Search Results (7,497)

Dickkopf-1 (DKK1) is a 266-amino-acid secreted glycoprotein originally identified as a high-affinity antagonist of the canonical Wnt/β-catenin signaling pathway and has emerged as a complex regulator in oncology. While historically considered as a tumor suppressor due to its ability to abrogate Wnt-driven proliferation, recent discoveries highlight a paradoxical pro-oncogenic role across various malignancies. The molecular mechanisms by which DKK1 promotes tumor progression, metastasis, and immune evasion are driven by its interaction with cell-surface receptors, specifically LRP5/6 and CKAP4. The DKK1-CKAP4 axis independently activates PI3K/AKT signaling, facilitating epithelial–mesenchymal transition (EMT), chemoresistance, and the formation of osteolytic bone lesions. Furthermore, DKK1 serves as a critical orchestrator of the tumor microenvironment (TME) by driving comprehensive immune reprogramming. It mediates the recruitment of myeloid-derived suppressor cells (MDSCs) and inactivates cytotoxic CD8⁺ T cells and natural killer (NK) cells, thereby fostering an immunosuppressive tumor microenvironment and resistance to checkpoint inhibitors. Interestingly, cancer-associated fibroblasts (CAFs) are a primary source of DKK1 in the stroma, where they facilitate immune evasion. Clinically, elevated circulating DKK1 levels correlate with advanced disease stages, increased metastatic potential, and poor overall survival in solid and hematological tumors. When used in combination with established biomarkers, serum DKK1 levels demonstrate significant utility for early detection and therapeutic monitoring. Given its intricate impact on malignancy, DKK1 has become a promising therapeutic target, with ongoing clinical trials investigating neutralizing antibodies such as DKN-01 to disrupt its oncogenic and immunosuppressive signaling. Understanding the context-dependent nature of DKK1 signaling remains essential for refining its application as both a biomarker and a component of emerging precision immunotherapy strategies. By prioritizing the literature from the last decade, this review characterizes DKK1 as a key mediator of tumor progression and immune reprogramming, while assessing its clinical potential as a biomarker and therapeutic target. Full article

Background: Aberrant protein O-fucosylation mediated by protein O-fucosyltransferase 1 (POFUT1), has emerged as a hallmark of tumorigenesis that regulates key signaling pathways, including Notch, which is frequently dysregulated in cancers. Protein O-fucosylation, catalyzed by POFUT1, regulates Notch signaling and has been implicated in individual cancers, but its pan-cancer expression patterns, clinical significance, and relationship to tumor immunity remain incompletely characterized. Methodology: We conducted a multi-omics bioinformatics analysis using TCGA and other public datasets to evaluate POFUT1 expression across 33 cancer types (n > 10,000). Differential expressions, tumor stage correlations, and survival outcomes were assessed. Immune cell infiltration was estimated using SangerBox and TIMER algorithms, while promoter methylation patterns were analyzed through UALCAN. Functional enrichment and protein–protein interaction networks were constructed to elucidate functional mechanism. Western blot validation in prostate and ovarian cancer cell lines confirmed our computational analysis. Results: POFUT1 showed significant overexpression in 16 of 33 cancer types (FDR-adjusted p < 0.05), with the highest elevation in BRCA (breast invasive carcinoma; log2FC = 2.31) and LUAD (lung adenocarcinoma; log2FC = 2.1). A high POFUT1 expression correlated with poor overall survival in eight cancer types (HR range: 1.8–3.2, p < 0.01) and disease-free survival in seven cancers. POFUT1 levels positively correlated with myeloid-derived suppressor cells (MDSCs) infiltrating in 15 cancer types, while inversely correlated with natural killer T (NKT) cells presence in 15 cancers (mean R = −0.34, p < 0.05), indicating an association with immunosuppressive microenvironments. Promoter hypomethylation in tumors suggested epigenetic dysregulation as a potential driver of its overexpression. Western blot analysis confirmed POFUT1 protein upregulations in prostate and ovarian cancer cell lines (1.7–2.1-fold. p < 0.01), corroborating transcriptomic findings. Conclusion: This pan-cancer study establishes POFUT1 as a critical oncogenic factor linked to aggressive disease, immune evasion, and poor prognosis. Its consistent overexpression and functional impact highlight its potential as a biomarker and target for anticancer therapy. While these computational findings require experimental validation, POFUT1 emerges as a candidate biomarker warranting functional studies and potential therapeutic targeting Full article

Digestive tract tumors represent a predominant contributor to the global public health burden, with conventional therapeutic modalities experiencing inherent limitations and immunotherapy being impeded by the immunosuppressive property and heterogeneity of the tumor microenvironment (TME). This makes the gut microbiota–immune axis a promising therapeutic target. Marine polysaccharides, endowed with distinctive structural characteristics, exhibit potential in the modulation of this regulatory axis, yet their structure–activity relationships (SARs) and the intrinsic limitations in delivery efficiency remain largely unelucidated. In this review, we systematically synthesized the latest research advances pertaining to the modulation of the gut microbiota–immune axis by marine polysaccharides in digestive tract tumors, in accordance with the logical framework of polysaccharide structure, flora regulation, immune activation, tumor inhibition, and delivery optimization. We elaborated on the bidirectional crosstalk between the gut microbiota and the immune axis during tumorigenesis, as well as the regulatory effects and core underlying mechanisms of marine polysaccharides derived from algal, animal and microbial sources on this axis, including targeted floral regulation, microbiota-mediated immune activation, and direct/indirect tumor suppression. We also analyzed the key structural determinants and structural modification strategies of marine polysaccharides, alongside the development of nanodelivery systems for the improvement of their oral bioavailability. Furthermore, we identified critical existing research gaps, such as the ambiguous SARs and poor oral bioavailability of marine polysaccharides, and propose the integration of multi-omics analysis, synthetic biology technology and advanced nanodelivery strategies as the core future research directions in this field. Collectively, marine polysaccharides hold tremendous promise as novel therapeutic agents for digestive tract tumors, and interdisciplinary collaboration is regarded as indispensable for their successful clinical translation and translational application. Full article

The gut microbiota serves as a critical interface for host immunity, making it a promising target for probiotic intervention. In this study, we investigated the immunomodulatory potential of the strain Bifidobacterium breve (B. breve) MN15965 and the underlying role of gut bacterial communities in this process. We first assessed its in vitro immunomodulatory activity by measuring nitric oxide and cytokine secretion in THP-1 macrophages. Subsequently, an immunosuppressed mouse model was established by treating BALB/c mice with cyclophosphamide (CTX), a chemotherapeutic agent known to cause immune dysfunction and mucosal damage. In this model, we performed a series of analyses, including H&E staining, measurement of hematological parameters and serum cytokines/immunoglobulins, quantification of fecal short-chain fatty acids (SCFAs) by gas chromatography, and profiling of gut microbiota composition via 16S rRNA gene amplicon sequencing. The results showed that MN15965 supernatant enhanced TNF-α, IL-1β, and GM-CSF secretion in THP-1 cells, promoting M1 macrophage activation in vitro. In the in vivo model, MN15965 administration restored spleen and thymus tissue integrity and improved physiological indices, hematological parameters, and immunoglobulin levels. Furthermore, MN15965 increased fecal SCFAs, particularly butyric and valeric acid, increased gut bacterial diversity, and enriched potentially beneficial SCFA-producing taxa, including Lachnospiraceae and Eubacterium. These findings demonstrate that B. breve MN15965 alleviated CTX-induced immunosuppression by activating immune responses, regulating gut bacterial communities, and boosting SCFA production. Full article

Infectious bursal disease virus (IBDV) is an immunosuppressive pathogen posing a major threat to poultry health worldwide. Its marked phenotypic variability is driven by the rapid evolution of its double-stranded RNA genome, primarily achieved through mutation and reassortment. Although extensive evidence has been generated on molecular determinants of antigenicity and pathogenicity, interpretation is often hindered by heterogeneity and lack of systematicity. This scoping review synthesizes over 35 years of research on amino acid positions influencing IBDV phenotype. A total of 62 studies reporting 107 functionally relevant sites were identified and critically appraised based on evidence type, methodological approach, and ability to infer causality. The results confirmed the central role of VP2, particularly its hypervariable region, while also highlighting the increasingly recognized contribution of other viral proteins. Despite good agreement, comparability across studies was limited by substantial heterogeneity in experimental design and the frequent focus on partial genomic regions. Notably, some molecular markers were context-dependent or inconsistently associated with phenotypic outcomes, underscoring the need for proper interpretation of molecular determinants and for more standardized and comprehensive approaches, including full-genome analyses and reverse genetics. Overall, these findings provide a valuable framework for enhancing molecular diagnostics and supporting the rational design of next-generation vaccines. Full article

Intestinal dysbiosis is common in people living with HIV/AIDS (PLWH), yet fungal communities of the gut microbiota (mycobiota) remain poorly characterized, especially in severely immunosuppressed patients. We analyzed the gut mycobiota of 33 PLWH and 20 healthy controls from a public hospital in central Argentina. Most PLWH presented with severe immunosuppression (<200 CD4⁺ T cells/μL) and acute or chronic diarrhea, with or without antibiotic exposure or antiretroviral therapy. Fecal DNA was extracted and the ITS2 region was sequenced using next-generation sequencing. Beta-diversity analyses revealed significant segregation between PLWH and controls (PERMANOVA, Adonis: p = 0.001, R² = 0.0989). LEfSe analysis identified 17 fungal species enriched in PLWH, predominantly Candida albicans, Candida dubliniensis, and Nakaseomyces glabratus, whereas 31 species were differentially represented in controls, including Penicillium spp., Candida sake, and Clavispora lusitaniae. Histoplasma capsulatum, an endemic pathogen in the region, was more prevalent in PLWH and associated with low CD4⁺ T cell counts. Dirichlet multinomial mixture analysis revealed two mycobiotypes: M1, with a balanced fungal composition predominating in controls, and M2, dominated by Candida species and present in PLWH. These findings provide novel insights into gut mycobiota alterations in severely immunosuppressed PLWH in Argentina, highlighting Candida-driven dysbiosis and the regional relevance of H. capsulatum. Full article

Rheumatoid arthritis (RA) is a systemic autoimmune disease that can involve the ocular surface and deeper ocular tissues, leading to a spectrum of ophthalmic manifestations ranging from dry eye disease to vision-threatening inflammation, such as scleritis and peripheral ulcerative keratitis (PUK). This paper presents the results of a narrative review conducted using PubMed and Google Scholar from database inception to March 2026. Eligible publications describing clinical features and management of RA-associated ocular disease were synthesized, and no unpublished data were included. According to the literature, dry eye disease (DED) is the most frequent ocular manifestation of RA, and it is primarily managed with lubrication and topical anti-inflammatory therapies, including cyclosporine and lifitegrast. Additional options for refractory disease include neurostimulation and evaporation-targeted therapy. Scleritis and PUK are less common but represent severe inflammatory complications that generally require systemic immunosuppression. Conventional management includes systemic corticosteroids and steroid-sparing agents such as methotrexate (MTX), azathioprine (AZA), cyclophosphamide (CYC), and mycophenolate mofetil (MMF) in aggressive cases. Escalation to biologic disease-modifying antirheumatic drugs (bDMARDs), specifically tumor necrosis factor-alpha (TNF-α) inhibitors and rituximab (RTX), is supported for refractory scleritis and corneal melt, although evidence is largely observational. Among anti-TNF agents, monoclonal antibodies, such as infliximab and adalimumab, appear more effective than etanercept for ocular inflammation. Rituximab is preferred for vasculitis-associated or refractory disease, and Janus Kinase (JAK) inhibitors represent an emerging option requiring careful safety monitoring. Evidence for DED therapies includes randomized controlled trials (RCTs), whereas data for RA-associated scleritis and PUK are largely derived from registries, case series, and case reports. Prospective studies with standardized ocular outcomes are needed to refine treatment algorithms and compare the effectiveness of biologic versus targeted synthetic agents. Full article

Epstein–Barr virus (EBV)-positive primary central nervous system lymphoma (PCNSL) is a rare entity typically associated with profound immunosuppression, most commonly in transplant recipients or individuals with HIV. We report a case of EBV-positive PCNSL arising in a 75-year-old male with myasthenia gravis receiving chronic mycophenolate mofetil (MMF) therapy outside the transplant setting. The patient presented with progressive neurological deficits, and brain magnetic resonance imaging demonstrated multiple enhancing lesions. Stereotactic biopsy revealed diffuse large B-cell lymphoma of non–germinal center subtype with immunoblastic features and EBV-encoded RNA (EBER) positivity, confirming EBV-positive PCNSL. MMF was discontinued, and the patient was treated with rituximab and high-dose methotrexate, resulting in stable disease. This case highlights that prolonged MMF therapy may confer sufficient immunosuppression to permit EBV-driven lymphoproliferative disease even in non-transplant patients. Early recognition, withdrawal of immunosuppression, and initiation of methotrexate-based chemotherapy can lead to favorable outcomes. Full article

The bone marrow tumor microenvironment (TME) is critical for acute myeloid leukemia (AML) progression, immune evasion, and treatment resistance. SRC, a non-receptor tyrosine kinase involved in multiple oncogenic pathways, has not been systematically characterized in AML in relation to prognosis and immune regulation. We integrated bulk transcriptomic and single-cell RNA-sequencing datasets from TCGA, BeatAML, and GEO. Immune-related targets were identified using xCell-based immune scoring and weighted gene co-expression network analysis (WGCNA), followed by protein–protein interaction analysis and multi-algorithm machine-learning screening. We then evaluated SRC expression patterns, prognostic associations, immune microenvironment features, predicted drug sensitivity, single-cell differentiation dynamics, intercellular communication, and in silico virtual knockout perturbation (scTenifoldKnk). SRC emerged as the most robust hub gene after integration of WGCNA, PPI analysis, machine-learning feature selection, and survival screening. SRC was significantly upregulated in AML compared with normal controls and was independently associated with poor overall survival (HR = 1.231, p = 0.037). High SRC expression was linked to adverse ELN/FAB features, increased immune checkpoint expression, enrichment of inflammatory and immunoregulatory pathways, and a higher proportion of primitive leukemia-associated cell states. Single-cell analyses further suggested that SRC was enriched in CD34⁺ progenitor compartments, associated with altered cell–cell communication, and accompanied by distinct mutation and pathway profiles. Drug-response prediction and in silico network perturbation analysis further supported the potential biological and translational relevance of SRC-centered programs. SRC is a prognostically relevant and immune-associated hub linked to AML microenvironment remodeling, and may serve as a candidate biomarker and potential therapeutic target that warrants further experimental validation. Full article

Salmonella spp. is a major zoonotic pathogen. Although reptiles are mostly considered subclinical carriers, clinical disease may develop following immunosuppression. Clinical salmonellosis in reptiles has been extensively reported; however, the condition has been rarely described in bearded dragons (Pogona vitticeps). We retrospectively analyzed six cases of salmonellosis in bearded dragons and characterized the pathological, immunohistochemical, and bacteriological findings. Clinical signs and gross findings were mostly non-specific. Histological findings mainly consisted of fibrinonecrotizing enterocolitis (83.3%); necrotizing or granulomatous hepatitis (66.7%); pneumonia including bronchopneumonia or interstitial pneumonia in one case each (33.3%); tubulointerstitial nephritis with tubular necrosis (16.7%); and coelomitis (16.7%). Salmonella enterica subsp. houtenae was cultured in three cases (33.3%), whereas S. enterica subsp. enterica serovar Rissen, S. enterica subsp. enterica serovar Cotham, and S. enterica subsp. diarizonae were cultured in one case each. Intralesional bacteria were detected via immunohistochemistry in kidneys and colon in two cases (33.3%). The predominance of lesions in the intestines and liver likely reflects initial intestinal colonization followed by hematogenous dissemination to the liver. Hepatic lesions are thought to represent different stages along a continuum, progressing from acute necrosis to discrete granuloma formation. Renal and respiratory involvement was infrequent, as reported in other reptile species. Some of the isolated Salmonella subspecies (S. diarizonae and S. houtenae) are well-recognized causes of clinical disease in other reptile species but not previously identified in bearded dragons. This study provides a comprehensive pathological, immunohistochemical, and bacteriological characterization of salmonellosis in bearded dragons, thus raising awareness and assisting in the identification of this condition. Full article

Immune checkpoint inhibitors (ICIs) have transformed non-small cell lung cancer (NSCLC) treatment; however, durable responses occur in only a subset of patients, underscoring the need for robust predictive biomarkers. Serine/threonine kinase 11 (STK11) is an emerging biomarker that portends poor prognosis and predicts therapeutic resistance. Loss of STK11 disrupts AMPK signaling, leading to unchecked mTOR activation, metabolic reprogramming, angiogenesis, and epithelial–mesenchymal transition, fostering tumor progression and immune evasion. STK11 mutations frequently co-occur with KRAS and KEAP1 alterations, exhibit low PD-L1 expression, an immunosuppressive tumor microenvironment that leads to the development of PD-1/PD-L1 resistance. Clinical studies consistently demonstrate inferior outcomes with ICIs in STK11-mutant NSCLC, particularly in the presence of KRAS and KEAP1 co-mutations. Dual checkpoint inhibition combining PD-1/PD-L1 and CTLA-4 blockade shows promise in overcoming resistance, results remain inconsistent, and prospective trials are ongoing. Beyond immunotherapy, STK11 mutations confer poor outcomes across targeted therapies, including KRAS G12C inhibitors, with KEAP1 co-mutation serving as a strong negative predictor of efficacy. In this review we present an overview of STK11 function and its role in tumor biology, highlight the prognostic and predictive potential of STK11 mutations in the context of NSCLC treatment and summarize the emerging treatment strategies. Full article

Laryngeal squamous cell carcinoma (LSCC) remains a major clinical challenge within head and neck oncology, with five-year survival rates showing minimal improvement over recent decades despite advances in surgical and multimodal therapeutic strategies. Increasing evidence identifies metabolic reprogramming as a central driver of tumor progression, therapeutic resistance, and immune evasion in LSCC. Beyond the classical Warburg effect, LSCC exhibits profound metabolic reprogramming, involving coordinated alterations in carbohydrate, amino acid, lipid, and iron metabolism that support adaptation to hypoxic and nutrient-deprived microenvironments. Hypoxia-inducible factors, particularly HIF-1α, coordinate these key biochemical pathways and enzymatic steps by integrating glycolysis, glutaminolysis, folate-dependent one-carbon pathways, lipid synthesis, and mitochondrial remodeling, while also influencing stromal and immune components of the tumor microenvironment. Metabolic crosstalk between tumor cells, cancer-associated fibroblasts, and immune populations promotes immunosuppression through nutrient competition and accumulation of metabolites such as lactate and lipid-derived mediators. In parallel, dysregulated iron handling and altered ferroptosis susceptibility emerge as key determinants of tumor aggressiveness and treatment response. This review synthesizes current evidence on metabolic rewiring in laryngeal squamous cell carcinoma, highlighting how alterations in metabolic pathways create targetable vulnerabilities that drive tumor biology, immune modulation, and resistance to conventional and emerging therapies. Elucidating these metabolic dependencies may support the development of metabolism-based biomarkers and therapeutic strategies in laryngeal squamous cell carcinoma, providing an integrated and translational perspective that links tumor metabolism with microenvironmental interactions and immune modulation, while highlights emerging therapeutic vulnerabilities. Full article

Background: Hematological patients have a high risk of developing severe COVID-19 (37%). Most mRNA vaccine trials in hematological patients showed a low immunogenicity after two doses, while long-term data are scarce. Methods: In this monocentric retrospective observational study, we evaluated humoral and T cell-mediated immune responses in 230 hematological patients after three doses of the Pfizer-BioNTech mRNA COVID-19 vaccine. Patients were stratified by age, disease type/state, prior COVID-19 infection, and treatment status and regimens (anti-CD20 monoclonal antibodies, BTK and BCL-2 inhibitors, and treatment line). Antibody titer to SARS-CoV-2 was assessed by electrochemiluminescence immunoassay and T cell response by QuantiFERON interferon-γ release assay (IGRA). Data were analyzed using univariate (Fisher’s exact test) and Firth’s bias-reduced penalized-likelihood logistic regression. Results: A robust humoral response was observed with 91.55% of patients developing anti-spike antibodies (GMT 988.83 U/mL). Anti-CD20-bendamustine treatment was associated with a significantly lower antibody positivity compared to untreated subjects. Prior COVID-19 infection significantly boosted both antibody positivity (95.9% vs. 85.2%) and GMT (847.02 U/mL vs. 258.79 U/mL). Conversely, T cell response was suboptimal (36.1% positive), particularly in anti-CD20-bendamustine-treated and multi-treated patients (27.1%), but highest in those treated with BTK inhibitors (50%). Multivariable logistic regression analysis linked multiple treatments to lower T cell response. Following vaccination, 29.1% of patients contracted SARS-CoV-2, but only 0.89% developed severe COVID-19. Conclusions: Three doses of mRNA vaccine elicit a strong humoral but a low T cell response, as detected by IGRA, in hematological patients. These findings underscore the importance of completing vaccination before initiating immunosuppressive therapies. Full article

Celastrol, a natural compound with potent antitumor activity, has gained considerable attention in drug research and development. Although its use is limited by high toxicity, a narrow therapeutic window, and severe side effects, studies show that celastrol can inhibit tumors through multiple targets and pathways, including by inducing apoptosis, autophagy, as well as suppressing invasion and adhesion. It also enhances antitumor effects by reshaping the immunosuppressive tumor microenvironment, regulating stromal components, and suppressing angiogenesis. This review systematically summarizes recent advances in related research and elaborates on the molecular mechanisms underlying the antitumor activity of celastrol and the key factors contributing to its toxicity. In addition, we further discuss current progress in research focused on reducing celastrol’s toxicity and enhancing its efficacy, aiming to promote its safety and druggability through rational structural modification, target optimization, and advanced formulation development. Full article

The immunosuppression inherent to chronic lymphocytic leukemia (CLL) is the most frequent cause of morbidity and mortality associated with this pathology. Both the innate and adaptive immune responses exhibit marked functional alterations, with a bias towards a tolerant environment that favors the spread of the disease. This condition is reflected in increased risk of infections, immune-mediated cytopenias, and associated second malignancies. Knowledge of these alterations, both in the molecular pathways that modulate T cell activity in CLL (the T lymphocyte cytotoxic antigen-4 (CTLA-4) axis and programmed cell death 1 (PD-1)) and at the T cell immunoreceptor level, could be of interest as therapeutic targets in CLL. In this review, we will analyze the main consequences of this dysfunction and its management strategies. Full article