Background Using surrogates for overall survival (OS) may expedite the development of, and patient access to, novel treatments. We assessed potential surrogates for OS in patients with metastatic melanoma treated with nivolumab-containing regimens in the first-line treatment setting.Methods We used individual-patient data from 1865 patients enrolled in four randomized controlled trials studying single-agent nivolumab or combinations of nivolumab and ipilimumab against dacarbazine or immunotherapy. Using the two-level meta-analytic framework, we evaluated three candidate surrogates: objective response rate (ORR), progression-free survival (PFS), and time to next treatment or death (TNTD). We measured the patient-level associations between candidates and OS using ORs in the case of ORR and Spearman’s correlation coefficient (ρ) in the case of time-to-event surrogate endpoints. We used R2 to measure the trial-level association between ORs or HRs for each surrogate and the HRs for OS.Results For ORR, at the individual-level, OR of survival was equal to 12.29 (95% CI 9.78 to 14.80), and at the trial-level R2 was equal to 0.62 (95% CI 0 to 1.00). For PFS, at the individual-level ρ was equal to 0.72 (95% CI 0.70 to 0.73), and at the trial-level R2 was equal to 0.73 (95% CI 0.27 to 1.00). For TNTD, at the individual-level ρ was equal to 0.77 (95% CI 0.76 to 0.78), and at the trial-level R2 was equal to 0.77 (95% CI 0.37 to 1.00). In cross-validation, the 95% prediction intervals for HRs for OS predicted by regression models always contained the observed HRs for OS, indicating the stability of the models.Conclusion At the individual-level, ORR exhibited a strong correlation with OS, whereas PFS and TNTD showed a moderate level correlation with OS. At the trial level, the key requirement for validating surrogates, all candidate surrogates demonstrated moderate predictive abilities for OS in future trials. These findings should be interpreted within the context of anti-PD-1-based therapies, with or without anti-CTLA-4 combinations, consistent with the trial evidence base included in this study.
Background Tertiary lymphoid structures (TLS) are spatially organized immune niches associated with therapeutic response and favorable outcomes in breast cancer (BC). However, TLS assessment currently relies on invasive tissue-based analyses, and the biological mechanisms underlying imaging-based TLS prediction remain poorly understood.Methods We developed and validated a spatial heterogeneity-based radiomic TLS signature (shTLS) using dynamic contrast-enhanced MRI to non-invasively predict TLS status across multicenter BC cohorts. Spatial habitat radiomics were used to capture intratumoral and peritumoral immune-related heterogeneity. Integrated multi-omics analyses, including transcriptomics, pathomics, genomics, single-cell RNA sequencing, immunohistochemistry, and multiplex immunofluorescence, were performed to biologically interpret shTLS-defined subgroups. Functional drug-sensitivity assays were conducted to assess therapeutic implications.Results The shTLS model achieved robust predictive performance across independent cohorts and molecular subtypes. High shTLS scores were associated with immune-inflamed tumors characterized by spatially clustered activated T cells and dendritic cells (DCs). In contrast, shTLS-low tumors exhibited an immunosuppressive spatial niche with peripheral accumulation of CD4+ PD-1+ T cells and plasma cells, increased immune-tumor separation, and enhanced inflammatory and immunoregulatory signaling. An indoleamine 2,3-dioxygenase 1 (IDO1)-associated immunoregulatory program was observed in the shTLS-low tumors, which appeared to be preferentially expressed by LAMP3+CCR7+ migratory DCs. Pharmacologic inhibition of IDO1 enhanced chemotherapy and CDK4/6 inhibitor sensitivity in vitro.Conclusion This study establishes spatial radiomics as a non-invasive approach to decode TLS-associated immune ecosystems and supports the presence of an IDO1-associated immunosuppressive phenotype, providing biological insight and translational rationale for patient stratification and future combination strategies.
Background A substantial amount of research has been dedicated to the mechanisms by which tumor cells evade immune system recognition and manipulate the immune microenvironment to facilitate immune escape. Recent studies have shown that viruses and tumors can protect themselves from immune cytotoxicity by remodeling the actin cytoskeleton. However, cytoskeleton-mediated immune resistance and the specific cytoskeleton-related proteins involved require further research. Methods Single-cell RNA sequencing was used to identify cytoskeleton-related genes associated with the response to anti-programmed cell death protein 1 (PD-1) therapy across four digestive tumors. Immunohistochemistry was used to detect LASP1 expression in gastric cancer and analyze its prognostic value for survival and anti-PD-1 response. The impact of LASP1 deficiency on tumor response to anti-PD-1 treatment and cytotoxic lymphocyte-mediated lysis was determined in vivo and in vitro. Live-cell imaging was used to compare actin cytoskeletal dynamics at the immunological synapse between LASP1-deficient and mock tumor cells. Molecular mechanisms underlying LASP1-mediated immune-resistance were dissected using co-immunoprecipitation, immunofluorescence, domain deletion complementation, and Laurdan staining. Results The deficiency of LASP1 in gastric cancer affected the sensitivity of tumor cells to immunotherapy and induced cytotoxic lymphocytes exhaustion. LASP1 may act as a scaffold protein to regulate the Arp2/3 complex and remodel the cytoskeleton at the immunological synapses. LASP1 deficiency in tumor cells impairs lytic immunological synapse function by disrupting cytoskeletal dynamics-mediated cell membrane lipid organization at the immunological synapse. Finally, simvastatin combined with anti-PD-1 therapy reversed immunotherapy resistance in LASP1-deficient tumors. Conclusions The deficiency of LASP1 in tumors mediates immunological synapse dysfunction by affecting cytoskeletal dynamics-mediated cell membrane lipid organization, thus enabling tumors to protect themselves from immune cytotoxicity and immunotherapy.
Background Tumor-associated macrophages (TAMs) play pivotal roles in shaping the tumor-microenvironment (TME) through functional plasticity, which is regulated by extrinsic and intrinsic signals. However, the role of vesicular trafficking in TAMs remains poorly understood. RAB31, a small GTPase enriched in myeloid cells, was proposed as a potential regulator of TAM polarization through clathrin-mediated endocytosis (CME). We hypothesized that RAB31 modulates TAM education by tumor-derived signals and thereby shapes antitumor immunity.Methods We profiled RAB31 expression in human cancers using public single-cell RNA sequencing (scRNA-seq) datasets and clinical sample immunofluorescence staining. Rab31 knockout mice were employed in subcutaneous tumor models. The TME was profiled by scRNA-seq, bulk RNA-seq, and flow cytometry. Bone marrow transplantation, adoptive cell transfer, and antibody-mediated depletion were performed to identify the effector cell populations. Co-immunoprecipitation coupled with mass spectrometry, receptor half-life assays, inhibitor intervention and lysosomal colocalization experiments dissected the molecular mechanism. Functional T-cell chemotaxis, activation, and anti-programmed death-ligand 1 (PD-L1) response assays were performed.Results RAB31 was highly expressed in TAMs across multiple cancers and correlated with poor prognosis and immunosuppressive TME. Rab31 deficiency reprogrammed TAMs to M1-like phenotype, enhanced CD8+ T-cell infiltration and activation, and suppressed tumor growth. Mechanistically, Rab31 preserves FPR2 cell surface stability through a CME-dependent mechanism; its loss redirected FPR2 to lysosomal degradation, disrupted tumor-derived ANXA1 signaling, and unleashed NF-κB activity. Rab31 deficiency synergized with anti-PD-L1 therapy in a CD8+ T cell-dependent manner.Conclusions These findings establish the CME/RAB31 pathway as an indispensable regulator of TAM polarization, underscoring the pivotal role of vesicular trafficking in the TME.
Background Metabolic reprogramming within the tumor microenvironment is a pivotal barrier to effective immune checkpoint blockade (ICB). While programmed death ligand 1 (PD-L1) is well characterized as a ligand inhibiting T-cell function, its intrinsic ‘reverse signaling’ role in regulating tumor metabolism and shaping the immune landscape remains poorly understood. Here, we investigated the metabolic determinants of resistance to anti-programmed cell death protein 1 (anti-PD-1) therapy and the underlying molecular mechanisms.Methods Integrated metabolomics and transcriptomics were performed on tumor samples from patients with non-small cell lung cancer and cell lines. Mechanisms were delineated using RNA sequencing, cleavage under targets and tagmentation assays, metabolic flux analysis, and coculture systems. The therapeutic efficacy of targeting metabolic effectors was evaluated in syngeneic mouse models and correlated with immune profiling.Results We identified a distinct metabolic signature characterized by aberrant pyruvate accumulation in patients resistant to anti-PD-1 therapy. Mechanistically, we demonstrate that antibody-mediated ligation of PD-L1 triggers an intrinsic endoplasmic reticulum (ER) stress response via the PERK–ATF4–CHOP axis. ATF4 acts as a transcriptional activator that directly upregulates pyruvate dehydrogenase kinase 4 (PDK4) (blocking pyruvate oxidation) and glutaminase (GLS) (promoting glutaminolysis), creating a ‘dual-hit’ metabolic rewiring that drives intracellular pyruvate build-up. Subsequently, tumor-secreted pyruvate is taken up by tumor-associated macrophages (TAMs) via MCT1, inducing mitochondrial reactive oxygen species accumulation and driving them into a state of cellular senescence. These senescent TAMs upregulate PD-L1 via STAT3 signaling, thereby reinforcing an immunosuppressive feedback loop. Pharmacological inhibition of PDK4 and GLS effectively abolished pyruvate accumulation, prevented macrophage senescence, and restored CD8+ T-cell cytotoxicity.Conclusions Our study identifies a novel ‘PD-L1–ER stress–pyruvate–macrophage senescence’ axis as a key mechanism underlying primary resistance to ICB. These findings highlight the non-canonical reverse-signaling function of PD-L1 in metabolic remodeling and propose that targeting the PDK4/GLS-dependent pyruvate surge offers a promising therapeutic strategy to sensitize tumors to anti-PD-1 immunotherapy.
Background Immune checkpoint inhibitors (ICIs) have limited efficacy in proficient mismatch repair/microsatellite stable (pMMR/MSS) metastatic colorectal cancer (mCRC). However, selected patients with specific metastatic patterns may derive benefit.Methods Patients with chemorefractory pMMR/MSS mCRC treated with ICI-based regimens were retrospectively identified. A comparison cohort treated with trifluridine/tipiracil±bevacizumab, regorafenib, or fruquintinib as standard of care (SOC) was generated through 1:1 propensity score matching by age, sex, Eastern Cooperative Oncology Group performance status (ECOG PS), liver metastases (present/absent), and RAS/BRAF status. Overall survival (OS) was compared using Cox regression.Results A total of 354 patients treated with ICIs and 354 treated with SOC were matched. Median age was 55 years, 52% male, 32% ECOG PS 0, 30% right-sided, and 69% RAS mutated in both groups, while 61% and 60% had liver metastases, respectively. Median OS (mOS) was 10.8 months with ICIs and 9.0 months with SOC (HR 0.76, 95% CI 0.64 to 0.92, p=0.004). In patients without liver metastases, mOS was longer with ICIs than SOC (19.1 vs 13.2 months, HR 0.59, 95% CI 0.43 to 0.80, p<0.001), whereas outcomes were similar in patients with liver metastases (6.4 vs 6.5 months, p=0.303). In univariable analyses, age, sex, primary tumor site, and RAS/BRAF status were not associated with OS. Treatment with ICIs, absence of liver metastases, one prior line of therapy, less than three metastatic sites, and ECOG PS 0 were associated with the most favorable outcomes in univariable and multivariable models.Conclusions In chemorefractory pMMR/MSS mCRC without liver metastases, ICI-based regimens yielded longer OS than SOC. Further investigation of ICIs in this patient population is warranted.
BACKGROUND:Antibody-drug conjugates (ADCs) and bispecific antibodies represent a rapidly advancing frontier in oncology, yet the abnormal tumor microenvironment (TME) hinders their delivery and reduces efficacy. Emerging immunomodulatory ADCs (IM-ADCs) demand mechanistic mathematical models that couple drug transport with immune dynamics. METHODS:Here, we present a mechanistic framework for the delivery of HE-S2 ADC, an anti-programmed cell death ligand 1 (PD-L1) antibody bearing the bifunctional immunomodulator D18. Our model integrates cancer-immune cells interactions, TME properties, such as dysfunctional vessels, elevated interstitial fluid pressure, tissue hydraulic conductivity, and vascular permeability, spatiotemporal distributions across growing tumor and adjacent host tissue, convective-diffusive transport, ADCs binding and internalization kinetics and tumor-draining lymph node biology governing antigen presentation and the generation of effector CD8+ T cells. Parameters were calibrated simultaneously with the murine MC38 and B16 tumor growth data and effector CD8+T cell data following treatment with D18, anti-PD-L1, and ADC. RESULTS:Our mechanistic spatiotemporal model captures the superior antitumor efficacy of the HE-S2 ADC relative to its individual components and provides mechanistic predictions for unmeasured variables, such as spatiotemporal dynamics of drug/immune-cell distributions. It explains reduced intratumoral D18 exposure via rapid clearance, while antibody/ADC achieves higher tumor retention through leaky tumor vasculature. The model suggests a reinforcing loop in which improved ADC exposure enhances CD8+T cell infiltration, driving tumor shrinkage that lowers fluid pressure and improves drug delivery. Parametric analyses findings support TME normalization strategies that increase functional vessel density prior to ADC administration; however, such approaches should preserve sufficient vascular permeability by maintaining vessel pore radius >~40 nm, ensuring pores remain large enough for ADC extravasation and effective intratumoral delivery. CONCLUSION:The proposed mechanistic model successfully captures how TME properties regulate the delivery and efficacy of IM-ADCs while suggesting TME normalization as a potential strategy to improve treatment outcomes.
Proteogenomic cancer antigen discovery now extends beyond somatic mutations to include unmutated, aberrantly expressed, and non-canonical sources. We distinguish two orthogonal dimensions: molecular origin (canonical or non-canonical) and normal-tissue distribution (tumor-specific antigen, tumor-associated antigen, or lineage-specific antigen). Importantly, non-canonical origin does not imply tumor specificity. For human leukocyte antigen (HLA)-restricted immunotherapy, selectivity must be established at the level of naturally presented peptide-HLA (pHLA) complexes rather than inferred from RNA expression or total protein abundance. We therefore propose a normal-immunopeptidome denominator: a context-aware atlas of benign pHLA ligands that can be used to exclude unsafe candidates before therapeutic nomination. However, this denominator is necessary but not sufficient. Candidate nomination also requires evidence of analytical confidence, natural presentation on tumor cells, and, where available, peptide abundance and tumor heterogeneity. Additional considerations include whether the target is patient-specific or shared, its functional selectivity, the potential for immune escape, receptor cross-reactivity, HLA alloreactivity, and the modality-specific therapeutic index. We present a tiered framework that distinguishes core requirements, risk-triggered evaluation criteria, and recommended enhancements. These requirements escalate as uncertainty increases. Importantly, the absence of a peptide from existing databases should not be interpreted as evidence of its absence in humans.
BACKGROUND:Acute myeloid leukemia (AML) is an aggressive hematologic malignancy with dismal outcomes, especially in relapsed/refractory settings. Chimeric antigen receptor natural killer (CAR-NK) cell therapy holds promise but is constrained by the immunosuppressive tumor microenvironment (TME), where adenosine-mediated suppression is a key barrier. OBJECTIVE:To develop a novel CAR-NK construct cotargeting AML cells and the adenosine-rich TME to enhance antileukemia efficacy. METHODS:Ex vivo expanded primary NK cells were used to compare the effects of CD39 versus CD73 blockade on NK cell function via messenger RNA-electroporated antibodies. A CD33-CD73 dual-function CAR-NK construct (integrating CD33-specific lysis and anti-CD73scFv secretion for TME disruption) was designed and transduced into NK cells via retrovirus. Engineered NK cells were characterized for transduction efficiency, expansion, purity, viability, and CAR stability. In vitro cytotoxicity against AML cell lines and primary blasts was assessed, and in vivo efficacy was evaluated in a MOLM-13 xenograft mouse model. RESULTS:CD73 blockade more potently enhanced NK cell activity than CD39 blockade. Retroviral transduction achieved >50% efficiency, and expansion with K562-4-1BBL-mbIL-21/-15 feeder cells yielded NK cells with ≥6,000 fold expansion, >93% purity, >98% viability, and stable CAR expression. At an effector-to-target ratio of 0.5:1, CD33-CD73 CAR-NK cells mediated ~80% specific lysis, with superior cytotoxicity vs conventional CD33 CAR-NK cells. In xenografts, CD33-CD73 CAR-NK cells achieved robust tumor clearance, extended median survival by 24.5 days (59.5 vs 35 days) versus standard CD33 CAR-NK cells, and five out of six mice achieved long-term survival (>50 days). CONCLUSION:The CD33-CD73 dual-targeting CAR-NK platform synergistically targets AML cells and the adenosine-rich TME, exhibiting superior anti-leukemia efficacy. This strategy advances AML immunotherapy and provides a translational blueprint for TME-targeted therapies in other cancers.
Background Allogeneic hematopoietic stem cell transplantation (alloHSCT) can be a curative treatment for hematological diseases. After HLA-matched alloHSCT, donor T cells may recognize minor histocompatibility antigens (MiHAs), which are polymorphic HLA-binding peptides on patient cells that are absent from donor cells due to genetic differences. Donor T cells can induce beneficial anti-tumor effects if MiHAs are targeted on malignant hematopoietic cells in the patient, while graft-versus-host disease (GvHD) may develop if MiHAs are targeted on patients’ healthy non-hematopoietic tissues.Methods We previously isolated T-cell clones from patients responding to donor lymphocyte infusions (DLIs) after HLA-matched alloHSCT, and identified HLA class I-restricted MiHAs. To investigate MiHA-specific T-cell responses in patients, we here sequenced the T-cell receptors (TCRs) of MiHA-specific T-cell clones and identified 394 distinct TCRs against 122 MiHAs. We used the collection of identified TCRs to measure frequencies of matched MiHA-specific TCRs in 39 patients responding to DLI with antitumor responses accompanied with no (n=9), limited (n=8) or severe (n=22) GvHD.Results The data showed higher MiHA-specific TCR frequencies in patients with severe GvHD, which were mainly driven by clonal expansion. Moreover, within the diverse MiHA-specific TCR repertoires in these patients, we identified five public TCRs against four MiHAs with identical CDR3 regions and several TCRs targeting MiHAs with similar, but not identical, CDR3 regions.Conclusion Patients with severe GvHD have high MiHA-TCR frequencies mainly driven by clonal expansion, and that MiHA-specific TCR repertoires in patients responding to DLI after alloHSCT are highly diverse with a few public clonotypes.
Background Metastatic melanoma resistant to immune checkpoint inhibitors remains difficult to treat, and while adoptive tumor-infiltrating lymphocyte (TIL) therapy has shown durable responses, its reliance on lymphodepleting chemotherapy and high-dose interleukin (IL)-2 causes toxicity that may limit patient eligibility. The dual-cytokine-armed oncolytic adenovirus igrelimogene litadenorepvec (TILT-123) was administered with TILs in the TUNINTIL trial (trial registration: NCT04217473) in patients with metastatic melanoma resistant to immune checkpoint inhibitors, without lymphodepleting chemotherapy or IL-2 post-conditioning. This study presents a correlative immunological analysis of the phase I TUNINTIL trial evaluating TILT-123 in combination with TIL therapy.Methods The TUNINTIL trial was a first-in-human, open-label, dose-escalation, multicenter, multinational phase I trial. 17 patients with checkpoint-inhibitor-resistant metastatic melanoma received up to six intratumoral TILT-123 injections followed by TIL infusion, without lymphodepleting chemotherapy or IL-2 post-conditioning. Systemic immune profiling (serum proteomics, flow cytometry, interferon-γ ELISpot assay), intratumoral immune cell–cell profiling (multiplex immunofluorescence, H&E, adenovirus E1a immunohistochemistry), quantitative PCR, and neutralizing antibody responses were assessed at defined time points through the trial, with survival follow-up updated to March 2026. Response criteria were evaluated using Response Evaluation Criteria in Solid Tumors V.1.1 and positron emission tomography-based criteria. Statistical analyses included Kaplan-Meier survival with log-rank tests, Mann-Whitney U tests, Pearson correlation, and receiver operating characteristic/area under the curve analysis for biomarker cut-off determination.Results Tumor biopsy analyses revealed an early innate immune activation marked by natural killer-cell expansion and cytotoxic gene upregulation, followed by increased intratumoral T-cell infiltration. This occurred without lymphodepleting chemotherapy or post-conditioning IL-2. Intratumoral viral DNA was detectable in a subset of patients. The enrichment of CD27+CD28+ memory-precursor CD8+ T cell was associated with favorable clinical outcomes. Elevated monocytic myeloid-derived suppressor cells and angiogenic/inflammatory cytokines following combination treatment were associated with disease progression, highlighting the role of immunosuppressive myeloid subsets as potential mediators of therapeutic resistance. Additionally, correlative analysis in pooled TILT-123 cohorts identified serum epidermal growth factor as a candidate biomarker for stratifying and monitoring patients.Conclusions These findings provide mechanistic insights into TILT-123 combined with TIL therapy and propose future directions for biomarker-guided clinical studies.Trial registration number NCT04217473.
Background Treatment with immune checkpoint inhibitors (ICIs) has radically improved outcomes for patients with microsatellite instability-high (MSI-H) metastatic colorectal cancer (mCRC). Intrinsic and acquired resistance, however, remains an important concern. Pyrimidine pathway regulates the innate immune response and may offer an opportunity to enhance ICI efficacy via modulation of pyrimidine metabolism. Identification of primary, adaptive and acquired resistance mechanisms and development of actionable strategies to overcome resistance and expand the benefit of ICI is paramount. Our group is the first to show that the dihydropyrimidine dehydrogenase (DPD; gene DPYD ) metabolic pathway predicts the efficacy of ICI in MSI-H tumors. Methods Retrospective analysis of germline single nucleotide polymorphisms was done in patients with MSI-H CRC cohort (Veneto Institute of Oncology; OIOV-IRCCS, Padua, Italy) treated with immunotherapy. Dpyd knockout or overexpressed MC38 MSI-H syngeneic mice models were treated with anti-programmed cell death protein 1 (PD-1) and anti-cytotoxic T-lymphocyte associated protein 4 (CTLA-4) alone or in combination and their effect on tumor growth and its microenvironment was studied. Results In our real-world data analysis, genetic variants in DPYD were associated with progression-free survival and tumor response in patients with MSI-H mCRC treated with ICI. In preclinical studies, complete tumor elimination was observed in 100% of mice bearing Dpyd knockout tumors treated with a combination of anti-PD-1 and anti-CTLA-4, further validated by pharmacologically inhibiting DPD using eniluracil. Conclusion Our results showed that the pyrimidine pathway has a strong association with immunotherapy treatment response in CRC. These findings may support the development of novel treatment strategies exploiting DPD inhibition in MSI-H tumors and their quick integration into clinic.
Background Long-term survival of extensive-stage small-cell lung cancer (ES-SCLC) remains rare, with most patients experiencing disease progression during maintenance therapy. Poly (ADP-ribose) polymerase (PARP) inhibitors have the potential to confer antitumor activity, modify tumor immunogenicity, and sensitize tumors to anti-programmed cell death protein 1/programmed death-ligand 1 therapy. We conducted this phase 2 trial to investigate the efficacy and safety of durvalumab plus olaparib as maintenance therapy in patients with ES-SCLC. Methods This was a multicenter, single-arm, phase II trial that enrolled 60 patients with previously untreated ES-SCLC ( NCT05245994 ). Patients received durvalumab (1,500 mg) combined with platinum-etoposide chemotherapy intravenously every 21 days for up to four cycles, followed by maintenance therapy with durvalumab (1,500 mg every 28 days) and oral olaparib (300 mg two times a day) until disease progression or unacceptable toxicity. Multi-omics analyses were performed to characterize molecular subtypes associated with clinical outcomes. Results The combination regimen demonstrated promising efficacy, with an alive and progression-free at 12 months rate of 25.0%, an objective response rate of 73.3%, a median progression-free survival of 6.8 months, and a median overall survival of 14.6 months. Multi-omics profiling identified a hypomethylation subgroup (cluster 1) that was associated with significantly improved survival outcomes. Further analysis revealed that this subtype exhibited enhanced antigen presentation machinery, a favorable cytokine profile, and suppression of DNA damage repair (DDR) pathways, potentially through elevated promoter methylation and transcriptional silencing of specific DDR genes, which together were associated with the favorable outcomes. Conclusions This study presents the first prospective evidence supporting durvalumab plus olaparib as maintenance therapy in ES-SCLC. Multi-omics analysis identifies that DNA hypomethylation status may enrich for patients who benefit from PARP inhibition and immunotherapy. Trial registration number NCT05245994 .
Background Tumor-derived lactate has long been regarded as a metabolic waste product. However, accumulating evidence indicates that lactate also functions as a signaling molecule that actively remodels the tumor immune microenvironment. How lactate-driven post-translational modifications in immune cells contribute to immune evasion in hepatocellular carcinoma (HCC) remains incompletely understood. This study aimed to identify the immune cell population responsible for lactylation-driven immunosuppression in HCC and to elucidate the molecular mechanism by which lactylation rewires macrophage metabolism to impair CD8 + T cell-mediated antitumor immunity. Methods Selective in vivo immune cell depletion models were employed to define the key immune mediators of lactate-induced immunosuppression. Proteomic screening, site-directed mutagenesis, and lipidomic profiling were used to characterize lactylation targets and lipid metabolic alterations. Functional assays, including signaling pathway analyses, cytokine measurements, and tumor immune profiling, were performed in both in vitro systems and mouse HCC models. Results Macrophages were identified as the principal immune cell type mediating lactylation-dependent immunosuppression in HCC. Alanyl-tRNA synthetase 1 (AARS1) functioned as a non-canonical lactyltransferase, catalyzing lactylation of carnitine palmitoyltransferase 1A at lysine 675. This modification impaired long-chain fatty acid transport into mitochondria, leading to cytosolic accumulation of oleic acid (OA). OA directly disrupted cGAS binding to cytosolic DNA, thereby suppressing STING activation and type I interferon (IFN-I) production. Attenuated IFN-I signaling resulted in reduced major histocompatibility complex-I expression on tumor cells and impaired CD8 + T cell-mediated recognition and cytotoxicity. Conclusion These findings uncover a lactate-lipid metabolism axis that links tumor-derived lactate to innate immune suppression in HCC. Targeting AARS1-mediated lactylation represents a potential therapeutic strategy to restore macrophage immunostimulatory function and enhance antitumor immunity.
Background Pre-metastatic niches composed of mainly myeloid cells are recognized as critical for tumor metastasis. However, whether adaptive immune cells also play an important role in pre-metastatic niche formation remains to be explored.Methods CD4+ T cell accumulation in tumor-free lung tissues from mice bearing subcutaneous mouse tumors was detected by immunofluorescence/confocal microscopy. Tumor-conditioned media (TCM) from MB49-S1pr1high mouse bladder tumor cells or ID8 ovarian tumor cells were administered to tumor-free mice to induce pre-metastatic niche formation. We used mice lacking functional Signal Transducer and Activator of Transcription 3 (STAT3) in T cells and Il17a‒/‒ mice to investigate the roles of STAT3 and interleukin (IL)-17. In vivo time-course experiments were performed to assess whether CD4+ T cell clusters contribute to CD11b+ pre-metastatic clusters. CD4+ T cell migration and chemokine receptor expression assays were employed to identify tumor factors driving CD4+ T cell recruitment. A co-culture system with human MRC-5 lung fibroblasts, healthy donor-derived CD4+ T cells, myeloid cells, and TCM derived from human cancer cells was used to evaluate CD4+ T cell-driven fibroblast activation and IL-17A dependency for myeloid cell migration. Microscopic analyses were performed to confirm CD4+ T cell clusters in tumor-free lymph node tissues from patients with prostate cancer and postmortem lung and liver specimens from patients with ovarian cancer.Results We demonstrate that CD4+ T cells accumulate in tumor-free lungs and promote tumor metastasis in mouse models. CD4+ T-cell pre-metastatic niche formation requires STAT3, which regulates Th17 CD4+ T cells. TCM drives IL-6-dependent CCR4/CCR6 upregulation on naive CD4+ T cells. CD4+ T cell clusters contribute to myeloid cell accumulation, and ablating STAT3 in T cells abrogates both T cell and myeloid cluster formation. IL-17 inhibition reduces myeloid lung infiltration. In human co-cultures, CD4+ T cells amplify TCM-induced fibroblast pre-metastatic niche-like activation and myeloid recruitment in an IL-17A-dependent manner. CD4+ and IL-17+ or p-STAT3+ clusters were also detected in non-metastatic tissues from patients with several cancers.Conclusions CD4+ T cells form pre-metastatic niches through the STAT3-IL-17 axis, contributing to myeloid cell cluster formation, in part through amplifying fibroblast pre-metastatic niche-like activation. STAT3 and IL-17 in CD4+ T cells therefore are important for pre-metastatic niche formation and metastasis.
Background Immunotherapeutic approaches for cutaneous squamous cell carcinoma (cSCC) remain limited to programmed cell death protein 1 (PD-1) blockade. Although genomics studies have characterized key driver mutations in cSCC, preclinical models that faithfully recapitulate both the genetic landscape and immune microenvironment of the human disease, that could drive the development of novel, effective therapies, are lacking. Methods To address this need, we generated genetically engineered mouse models harboring inducible p53 wmR172H expression and Cdkn2a deletion in stratified epithelia. These mice spontaneously developed well-differentiated and spindle cell cSCCs, whose histopathological and immunological features mimicked those observed in patients. We established syngeneic cell lines and characterized their genomic and transcriptomic profiles through whole exome sequencing and RNA sequencing. We used these syngeneic tumor models to test the effect of STING agonist, PD-1, VISTA and CTLA-4 blockade applied at different schedules and combinations. Finally, immune checkpoint molecules detected in the syngeneic models were validated in human cSCC tissue arrays. Results Whole exome sequencing confirmed alterations overlapping with human cSCC, including mutations in Notch , interferon signaling, and cytokine pathways. Transcriptomic analysis revealed the upregulation of immunoregulatory genes, including Cd274 , Lgals9 , and Il33 , suggesting a suppressive tumor immune microenvironment (TIME). Preclinical therapeutic evaluation in this model demonstrated that PD-1 blockade and the treatment with a STING agonist elicited partial responses. The combination of STING agonist with checkpoint inhibition targeting either PD-1/CTLA-4 or PD-1/VISTA significantly enhanced antitumor immunity in tumors resistant to anti-PD-1 monotherapy. Conclusions These results establish a robust, genetically defined, immunocompetent platform for modeling cSCC and evaluating novel immunotherapeutic strategies for treating patients with this disease. Our findings also identify VISTA and CTLA-4 as promising immune checkpoints to target in cSCC and support clinical evaluation of this combination of immune checkpoint blockade to overcome immune checkpoint inhibitor resistance and improve clinical outcomes.
Background Metabolic reprogramming through enhanced glycolysis is a hallmark of cancer that supports tumor progression and promotes protumor immune responses. Methylglyoxal (MG), a reactive by-product of glycolysis, has recently emerged as an oncometabolite implicated in cancer progression and therapy resistance. Our previous work demonstrated that an imbalance between MG production and detoxification by the glyoxalase system, referred to as MG stress, contributes to progression and metastatic dissemination in triple-negative breast cancer (TNBC). However, the impact of MG stress on the tumor immune microenvironment remains poorly understood. Methods Using two preclinical breast cancer models, we investigated the relationship between MG stress and immune modulation, with a focus on granulocytic myeloid-derived suppressor cells (g-MDSCs), major mediators of immune evasion. In silico analyses were performed to assess correlations between MG stress-related gene signatures and transcriptional markers of MDSC infiltration in patients with TNBC, as well as associations with anti-programmed cell death protein 1 (PD-1) immunotherapy response in melanoma cohorts. In vivo experiments combined the MG scavenger carnosine with PD-1 blockade in the immunotherapy-resistant 4T1 breast cancer model. Results MG stress was associated with the expansion of g-MDSCs in breast cancer models. Importantly, MG stress conferred metastatic potential to non-metastatic 67NR breast tumors, potentially through activation of the Nuclear Factor kappa B (NF-κB) pathway, increased granulocyte-macrophage colony-stimulating factor expression, and systemic expansion of g-MDSCs. In silico analyses revealed a positive correlation between MG stress-related gene signature and transcriptional markers of MDSC infiltration in patients with TNBC. Furthermore, this signature distinguished anti-PD-1 responder (low MG stress), from non-responders (high MG stress) in patients with melanoma. Therapeutically, combined targeting of MG stress with carnosine and PD-1 signaling significantly reduced g-MDSC accumulation in tumors, spleens, and lungs, and decreased lung metastatic burden in the 4T1 model. Conclusions These findings identify MG stress as a driver of an immunosuppressive tumor microenvironment that may impair immunotherapy efficacy and promote metastatic progression in TNBC. Dual targeting of MG stress and PD-1 signaling represents a promising therapeutic strategy to overcome immune suppression and limit metastasis in immunotherapy-resistant breast cancer.
BACKGROUND:Orally administered small-molecule programmed death ligand 1 (PD-L1) inhibitors may have the potential to improve patient outcomes in the treatment of a range of cancers compared with their antibody-based counterparts. A small molecule might achieve better tumor tissue penetration, and oral administration could significantly improve convenience and access for patients. METHODS:Three phase 1 open-label, non-randomized, dose escalation, and expansion studies evaluated the safety, preliminary efficacy, pharmacokinetics (PK), and pharmacodynamics (PD) of three agents in patients with advanced solid tumors: INCB086550 (NCT03762447), INCB099280 (NCT04242199), and INCB099318 (NCT04272034). RESULTS:Overall, 138, 182, and 104 patients received INCB086550, INCB099280, and INCB099318, respectively. Most had previously received ≥2 lines of cancer therapy for advanced or metastatic disease; 9.6%-16.5% had received prior immunotherapy. All three agents were rapidly absorbed and showed stable dose-dependent PK. With INCB086550, 88 patients (63.8%) had ≥1 treatment-related treatment-emergent adverse event (TEAE), and 19 (13.8%) had ≥1 treatment-related grade ≥3 TEAE. In total, 14 patients (10.1%) had a nervous system-associated TEAE for which an immune-mediated etiology could not be ruled out; events were predominantly peripheral sensory and motor neuropathies. With INCB099280 and INCB099318, 144 (79.1%) and 69 (66.3%) of patients had ≥1 treatment-related TEAE, and 25 (13.7%) and 12 (11.5%) had ≥1 treatment-related grade ≥3 TEAE, respectively. The most frequent immune-related adverse events were skin reactions (INCB099280 and INCB099318) and hepatitis (INCB099280). No dose-limiting toxicities (DLTs) occurred during dose escalation with INCB086550 or INCB099318; two DLTs occurred in two patients with INCB099280 (grade 2 vomiting with 600 mg once daily and grade 2 maculopapular rash with 800 mg two times per day). Overall objective response rates for INCB086550, INCB099280, and INCB099318 were 10.9% (95% CI 6.2% to 17.3%; n=15), 8.8% (95% CI 5.1% to 13.9%; n=16), and 8.7% (95% CI 4.0% to 15.8%; n=9), respectively. Target engagement and PD activity were demonstrated, including PD-L1 binding, and increases in cytokine and chemokine production, as well as T-cell activation and proliferation. CONCLUSIONS:Both INCB099280 and INCB099318 had an acceptable safety profile, with preliminary evidence of antitumor activity. The risk of immune-mediated neuropathy led to discontinuation of the clinical program for INCB086550.
Background Acquired resistance limits the durability of programmed cell death protein-1 (PD-1) blockade in lung adenocarcinoma, yet the tumor-intrinsic programs and immune circuits that drive acquired resistance relapse remain poorly defined. The purpose of this study was to identify tumor-intrinsic mediators of acquired resistance and determine how they remodel antitumor immunity.Methods An orthotopic bioluminescence-tracked Lewis lung carcinoma (LLC1) lung adenocarcinoma model was established in immunocompetent mice treated with anti-PD-1. Tumor-intrinsic regulators were identified by an in vivo genome-wide CRISPR loss-of-function screen and validated using inducible tetracycline-off knockdown. Prostaglandin E2 (PGE2) signaling was interrogated through tumor-cell Ptgs2 knockdown/deletion, 16,16-dimethyl PGE2 administration, selective EP2/EP4 antagonists, and celecoxib treatment. Natural killer (NK)-cell function was analyzed by flow cytometry, immunofluorescence, RNA sequencing, cAMP measurement, calcium flux assays, mouse and human NK-cell co-culture cytotoxicity assays, and NK-cell adoptive transfer. Celecoxib was used to evaluate the therapeutic potential of pharmacologic PGE2 blockade in vivo. Public immunotherapy datasets were analyzed to assess the clinical relevance of PTGS2.Results The orthotopic LLC1 model captured key features of heterogeneous anti-PD-1 responses, including relapse after initial regression. The CRISPR screen identified Ptgs2 as a key driver of acquired resistance. Tumor-derived PGE2 progressively increased in resistant tumors, and its genetic silencing overcame resistance by restoring NK-cell infiltration and function. Mechanistically, PGE2 signaled through EP2/EP4 receptors to elevate cAMP and induce CREM, thereby suppressing NK-cell cytotoxicity and cytokine production. This axis was validated in human NK cells. Pharmacologic inhibition of cyclooxygenase-2 with celecoxib reversed acquired resistance, an effect abrogated by NK-cell depletion.Conclusions Tumor-derived PGE2 is an important contributor to acquired resistance to PD-1 blockade in lung adenocarcinoma. Therapeutic disruption of the EP2/EP4–cAMP–CREM axis restores NK-cell function and overcomes acquired resistance.
BACKGROUND:Chimeric antigen receptor (CAR) T-cell therapy has shown limited efficacy in solid tumors, largely due to immunosuppressive mechanisms within the tumor microenvironment (TME). While tumor-associated glycans are known to protect malignant cells from immune attack, the contribution of N-glycans expressed by non-malignant TME populations to CAR-T cell dysfunction remains poorly defined. METHODS:We investigated the role of N-glycans in non-malignant TME populations, focusing on M2-like macrophages and hepatic stellate cells in liver metastasis of colorectal (CRC) and pancreatic cancer (PDAC). Using in vitro co-culture systems, transcriptomic analysis, and tumor-bearing humanized mouse models, we assessed how pharmacologic or genetic disruption of key nodes of the N-glycosylation pathway (MGAT5, MAN2A1 and ST6GAL1) in immune and stromal compartments shapes T-cell function. RESULTS:In patient samples, a branched N-glycan signature was associated with transcriptional programs characteristic of tumor-promoting macrophages and stromal cells, linking N-glycosylation to an immunosuppressive TME. Disruption of N-glycan synthesis in non-malignant TME cells reduced their immunosuppressive and tumor-supporting functions. Single-cell RNA sequencing of tumor-bearing humanized mice showed depletion of protumor IL1β+ macrophages and diminished inhibitory macrophage-T cell interactions following N-glycosylation blockade. Selective MGAT5 disruption in immune and stromal compartments suppressed immunosuppressive programs and enhanced CAR-T cell antitumor activity independently of tumor cell glycosylation. CONCLUSIONS:These findings show that N-glycans expressed by non-malignant TME cells restrain CAR-T cell responses in CRC and PDAC, highlighting MGAT5-dependent branching as a potentially actionable axis and supporting a broader role for multiple nodes of the N-glycosylation pathway.
