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GFER Represents a Target for Dual Disruption of Redox Homeostasis and Reactivation of the Immune Response in Pancreatic Adenocarcinoma.

UNLABELLED: Both metabolic dysregulation and the immunosuppressive tumor microenvironment of pancreatic ductal adenocarcinoma (PDAC) contribute to the recalcitrance of this lethal disease to treatment. Accordingly, we aimed to identify and characterize a target that elicits an anticancer response through both disrupting cancer cell redox homeostasis and increasing the immunogenicity of PDAC. First, mitochondrial metabolic dependencies in PDAC were identified by using a CRISPR-Cas9 screening system with a custom single-guide RNA library. Functional validation analyses revealed GFER, a mitochondrial FAD-dependent sulfhydryl oxidase, as an essential regulator of tumor growth. In vitro and in vivo methodologies demonstrated that GFER depletion perturbed redox homeostasis and stimulated tumor immunogenicity, including sensitization to immune checkpoint blockade. In patient-derived xenograft models of PDAC, the growth-inhibitory response induced by GFER depletion was mediated by an altered oxidative balance that released damaged mitochondrial DNA into the cytoplasm of tumor cells, leading to the activation of the cGAS-STING pathway and expression of type I IFNs. This effect was recapitulated in a mouse immunocompetent syngeneic PDAC model, in which GFER depletion suppressed tumor growth and promoted T-cell infiltration to enhance tumor-killing effects. Consequently, GFER depletion significantly increased the antitumor efficacy of immune checkpoint blockade. Overall, these findings identify GFER as a critical node for both mitochondrial redox homeostasis and immunomodulation in PDAC and reveal a therapeutic opportunity for sensitizing PDAC to immune checkpoint blockade. SIGNIFICANCE: GFER is essential for mitochondrial redox balance and suppressing tumor immunogenicity in pancreatic tumors, with the combination of GFER inhibition with immune checkpoint blockade resulting in a strong antitumor response.

Animals↗

Tracking Nongenetic Evolution from Primary to Metastatic ccRCC: TRACERx Renal.

While the key aspects of genetic evolution and their clinical implications in clear cell renal-cell carcinoma (ccRCC) are well-documented, how genetic features co-evolve with the phenotype and tumor microenvironment (TME) remains elusive. Here, through joint genomic-transcriptomic analysis of 243 samples from 79 patients recruited to the TRACERx Renal study, we identify pervasive non-genetic intratumor heterogeneity, with over 40% not attributable to genetic alterations. By integrating tumor transcriptomes and phylogenetic structures, we observe convergent evolution to specific phenotypic traits, including cell proliferation, metabolic reprogramming and overexpression of putative cGAS-STING repressors amid high aneuploidy. We also uncover a co-evolution between the tumor and the T cell repertoire, as well as a longitudinal shift in the TME from an anti-tumor to an immunosuppressive state, linked to the acquisition of recurrently late ccRCC drivers 9p loss and SETD2 mutations. Our study reveals clinically-relevant and hitherto underappreciated non-genetic evolution patterns in ccRCC.

Journal Article↗

Engineered Bacteriophages in Cancer Immunotherapy: Emerging Concepts and Potential Integration with CAR-T Cell Therapy.

Due to antigen heterogeneity, restricted immune cell trafficking and an immunosuppressive, nutrient-restricted tumour microenvironment, solid tumours remain resistant to modern immunotherapies. Engineered bacteriophages offer a modular framework to overcome these obstacles: programmable virus-like particles with scalable production. Through genome engineering, capsid decoration with mammalian cell-targeting ligands, or hybrid AAV/phage systems, engineered bacteriophages can display tumour-associated antigens, enhance receptor-mediated uptake and deliver therapeutic payloads such as cytokines, chemokines and suicide genes without naturally infecting mammalian cells. These features support their use as vaccine platforms, immunological adjuvants and targeted gene-delivery vehicles. These may enable more precise, tumour-localized therapeutic intervention. Phages can engage innate immune pathways, including TLR9, TLR3/7/8, cGAS-STING and AIM2, promoting dendritic cell maturation and inflammatory mediators that may convert immunologically "cold" tumours into inflamed microenvironments. Their multivalent antigen display enhances B- and T-cell priming, while cDC1-mediated cross-presentation supports cytotoxic CD8+ T-cell responses and immunological memory. In CAR-T therapy, engineered phages may improve tumour homing through chemokine modulation, support persistence through local cytokine delivery, reduce antigen escape by presenting multiple tumour epitopes, and limit T-cell exhaustion through dominant-negative receptor strategies or local checkpoint blockade. This review summarizes engineering approaches, delivery systems, manufacturing, biodistribution, dosing, and safety issues, including immunogenicity, pre-existing anti-phage antibodies and horizontal gene transfer. It also distinguishes therapeutic engineered phage particles from phage display technologies used for molecular discovery. Despite encouraging results integrating modified bacteriophages with CAR-T cell therapy, the evidence remains mostly preclinical, indicating both substantial translational prospects and crucial obstacles for future clinical development.

CAR-T cell therapy↗

Divergent viral phosphodiesterases for immune signaling evasion.

Cyclic dinucleotides (CDNs) and other short oligonucleotides play fundamental roles in immune system activation in organisms ranging from bacteria to humans. In response, viruses use phosphodiesterase (PDE)-mediated oligonucleotide cleavage for immune evasion, a strategy whose diversity has not yet been explored. Here, we use a canonical 2H PDE (2H PDE) structure-based search of prokaryotic and eukaryotic viral sequences to identify an exceptional diversity of 2H PDEs across the virome, including enzymes not detectable with sequence search methods alone. Despite active site conservation, biochemical experiments reveal remarkable substrate specificity of these PDEs that corresponds to variations in the core 2H fold. This nuanced specificity allows 2H PDEs to selectively degrade oligonucleotide messengers to avoid interfering with host nucleotide signaling. Together, these findings nominate viral 2H PDEs as key regulators of CDN signaling across the tree of life.

Immune Evasion↗

A TIGIT nanotrapping-guided STING-activatable immunometabolic strategy overcomes innate immune silence and T cell exhaustion in breast cancer.

Breast cancer exhibits a profoundly immunosuppressive tumor microenvironment (TME), where innate immune silence prevents antigen sensing and persistent T cell exhaustion limits effector responses, rendering most immunotherapies ineffective. Clinical profiling of 1093 The Cancer Genome Atlas (TCGA) cases identified a glucose-fueled glutathione (GSH)-glutathione peroxidase 4 (GPX4)-dihydrolipoamide S-acetyltransferase (DLAT) axis as a dominant metabolic shield that suppresses oxidative stress, and thereby enforces both stimulator of interferon genes (STING) silence and CD8+ T cell exclusion. To dismantle this barrier, we developed an immunometabolic nanotherapy, GOx/ES-CO-LDH@TIGIT-Nanotrap (TNT). In acidic tumors, proton-driven layered double hydroxide (LDH) disassembly releases glucose oxidase (GOx) and extremely small cuprous oxide (ES-CO). GOx depletes glucose and nicotinamide adenine dinucleotide phosphate (NADPH) to induce disulfidptosis, while ES-CO releases cuprous ions (Cu+) that trigger cuproptosis via binding to lipoylated mitochondrial proteins. Their mutual biochemical amplification produces a cycloacclerated disulfidptosis-cuproptosis cascade that collapses the GSH-GPX4-DLAT axis and restores STING activation. Meanwhile, the macrophage-derived T cell immunoreceptor with Ig and ITIM domains (TIGIT) Nanotrap sequesters CD155 to prevent T cell suppression. Together, this coordinated innate reactivation and adaptive rescue converts immune-cold tumors into STING-inflamed and T cell responsive lesions.

Female↗

tRNA m1A modification orchestrates STING translation in macrophages to enhance antitumor immunity and CAR-macrophage immunotherapy.

Tumor-associated macrophages (TAMs) play crucial roles in tumor progression. However, the mechanisms underlying the posttranscriptional regulation of TAMs remain largely unknown. Here, we demonstrated that Trmt61a, the "writer" enzyme of tRNA N1-methyladenosine (m1A) modification, is highly expressed in proinflammatory macrophages in tumor microenvironment. We generated conditional knockout (KO) mice for Trmt61a and observed that Trmt61a deletion in macrophages significantly promoted tumor growth. Mechanistically, we identified that m1A maintains the translation of STING, enhances STING-TBK1-IFN-β signaling in macrophages and therefore suppresses tumor cell growth. We further generated TRMT61A-overexpressing human iPSC-derived CAR-macrophage and demonstrated that human TRMT61A effectively promoted antitumor CAR-macrophage therapy in vivo. Collectively, our findings reveal a novel regulatory mechanism of tRNA m1A modification in macrophages, highlighting the antitumor therapeutic potential of targeting tRNA m1A modification in macrophages.

Animals↗

VHL synthetic lethality screens uncover CBF-β as a negative regulator of STING.

Clear cell renal cell carcinoma (ccRCC) represents the most common form of kidney cancer and is typified by biallelic inactivation of the von Hippel-Lindau (VHL) tumour suppressor gene. Here, we undertake genome-wide CRISPR/Cas9 screening to reveal synthetic lethal interactors of VHL, and uncover that loss of Core Binding Factor β (CBF-β) causes cell death in VHL-null ccRCC cell lines and impairs tumour establishment and growth in vivo. This synthetic relationship is independent of the elevated activity of hypoxia inducible factors (HIFs) in VHL-null cells, but does involve the RUNX transcription factors that are known binding partners of CBF-β. Mechanistically, CBF-β loss leads to upregulation of type I interferon signalling, and we uncover a direct inhibitory role for CBF-β at the STING locus controlling Interferon Stimulated Gene expression. Targeting CBF-β in kidney cancer both selectively induces tumour cell lethality and promotes activation of type I interferon signalling.

Humans↗

CAFs shape the immunosuppressive microenvironment of pancreatic cancer through the Lin28b-STING Axis.

Cancer-associated fibroblasts comprise diverse functionally distinct cellular subsets, with certain subpopulations exerting pivotal influence in shaping the pancreatic cancer immune microenvironment. Here we show that Lin28b+ cancer-associated fibroblasts contribute to establishing an immunologically cold tumor microenvironment in pancreatic ductal adenocarcinoma. Mechanistically, Lin28b directly binds to STING mRNA and promotes its degradation, thereby suppressing STING expression and downstream type I interferon signaling. Loss of Lin28b in cancer-associated fibroblasts activates the cGAS-STING-interferon signaling cascade, enhancing dendritic cell antigen presentation and CD8+ T cell cytotoxic function. Importantly, genetic inhibition of Lin28b in cancer-associated fibroblasts enhances sensitivity to anti-PD-L1 immune checkpoint blockade therapy. These findings reveal that targeting the Lin28b-STING axis represents a promising therapeutic strategy for overcoming the intrinsic resistance of pancreatic ductal adenocarcinoma to immunotherapy.

Humans↗

A versatile cGAMP reporter reveals principles of cGAS activation by DNA damage and chromosome instability.

cGAS is the primary innate immune DNA sensor. On binding DNA, cGAS generates cGAMP, ultimately driving inflammation. Although normally silenced on self-DNA, genotoxic stress can activate cGAS, proposed to be mediated by micronuclei, chromosome bridges and DNA:RNA hybrids. However, mechanistically, this is poorly understood due to a lack of sensitive and selective single-cell cGAS activation assays. Here we solve this with an improved cGAMP reporter for microscopy, flow cytometry and biochemical assays. Strikingly, we find that genotoxic stress-mediated cGAS activation is a rare event that is not driven by enrichment on micronuclei and occurs by mechanisms that vary in dependence on the genotoxic stress. Following chromosome mis-segregation, cGAS activation correlates with bridge association but, notably, ionizing radiation activates cGAS independently of bridges. Whereas simple DNA:RNA hybrids are inert, more complex structures such as R-loops activate cGAS. Our work revises the cGAS signalling framework and introduces a flexible tool to examine it.

Nucleotidyltransferases↗

Inhibiting cyclin D1-CDK6 suppresses senescence-associated inflammatory gene expression and age-related functional decline.

Cellular senescence contributes to aging and age-related diseases by driving chronic inflammation through the senescence-associated secretory phenotype (SASP), including interferon-stimulated genes (ISGs). Here we confirm and extend previous observations that cyclin D1 (CCND1), a key cell cycle regulator, is paradoxically upregulated across models of nonproliferating senescent cells. We show that CCND1 and its kinase partner CDK6 drive SASP and ISG expression in senescent cells by promoting DNA damage accumulation. This leads to the formation of cytoplasmic chromatin fragments that activate pro-inflammatory cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) signaling. In aged mouse livers, senescent hepatocytes show increased Ccnd1 expression. Hepatocyte-specific Ccnd1 knockout or treatment with the clinical grade CDK4/6 inhibitor palbociclib reduces DNA damage and ISGs in aged mouse liver. Further, palbociclib suppresses frailty and improves physical performance of aged mice. These findings demonstrate a role for CCND1/CDK6 in regulating DNA damage and inflammation in senescence and aging, highlighting it as a promising target for therapeutic repurposing.

Animals↗