Achieving a cure is an urgent need for patients with advanced solid tumors. Here, we discover that oncolytic virus (OV) infection enhances IL-18 receptor expression but fails to increase IL-18 ligand expression. Therefore, we engineer armed oncolytic alphavirus M1 expressing wild-type IL-18 (wtIL-18) or a mutant variant (mutIL-18) that evades IL-18 binding protein (IL-18BP) while maintaining IL-18 receptor (IL-18R) binding. Intravenous administration of M1-mutIL-18 suppresses the growth of multiple advanced solid tumors in C57BL/6 and BALB/c mouse models and promotes long-term systemic immune memory. Mechanistically, armed M1-mutIL-18 enhances directed clonal expansion and differentiation of CD8+ T cells and sustains IFN-γ production. Thus, armed M1-mutIL-18 promotes dendritic cell (DC) activation, priming and activation of CD8+ T cells in lymphatic organs, and infiltration of IL-18R+ CD8+ T cells in the tumor microenvironment, establishing a positive feedback loop. We further show that a PD-L1 inhibitor enhances the anti-tumor efficacy of mutIL-18 OVs. These results highlight the importance of the IL-18 pathway in oncolytic virus therapy and implicate reprogramming ligand-receptor interaction as an effective strategy for immunotherapy.
© 2025. The Author(s).

Osteosarcoma (OS) with pulmonary metastasis remains challenging due to limited treatment options and the immunosuppressive nature of the tumor microenvironment (TME). Bacteria-mediated cancer therapy has emerged as a promising strategy for solid tumors but often suffers from limited efficacy due to the immunosuppressive TME, which restricts the intensity and durability of the antitumor immune response. To overcome these challenges, we engineered a novel Salmonella strain, VNP20009-CCL2-CXCL9 (VNP-C-C), leveraging the intrinsic tumor tropism of Salmonella typhimurium VNP20009 (VNP) and improving immune modulation through the recruitment of effector immune cells into the TME by the chemokines CCL2 and CXCL9.
VNP-C-C was genetically engineered through electroporation of Plac-CCL2-CXCL9 plasmid and validated in vitro. Its antitumor efficacy, immune regulation capacity and immunomodulatory mechanisms were evaluated in vitro by using OS cell lines and immune cells (dendritic cells (DCs) and macrophages (Mφs)) and in vivo by using both immunocompromised and immunocompetent mouse models of OS lung metastasis.
VNP-C-C effectively accumulated within tumors, triggering immunogenic cell death and subsequently activating the cyclic GMP-AMP synthase (cGAS)/stimulator of interferon genes (STING) pathway, thereby robustly promoting type I interferon secretion. The chemokines CCL2 and CXCL9 amplified the immune response by recruiting DCs, Mφs, and T cells to the TME. This orchestrated immune modulation reprogrammed tumor-associated macrophages to an antitumor phenotype, induced DCs maturation, significantly increased T-cell infiltration and activation within tumors, and promoted systemic T-cell memory formation in peripheral lymphoid organs. These effects collectively inhibited OS lung metastasis progression and provided survival benefits in mouse models.
The engineered bacterial strain VNP-C-C effectively converts the OS lung metastatic TME into a pro-inflammatory milieu, thereby stimulating robust innate and adaptive immune responses. This offers a highly promising therapeutic avenue for OS lung metastasis with considerable translational potential in cancer immunotherapy.
© Author(s) (or their employer(s)) 2025. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ Group.

Recent studies have revealed a structural role for DNA ligase 4 (Lig4) in the maintenance of a repair complex during non-homologous end joining (NHEJ) of DNA double-strand breaks. In cultured cell lines, catalytically inactive Lig4 can partially alleviate the severe DNA repair phenotypes observed in cells lacking Lig4. To study the structural role of Lig4 in vivo, a mouse strain harboring a point mutation to Lig4's catalytic site was generated. In contrast to the ablation of Lig4, catalytically inactive Lig4 mice are born alive. These mice display marked growth retardation and have clear deficits in lymphocyte development. We considered that the milder phenotype results from inactive Lig4 help to recruit another ligase to the repair complex. We next generated a mouse strain deficient for nuclear Lig3. Nuclear Lig3-deficient mice are moderately smaller and have elevated incidences of cerebral ventricle dilation but otherwise appear normal. Strikingly, in experiments crossing these two strains, mice lacking nuclear Lig3 and expressing inactive Lig4 were not obtained. Timed mating revealed that fetuses harboring both mutations underwent resorption, establishing an embryonic lethal genetic interaction. These data suggest that Lig3 is recruited to NHEJ complexes to facilitate end joining in the presence (but not activity) of Lig4.
© The Author(s) 2024. Published by Oxford University Press on behalf of Nucleic Acids Research.

Mutations of the CBP/p300 histone acetyltransferase (HAT) domain can be linked to leukemic transformation in humans, suggestive of a checkpoint of leukocyte compartment sizes. Here, we examined the impact of reversible inhibition of this domain by the small-molecule A485. We found that A485 triggered acute and transient mobilization of leukocytes from the bone marrow into the blood. Leukocyte mobilization by A485 was equally potent as, but mechanistically distinct from, granulocyte colony-stimulating factor (G-CSF), which allowed for additive neutrophil mobilization when both compounds were combined. These effects were maintained in models of leukopenia and conferred augmented host defenses. Mechanistically, activation of the hypothalamus-pituitary-adrenal gland (HPA) axis by A485 relayed shifts in leukocyte distribution through corticotropin-releasing hormone receptor 1 (CRHR1) and adrenocorticotropic hormone (ACTH), but independently of glucocorticoids. Our findings identify a strategy for rapid expansion of the blood leukocyte compartment via a neuroendocrine loop, with implications for the treatment of human pathologies.
Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.

Background: The Fangji Dihuang formulation (FJDHF) is a widely recognized Traditional Chinese Medicine (TCM) formula that consists of five plant drugs: Stephaniae Tetrandrae Radix, Cinnamomi Ramulus, Rehmanniae Radix, Saposhnikoviae Radix, and Glycyrrhiza Urensis Fisch. This formulation has been known to exhibit clinical therapeutic effects in the treatment of inflammatory skin diseases. However, there is a lack of pharmacological research on its anti-atopic dermatitis (AD) activity. Methods: To investigate the potential anti-AD activity of FJDHF, DNCB was used to induce AD-like skin inflammation in the back of mice. Following successful modeling, the mice were administered FJDHF orally. The extent of the inflammatory skin lesions was recorded at day 4, 7, 14 and 28. UHPLC-Q-Exactive Orbitrap MS was used to identify and match the compounds present in FJDHF with ITCM, TCMIP and TCMSID. In silico predictions of potential target proteins of the identified compounds were obtained from SwishTargetPrediction, ITCM and TargetNet databases. AD-related genes were identified from GSE32924 data set, and FJDHF anti-AD hub genes were identified by MCODE algorithm. ClueGo enrichment analysis was employed to identify the core pathway of FJDHF's anti-AD effect. To further investigate the anti-AD effect of FJDHF, single-cell RNA sequencing data set (GSE148196) from AD patients was analyzed to determine the target cells and signaling pathways of FJDHF in AD. Finally, rt-PCR, flow cytometry, and mouse back skin RNA sequencing were utilized to validate our findings. Results: FJDHF was found to be effective in improving the degree of the AD-like lesions in the mice. Network pharmacological analysis revealed the core pathway of FJDHF to be the IL-17 signaling pathway, which is interactively associated with cytokines. Single-cell RNA sequencing analysis suggested that FJDHF may play an anti-AD role by influencing dendritic cells. Flow cytometry and rt-PCR results showed that FJDHF can reduce the influence of AD sample of IL-4, IFN-γ and the expression of IL-17. The RNA sequencing of mouse back skin also confirmed our conclusion. Conclusion: FJDHF may inhibit DNCB-induced AD-like skin inflammation in mice by inhibiting the IL-17 signaling pathway. Thus, FJDHF can be considered as a potential therapeutic agent for AD.
Copyright © 2023 Zhao, Jiang, Gu, Zhang, Bao, Dai, Dong, Yang, Li, Qin and Zeng.