InVivoMAb anti-mouse PD-1 (CD279)

Immune checkpoint blockade (ICB) therapies, such as anti-PD-1, have transformed cancer treatment, but many patients do not respond due to a non-inflammatory tumor microenvironment (TME). Here, we investigated the impact of targeting Atypical Chemokine Receptor 2 (ACKR2), which scavenges key chemokines involved in immune cell recruitment, on the improvement of anti-PD-1-based therapy. In a melanoma mouse model, we demonstrated that Ackr2 inhibition increases the release of proinflammatory chemokines CCL5 and CXCL10 and enhances the infiltration of NK cells, activated CD8+ and CD4+ effector T cells while reducing regulatory T cells (Tregs) in the TME. Targeting Ackr2 led to tumor growth inhibition, improved survival, and enhanced response to anti-PD-1 therapy. In BRAF- and NRAS-mutant melanoma patients, low ACKR2 expression or high CCL5/CXCL10 levels correlated with improved survival and higher CD8+ T cell markers. Targeting ACKR2 represents a promising approach for developing combination therapies, particularly for 'cold' ICB resistant tumors.

Extensive studies have demonstrated the relationship between metabolic reprogramming and the tumor microenvironment. Here, we characterized the head and neck squamous cell carcinoma (HNSCC) evolutionary landscape using spatial metabolomics/transcriptomics, single-cell transcriptomics, and bulk multi-omics. Metabolic heterogeneity during HNSCC malignant transformation was identified, with significant enrichment in the purine metabolism. Integrating single-cell and bulk data, we developed a robust ligand-receptor-based signature (LRS) linked to NT5E, a key upstream regulator of purine metabolism, which served as an independent prognostic indicator. The low LRS subtype was associated with a high proportion of immune cell infiltration and improved response to immunotherapy. Notably, in vitro and in vivo experiments demonstrated that AMIGO2, a core molecule within the LRS, regulates tumor-associated purine metabolism, and that its downregulation suppresses tumor cell invasion and migration, inhibits myofibroblast differentiation, and promotes immune effector cell infiltration. Moreover, combining AMIGO2 targeting with anti-PD-1 therapy yielded superior efficacy. Consistent validation was also obtained in a clinical cohort of HNSCC and premalignancy patients.

Metabolic reprogramming, particularly upregulated de novo pyrimidine biosynthesis, drives cancer progression and immune evasion. Dihydroorotate dehydrogenase (DHODH), a key enzyme in this pathway, is a promising therapeutic target, but its inhibitors often face resistance in immune-refractory melanoma, linked to low basal stimulator of interferon genes (STING) expression.

The skull marrow niche has recently been identified as a reservoir that supplies the brain with monocytes and neutrophils in the context of disease and injury, but its role in brain cancers remains unknown. Here we show that glioblastoma, the most malignant type of brain tumor, induces calvarial bone abnormalities in murine models and patients with glioblastoma, altering osteoclast activities and increasing the number of skull channels in mice. Single-cell RNA sequencing revealed glioblastoma-mediated alterations in the immune landscape of skull marrow and femoral bone marrow, including expansion of neutrophils and deterioration of various B cell subsets. In vivo inhibition of bone resorption reduced bone abnormalities, but promoted tumor progression in mesenchymal subtype tumors. This also abolished the survival benefit of the checkpoint inhibitor anti-PD-L1, by reducing activated T cell and increasing inflammatory neutrophil numbers. Together, these data provide insight into how brain tumors affect skull bone and the immune environment.

The tumor microenvironment (TME) in gastric cancer (GC) exhibits immunosuppressive features that facilitate tumor advancement and obstruct the effectiveness of immunotherapy. The role of tripartite motif 32 (TRIM32) in the TME has not been extensively studied.

The E3 ligase SPOP plays a context-dependent role in cancer by targeting specific cellular proteins for degradation, thereby influencing cell behavior. However, its role in tumor immunity remains largely unexplored. In this study, we revealed that SPOP targeted the innate immune sensor STING for degradation in a CK1γ phosphorylation-dependent manner to promote melanoma growth. Stabilization of STING by escaping SPOP-mediated degradation enhanced anti-tumor immunity by increasing IFNβ production and ISG expression. Notably, small-molecule SPOP inhibitors not only blocked STING recognition by SPOP, but also acted as molecular glues, redirecting SPOP to target neo-substrates such as CBX4 for degradation. This CBX4 degradation led to increased DNA damage, which in turn activated STING and amplified innate immune responses. In a xenografted melanoma B16 tumor model, single-cell RNA-seq analysis demonstrated that SPOP inhibition induced the infiltration of immune cells associated with anti-PD1 responses. Consequently, SPOP inhibitors synergized with immune checkpoint blockade to suppress B16 tumor growth in syngeneic murine models and enhanced the efficacy of CD19-CAR-T therapy. Our findings highlight a molecular glue degrader property of SPOP inhibitors, with potential implications for other E3 ligase-targeting small molecules designed to disrupt protein-protein interactions.

Increasing studies have reported that dysregulated lipid metabolism is an independent risk factor for breast cancer (BC); it would be, therefore, enlightening to investigate the relationship between metabolic reprogramming and the tumor microenvironment in the future. Ferroptosis, a novel form of programmed cell death, is characterized by glutathione (GSH) depletion and inactivation of glutathione peroxidase 4 (GPX4), the central regulator of the antioxidant system. While the close association between fatty acid metabolism and ferroptosis has been studied in various diseases, the interplay between the key fatty acid metabolic enzyme fatty acid synthase (FASN) and ferroptosis in BC remains unexplored. At the beginning of the current study, we demonstrated that FASN expression positively correlates with an immune-cold tumor microenvironment in BC. Subsequent findings revealed that FASN knockdown promotes GPX4 degradation-induced ferroptosis, thereby enhancing the efficacy of anti-programmed cell death protein 1 (PD-1) immunotherapy. Co-immunoprecipitation coupled with mass spectrometry (IP/MS) and co-IP experiments demonstrated that ubiquitin specific protease 5 (USP5) stabilizes GPX4 by binding to and deubiquitinating it. Furthermore, knockdown of FASN inhibited the palmitoylation of USP5, reducing its interaction with GPX4 and consequently increasing GPX4 ubiquitination and degradation. Our results demonstrate that FASN suppresses ferroptosis in BC by stabilizing GPX4 via USP5-mediated mechanisms, highlighting FASN inhibition as a potential therapeutic approach to enhance immunotherapy response.

Cervical carcinoma remains a leading cause of cancer-related mortality in women worldwide, with poor prognosis often linked to immune evasion mechanisms. The Basic Leucine Zipper Activating Transcription Factor (BATF) has emerged as a critical regulator of T-cell functionality, yet its role in cervical cancer progression and immune modulation remains poorly understood. This study investigates the role of BATF in cervical carcinoma, focusing on its effects on tumor progression, immune modulation, and immune checkpoint regulation, to identify BATF as a therapeutic target to enhance anti-tumor immunity.

While RTP4 is known to regulate odorant receptor trafficking, its role in colorectal cancer (CRC) remains unclear. This study investigates the clinical relevance and functional mechanisms of RTP4 in CRC. Comprehensive analyses revealed significant downregulation of RTP4 expression in CRC tissues, correlating with poor patient prognosis. RTP4 expression showed strong associations with immune-related genes, biological processes and anti-tumour immune cell infiltration. Mechanistic studies demonstrated that RTP4 upregulates MHC-I expression, which enhances CD8+ T cell recruitment and strengthens anti-tumour immunity in both cellular and animal models. Furthermore, RTP4 overexpression markedly improved the efficacy of immune checkpoint blockade therapy. All in all, our findings establish RTP4 as a dual-functional biomarker for prognosis prediction and a potential target to enhance immunotherapy responsiveness in CRC.

In the previous study, patients with tumors based on collagen deposition and immunoreactivity are classified and identified the armored & cold subtype as the most treatment-refractory tumor type. Triple-negative breast cancer (TNBC) is the most lethal tumor type globally, making it critical to overcome the armored and cold tumor microenvironment (TME) for effective treatment of these patients. In this study, the transcriptomic collagen activity and immune profiles of cancer patients treated with immune checkpoint blockade (ICB) are analyzed, and found that intratumoral collagen is associated with an unfavorable immunotherapeutic response and T cell exhaustion. Additionally, collagen is shown to regulate IGF1R expression at both transcriptional and post-translational levels via SOX4 and DDR1, respectively. It is also found that IGF1R promotes tumor cell migration and invasion, as well as T cell exhaustion, with these effects mediated through collagen. Moreover, in vivo inhibition of IGF1R reversed the armored & cold TME, thereby enhancing anti-PD-1 therapy. In conclusion, this study identified IGF1R as a novel therapeutic target for the immuno-collagenic subtype, and combining IGF1R inhibition with anti-PD-1 therapy provides a promising foundation for a novel combination immunotherapy regimen for TNBC.

Inadequate antigen presentation by MHC-I in tumor microenvironment (TME) is a common immune escape mechanism. Here, we show that glycine decarboxylase (GLDC), a key enzyme in glycine metabolism, functions as an inhibitor of MHC-I expression in EGFR-activated tumor cells to induce immune escape by a mechanism independent of its enzymatic activity. Upon EGFR activation, GLDC is phosphorylated by SRC and subsequently translocated to the nucleus in human NSCLC cells. Nuclear GLDC sequesters STAT1 co-activator SMARCE1, inhibiting STAT1-dependent transcription of the inflammatory genes IRF1 and NLRC5. Further, GLDC recruits DNMT1 to the IRF1/NLRC5 promoter inducing DNA hypermethylation, suppressing transcription of downstream MHC-I genes. Inhibition of GLDC restores MHC-I levels in tumor cells, improves tumor-specific CD8+ T cells functions in the TME, and rescues anti-tumor effects of PD-1 blockade therapy in mice. Our findings reveal a non-enzymatic nuclear function for GLDC in the suppression of MHC-I antigen presentation, suggesting new strategies for ICB-based combination immunotherapy.

Immune checkpoint blockers (ICBs) have demonstrated substantial efficacy across various malignancies, yet the benefits of ICBs are limited to a subset of patients. Therefore, it is essential to identify novel therapeutic targets. By integrating multi-omics data from cohorts of patients with melanoma treated with ICBs, a positive correlation is observed between tumor CD137L expression and the efficacy of PD-1 blockade. Functionally, CD137L induction in cancer cells significantly enhances anti-tumor immunity by promoting CD8+ T cell survival, both in vivo and in vitro. Mechanistically, helicase-like transcription factor (HLTF) is identified as a pivotal transcriptional regulator of CD137L, controlling its expression through phosphorylation of serine at position 398. Therapeutically, the AMPK agonist AICAR (acadesine) as an inducer of CD137L, exhibiting synergistic effects with PD-1 or CTLA-4 blockade. In summary, our findings elucidate a mechanism controlling CD137L expression and highlight a promising combination therapy to enhance the efficacy of ICBs in melanoma. One Sentence Summary: Inducing co-stimulatory immune checkpoint CD137L expression in melanoma cells enhances T cell-mediated anti-tumor immunity.

Neutrophils constitute a substantial proportion of the immune cell population infiltrating tumors, where they play a pivotal role in establishing an immunosuppressive microenvironment to facilitate tumor growth. Our clinical investigation has unveiled that, following oncolytic virus (OV) treatment, immunosuppressive neutrophils could lead to T cell exhaustion and compromised antitumor efficacy. In this study, we devise a dual-functional conjugation strategy that enables OVs to selectively bind with circulating neutrophils and initiate their death. Prior to dysfunction, neutrophils can harbor OVs and facilitate their infiltration into tumors, leading to a 5.38-fold increase in OV levels within tumors compared to direct intravenous injection. Additionally, infiltrated neutrophils undergo dying after 8 h, which promotes T cell priming, reduces T cell exhaustion, and remodels the tumor immune microenvironment. Our findings illuminate the determinants influencing the efficacy of OVs and propose targeted solutions, thereby offering insights for the clinical translation of these therapeutic agents.

This protocol describes the preparation, administration, and analysis of a nanoparticle-based therapeutic strategy (nanoPDLIM2) in combination with PD-1 immune checkpoint blockade immunotherapy and chemotherapy for the treatment of lung cancer in mouse preclinical studies. NanoPDLIM2 uses a polyethyleneimine (PEI)-based delivery system that encapsulates PDLIM2 expression plasmids for reconstituting PDLIM2 that is repressed in tumors. This approach induces tumor immunogenicity, suppresses drug resistance, and improves treatment efficacy when used in combination with carboplatin, paclitaxel, and anti-PD-1 antibodies. The protocol describes steps for mouse lung tumor induction, nanoPDLIM2 and other therapeutic reagents' preparation and administration, and subsequent analysis of tumor burden, immune response, and toxicity, providing a reproducible approach for investigators. Key features • Comprehensive workflow for preparation and delivery of nanoPDLIM2. • Combination of nanoPDLIM2 with PD-1 blockade and chemotherapeutics for superior efficacy in lung cancer treatment. • Detailed protocols for therapeutic reagents preparation, administration, tumor examination, immune analysis, health monitoring, and toxicity evaluation in a preclinical lung cancer model.

The interaction between SCAF4 and RNA polymerase II (POLR2A) is crucial for proper mRNA termination, with its dysregulation leading to truncated mRNAs and nonfunctional proteins, impairing cellular growth. Despite its potential relevance, the role of this interaction in triple-negative breast cancer (TNBC) remains unexplored due to the lack of effective molecular tools. To address this, we employed SRiApt, an aptamer generated through the recently established Blocker-SELEX pipeline. Its biological stability is improved by phosphorothioate modifications to form PTf-SRiApt. Using this aptamer, the critical role of the SCAF4-POLR2A interaction in driving TNBC tumor growth and immune regulation is uncovered. PTf-SRiApt effectively inhibits tumor growth and induces cell cycle arrest in TNBC cells with elevated SCAF4 and POLR2A expression. Additionally, PTf-SRiApt promotes premature mRNA termination, boosting antigen presentation and promoting T-cell infiltration. Analysis of patient samples further confirmed the negative correlation between SCAF4-POLR2A interaction and the effectiveness of immunotherapy, highlighting the potential of PTf-SRiApt in improving immune efficacy. Together, the work provides a powerful tool not only for dissecting previously "undruggable" protein-protein interactions but also for enhancing tumor immunogenicity and reshaping the tumor microenvironment.

Cancer immunotherapy, particularly using immune checkpoint inhibitors, has revolutionized cancer treatment; however, its efficacy remains limited to a subset of patients. Nanoparticles have potential in cancer treatment because they offer advantages such as biocompatibility, greater stability, and precise targeting capabilities.

Although obesity is a major risk factor for cancer, it may also improve the response to cancer therapy. Here we investigated the impact of obesity on the efficacy of immune checkpoint inhibitors (ICI). In male mice, obesity promoted tumor growth but enhanced the response to ICI. This was associated with higher expression of immune-related genes within the tumor and enhanced infiltration of tumor-specific CD8+ T cells. Further, obesity in mice was associated with higher estrogen levels and enrichment of estrogen response genes in the tumor, and anti-programmed cell death 1 (anti-PD-1) efficacy was reduced upon administration of the aromatase inhibitor letrozole, which blocks the production of estrogens. Mechanistically, adipocyte-derived estrogens increased antigen presentation by dendritic cells and tumor-specific CD8+ T cell cytotoxicity. Last, overweight and obese men with melanoma responded better to ICI, with high estrogen levels being associated with improved response and survival. Our results suggest that estrogens may serve as a predictive factor of response to ICI in men with melanoma.

Although three proteasome inhibitors are used for liquid tumor treatment, their effectiveness against solid tumors remains inadequate. To address this issue, we employ a drug combination strategy and discover that ammonium tetrathiomolybdate (TM) and AMD3100 can sensitize solid cancer cell lines to proteasome inhibitors. Mechanistically, we find that TM and AMD3100 reduce proteasome activity by decreasing the protein level of PSMB5. This reduction occurs through the activation of the AMP-activated protein kinase (AMPK) pathway, which inhibits STAT3 phosphorylation. Notably, our in vivo studies reveal that drug combinations retard tumor growth dependent on CD8+ T cells. The combination of bortezomib with TM or AMD3100 induces cancer cell antigen presentation and the production of CCL5, which together stimulate the recruitment and generation of cytotoxic CD8+ T cells. This study identifies synergistic lethal pairs that enhance the effectiveness of bortezomib-centered therapy for breast cancer treatment in a way relied on intact immune system.

Ultrasensitive antigen recognition between T lymphocytes and cognate targets via immunological synapse (IS) formation enables live cell-based antigen-specific T cell detection. However, unpredictable antigen processing and major histocompatibility complex (MHC) turnover limit specificity. Here, intracellularly polymerized antigen-presenting cells (pAPCs) are developed for modular, persistent antigen display via kinetically driven loading. Although inanimate, pAPCs mimic cellular interactions, inducing IS hallmarks such as supramolecular activation cluster formation, cytoskeletal contraction, and trogocytosis. Incorporation of superparamagnetic nanoparticles allows label-free magnetic isolation of antigen-specific T cells, surpassing MHC-conjugated beads in sensitivity and specificity. In tumor-bearing hosts, pAPCs enrich tumor-reactive lymphocytes, enhancing adoptive T cell therapy and neoantigen-specific T cell identification. Additionally, pAPCs from engineered cells expressing monovalent human MHC enrich virus- and tumor-specific CD8 T cells from human peripheral blood mononuclear cells and human leukocyte antigen-transgenic mice, demonstrating the potential of this cell-gel hybrid platform for precise antigen-specific T cell capture.