搜索结果：Oncoimmunology

Colorectal cancer (CRC) treatment represents a major clinical challenge, with immunotherapy providing durable responses only in a minority of patients. A deeper understanding of CD8⁺ T cell exhaustion and its contribution to immune checkpoint inhibitor (ICI) responsiveness is essential for the development of more effective therapeutic strategies. Preclinical models that faithfully reproduce the immune landscape of human CRC are therefore critical to address these challenges. Here, we established a syngeneic organoid-based orthotopic CRC mouse model by transplanting quadruple mutant Apc⁻/⁻KrasG12D/+Trp53R172H/⁻Smad4⁻/⁻ (AKPS) intestinal organoids into the rectal submucosa of immunocompetent mice. Single-cell transcriptomic profiling revealed that CD8⁺ T cells represent the predominant leukocyte population within the tumor infiltrate and comprise populations transitioning toward dysfunction. Functionally, CD8⁺ T cell depletion led to increased tumor burden in orthotopic AKPS implants, underscoring their antitumor activity. Importantly, anti-PD-1 treatment increased the abundance of dysfunctional CD8⁺ T cell populations within AKPS tumors and reduced tumor growth, demonstrating the responsiveness of this model to ICIs. In contrast, subcutaneous implants of AKPS were infiltrated by mixed CD4⁺ and CD8⁺ T cell subsets, with CD8⁺ T cells exhibiting a markedly less dysfunctional profile, highlighting the limitations of heterotopic tumor models for studying antitumor immune responses. Together, our findings establish the AKPS orthotopic CRC model as a platform to dissect the molecular mechanisms of early CD8⁺ T cell dysfunction and to preclinically evaluate novel immunotherapeutic interventions in CRC. We established a mouse model of colorectal cancer (CRC) based on the orthotopic transplantation of quadruple mutant (Apc-/-KrasG12D/+Trp53R172H/-Smad4-/-) intestinal organoids which is well suited for studying the molecular mechanisms underlying early phases of CD8⁺ T cell exhaustion and for evaluating the efficacy of immune checkpoint inhibitors (ICIs) in CRC.

Metastasis is a major determinant of treatment failure and mortality in thyroid cancer, yet the interplay between malignant evolution and the immune microenvironment remains poorly characterized. Immunotherapy offers promise, but its efficacy requires a deeper understanding of tumor-associated immune infiltration and checkpoint regulation. In this study, we constructed a high-resolution transcriptomic atlas of the thyroid cancer ecosystem by analyzing 55,005 single cells from paired primary tumors and lymph node metastases. By integrating chromosomal copy number variation (CNV) inference with consensus nonnegative matrix factorization (cNMF), we deciphered the intrinsic heterogeneity of malignant epithelial cells, revealing distinct transcriptional programs and developmental trajectories driving the metastatic cascade. The metastatic niche exhibited significant reprogramming of the immunosuppressive landscape, characterized by the enrichment of FOXP3⁺ regulatory T (Treg) cells, LAMP3⁺ dendritic cells (DCs), and CCL18⁺ M2-like macrophages. Notably, while canonical checkpoints PD-1 and PD-L1/2 showed minimal expression, ligand-receptor interaction analysis identified the LAG3-LGALS3 axes as dominant immune evasion pathways mediating the crosstalk between CD8⁺ T cells and the tumor stroma. In conclusion, this study comprehensively maps the coevolution of malignant thyrocyte plasticity and the immunosuppressive metastatic niche. By uncovering the specific role of LAMP3⁺ DCs and identifying LAG3/TIGIT as critical alternative checkpoints, our findings challenge the utility of conventional PD-1 blockade in this context and provide a robust molecular rationale for developing next-generation immunotherapeutic strategies tailored to thyroid cancer. Although limited by a modest sample size, these findings provide a foundation for further investigation of the metastatic immune landscape in thyroid cancer.

The clinical development of 4-1BB agonists for cancer immunotherapy has been constrained by dose-limiting toxicities, particularly hepatotoxicity. To overcome this challenge, we developed FTL008.16, a novel bispecific antibody targeting 4-1BB (CD137) on T cells and the tumor-associated antigen 5T4. FTL008.16 is a human IgG1 antibody bearing an effector-deficient Fc region that specifically binds 4-1BB at an epitope overlapping with that of its natural ligand (4-1BBL), potentially mimicking physiological 4-1BBL-mediated co-stimulation. As demonstrated through in vitro reporter assays and primary cell-based systems, FTL008.16 elicits dose-dependent 4-1BB activation strictly contingent on 5T4 engagement, enhancing T-cell proliferation, cytokine secretion, and tumor cell lysis, thereby demonstrating potent antitumor efficacy in preclinical models. In vivo, FTL008.16 exhibited superior efficacy over a conventional anti-4-1BB monoclonal antibody, suppressing established tumors in both CT26 and MC38 models, with complete regression observed in CT26 tumors. In cynomolgus monkeys, FTL008.16 demonstrated an excellent safety profile, with no elevations in alanine aminotransferase (ALT) or aspartate aminotransferase (AST) observed even at 50 mg/kg. Importantly, this 5T4-restricted activation mechanism confines immune stimulation to the tumor microenvironment, thereby circumventing the systemic toxicity associated with conventional 4-1BB agonists. Collectively, these findings establish FTL008.16 as a conditionally active immunotherapeutic agent that successfully achieves both robust antitumor efficacy and a favorable safety profile.

While existing cancer therapies manage to reduce tumor burden, they often fail to produce durable or curative outcomes. Alternatively, cell-based approaches - particularly dendritic cell (DC) vaccines conceal the potential to elicit robust tumor-specific T-cell responses, equipping patients with T-cells capable of eradicating tumor cells and preventing future relapses. To date, most DC vaccines have been generated with monocyte-derived DCs (moDCs), nowadays considered less potent at priming T-cells than blood-derived DC subsets, arguing for the usage of blood DCs for vaccine development. However, their scarcity in blood has hindered their clinical application, limiting their use in DC-based vaccination trials. To overcome this limitation, we developed a protocol to generate clinically relevant quantities of conventional DC type 1 (cDC1s) and DC2-like cells (cDC2s) from progenitor cells isolated from peripheral blood without the need for G-CSF mobilization, enabling their use for autologous vaccinations. The protocol is feeder layer free, yields clinically relevant amounts of cDC1s and cDC2s-like cells, and can be translated into a GMP-compliant setup. The ex vivo-generated DCs resemble their natural counterparts, acquire a robust pro-inflammatory phenotype (e.g., CD83, CCR7, and IL-12p70), and efficiently expand pro-inflammatory T-cells (e.g., IFN-γ). Notably, in an in vitro immunization model, these DCs primed naive T-cells for the expansion of tumor-antigen-specific CD8 T-cells exhibiting strong immune-stimulating features (e.g., IFN-γ, CD107a). In summary, this study demonstrates that blood progenitors differentiate into cDC1 and cDC2-like cells capable of eliciting potent antigen-specific T-cell subsets, offering a promising avenue for the development of more effective DC-based cancer therapies.

The local immune effects of cancer radiotherapy remain poorly characterized in humans due to limited access to irradiated tissue. Mechanistic insights largely derive from preclinical models employing tumor-intact, neoadjuvant-like settings. Here, we present real-world immunoprofiling data from breast cancer patients undergoing breast-conserving surgery with (n = 20) or without (n = 29) intraoperative radiotherapy (IORT). Postoperative wound fluid samples were analyzed by flow cytometry, multiplex cytokine profiling, and bulk RNA-sequencing, alongside systemic immune monitoring in peripheral blood. IORT triggered rapid local accumulation of distinct innate immune cell subsets and cytokines mediating recruitment, activation, and innate-adaptive crosstalk, accompanied by systemic features consistent with emergency hematopoiesis. Transcriptomic profiling of wound fluid mononuclear cells revealed enrichment of proinflammatory IL-6-JAK/STAT3 signaling. In vitro, irradiation of primary breast tissue cells recapitulated key cytokine patterns and led to robust senescence induction, suggesting irradiated, senescent normal tissue cells as drivers of early immune activation in postsurgical radiotherapy. These data provide direct clinical evidence that radiotherapy shapes local and systemic immune responses, offering mechanistic insights with clear relevance for tumor immunology and the development of rational radiotherapy‒immunotherapy combination strategies.

DNA2 coordinates essential maintenance processes, including cell-cycle progression; however, its aberrant activity has been implicated in cancer cell survival under oncogene-induced replication stress. To date, no comprehensive pan-cancer investigation of DNA2 has been conducted. Employing TCGA cohorts and complementary public databases, we executed the first pan-cancer multi-omics study of DNA2, examining transcriptomic, genomic variations, survival, immune infiltration, single-cell functional states, protein-protein interaction enrichment, and pharmacogenomic drug-response data across tumor profiles. DNA2 was considerably overexpressed in 17 tumors compared with matching normal tissues. In endometrial cancer, the highest frequency of genetic changes (~ 7%) was observed. Univariable analyses of survival showed that elevated DNA2 expression was related to worse overall survival in malignancies, including adrenocortical carcinoma (HR = 17.06) and mesothelioma (HR = 2.67). Single-cell omics revealed a tumor-specific correlation between DNA2 expression and functional annotations that encompass DNA damage, angiogenesis, and proliferation. Moreover, DNA2 expression was consistently positively associated with regulatory T-cell subtypes, but negatively related with NK cells, and cytotoxic T cells in multiple tumors as per immune landscape profiling. According to the pharmacogenomic analysis from GDSC2 dataset, tumor cells that express higher DNA2 are more sensitive to Tozasertib, and Daporinad. DNA2 is at the core of several interrelated modules, including flap processing, telomerase extension, and cell-cycle progression, according to the enrichment study. These findings have suggested DNA2 as a therapeutic vulnerability in cancer, a context-dependent biomarker with implications for treatment response, prognosis, and immunity.

Glioblastoma remains one of the most lethal malignancies, characterized by rapid recurrence, profound intratumoral heterogeneity, and a highly immunosuppressive microenvironment. Among immunotherapeutic strategies, peptide-based vaccines have attracted attention for their safety, specificity, and capacity to elicit tumor-directed T cell responses. Over the past two decades, several platforms targeting tumor-associated or tumor-specific antigens, including EGFRvIII, WT1, and survivin, have advanced into clinical trials. While early-phase studies demonstrated immunogenicity and occasional survival benefits, phase III trials have largely failed to confirm durable efficacy, underscoring the challenges posed by the ongoing complexity of tumor evasion mechanisms among which down regulation of MHC (HLA) expression in tumor cells, lack or reduced tumor antigen expression and a suppressive tumor microenvironment certainly play a role. As far as tumor antigens, recent insights also question the centrality of neoantigens, highlighting instead the immunogenicity of shared tumor-associated antigens, which may provide a more reliable foundation for broadly applicable vaccines in GBM. A major barrier to efficacy remains impaired antigen presentation, particularly the downregulation of MHC-II pathways. In this context, strategies leveraging the transcriptional activator CIITA to restore MHC-II expression hold promise both for reprogramming GBM cells into effective antigen-presenting cells and for the isolation of new families of MHC class II-bound peptides relevant for the triggering of tumor-specific CD4+ T cells. This new approach could pave the way for next-generation peptide vaccines, particularly when integrated with combinatorial modalities such as checkpoint inhibitors, myeloid-targeted therapies, or oncolytic viruses.

Tumor-induced manipulations of myelomonocytic differentiation have been widely reported. Here, we describe the elicitation of a tumor-supportive cell type in a T lymphoma model in mice. We observed that the development of T lymphoma coincided with the appearance of a lymphoma-associated monocytic cell type (LAM) of host origin accompanied by a diminished dendritic cell (DC) population. RNA-sequencing and cytometric analyses revealed that LAMs shared markers with both DCs and with resident macrophages, most closely resembling monocyte-derived DCs (moDCs). The numbers of T lymphoma cells were negatively affected by reducing LAMs suggesting a helper function of LAMs for tumor growth. LAMs expressed Notch ligands, and treatments of lymphoma-carrying mice with Notch signaling-inhibitors LY3039478 and DAPT selectively decreased expansions of T lymphomas with or without Notch1 mutations, respectively. Mature LAMs did not proliferate in the periphery. Instead, their expansion resulted from altered myelomonocytic differentiation in the bone marrows of lymphoma-carrying mice with increases in common monocyte/DC precursors but with reduced granulocyte, monocyte and DC precursor populations. These data suggest that developing T lymphomas are capable of reprogramming monocyte/DC differentiation to increase the numbers of a tumor-promoting DC type, attract it to tumor locations and may engage in Notch ligand-dependent signaling to support lymphoma survival.

Antibody-drug conjugates (ADCs) combine the target specificity of monoclonal antibodies with the cytotoxic potency of small-molecule payloads. In recent years ADCs have emerged as a clinically validated component of modern precision oncology. To date, more than a dozen ADCs have received FDA approval for oncologic indications, with additional agents approved regionally and hundreds of ADC-based regimens in clinical development. Collectively, these therapies have demonstrated clinical benefit across hematologic malignancies and solid tumors, including significant overall survival improvements in advanced phase clinical trials. In this Trial Watch, we provide an overview on available ADCs from early preclinical development to current clinical applications. We also summarize design principles underpinning clinically successful ADCs, including epitope targeting, linker chemistry, payload toxicity and drug-to-antibody ratio, and discuss how these features can influence pharmacokinetics, intracellular trafficking, bystander effect and toxicity. Finally, we discuss results from advanced-stage clinical trials and approved agents to define future directions.

Early-stage colorectal cancer (CRC) with confirmed microsatellite instability generally has a favorable prognosis associated with pronounced immune infiltration. However, some patients still develop metastases. The underlying mechanisms, particularly those related to the tumor immune microenvironment, remain incompletely understood. The study included tissue samples from 217 patients with dMMR/MSI-H CRC, comprising 89 stage III/IV and 128 stage I/II cases. Tissue microarrays and immunohistochemical analyzes were performed for all cases. We evaluated immune markers identifying T cells, B cells, dendritic cells, natural killer cells, macrophages, immunosuppressive markers, and immune checkpoint targets in epithelial and stromal compartments, and additionally performed a cohort-derived immune infiltration score (IIS). The survival analysis assessed the prognostic impact of immune markers stratified by tumor stage. Stage I/II dMMR/MSI-H CRCs showed significantly higher CD3⁺ T-cell and natural killer cell levels, higher IIS metrics across all regions, and higher CD4⁺ T helper cell levels in the stroma. Stage III/IV cases exhibited increased epithelial expression of indoleamine 2,3-dioxygenase 1. Given the limited number of stage IV patients, an additional stage III vs. stage I/II comparison was performed, revealing that these immune differences were already evident at the level of nodal progression. In addition, CD3⁺, CD4⁺, and CD8⁺ T cells and the IIS showed varying prognostic associations across tumor stages. These findings suggest that the overall immunogenicity and prognostic relevance of immune markers in dMMR/MSI-H CRC depend on tumor stage. Immune profiling could be used for early-stage patient stratification and also suggests the potential benefit of early immunotherapeutic intervention.

Circulating tumor DNA (ctDNA) is a promising biomarker in melanoma, with higher sensitivity for tumor burden detection than conventional diagnostics. While well established in research, clinical routine implementation remains pending. Key global questions concern optimal clinical applications and barriers to adoption. A web-based survey of 116 members of the Melanoma World Society Study Group assessed international expert opinions on ctDNA utility across predefined clinical scenarios. The questionnaire included 18 general questions on ctDNA use and 5 clinical vignettes with de-identified patient data and retrospectively obtained ctDNA results. ctDNA was rated most valuable for detecting minimal residual disease (mean score 3.63), surveillance of recurrent disease (3.85), and stage IV melanoma (3.82), with limited utility in early stages. Experts considered ctDNA superior to S100 and LDH for early relapse detection and identifying progressive disease. Most participants (80%) agreed that ctDNA correlates with radiographic response, and 82% favored its integration into routine follow-ups. In urgent high-tumor-burden settings, 82.8% would initiate BRAFi/MEKi therapy based on ctDNA if tissue analysis was pending, and 93.9% if unavailable. For central nervous system lesions, 62% did not support blood ctDNA, while 66% considered cerebrospinal fluid valuable. Pragmatic approaches with small to mid-size targeted panels and short turnaround times were preferred. Major barriers included the need for prospective trials (85%), standardized guidelines (83%), and reimbursement policies (82%). Key opinion leaders regarded ctDNA as a valuable adjunct selected melanoma scenarios. Validation through prospective studies, guideline development, and reimbursement frameworks are essential for broader clinical implementation.

Pulmonary spindle cell tumors are aggressive neoplasms with limited systemic treatment options, although a subset may harbor actionable genomic alterations. Because conventional fusion assays may miss rearrangements involving atypical or previously uncharacterized partners, we systematically investigated oncogenic fusions in pulmonary spindle cell tumors using anchored multiplex PCR-based targeted RNA sequencing. Formalin-fixed, paraffin-embedded tumor samples from 11 surgically resected pulmonary spindle cell tumors, excluding metastatic sarcomas, were analyzed using the FusionPlex Sarcoma panel supplemented with custom primers for RET, NTRK1, NTRK2, and NRG1. Two tumors (18.2%) harbored ALK fusions, identified as PPFIBP1::ALK and SYCL3::ALK. Both tumors showed positive ALK immunohistochemical staining. Histologically, the PPFIBP1::ALK-positive tumor was composed of spindle-shaped cells with a layered architecture, whereas the SYCL3::ALK-positive tumor showed relatively round cells arranged in clusters with collagenous stroma, highlighting the morphologic heterogeneity of ALK-rearranged pulmonary spindle cell tumors. These findings expand the molecular spectrum of pulmonary spindle cell tumors and identify rare ALK fusion partners in this setting. Our results support the incorporation of ALK immunohistochemistry as a screening tool and demonstrate the utility of anchored multiplex PCR-based RNA sequencing for the detection of therapeutically relevant fusions, particularly those with uncommon partners. This integrated approach may refine the diagnosis and support consideration of ALK-directed therapy in these rare tumors.

Accurate imaging diagnosis is essential for evaluating liver transplantation (LT) eligibility in hepatocellular carcinoma (HCC) patients. This study investigated whether pre-transplant imaging assessment using the Liver Imaging Reporting and Data System (LI-RADS) and Asia-Pacific guideline-based criteria could effectively predict long-term prognosis when determining LT eligibility. From a prospective registry, we analyzed 1,094 patients with a preoperative HCC diagnosis who had dynamic CT available within 1 month before LT. LT eligibility was assessed with Milan criteria (MC) and Up-to-Seven criteria (UTS). Imaging evaluation was performed using the LI-RADS, Asian Pacific Association for the Study of the Liver, Japan Society of Hepatology, and Korean Liver Cancer Association-National Cancer Center guidelines. We compared HCC-related mortality using competing risk analysis, overall survival, and prognostic performance between imaging-based and pathologic assessments. The cohort comprised 158 (14.4%) anti-HCC treatment naïve patients and 936 (85.6%) patients who received anti-HCC treatments in the pre-LT setting. No significant difference in HCC-related mortality was observed between patients meeting imaging-based MC and pathological MC (5-year HCC-related mortality: 8.6-8.7% vs. 6.6%; all p > 0.05). Prognostic performance, assessed by 5-year area under the precision-recall curve and integrated Brier score, showed no significant differences between imaging-based MC and pathological MC groups (all p > 0.05). Similar results were observed for overall survival, UTS-based analyses, and pre-LT treatment subgroup analyses. Concordance between imaging-based MC and pathology-based MC was 84.0-84.4%. Although some discordance between imaging-based and pathology-based LT eligibility criteria was observed, pre-transplant imaging provided prognostic stratification comparable to pathology. Given that comprehensive pathological assessment is unattainable before LT, imaging-based evaluation using both LI-RADS and Asia-Pacific guidelines represents a practical and clinically relevant approach for determining LT eligibility.

Innate immunity constitutes the primary barrier against invading pathogens and plays a crucial role in coordinating the initiation and modulation of adaptive immune responses. Transglutaminase 2 (TG2), a ubiquitously expressed multifunctional enzyme, has recently been identified as a key regulator of innate immune signaling. Mounting evidence highlights TG2's involvement in modulating type I interferons and pro-inflammatory cytokines in response to microbial infections and cellular stress, serving as an critical element in diverse signaling pathways. TG2 engages in various immune-related processes, such as inflammation, phagocytosis, and host defense, by integrating into essential intracellular signaling cascades. In this review, we synthesize the current knowledge of TG2's roles in the innate immune system, emphasizing its interactions with TBK1 (TANK-binding kinase 1)-a central node in type I interferon signaling-and other innate immune mediators. We also examine the implications of TG2 dysregulation in immune-mediated diseases and evaluate its promise as a therapeutic target. Collectively, this review integrates recent progress and encourages further exploration of TG2's multifaceted contributions to innate immunity.

Mesothelin (MSLN) is a GPI-anchored cell surface glycoprotein that is overexpressed in various solid tumors, including mesothelioma, triple-negative breast cancer, colon, ovarian and pancreatic cancer, with restricted normal tissue expression. To explore the immunogenicity and immunotherapeutic potential of MSLN to T cells with native receptor specificity, 29 individuals of diverse HLA backgrounds were interrogated for T cell activity against MSLN. Twenty one (72%) subjects (21/29) mounted a specific T cell response when repetitively challenged with MSLN antigen. Reactive cells were Th1-polarized, polyfunctional, predominantly detected in the CD8+ T cell compartment and cytotoxic toward autologous and MSLN+/HLA-matched tumor cell lines in conventional 2D in vitro assays. Furthermore, these cells produced anti-tumor effects in a novel 3D tumor spheroid model system established to evaluate the potency of reactive cells against tumors including pancreatic, cervical, and colorectal cancer and mesothelioma. These preclinical findings lay the groundwork for further exploration of MSLN as a potential immunotherapeutic target for T cells via the native T cell receptor.

BACKGROUND: Checkpoint inhibitors targeting PD-1 and PD-L1 have revolutionized cancer immunotherapy; however, their efficacy remains limited in immune-excluded tumors characterized by scarce T-cell infiltration and a profoundly immunosuppressive tumor microenvironment (TME). Activation of the stimulator of interferon genes (STING) pathway represents a promising strategy to overcome immune exclusion by promoting TME remodeling and immune cell recruitment. This study investigated the therapeutic potential of combining 8803, a potent STING agonist with broad cross-species activity, and 27907, a novel Fc-engineered dual-specific antibody targeting PD-L1 and PD-L2, designed to enhance antibody-dependent cytotoxicity and phagocytosis. METHODS: The activity of 8803 was assessed in human and murine STING reporter cell lines and in co-culture systems with tumor, endothelial, and immune cells. The Fc-mediated effector functions of 27907 were characterized through ADCC and ADCP reporter bioassays. Antitumor efficacy was evaluated in B16-PD-L2 melanoma (C57BL/6) and TS/A mammary carcinoma (BALB/c) mouse models treated with intratumoral 8803 and/or systemic 27907. Tumor growth and survival were monitored, and immune and vascular remodeling were analyzed by flow cytometry, immunohistochemistry, and immunofluorescence. Statistical analyses were performed using two-way ANOVA with Bonferroni post-test for tumor growth, Mantel–Cox log-rank test for survival, and unpaired Student’s t-test or one-way ANOVA for in vitro and ex vivo data. RESULTS: The combination of 8803 and 27907 resulted in significant tumor growth inhibition and prolonged survival compared with single-agent treatments. STING activation by 8803 remodeled the TME by reducing intratumoral M2-like macrophages and mature regulatory dendritic cells (mregDCs) while enhancing T-cell and myeloid cell infiltration. It also induced PD-L1 and PD-L2 upregulation on tumor and endothelial cells. The dual-specific antibody 27907 efficiently mediated antibody-dependent cellular cytotoxicity and phagocytosis, leading to selective endothelial cell killing, vascular disruption, extensive necrosis, and enhanced immune infiltration in the combination treatment group. CONCLUSIONS: Dual PD-L1/PD-L2 blockade synergizes with STING pathway activation to promote immune and vascular remodeling, resulting in superior antitumor efficacy in preclinical tumor models. These findings provide a strong rationale for the clinical development of combination strategies that integrate STING agonists with cytotoxic checkpoint antibodies to overcome immune exclusion and enhance cancer immunotherapy outcomes.

Immune checkpoint inhibitors (ICIs) have improved outcomes in advanced non-small cell lung cancer (NSCLC), however reliable predictive biomarkers are lacking. Our group previously reported an association between high levels of circulating low-density neutrophils (LDNs) and resistance to ICI monotherapy. We present updated results, including a validation cohort, proteomic characterization of LDNs, and in vivo experiments exploring mechanisms of resistance. NSCLC patients treated with first line ICI monotherapy (n=60) or combined with chemotherapy (CT+ICI) (n=60) were recruited. LDNs were quantified by flow cytometry and correlated with clinical outcomes. Phenotypes of LDNs and conventional neutrophils were characterised by flow cytometry and quantitative proteomics. Plasma cytokine measurements and in vivo experiments were conducted to assess the role of LDNs in ICI resistance. High baseline LDN levels were significantly associated with primary resistance to ICI monotherapy, with patients showing an overall response rate (ORR) of 17% vs 50% (p=0.04) and median progression free survival (mPFS) of 2.3 months vs 21.8 months (p < 0.001). No such association was seen in patients treated with CT+ICI, showing a LDN depletion in responders. LDNs exhibited an aged phenotype and distinct proteomic profile. Plasma from high-LDN patients showed elevated myeloid-expansion (M-CSF, IL1&#x3b2;) and inflammatory cytokines (CXCL9, IL-25). Depletion of Gr1+ population enhanced response to ICI and CT+ICI in the Lewis Lung Carcinoma (LLC) model with high LDNs. High baseline LDNs predict resistance to ICI monotherapy in NSCLC and combination with chemotherapy may overcome this resistance. Additional therapeutic strategies targeting LDNs could enhance immunotherapy efficacy.

Colorectal cancer (CRC) progression is driven by dynamic interactions among tumor cells, immune infiltrates, and the gut microbiota. While regulatory T cells (Tregs) may contribute to immune suppression in CRC, the role of non-conventional Tregs remains poorly defined. We identified a non-conventional population of microbiota-induced Tregs in the human colonic mucosa that co-expressed CD4, CD8&#x3b1;, CXCR6, and CCR6, termed DP8&#x3b1; Tregs, that exert potent immunomodulatory properties in different inflammatory settings. Their status and role in CRC, however, have not been investigated. Here, using multiparametric flow cytometry in a prospective cohort of CRC patients, we showed that DP8&#x3b1; Tregs are significantly enriched in tumors compared to paired non-tumoral colonic mucosa. Tumor-infiltrating DP8&#x3b1; Tregs displayed elevated expression of the CD39/CD73 ectonucleotidases, as well as CCR5, consistent with a suppressive phenotype within the tumor microenvironment. Functional co-culture assays further demonstrated that sorting DP8&#x3b1; Tregs from CRC tumors inhibited both CD4 and CD8 T-cell proliferation, an effect largely reversed by pharmacological inhibition of CD39 and CD73, which was associated with reduced IL-2 levels. Together, these findings show that DP8&#x3b1; Tregs enriched in the CRC tumor microenvironment, are able to suppress effector T-cell responses through the purinergic pathway and support further investigation of their contribution to immune regulation in CRC.

Triple-negative breast cancer (TNBC) remains one of the most lethal breast cancer subtypes, driven by early dissemination and resistance to therapy. Here, we reveal a macrophage-centered cytokine circuit that fuels TNBC metastasis and immune evasion. Tumor cells reprogram na&#xef;ve macrophages into tumor-associated macrophages (TAMs) that secrete CCL3, CCL4, CXCL2, and IL-1&#x3b2;, collectively promoting epithelial-to-mesenchymal transition, migration, transendothelial invasion, and lung colonization. These TAMs, in turn, convert na&#xef;ve CD4&#x207a; T cells into FOXP3&#x207a; Tregs, establishing a self-reinforcing immunosuppressive niche. Pharmacological inhibition of CCR5, CXCR2, and IL1R1 with maraviroc, navarixin, and anakinra, respectively, disrupted this cytokine axis, suppressing metastatic colonization in vivo. Our findings reveal that blocking cytokine receptor signaling disrupts the pro-metastatic crosstalk between macrophages and TNBC cells, offering a clinically actionable strategy to restrain metastasis and overcome therapy resistance in TNBC.