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Poliovirus receptor-related 2 (PVRL2, also known as nectin-2 or CD112) is believed to act as an immune checkpoint protein in cancer; however, most insight into its role is inferred from studies on its known receptor, poliovirus receptor (PVR)-related immunoglobulin domain protein (PVRIG, also known as CD112R). Here, we study PVRL2 itself. PVRL2 levels were found to be high in tumor cells and tumor-derived exosomes. Deletion of PVRL2 in multiple syngeneic mouse models of cancer showed a dramatic reduction in tumor growth that was immune dependent. This effect was even greater than that seen with deletion of PD-L1. PVRL2 was shown to function by suppressing CD8+ T and natural killer cells in the tumor microenvironment. The loss of PVRL2 suppressed tumor growth even in the absence of PVRIG. In contrast, PVRIG loss showed no additive effect in the absence of PVRL2. T-cell immunoreceptor with Ig and ITIM domains (TIGIT) blockade combined with PVRL2 deletion resulted in a near complete block in tumor growth. This effect was not recapitulated by the combined deletion of PVRL2 with its paralog, PVR, which is the ligand for TIGIT. These data uncover PVRL2 as a distinct inhibitor of the antitumor immune response with functions beyond that of its known receptor PVRIG. Moreover, the data provide a strong rationale for combinatorial targeting of PVRL2 and TIGIT for cancer immunotherapy.

Poliovirus receptor-related 2 (PVRL2, also known as nectin-2 or CD112) is believed to act as an immune checkpoint protein in cancer; however, most insight into its role is inferred from studies on its known receptor, poliovirus receptor (PVR)-related immunoglobulin domain protein (PVRIG, also known as CD112R). Here, we study PVRL2 itself. PVRL2 levels were found to be high in tumor cells and tumor-derived exosomes. Deletion of PVRL2 in multiple syngeneic mouse models of cancer showed a dramatic reduction in tumor growth that was immune dependent. This effect was even greater than that seen with deletion of PD-L1. PVRL2 was shown to function by suppressing CD8+ T and natural killer cells in the tumor microenvironment. The loss of PVRL2 suppressed tumor growth even in the absence of PVRIG. In contrast, PVRIG loss showed no additive effect in the absence of PVRL2. T-cell immunoreceptor with Ig and ITIM domains (TIGIT) blockade combined with PVRL2 deletion resulted in a near complete block in tumor growth. This effect was not recapitulated by the combined deletion of PVRL2 with its paralog, PVR, which is the ligand for TIGIT. These data uncover PVRL2 as a distinct inhibitor of the antitumor immune response with functions beyond that of its known receptor PVRIG. Moreover, the data provide a strong rationale for combinatorial targeting of PVRL2 and TIGIT for cancer immunotherapy. ©2024 The Authors; Published by the American Association for Cancer Research.

Poliovirus receptor-related 2 (PVRL2, also known as nectin-2 or CD112) is believed to act as an immune checkpoint protein in cancer; however, most insight into its role is inferred from studies on its known receptor, poliovirus receptor (PVR)-related immunoglobulin domain protein (PVRIG, also known as CD112R). Here, we study PVRL2 itself. PVRL2 levels were found to be high in tumor cells and tumor-derived exosomes. Deletion of PVRL2 in multiple syngeneic mouse models of cancer showed a dramatic reduction in tumor growth that was immune dependent. This effect was even greater than that seen with deletion of PD-L1. PVRL2 was shown to function by suppressing CD8+ T and natural killer cells in the tumor microenvironment. The loss of PVRL2 suppressed tumor growth even in the absence of PVRIG. In contrast, PVRIG loss showed no additive effect in the absence of PVRL2. T-cell immunoreceptor with Ig and ITIM domains (TIGIT) blockade combined with PVRL2 deletion resulted in a near complete block in tumor growth. This effect was not recapitulated by the combined deletion of PVRL2 with its paralog, PVR, which is the ligand for TIGIT. These data uncover PVRL2 as a distinct inhibitor of the antitumor immune response with functions beyond that of its known receptor PVRIG. Moreover, the data provide a strong rationale for combinatorial targeting of PVRL2 and TIGIT for cancer immunotherapy. ©2024 The Authors; Published by the American Association for Cancer Research.

Inflammatory bowel disease lacks a long-lasting and broadly effective therapy. Here, by taking advantage of the anti-infection and anti-inflammatory properties of natural antibodies against the small-molecule epitope phosphorylcholine (PC), we show in multiple mouse models of colitis that immunization of the animals with self-assembling supramolecular peptide nanofibres bearing PC epitopes induced sustained levels of anti-PC antibodies that were both protective and therapeutic. The strength and type of immune responses elicited by the nanofibres could be controlled through the relative valency of PC epitopes and exogenous T-cell epitopes on the nanofibres and via the addition of the adjuvant CpG. The nanomaterial-assisted induction of the production of therapeutic antibodies may represent a durable therapy for inflammatory bowel disease.

Two important factors that contribute to resistance to immune checkpoint inhibitors (ICI) are an immune-suppressive microenvironment and limited antigen presentation by tumor cells. In this study, we examine whether inhibition of the methyltransferase enhancer of zeste 2 (EZH2) can increase ICI response in lung squamous cell carcinomas (LSCC). Our in vitro experiments using two-dimensional human cancer cell lines as well as three-dimensional murine and patient-derived organoids treated with two inhibitors of the EZH2 plus IFNγ showed that EZH2 inhibition leads to expression of both MHC class I and II (MHCI/II) expression at both the mRNA and protein levels. Chromatin immunoprecipitation sequencing confirmed loss of EZH2-mediated histone marks and gain of activating histone marks at key loci. Furthermore, we demonstrate strong tumor control in models of both autochthonous and syngeneic LSCC treated with anti-PD1 immunotherapy with EZH2 inhibition. Single-cell RNA sequencing and immune cell profiling demonstrated phenotypic changes toward more tumor suppressive phenotypes in EZH2 inhibitor-treated tumors. These results indicate that EZH2 inhibitors could increase ICI responses in patients undergoing treatment for LSCC.

KRAS mutation is one of the most common oncogenic drivers in NSCLC, however, the response to immunotherapy is heterogeneous owing to the distinct co-occurring genomic alterations. KRAS/LKB1 co-mutated lung adenocarcinoma displays poor response to PD-1 blockade whereas the mechanism remains undetermined.

Polymicrobial intra-abdominal infections are serious clinical infections that can lead to life-threatening sepsis, which is difficult to treat in part due to the complex and dynamic inflammatory responses involved. Our prior studies demonstrated that immunization with low-virulence Candida species can provide strong protection against lethal polymicrobial sepsis challenge in mice. This long-lived protection was found to be mediated by trained Gr-1+ polymorphonuclear leukocytes with features resembling myeloid-derived suppressor cells (MDSCs). Here we definitively characterize these cells as MDSCs and demonstrate that their mechanism of protection involves the abrogation of lethal inflammation, in part through the action of the anti-inflammatory cytokine interleukin (IL)-10. These studies highlight the role of MDSCs and IL-10 in controlling acute lethal inflammation and give support for the utility of trained tolerogenic immune responses in the clinical treatment of sepsis.

Glucose metabolism is known to orchestrate oncogenesis. Whether glucose serves as a signaling molecule directly regulating oncoprotein activity for tumorigenesis remains elusive. Here, we report that glucose is a cofactor binding to methyltransferase NSUN2 at amino acid 1-28 to promote NSUN2 oligomerization and activation. NSUN2 activation maintains global m5C RNA methylation, including TREX2, and stabilizes TREX2 to restrict cytosolic dsDNA accumulation and cGAS/STING activation for promoting tumorigenesis and anti-PD-L1 immunotherapy resistance. An NSUN2 mutant defective in glucose binding or disrupting glucose/NSUN2 interaction abolishes NSUN2 activity and TREX2 induction leading to cGAS/STING activation for oncogenic suppression. Strikingly, genetic deletion of the glucose/NSUN2/TREX2 axis suppresses tumorigenesis and overcomes anti-PD-L1 immunotherapy resistance in those cold tumors through cGAS/STING activation to facilitate apoptosis and CD8+ T cell infiltration. Our study identifies NSUN2 as a direct glucose sensor whose activation by glucose drives tumorigenesis and immunotherapy resistance by maintaining TREX2 expression for cGAS/STING inactivation.

Malignant peripheral nerve sheath tumors (MPNST) are lethal, Ras-driven sarcomas that lack effective therapies. We investigated effects of targeting cyclin-dependent kinases 4 and 6 (CDK4/6), MEK, and/or programmed death-ligand 1 (PD-L1) in preclinical MPNST models.

High-grade serous ovarian cancer (HGSOC) is responsible for the majority of gynecology cancer-related deaths. Patients in remission often relapse with more aggressive forms of disease within 2 years post-treatment. Alternative immuno-oncology (IO) strategies, such as immune checkpoint blockade (ICB) targeting the PD-(L)1 signaling axis, have proven inefficient so far. Our aim is to utilize epigenetic modulators to maximize the benefit of personalized IO combinations in ex vivo 3D patient-derived platforms and in vivo syngeneic models. Using patient-derived tumor ascites, we optimized an ex vivo 3D screening platform (PDOTS), which employs autologous immune cells and circulating ascites-derived tumor cells, to rapidly test personalized IO combinations. Most importantly, patient responses to platinum chemotherapy and poly-ADP ribose polymerase inhibitors in 3D platforms recapitulate clinical responses. Furthermore, similar to clinical trial results, responses to ICB in PDOTS tend to be low and positively correlated with the frequency of CD3+ immune cells and EPCAM+/PD-L1+ tumor cells. Thus, the greatest response observed with anti-PD-1/anti-PD-L1 immunotherapy alone is seen in patient-derived HGSOC ascites, which present with high levels of systemic CD3+ and PD-L1+ expression in immune and tumor cells, respectively. In addition, priming with epigenetic adjuvants greatly potentiates ICB in ex vivo 3D testing platforms and in vivo tumor models. We further find that epigenetic priming induces increased tumor secretion of several key cytokines known to augment T and NK cell activation and cytotoxicity, including IL-6, IP-10 (CXCL10), KC (CXCL1), and RANTES (CCL5). Moreover, epigenetic priming alone and in combination with ICB immunotherapy in patient-derived PDOTS induces rapid upregulation of CD69, a reliable early activation of immune markers in both CD4+ and CD8+ T cells. Consequently, this functional precision medicine approach could rapidly identify personalized therapeutic combinations able to potentiate ICB, which is a great advantage, especially given the current clinical difficulty of testing a high number of potential combinations in patients.

The characterization of microbiota mechanisms in health and disease has reinvigorated pattern recognition receptors as prominent targets for immunotherapy. Notably, our recent studies on Enterococcus species revealed peptidoglycan remodeling and activation of NOD2 as key mechanisms for microbiota enhancement of immune checkpoint inhibitor therapy. Inspired by this work and other studies of NOD2 activation, we performed in silico ligand screening and developed N-arylpyrazole dipeptides as novel NOD2 agonists. Importantly, our N-arylpyrazole NOD2 agonist is enantiomer-specific and effective at promoting immune checkpoint inhibitor therapy and requires NOD2 for activity in vivo. Given the significant functions of NOD2 in innate and adaptive immunity, these next-generation agonists afford new therapeutic leads and adjuvants for a variety of NOD2-responsive diseases.

Diffusing alpha-emitters Radiation Therapy (DaRT) releases alpha-emitting atoms into the tumor microenvironment. The treatment effectively ablates human and mice xenografts and shows 100% response rates in skin or head and neck squamous cell carcinoma patients. DaRT induces specific and systemic antitumor immune activation and synergizes with immune stimulation and modulation in mice. Here, the transcriptional profile activated by DaRT, and its potential to enhance responsiveness to immune checkpoint inhibition by programmed cell death protein 1 (PD-1) blockade were studied.

Therapeutic antibodies targeting immune checkpoints have shown limited efficacy in clinical trials in glioblastoma (GBM) patients. Ultrasound-mediated blood-brain barrier opening (UMBO) using low-intensity pulsed ultrasound improved drug delivery to the brain. We explored the safety and the efficacy of UMBO plus immune checkpoint inhibitors in preclinical models of GBM. A blood-brain barrier (BBB) opening was performed using a 1 MHz preclinical ultrasound system in combination with 10 µL/g microbubbles. Brain penetration of immune checkpoint inhibitors was determined, and immune cell populations were evaluated using flow cytometry. The impact of repeated treatments on survival was determined. In syngeneic GL261-bearing immunocompetent mice, we showed that UMBO safely and repeatedly opened the BBB. BBB opening was confirmed visually and microscopically using Evans blue dye and magnetic resonance imaging. UMBO plus anti-PDL-1 was associated with a significant improvement of overall survival compared to anti-PD-L1 alone. Using mass spectroscopy, we showed that the penetration of therapeutic antibodies can be increased when delivered intravenously compared to non-sonicated brains. Furthermore, we observed an enhancement of activated microglia percentage when combined with anti-PD-L1. Here, we report that the combination of UMBO and anti-PD-L1 dramatically increases GL261-bearing mice's survival compared to their counterparts treated with anti-PD-L1 alone. Our study highlights the BBB as a limitation to overcome in order to increase the efficacy of anti-PD-L1 in GBM and supports clinical trials combining UMBO and in GBM patients.