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.

Although nerve injury-associated neuroinflammation contributes to neuropathic pain, the long-term impact of such injury on systemic homeostasis and its potential role in pain remains elusive. In this study, we aim to understand the systemic changes that are present alongside chronic pain in nerve-injured male and female mice across their lifespan. We monitored mechanical and cold sensitivity in male and female mice starting at the age of 3–4 months old when they received spared nerve injury (SNI), up to 20-month post-injury. Alongside, we collected blood samples to track changes in immune cells with flow cytometry, and to assess inflammation-related serum proteome using a 111-target Proteome Profiler. We also transferred serum from sham/SNI mice to naïve mice to determine the potential of systemic contribution to pain. While nerve injury did not affect immune cell composition in the blood, it triggered a long-lasting disturbance of molecular profile in the serum of sham/SNI mice, in a sex-dependent manner. Compared to sham surgery, nerve injury amplified regulation of inflammatory proteins in males, but slightly reduced it in females. These changes in the serum occurred in parallel with long-lasting mechanical and cold hypersensitivity in the nerve-injured mice. Both male and female SNI serum induced hypersensitivity when transferred to naïve mice, regardless of a sex-matched or sex-crossed transfer. Our results highlight that a local nerve injury can have persistent systemic impact. Injury-associated systemic inflammation could contribute to neuropathic pain, but the underlying mechanisms may be sexually dimorphic.

Anti-programmed death 1 (αPD1) immune checkpoint blockade is used in combination for cancer treatment but associated with cardiovascular toxicity. Leflunomide (Lef) can suppress the growth of several tumor and mitigate cardiac remodeling in mice. However, the role of Lef in αPD1-induced cardiotoxicity remains unclear. Here, we report that Lef treatment inhibits αPD1-related cardiotoxicity without compromising the efficacy of αPD1-mediated immunotherapy. Lef changes community structure of gut microbiota in αPD1-treated melanoma-bearing mice. Moreover, mice receiving microbiota transplants from Lef+αPD1-treated melanoma-bearing mice have better cardiac function compared to mice receiving transplants from αPD1-treated mice. Mechanistically, we analyze metabolomics and identify indole-3-propionic acid (IPA), which protects cardiac dysfunction in αPD1-treated mice. IPA can directly bind to the aryl hydrocarbon receptor and promote phosphoinositide 3-kinase expression, thus curtailing the cardiomyocyte response to immune injury. Our findings reveal that Lef mitigates αPD1-induced cardiac toxicity in melanoma-bearing mice through modulation of the microbiota-IPA-heart axis.
© 2025. The Author(s).

CD4+CD25+Foxp3+ regulatory T cells (Treg) have been implicated in pain modulation in various inflammatory conditions. However, whether Treg cells hamper pain at steady state and by which mechanism is still unclear. From a meta-analysis of the transcriptomes of murine Treg and conventional T cells (Tconv), we observe that the proenkephalin gene (Penk), encoding the precursor of analgesic opioid peptides, ranks among the top 25 genes most enriched in Treg cells. We then present various evidence suggesting that Penk is regulated in part by members of the Tumor Necrosis Factor Receptor (TNFR) family and the transcription factor Basic leucine zipper transcription faatf-like (BATF). Using mice in which the promoter activity of Penk can be tracked with a fluorescent reporter, we also show that Penk expression is mostly detected in Treg and activated Tconv in non-inflammatory conditions in the colon and skin. Functionally, Treg cells proficient or deficient for Penk suppress equally well the proliferation of effector T cells in vitro and autoimmune colitis in vivo. In contrast, inducible ablation of Penk in Treg leads to heat hyperalgesia in both male and female mice. Overall, our results indicate that Treg might play a key role at modulating basal somatic sensitivity in mice through the production of analgesic opioid peptides.
© 2024, Aubert et al.

DNA damage plays a significant role in the tumorigenesis and progression of the disease. Abnormal DNA repair affects the therapy and prognosis of cancer. In this study, it is demonstrated that the deubiquitinase USP25 promotes non-homologous end joining (NHEJ), which in turn contributes to chemoresistance in cancer. It is shown that USP25 deubiquitinates SHLD2 at the K64 site, which enhances its binding with REV7 and promotes NHEJ. Furthermore, USP25 deficiency impairs NHEJ-mediated DNA repair and reduces class switch recombination (CSR) in USP25-deficient mice. USP25 is overexpressed in a subset of colon cancers. Depletion of USP25 sensitizes colon cancer cells to IR, 5-Fu, and cisplatin. TRIM25 is also identified, an E3 ligase, as the enzyme responsible for degrading USP25. Downregulation of TRIM25 leads to an increase in USP25 levels, which in turn induces chemoresistance in colon cancer cells. Finally, a peptide that disrupts the USP25-SHLD2 interaction is successfully identified, impairing NHEJ and increasing sensitivity to chemotherapy in PDX model. Overall, these findings reveal USP25 as a critical effector of SHLD2 in regulating the NHEJ repair pathway and suggest its potential as a therapeutic target for cancer therapy.
© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.