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The hypoxic tumor microenvironment, particularly hypoxia-conditioned cancer-associated fibroblasts (CAFs), drives breast cancer (BC) progression and therapy resistance. However, the molecular mechanisms linking hypoxic CAFs to BC plasticity and chemoresistance remain elusive. Primary CAFs were isolated from high-grade BC tissues (Grade III) and characterized (α-SMA⁺/CD34⁻/pan-CK⁻), with normal fibroblasts (NFs) from reduction mammoplasty as controls. Hypoxic CAF-derived exosomal circSTAT3 stability was validated using RNase R resistance and actinomycin D assays. Exosomes were characterized via transmission electron microscopy (TEM), dynamic light scattering (DLS), and marker profiling (CD63⁺/TSG101⁺/Alix⁺, calnexin⁻). Functional effects of hypoxic CAF exosomes on TNBC cells (MDA-MB-231, SUM159) were assessed through proliferation/migration assays, stemness/epithelial-mesenchymal transition (EMT) marker analysis, and siRNA-mediated circSTAT3 knockdown. Mechanistic studies employed luciferase assays and RNA immunoprecipitation (RIP). Chemoresistance was evaluated by cisplatin half-maximal inhibitory concentration (IC₅₀). In vivo tumor growth and stemness enrichment were analyzed in xenografts. Clinical validation used BC tissues (n = 60) and plasma exosomes from BC patients (n = 40) versus healthy controls (n = 25). Hypoxic CAF-derived exosomes efficiently transferred circSTAT3 to TNBC cells, promoting proliferation, migration, EMT, and stemness marker expression. SiRNA-mediated circSTAT3 knockdown reversed these effects. Mechanistically, circSTAT3 acted as a competitive endogenous RNA (ceRNA), sponging miR-671-5p to derepress NOTCH1. Hypoxic CAF exosomes increased cisplatin IC₅₀ in TNBC cells, while circSTAT3 depletion restored chemosensitivity. In vivo, hypoxic CAF exosomes accelerated tumor growth, enriched CD44⁺/NOTCH1⁺ populations, and elevated circulating exosomal circSTAT3. Clinically, circSTAT3 was significantly upregulated in advanced BC tissues (p < 0.01) and patient plasma exosomes (p < 0.01), correlating with lymph node metastasis. This study identifies a hypoxia-driven feedforward loop wherein CAF-derived exosomal circSTAT3 promotes TNBC stemness and chemoresistance via miR-671-5p/NOTCH1 signaling. CircSTAT3 redefines stromal-tumor crosstalk as a circRNA-driven process and serves as both a circulating non-invasive biomarker and a promising therapeutic target to disrupt stromal-mediated resistance in aggressive TNBC. The online version contains supplementary material available at 10.1186/s12967-025-06794-8.

Background: Human cytomegalovirus (CMV) is a major pathogen that poses significant risks to immunocompromised individuals and neonates. The tegument protein pp71, encoded by the UL82 gene, plays a pivotal role in initiating viral lytic replication and evading host immune responses. Despite its clinical relevance, standardized monoclonal antibodies (mAbs) for pp71 remain limited, prompting the need to expand the available repertoire of antibodies targeting this critical protein. Methods: In this study, we constructed a diverse human single-chain variable fragment (scFv) library using RNA derived from the B cells of four healthy donors. The library was expressed in Saccharomyces cerevisiae , and iterative rounds of magnetic-activated cell sorting (MACS) were performed against recombinant pp71. Clonal enrichment was monitored using flow cytometry. Results: Among the isolated clones, one designated ID2 exhibited high sensitivity and specificity for pp71, as demonstrated by flow cytometry, immunofluorescence, an enzyme-linked immunosorbent assay (ELISA), and biolayer interferometry (BLI). Conclusions: Collectively, these findings establish a novel pp71-specific mAb and underscore the utility of yeast surface display combined with MACS for expanding the antibody toolkit available for CMV research and diagnostics.

Respiratory syncytial virus (RSV) infection in the upper respiratory tract promotes disease progression and transmission, with excessive inflammation contributing to severe lower respiratory tract involvement. This study investigates the immunomodulatory effects of Lactobacillus rhamnosus D3189 on viral kinetics and innate immune responses in well-differentiated nasal epithelial cells (WD-NECs). WD-NECs from healthy adult donors (N = 8) were cultured in vitro , treated with L. rhamnosus D3189, and then infected with RSV (strain RS4) 24 hours later. Viral replication and shedding were assessed via RT-qPCR and plaque assays. Cytotoxicity and epithelial integrity were evaluated using LDH release and transepithelial electrical resistance (TEER). Inflammatory and antiviral responses were investigated using multiplex immunoassays, AlphaLISA, and ELISA. RSV infection induced robust viral replication and shedding, disrupted epithelial barrier integrity, and triggered the release of pro-inflammatory cytokines and type I/III interferons. L. rhamnosus D3189 alone did not induce cytotoxicity or inflammation. While it had no effect on viral replication, TEER, LDH release, or IFN-λ1/3 levels, D3189 significantly enhanced IFN-β production, reduced viral shedding, and attenuated RSV-induced cytokine and chemokine responses. L. rhamnosus D3189 modulates the epithelial immune response to RSV, reducing inflammation and viral shedding without compromising epithelial integrity. These findings support its potential as a novel strategy to limit RSV-associated infection and transmission.

Resistance to chemotherapy remains a major clinical challenge in triple-negative breast cancer (TNBC), an intrinsic subtype with limited available therapeutic options. The expression of moesin (MSN) is upregulated in TNBC patients, but little is known about the role of MSN in breast carcinogenesis. We investigated the MSN-dependent autocrine loop between extracellular interleukin 6 (IL-6) and NF-κB, along with a signaling cascade involving GTPase-mediated STAT3 phosphorylation. Various in vitro and in vivo assays were used to evaluate tumor initiation, growth, and stemness properties in TNBC models. High MSN expression was correlated with shorter overall and disease-free survival in TNBC patients. In vivo, MSN promotes tumor initiation and growth. Mechanistically, MSN-mediated IL-6/NF-κB autoregulatory feedback enhances IL-6 transcription. IL-6 binding to LPAR1 activated MSN phosphorylation, which then sequentially phosphorylated the CDC42-PAK4 complex, triggering nuclear translocation of the pSTAT3-MSN complex. This led to pSTAT3-mediated activation of cancer stemness genes (IGFN1, EML1, and SRGN), contributing to Adriamycin resistance. Notably, combination treatment with the FDA-approved STAT3 inhibitor Atovaquone and Adriamycin restored drug sensitivity. Our findings uncover the critical role of MSN in regulating STAT3-mediated cancer stemness via the IL-6/NF-κB signaling axis. These results provide a strong rationale for repositioning STAT3 inhibitors such as Atovaquone as a therapeutic strategy in Adriamycin-resistant TNBC patients exhibiting pSTAT3-MSN complex upregulation. The online version contains supplementary material available at 10.1186/s13058-025-02072-z.

RNA 5-methylcytosine (m 5 C), a prevalent epitranscriptomic modification that critically regulates gene expression and cellular homeostasis. While its roles in solid tumors have been increasingly recognized, the functional landscape of m 5 C in acute myeloid leukemia (AML) remains unexplored. Here, we identified NSUN2, the principal RNA m 5 C methyltransferase, as a key regulator of AML progression. NSUN2 was aberrantly upregulated in AML patient samples and correlated with poor prognosis. Functional studies demonstrated that NSUN2 promoted leukemic cell proliferation, enhanced tumor growth in xenograft models, and conferred resistance to ferroptosis—a regulated cell death process driven by lipid peroxidation. Mechanistically, NSUN2 catalyzed m⁵C deposition on the 3’UTR of FSP1 (ferroptosis suppressor protein 1) mRNA, facilitating its recognition and stabilization by the m 5 C reader protein YBX1. This NSUN2-YBX1-FSP1 axis protected AML cells from ferroptotic stress by suppressing lipid peroxidation and oxidative damage. Depletion of NSUN2 or FSP1 induced mitochondrial remodeling, which primed cells for ferroptosis. Reconstitution of wild-type NSUN2 or FSP1 rescued ferroptosis resistance, whereas catalytically inactive NSUN2 (C271A/C321A) or non-functional FSP1 mutants (G2A/E156A) failed to reverse this phenotype. Pharmacological inhibition of NSUN2 with MY-1B or targeting FSP1 with iFSP1 exhibited potent anti-leukemic effects, synergizing robustly with ferroptosis inducers, standard chemotherapy, and the BCL-2 inhibitor venetoclax. Our study unveils NSUN2 and FSP1 as prognostic biomarkers and therapeutic targets in AML. We highlight a novel epitranscriptomic mechanism linking RNA methylation to ferroptosis evasion, providing a dual-strategy approach to overcome AML treatment resistance. The online version contains supplementary material available at 10.1186/s12943-025-02394-8.

Borisyuk et al. identify a signaling regulatory network of peroxisome proliferation, uncovering PKC as a positive regulator of peroxisome–ER interaction. During neuronal differentiation, activation of PKC contributes to an increase in peroxisome formation.

uveal melanoma (UM) is the most common primary intraocular tumor in adults, with metastasis being the leading cause of death. However, effective treatments for metastatic UM remain limited. Emerging evidence suggests that cholesterol metabolism plays a role in cancer progression, but its impact on UM metastasis is not well understood. we investigated the effects of miR-181a on UM metastasis using multiple UM cell lines and a suprachoroidal injection mouse model. Functional assays, including migration, invasion, and cancer stem-like cell (CSC) formation, were performed. The target of miR-181a was identified through bioinformatics, luciferase assays, and western blotting. Cholesterol levels were measured, and in vitro and in vivo studies assessed the therapeutic potential of combining miR-181a with crizotinib. miR-181a significantly decreases UM cell migration, invasion, and metastasis. Mechanistically, miR-181a was found to target sterol regulatory element-binding protein 2 (SREBP2), thereby inhibiting cholesterol biosynthesis. This decrease in cholesterol levels hindered reduced epithelial-to-mesenchymal transition (EMT) and led to a decline in cancer stem-like cell (CSC) populations in UM. Furthermore, elevated cholesterol or overexpression of SREBP2 abrogated the anti-metastatic effects of miR-181a. Additionally, a combination of miR-181a and crizotinib significantly inhibited metastasis, both in vitro and in vivo. miR-181a inhibits UM metastasis by targeting SREBP2 and reducing cholesterol biosynthesis. Its combination with crizotinib may provide a promising therapeutic strategy for metastatic UM. The online version contains supplementary material available at 10.1186/s13046-025-03459-8.

Age-related macular degeneration (AMD) is a leading cause of blindness worldwide, with a clinical presentation that varies between sexes. In late-stage AMD, choroidal neovascularization (CNV) triggers retinal inflammation and degeneration, processes that are exacerbated by an overactive response of retinal microglial cells. Short-chain fatty acids (SCFAs) have emerged as potential treatments for AMD due to their anti-inflammatory properties. In this study, we investigate the effects of SCFA treatment in a laser-induced CNV mouse model, focusing on sex-dependent differences in disease progression and microglial response. Our findings demonstrate distinct sex-specific patterns in the development of CNV and associated pathological hallmarks. SCFA treatment resulted in a slight increase in density of Iba1 + microglial cells in females at 3 days post-laser (3dpl), while it prevented an increase in males at 7 dpl, with both sexes showing enhanced microglial ramification. The dynamics of microglial density were likely linked to protective effects on CNV lesion, leakage size, and inflammation, which occurred earlier in females and later in males. At transcriptional level, SCFA showed mixed effects, mainly targeting inflammation resolution, mitochondrial support, and neuronal repair in a sex-dependent manner. In vitro, SCFAs reduced microglial phagocytosis of retinal debris, suggesting a potential anti-inflammatory action. This study underscores the importance of considering sex-specific responses in the development of AMD treatments, such as SCFAs, and highlights the need for personalized therapeutic strategies. The online version contains supplementary material available at 10.1186/s12974-025-03508-1.