain fatty acid propionate could be used to stabilize and maintain expression of MHC-I in tumor cells by binding to the E3 ligase STUB1, blocking the K30 and N34 residues, and thus the direct interactions that would lead to STUB1-mediated polyubiquitination and lysosomal degradation of MHC-I. In mice, dietary propionate increased MHC-I on tumor cells, resulting in enhanced CD8+ T cell-mediated antitumor immunity and IFNγ production, which further increased tumor MHC-I. Propionate also improved the efficacy of anti-PD-1, as did the propionate-producing probiotic A. muciniphila.

Contributed by Lauren Hitchings

ABSTRACT: Defective tumor antigen presentation promotes immune evasion and resistance to immune checkpoint blockade. Here, we identified the short-chain fatty acid propionate as a potent enhancer of major histocompatibility complex class I (MHC class I) antigen presentation. Propionate stabilizes MHC class I on tumor cells, promotes CD8(+) T cell infiltration and activation, and suppresses tumor growth. Mechanistically, the E3 ubiquitin (Ub) ligase STUB1 directly interacts with human leukocyte antigen (HLA)-A to mediate K168/K170 polyubiquitination and subsequent degradation. Propionate directly binds STUB1 through hydrogen bonds involving K30 and N34, residues that overlap with the MHC class I-binding interface. This interaction blocks STUB1-mediated MHC class I polyubiquitination, thereby stabilizing MHC class I, enhancing T cell receptor (TCR) engagement and T cell activation, and restraining tumor growth. Importantly, propionate or the propionate-producing probiotic Akkermansia muciniphila markedly enhanced anti-PD-1 efficacy. These findings uncover a non-metabolic moonlighting function of short-chain fatty acids in regulating tumor immunity and provide a rationale for leveraging dietary propionate or propionate-producing probiotics to enhance immune checkpoint therapy.

Author Info: (1) Zhejiang Key Laboratory of Pancreatic Disease, The First Affiliated Hospital, Zhejiang Key Laboratory of Frontier Medical Research on Cancer Metabolism, and Institute of Transl

Author Info: (1) Zhejiang Key Laboratory of Pancreatic Disease, The First Affiliated Hospital, Zhejiang Key Laboratory of Frontier Medical Research on Cancer Metabolism, and Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310029, China; Institute of Fundamental and Transdisciplinary Research, Zhejiang University Cancer Center, Zhejiang University, Hangzhou, Zhejiang 310029, China; The Center for Translational Research, The Second Affiliated Hospital and Institute of Translational Medicine, Zhejiang University, Hangzhou, Zhejiang 310029, China. (2) Department of Gastroenterology, Songjiang Research Institute, Shanghai Key Laboratory of Emotions and Affective Disorders, Songjiang Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 201600, China. Electronic address: dongguo@shsmu.edu.cn. (3) Zhejiang Key Laboratory of Pancreatic Disease, The First Affiliated Hospital, Zhejiang Key Laboratory of Frontier Medical Research on Cancer Metabolism, and Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310029, China; Institute of Fundamental and Transdisciplinary Research, Zhejiang University Cancer Center, Zhejiang University, Hangzhou, Zhejiang 310029, China; The Center for Translational Research, The Second Affiliated Hospital and Institute of Translational Medicine, Zhejiang University, Hangzhou, Zhejiang 310029, China. (4) Department of General Surgery, Pancreatic Disease Center, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China. (5) Zhejiang Key Laboratory of Pancreatic Disease, The First Affiliated Hospital, Zhejiang Key Laboratory of Frontier Medical Research on Cancer Metabolism, and Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310029, China. (6) Zhejiang Key Laboratory of Pancreatic Disease, The First Affiliated Hospital, Zhejiang Key Laboratory of Frontier Medical Research on Cancer Metabolism, and Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310029, China; Institute of Fundamental and Transdisciplinary Research, Zhejiang University Cancer Center, Zhejiang University, Hangzhou, Zhejiang 310029, China; The Center for Translational Research, The Second Affiliated Hospital and Institute of Translational Medicine, Zhejiang University, Hangzhou, Zhejiang 310029, China. (7) Department of Hepatobiliary and Pancreatic Surgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310029, China. (8) Zhejiang Key Laboratory of Pancreatic Disease, The First Affiliated Hospital, Zhejiang Key Laboratory of Frontier Medical Research on Cancer Metabolism, and Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310029, China; Institute of Fundamental and Transdisciplinary Research, Zhejiang University Cancer Center, Zhejiang University, Hangzhou, Zhejiang 310029, China; The Center for Translational Research, The Second Affiliated Hospital and Institute of Translational Medicine, Zhejiang University, Hangzhou, Zhejiang 310029, China. (9) Zhejiang Key Laboratory of Pancreatic Disease, The First Affiliated Hospital, Zhejiang Key Laboratory of Frontier Medical Research on Cancer Metabolism, and Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310029, China; Institute of Fundamental and Transdisciplinary Research, Zhejiang University Cancer Center, Zhejiang University, Hangzhou, Zhejiang 310029, China; The Center for Translational Research, The Second Affiliated Hospital and Institute of Translational Medicine, Zhejiang University, Hangzhou, Zhejiang 310029, China. (10) Zhejiang Key Laboratory of Pancreatic Disease, The First Affiliated Hospital, Zhejiang Key Laboratory of Frontier Medical Research on Cancer Metabolism, and Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310029, China; Institute of Fundamental and Transdisciplinary Research, Zhejiang University Cancer Center, Zhejiang University, Hangzhou, Zhejiang 310029, China; The Center for Translational Research, The Second Affiliated Hospital and Institute of Translational Medicine, Zhejiang University, Hangzhou, Zhejiang 310029, China. (11) Zhejiang Key Laboratory of Pancreatic Disease, The First Affiliated Hospital, Zhejiang Key Laboratory of Frontier Medical Research on Cancer Metabolism, and Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310029, China; Institute of Fundamental and Transdisciplinary Research, Zhejiang University Cancer Center, Zhejiang University, Hangzhou, Zhejiang 310029, China; The Center for Translational Research, The Second Affiliated Hospital and Institute of Translational Medicine, Zhejiang University, Hangzhou, Zhejiang 310029, China. (12) Zhejiang Key Laboratory of Pancreatic Disease, The First Affiliated Hospital, Zhejiang Key Laboratory of Frontier Medical Research on Cancer Metabolism, and Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310029, China; Institute of Fundamental and Transdisciplinary Research, Zhejiang University Cancer Center, Zhejiang University, Hangzhou, Zhejiang 310029, China; The Center for Translational Research, The Second Affiliated Hospital and Institute of Translational Medicine, Zhejiang University, Hangzhou, Zhejiang 310029, China. (13) Zhejiang Key Laboratory of Pancreatic Disease, The First Affiliated Hospital, Zhejiang Key Laboratory of Frontier Medical Research on Cancer Metabolism, and Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310029, China; Institute of Fundamental and Transdisciplinary Research, Zhejiang University Cancer Center, Zhejiang University, Hangzhou, Zhejiang 310029, China; The Center for Translational Research, The Second Affiliated Hospital and Institute of Translational Medicine, Zhejiang University, Hangzhou, Zhejiang 310029, China. (14) Key Laboratory of Cancer Prevention and Intervention, China National Ministry of Education, Zhejiang Provincial Clinical Research Center for Cancer, Department of Medical Oncology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Cancer Center, Zhejiang University, Hangzhou, Zhejiang 310058, China. (15) Zhejiang Key Laboratory of Pancreatic Disease, The First Affiliated Hospital, Zhejiang Key Laboratory of Frontier Medical Research on Cancer Metabolism, and Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310029, China; Institute of Fundamental and Transdisciplinary Research, Zhejiang University Cancer Center, Zhejiang University, Hangzhou, Zhejiang 310029, China; The Center for Translational Research, The Second Affiliated Hospital and Institute of Translational Medicine, Zhejiang University, Hangzhou, Zhejiang 310029, China. (16) Zhejiang Key Laboratory of Pancreatic Disease, The First Affiliated Hospital, Zhejiang Key Laboratory of Frontier Medical Research on Cancer Metabolism, and Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310029, China. (17) Zhejiang Key Laboratory of Pancreatic Disease, The First Affiliated Hospital, Zhejiang Key Laboratory of Frontier Medical Research on Cancer Metabolism, and Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310029, China; Institute of Fundamental and Transdisciplinary Research, Zhejiang University Cancer Center, Zhejiang University, Hangzhou, Zhejiang 310029, China; The Center for Translational Research, The Second Affiliated Hospital and Institute of Translational Medicine, Zhejiang University, Hangzhou, Zhejiang 310029, China. (18) Center for Regeneration and Aging Medicine, The Fourth Affiliated Hospital of School of Medicine, International School of Medicine, International Institutes of Medicine, Zhejiang University, Yiwu, Zhejiang 322000, China. (19) Key Laboratory of Cancer Prevention and Intervention, China National Ministry of Education, Zhejiang Provincial Clinical Research Center for Cancer, Department of Medical Oncology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Cancer Center, Zhejiang University, Hangzhou, Zhejiang 310058, China. (20) Zhejiang Key Laboratory of Pancreatic Disease, The First Affiliated Hospital, Zhejiang Key Laboratory of Frontier Medical Research on Cancer Metabolism, and Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310029, China; Institute of Fundamental and Transdisciplinary Research, Zhejiang University Cancer Center, Zhejiang University, Hangzhou, Zhejiang 310029, China; The Center for Translational Research, The Second Affiliated Hospital and Institute of Translational Medicine, Zhejiang University, Hangzhou, Zhejiang 310029, China. (21) Department of Hepatobiliary and Pancreatic Surgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310029, China. Electronic address: wam@zju.edu.cn. (22) Department of Hepatobiliary and Pancreatic Surgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310029, China. Electronic address: dingyuan@zju.edu.cn. (23) Zhejiang Key Laboratory of Pancreatic Disease, The First Affiliated Hospital, Zhejiang Key Laboratory of Frontier Medical Research on Cancer Metabolism, and Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310029, China; Institute of Fundamental and Transdisciplinary Research, Zhejiang University Cancer Center, Zhejiang University, Hangzhou, Zhejiang 310029, China; The Center for Translational Research, The Second Affiliated Hospital and Institute of Translational Medicine, Zhejiang University, Hangzhou, Zhejiang 310029, China. Electronic address: zhiminlu@zju.edu.cn.

Lifestyle-induced regulatory T cell fragility primes adverse events after immune checkpoint blockade

Patra et al. fed mice a low-fiber, high-fat Western diet (inducing dysbiosis and outgrowth of Akkermansia) and treated them with anti-PD-1 to obtain the lifestyle-induced susceptibility to immune-related adverse events (irAEs) mouse model, LISA. LISA recapitulated the ICB toxicity profile affecting many patients, and was influenced by known demographic factors. Cytotoxic tissue-resident memory CD8+ T cells (TRM) and Tregs were increased in affected tissues. Tregs were fragile, less suppressive, and secreted IFNγ. Treg-specific disruption of IFNγ production or signaling and dietary reversal reduced irAE severity, but not antitumor efficacy. Treg fragility and cytotoxic TRM were also present in human irColitis.

Contributed by Ute Burkhardt

Patra et al. fed mice a low-fiber, high-fat Western diet (inducing dysbiosis and outgrowth of Akkermansia) and treated them with anti-PD-1 to obtain the lifestyle-induced susceptibility to immune-related adverse events (irAEs) mouse model, LISA. LISA recapitulated the ICB toxicity profile affecting many patients, and was influenced by known demographic factors. Cytotoxic tissue-resident memory CD8+ T cells (TRM) and Tregs were increased in affected tissues. Tregs were fragile, less suppressive, and secreted IFNγ. Treg-specific disruption of IFNγ production or signaling and dietary reversal reduced irAE severity, but not antitumor efficacy. Treg fragility and cytotoxic TRM were also present in human irColitis.

Contributed by Ute Burkhardt

ABSTRACT: Immune checkpoint blockade has transformed cancer therapy, but immune-related adverse events (irAEs) remain a major, sometimes fatal, limitation, and the lack of robust preclinical models has hindered mechanistic insight. We present the lifestyle-induced susceptibility to irAEs (LISA) model, in which diet-driven metabolic and microbial alterations recreate human-like susceptibility to anti-PD-1 toxicity. LISA recapitulates multi-organ irAEs with immune infiltration and cytokine production, severity depending on sex, age, treatment modality, and immunotherapy response. Mechanistically, dysbiosis marked by Akkermansia muciniphila enrichment accompanies aberrant immune activation, driving regulatory T cell (Treg) fragility and CD8+ cytotoxic effector populations, both observed in patients with irColitis. Dietary reversal, metabolite supplementation, and blocking interferon (IFN)-γ production or signaling in Tregs restored Treg stability and resolved inflammation. Human-to-mouse fecal microbiome transfer interacts with recipient diet to shape susceptibility. Together, these findings identify dietary, microbial, and immune drivers of irAEs, which can be leveraged to improve immunotherapy responses while minimizing toxicity.

Author Info: (1) UPMC Hillman Cancer Center, Pittsburgh, PA 15206, USA; Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15206, USA; Tumor Microenvironment

Author Info: (1) UPMC Hillman Cancer Center, Pittsburgh, PA 15206, USA; Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15206, USA; Tumor Microenvironment Center, UPMC Hillman Cancer Center, Pittsburgh, PA 15206, USA. (2) UPMC Hillman Cancer Center, Pittsburgh, PA 15206, USA; Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15206, USA; Tumor Microenvironment Center, UPMC Hillman Cancer Center, Pittsburgh, PA 15206, USA; Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA. (3) UPMC Hillman Cancer Center, Pittsburgh, PA 15206, USA; Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15206, USA; Tumor Microenvironment Center, UPMC Hillman Cancer Center, Pittsburgh, PA 15206, USA; Program in Microbiology and Immunology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA. (4) Division of Laboratory Animal Resources, UPMC Hillman Cancer Center, Pittsburgh, PA 15213, USA. (5) UPMC Hillman Cancer Center, Pittsburgh, PA 15206, USA; Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15206, USA; Tumor Microenvironment Center, UPMC Hillman Cancer Center, Pittsburgh, PA 15206, USA; Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA. (6) UPMC Hillman Cancer Center, Pittsburgh, PA 15206, USA; Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15206, USA; Tumor Microenvironment Center, UPMC Hillman Cancer Center, Pittsburgh, PA 15206, USA. (7) UPMC Hillman Cancer Center, Pittsburgh, PA 15206, USA; Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15206, USA; Tumor Microenvironment Center, UPMC Hillman Cancer Center, Pittsburgh, PA 15206, USA; Program in Microbiology and Immunology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA. (8) UPMC Hillman Cancer Center, Pittsburgh, PA 15206, USA; Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15206, USA; Tumor Microenvironment Center, UPMC Hillman Cancer Center, Pittsburgh, PA 15206, USA. (9) UPMC Hillman Cancer Center, Pittsburgh, PA 15206, USA. (10) UPMC Hillman Cancer Center, Pittsburgh, PA 15206, USA; Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15206, USA; Tumor Microenvironment Center, UPMC Hillman Cancer Center, Pittsburgh, PA 15206, USA. (11) Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; Health Sciences Mass Spectrometry Core, University of Pittsburgh, Pittsburgh, PA 15213, USA. (12) UPMC Hillman Cancer Center, Pittsburgh, PA 15206, USA; Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15206, USA; Tumor Microenvironment Center, UPMC Hillman Cancer Center, Pittsburgh, PA 15206, USA; Cellular and Molecular Pathology Program, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA. (13) Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; Health Sciences Mass Spectrometry Core, University of Pittsburgh, Pittsburgh, PA 15213, USA. (14) UPMC Hillman Cancer Center, Pittsburgh, PA 15206, USA; Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15206, USA; Tumor Microenvironment Center, UPMC Hillman Cancer Center, Pittsburgh, PA 15206, USA. (15) UPMC Hillman Cancer Center, Pittsburgh, PA 15206, USA. (16) UPMC Hillman Cancer Center, Pittsburgh, PA 15206, USA; Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15206, USA; Tumor Microenvironment Center, UPMC Hillman Cancer Center, Pittsburgh, PA 15206, USA; Center for Systems Immunology, Department of Immunology, University of Pittsburgh, Pittsburgh, PA 15206, USA. (17) UPMC Hillman Cancer Center, Pittsburgh, PA 15206, USA; Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15206, USA; Tumor Microenvironment Center, UPMC Hillman Cancer Center, Pittsburgh, PA 15206, USA. (18) UPMC Hillman Cancer Center, Pittsburgh, PA 15206, USA; Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15206, USA; Tumor Microenvironment Center, UPMC Hillman Cancer Center, Pittsburgh, PA 15206, USA. Electronic address: overacre@pitt.edu.

Perforin triggers iron-induced mitochondrial damage to drive ferroptosis and anti-tumor immunity

Bell et al. discovered a previously unrecognized, granzyme-independent function of perforin (Prf1) in CTLs and NK cells that showed that Prf1 can directly kill tumor cells via ferroptosis. Mechanistically, Prf1 induced transferrin receptor (CD71) endocytosis, leading to increased cellular iron uptake. Via endosomal–mitochondrial contacts, this subsequently elevated mitochondrial iron and lipid peroxidation, and tumor cell ferroptosis. In murine studies, dietary iron supplementation potentiated antitumor immunity in a Prf1-dependent manner, while in patients with cancer, higher Prf1 expression correlated with longer survival and improved responses to ICB.

Contributed by Katherine Turner

Bell et al. discovered a previously unrecognized, granzyme-independent function of perforin (Prf1) in CTLs and NK cells that showed that Prf1 can directly kill tumor cells via ferroptosis. Mechanistically, Prf1 induced transferrin receptor (CD71) endocytosis, leading to increased cellular iron uptake. Via endosomal–mitochondrial contacts, this subsequently elevated mitochondrial iron and lipid peroxidation, and tumor cell ferroptosis. In murine studies, dietary iron supplementation potentiated antitumor immunity in a Prf1-dependent manner, while in patients with cancer, higher Prf1 expression correlated with longer survival and improved responses to ICB.

Contributed by Katherine Turner

ABSTRACT: Cytotoxic CD8(+) T cells and natural killer cells are critical effectors of anti-tumor immunity. Cytotoxic lymphocytes eliminate tumor cells by releasing perforin (Prf1), a pore-forming protein that enables granzymes (Gzms) to enter target cells and trigger both caspase-dependent and -independent cell death. Here, we uncover a previously unrecognized, Gzm-independent function of Prf1. We find that Prf1 directly induces tumoral ferroptosis, an iron- and lipid-dependent form of cell death. Mechanistically, Prf1-mediated pore formation drives endocytosis of the transferrin receptor, which increases cellular iron uptake. Prf1 promotes the formation of endosomal-mitochondrial contacts, which leads to mitochondrial iron accumulation, mitochondrial dysfunction, and tumor cell ferroptosis. Dietary iron supplementation suppresses tumor progression in murine tumor models in a Prf1-dependent manner. Higher Prf1 expression correlates with improved survival and enhanced response to immune checkpoint blockade in patients with cancer. These findings define a Gzm-independent function of Prf1 as a direct executioner of cancer cell death through ferroptosis.

Author Info: (1) Department of Surgery, University of Michigan School of Medicine, Ann Arbor, MI, USA; Center of Excellence for Cancer Immunology and Immunotherapy, University of Michigan Rogel

Author Info: (1) Department of Surgery, University of Michigan School of Medicine, Ann Arbor, MI, USA; Center of Excellence for Cancer Immunology and Immunotherapy, University of Michigan Rogel Cancer Center, Ann Arbor, MI, USA. (2) Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY, USA. (3) Department of Surgery, University of Michigan School of Medicine, Ann Arbor, MI, USA; Center of Excellence for Cancer Immunology and Immunotherapy, University of Michigan Rogel Cancer Center, Ann Arbor, MI, USA; Graduate Program in Immunology, University of Michigan, Ann Arbor, MI, USA. (4) Department of Surgery, University of Michigan School of Medicine, Ann Arbor, MI, USA; Center of Excellence for Cancer Immunology and Immunotherapy, University of Michigan Rogel Cancer Center, Ann Arbor, MI, USA. (5) Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA. (6) Department of Molecular & Physiology, University of Michigan, Ann Arbor, MI, USA. (7) Program in Cellular and Molecular Medicine, Boston Children's Hospital and Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA. (8) Program in Cellular and Molecular Medicine, Boston Children's Hospital and Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA. (9) Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA. (10) Department of Surgery, University of Michigan School of Medicine, Ann Arbor, MI, USA; Center of Excellence for Cancer Immunology and Immunotherapy, University of Michigan Rogel Cancer Center, Ann Arbor, MI, USA. (11) Department of Surgery, University of Michigan School of Medicine, Ann Arbor, MI, USA; Center of Excellence for Cancer Immunology and Immunotherapy, University of Michigan Rogel Cancer Center, Ann Arbor, MI, USA. (12) Department of Molecular & Physiology, University of Michigan, Ann Arbor, MI, USA. (13) Department of Molecular & Physiology, University of Michigan, Ann Arbor, MI, USA. (14) Program in Cellular and Molecular Medicine, Boston Children's Hospital and Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA. (15) Cancer Immunology Program, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia. (16) Department of Surgery, University of Michigan School of Medicine, Ann Arbor, MI, USA; Center of Excellence for Cancer Immunology and Immunotherapy, University of Michigan Rogel Cancer Center, Ann Arbor, MI, USA. (17) Department of Surgery, University of Michigan School of Medicine, Ann Arbor, MI, USA; Center of Excellence for Cancer Immunology and Immunotherapy, University of Michigan Rogel Cancer Center, Ann Arbor, MI, USA. (18) Department of Surgery, University of Michigan School of Medicine, Ann Arbor, MI, USA; Center of Excellence for Cancer Immunology and Immunotherapy, University of Michigan Rogel Cancer Center, Ann Arbor, MI, USA; Graduate Program in Immunology, University of Michigan, Ann Arbor, MI, USA. (19) Department of Surgery, University of Michigan School of Medicine, Ann Arbor, MI, USA; Center of Excellence for Cancer Immunology and Immunotherapy, University of Michigan Rogel Cancer Center, Ann Arbor, MI, USA; Graduate Program in Immunology, University of Michigan, Ann Arbor, MI, USA. (20) Department of Surgery, University of Michigan School of Medicine, Ann Arbor, MI, USA. (21) Department of Surgery, University of Michigan School of Medicine, Ann Arbor, MI, USA. (22) Department of Surgery, University of Michigan School of Medicine, Ann Arbor, MI, USA. (23) Cayman Chemical, Ann Arbor, MI, USA. (24) Cayman Chemical, Ann Arbor, MI, USA. (25) Department of Molecular & Physiology, University of Michigan, Ann Arbor, MI, USA; Department of Internal Medicine, Division of Gastroenterology, University of Michigan, Ann Arbor, MI, USA. (26) Department of Surgery, University of Michigan School of Medicine, Ann Arbor, MI, USA; Center of Excellence for Cancer Immunology and Immunotherapy, University of Michigan Rogel Cancer Center, Ann Arbor, MI, USA; Graduate Program in Immunology, University of Michigan, Ann Arbor, MI, USA. Electronic address: ilonak@umich.edu. (27) Cancer Immunology Program, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia. (28) Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY, USA. Electronic address: barrosm@amc.edu. (29) Program in Cellular and Molecular Medicine, Boston Children's Hospital and Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA. Electronic address: judy.lieberman@childrens.harvard.edu. (30) Department of Surgery, University of Michigan School of Medicine, Ann Arbor, MI, USA; Center of Excellence for Cancer Immunology and Immunotherapy, University of Michigan Rogel Cancer Center, Ann Arbor, MI, USA; Graduate Program in Immunology, University of Michigan, Ann Arbor, MI, USA. Electronic address: wzou@umich.edu.

A reciprocally masked anti-CD47/IL-2 fusion protein promotes antitumor immunity and limits systemic toxicity Spotlight 

To overcome the dose-limiting toxicity associated with both CD47-targeting antibodies and IL-2, Léchine, Cons, and Garnier et al. developed a reciprocally masked antibody-cytokine fusion (aCD47/IL-2c) that only unmasks its components when cleavable linkers are broken by MMP9 in the TIME. In mouse models, aCD47/IL-2c was better tolerated than either component alone. Antitumor efficacy was dependent on both components, which together induced pro-inflammatory macrophage polarization and increased effector CD8+ T cell infiltration. Antitumor efficacy and tolerability were also observed for a human aCD47/IL-2c in a humanized mouse model.

Contributed by Lauren Hitchings

To overcome the dose-limiting toxicity associated with both CD47-targeting antibodies and IL-2, Léchine, Cons, and Garnier et al. developed a reciprocally masked antibody-cytokine fusion (aCD47/IL-2c) that only unmasks its components when cleavable linkers are broken by MMP9 in the TIME. In mouse models, aCD47/IL-2c was better tolerated than either component alone. Antitumor efficacy was dependent on both components, which together induced pro-inflammatory macrophage polarization and increased effector CD8+ T cell infiltration. Antitumor efficacy and tolerability were also observed for a human aCD47/IL-2c in a humanized mouse model.

Contributed by Lauren Hitchings

ABSTRACT: Cancer immunotherapies have achieved meaningful clinical benefit but remain limited by systemic toxicities that restrict the use of potent immune modulators. CD47-targeting antibodies promote tumor cell phagocytosis but are hindered by hematologic toxicity, while IL-2 activates cytotoxic lymphocytes but induces broad, dose-limiting immune activation. Here, we engineered a reciprocally masked antibody-cytokine fusion (aCD47/IL-2c) designed for tumor-selective activation. In this construct, a CD47-specific antibody (aCD47) and an IL-2/IL-2 receptor complex (IL2c) sterically and functionally suppress each other via protease-cleavable linkers, preventing CD47 blockade and IL-2 receptor engagement in circulation while enabling protease-dependent unmasking within the tumor microenvironment. A human construct demonstrated masking and protease-dependent restoration of both CD47-SIRP_ blockade and IL-2 signaling, with improved systemic tolerability in human hCD47/hSIRP_ transgenic mice, supporting translational potential. A murine analog enabled mechanistic and efficacy studies in immunocompetent tumor models. The tolerability of mouse aCD47/IL-2c was improved in comparison to individual components. Antitumor activity required both CD47 blockade and IL-2 activity, and resulted in a robust antitumor efficacy, including in an immune checkpoint-resistant melanoma model. The robust antitumor efficacy was associated with inflammatory macrophage polarization and increased numbers of effector CD8_ T cells inside the tumor. Unlike conventional CD47 antibodies or IL-2 therapies, this approach enabled coordinated, tumor-localized activation of innate and adaptive immunity while limiting systemic exposure. Together, these data highlight reciprocal masking as a clinically relevant strategy to expand the therapeutic index of immune modulators constrained by systemic toxicity.

Author Info: (1) Light Chain Bioscience (Switzerland) Plan-les-Ouates Switzerland. ROR: https://ror.org/03a17f132 (2) Light Chain Bioscience (Switzerland) Plan-les-Ouates Switzerland. ROR: http

Author Info: (1) Light Chain Bioscience (Switzerland) Plan-les-Ouates Switzerland. ROR: https://ror.org/03a17f132 (2) Light Chain Bioscience (Switzerland) Plan-les-Ouates Switzerland. ROR: https://ror.org/03a17f132 (3) University of Geneva Geneva Switzerland. ROR: https://ror.org/01swzsf04 (4) Light Chain Bioscience (Switzerland) Plan-Les-Ouates, Geneva Switzerland. ROR: https://ror.org/03a17f132 (5) Light Chain Bioscience (Switzerland) Plan-Les-Ouates, Geneva Switzerland. ROR: https://ror.org/03a17f132 (6) Memorial Sloan Kettering Cancer Center New York City, New York United States. ROR: https://ror.org/02yrq0923 (7) Light Chain Bioscience. (8) Light Chain Bioscience (Switzerland) Plan-Les-Ouates, Geneva Switzerland. ROR: https://ror.org/03a17f132 (9) Geneva Medical School Geneva Switzerland. (10) University of Geneva Geneva Switzerland. ROR: https://ror.org/01swzsf04 (11) Light Chain Bioscience (Switzerland) Plan-les-Ouates, Geneva Switzerland. ROR: https://ror.org/03a17f132

The human gut microbiome primes fever after vaccination Spotlight 

Huus et al. studied the impact of the SARS-CoV-2 mRNA vaccine on the gut microbiome–immune axis in 171 healthy volunteers. Participants with temperatures ≥ 0.8ºC above personal baseline upon vaccination demonstrated chronic low-grade intestinal inflammation, high expression of flagellin, and abundance of flagellated bacteria. In mice, the microbiome from these participants drove innate immune detection of flagellin by TLR5 and NLRC4, and vaccine-induced adverse reactions. Western diet and common food additives boosted the abundance of flagellated bacteria and microbial flagellin production in vitro and in vivo.

Contributed by Ute Burkhardt

Huus et al. studied the impact of the SARS-CoV-2 mRNA vaccine on the gut microbiome–immune axis in 171 healthy volunteers. Participants with temperatures ≥ 0.8ºC above personal baseline upon vaccination demonstrated chronic low-grade intestinal inflammation, high expression of flagellin, and abundance of flagellated bacteria. In mice, the microbiome from these participants drove innate immune detection of flagellin by TLR5 and NLRC4, and vaccine-induced adverse reactions. Western diet and common food additives boosted the abundance of flagellated bacteria and microbial flagellin production in vitro and in vivo.

Contributed by Ute Burkhardt

ABSTRACT: Fever is a common adverse reaction to vaccination, contributing to vaccine hesitancy and reduced uptake. To understand variation in fever risk, we longitudinally profiled fecal microbiota, oral temperature, and serological markers in 171 healthy adults receiving Severe acute respiratory syndrome coronavirus 2 mRNA vaccines. Fever risk correlated with low-grade intestinal inflammation, increased abundance of flagellated Lachnospiraceae bacteria, and increased flagellin expression prevaccine. Microbiomes from fever-high donors triggered stronger inflammation in human intestinal organoids and drove flagellin-dependent vaccine reactions in gnotobiotic mice. Moreover, microbiome flagellin phenotypes and murine vaccine reactions were modifiable by diet. Consistent with this, human fever risk was associated with self-reported diet and metabolic markers. These findings identify the gut microbiome as a driver of vaccine-induced fever, suggesting that microbiome-targeting strategies could modulate immune tone and improve vaccine side effects.

Author Info: (1) Department of Microbiome Science, Max Planck Institute for Biology, TŸbingen, Germany. Controlling Microbes to Fight Infections (CMFI) Cluster of Excellence, TŸbingen, Germany.

Author Info: (1) Department of Microbiome Science, Max Planck Institute for Biology, TŸbingen, Germany. Controlling Microbes to Fight Infections (CMFI) Cluster of Excellence, TŸbingen, Germany. (2) Institute for Biomedical Sciences, Georgia State University, Atlanta, GA, USA. (3) Department of Microbiome Science, Max Planck Institute for Biology, TŸbingen, Germany. Controlling Microbes to Fight Infections (CMFI) Cluster of Excellence, TŸbingen, Germany. (4) Department of Microbiome Science, Max Planck Institute for Biology, TŸbingen, Germany. Controlling Microbes to Fight Infections (CMFI) Cluster of Excellence, TŸbingen, Germany. (5) Microbiome-Host Interactions, Institut Pasteur, UniversitŽ Paris CitŽ, Paris, France. (6) Department of Microbiome Science, Max Planck Institute for Biology, TŸbingen, Germany. Controlling Microbes to Fight Infections (CMFI) Cluster of Excellence, TŸbingen, Germany. (7) Department of Microbiome Science, Max Planck Institute for Biology, TŸbingen, Germany. Controlling Microbes to Fight Infections (CMFI) Cluster of Excellence, TŸbingen, Germany. (8) Mass Spectrometry Facility, Max Planck Institute for Biology TŸbingen, TŸbingen, Germany. (9) Department of Pediatrics and Child Health, University of Manitoba, Manitoba, Canada. (10) Department of Pediatrics; Center for Microbiome Innovation; Department of Computer Science and Engineering; Shu Chien-Gene Lay Department of Bioengineering; Halõcõo_lu Data Science Institute, University of California San Diego, La Jolla, CA, USA. Hong Kong University of Science and Technology Jockey Club Institute for Advanced Study, Hong Kong University of Science and Technology, Hong Kong SAR, China. (11) Department of Pediatrics and Child Health, University of Manitoba, Manitoba, Canada. (12) Department of Pediatrics and Child Health, University of Manitoba, Manitoba, Canada. (13) Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, OT, Canada. (14) Institute for Biomedical Sciences, Georgia State University, Atlanta, GA, USA. (15) Department of Microbiome Science, Max Planck Institute for Biology, TŸbingen, Germany. Controlling Microbes to Fight Infections (CMFI) Cluster of Excellence, TŸbingen, Germany. (16) Department of Microbiome Science, Max Planck Institute for Biology, TŸbingen, Germany. Controlling Microbes to Fight Infections (CMFI) Cluster of Excellence, TŸbingen, Germany. (17) Institute for Biomedical Sciences, Georgia State University, Atlanta, GA, USA. (18) Departments of Medicine and of Epidemiology and Population Health, Stanford University, Stanford, CA, USA. (19) Controlling Microbes to Fight Infections (CMFI) Cluster of Excellence, TŸbingen, Germany. Institute for Tropical Medicine, University of TŸbingen, TŸbingen, Germany. (20) Microbiome-Host Interactions, Institut Pasteur, UniversitŽ Paris CitŽ, Paris, France. (21) Controlling Microbes to Fight Infections (CMFI) Cluster of Excellence, TŸbingen, Germany. Interfaculty Institute of Microbiology and Infection Medicine, University of TŸbingen, TŸbingen, Germany. Centre de Recherches Medicales de LambarŽnŽ, LambarŽnŽ, Gabon. German Center for Infection Research (DZIF), partner site TŸbingen, TŸbingen, Germany. (22) Institute for Biomedical Sciences, Georgia State University, Atlanta, GA, USA. (23) Controlling Microbes to Fight Infections (CMFI) Cluster of Excellence, TŸbingen, Germany. Institute for Biomedical Sciences, Georgia State University, Atlanta, GA, USA. Centre de Recherches Medicales de LambarŽnŽ, LambarŽnŽ, Gabon. (24) Department of Microbiome Science, Max Planck Institute for Biology, TŸbingen, Germany. Controlling Microbes to Fight Infections (CMFI) Cluster of Excellence, TŸbingen, Germany.

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