Immune Checkpoint Regulators Research Articles

Recent advancements at ASCO 2024 in PD-L1 and PD-1 bispecific antibodies.

Recent advancements in cancer immunotherapy have spotlighted the PD-1/PD-L1 pathway, crucial for its role in immune checkpoint regulation. Traditional inhibitors, though successful, face challenges like resistance and adverse effects. Bispecific antibodies targeting PD-1 and PD-L1 present a ground-breaking solution by simultaneously engaging multiple immune regulatory molecules. Developments in PD-1/PD-L1 bispecific antibodies up to now have been summarized, and the latest findings from the 2024 ASCO conference are presented, revealing that bispecific antibodies exhibit robust efficacy in treating various types of cancers, marking a significant step forward in cancer treatment.

Gram-negative microflora dysbiosis facilitates tumor progression and immune evasion by activating CCL3/CCL5-CCR1-MAPK-PD-L1 pathway in esophageal squamous cell carcinoma.

Gram-negative micro-flora dysbiosis occurs in multiple digestive tumors and is found to be the dominant micro-flora in esophageal squamous cell carcinoma (ESCC) micro-environment. The continuous stimulation of G- bacterium metabolites may cause tumorigenesis and reshape the micro-immune environment in ESCC. However, the mechanism of G- bacilli causing immune evasion in ESCC remains underexplored. We identified CC Chemokine receptor 1 (CCR1) as a tumor-indicating gene in ESCC. Interestingly, expression levels of CCR1 and PD-L1 were mutually up regulated after G- bacilli metabolites lipopolysaccharide (LPS) stimulation. Firstly, we found CCR1 high expression level to be associated with poor overall survival in ESCC. Importantly, we found that high level expression of CCR1 up-regulated PD-L1 expression by activating MAPK phosphorylation in ESCC and induced tumor malignant behavior. Finally, we found that T cells exhaustion and cytotoxicity suppression were associated with CCR1 expression in ESCC, which were decreased after CCR1 inhibiting. Our work identifies CCR1 as a potential immune check point regulator of PD-L1 and may cause T cell exhaustion and cytotoxicity suppression in ESCC micro-environment and highlights the potential value of CCR1 as therapeutic target of immunotherapy. Implications: The esophageal microbial environment and its metabolites significantly affect the outcome of immunotherapy for ESCC.

Identification of genetic fingerprint of type I interferon therapy in visceral metastases of melanoma

Malignant melanoma is a difficult-to-treat skin cancer with increasing incidence worldwide. Although type-I interferon (IFN) is no longer part of guidelines, several melanoma patients are treated with type-I interferon (IFN) at some point of the disease, potentially affecting its genetic progression. We run genome-wide copy number variation (CNV) analysis on previously type-I IFN-treated (n = 17) and control (n = 11) visceral metastases of melanoma patients. Results were completed with data from the TCGA and MM500 databases. We identified metastasis- and brain metastasis-specific gene signatures mostly affected by CN gains. Some cases were genetically resistant to IFN showing characteristic gene alterations (e.g. ABCA4 or ZEB2 gain and alterations of DNA repair genes). Analysis of a previously identified type-I IFN resistance gene set indicates that only a proportion of these genes was exclusive for the IFN-treated metastases reflecting a possible selective genomic pressure of endogenous IFNs during progression. Our data suggest that previous type-I IFN treatment and/or endogenous IFN production by immune response affect genomic progression of melanoma which may have clinical relevance, potentially influence immune checkpoint regulation in the tumor microenvironment.

Mechanisms of Immune Evasion in PTEN Loss Prostate Cancer

PTEN (phosphatase and tensin homolog) is a frequently lost tumor suppressor gene in prostate cancer, leading to aggressive tumor behavior and poor clinical outcomes. PTEN loss results in aberrant activation of the PI3K/AKT/mTOR pathway, promoting oncogenesis. These alterations also lead to an immunosuppressive tumor microenvironment with altered immune cell infiltration, cytokine profiles, and immune checkpoint regulation. This review aims to provide a comprehensive overview of the mechanisms underlying PTEN loss in prostate cancer and the consequent immune alterations observed in this subtype, thus underscoring the importance of understanding PTEN-mediated immune modulation for the development of effective therapeutic interventions in prostate cancer.

Endoplasmic Reticulum Stress Nano-Orchestrators for Precisely Regulated Immunogenic Cell Death as Potent Cancer Vaccines.

Dying tumor cells regulated by immunogenic cell death (ICD) inducers are promising candidates for cancer vaccine development because of their comprehensive antigen spectrum. However, their limited immunogenicity and potential tumorigenicity hinder clinical translation. To address these challenges, a nano-orchestrator is developed that targets the endoplasmic reticulum (ER) stress, a critical pre-ICD event, to optimize the "precise dose" of ER stress. Using a clinical-range irradiation fluence (50‒200 J cm-2) with an 808 nm laser, the release of damage associated molecular patterns (DAMPs) and antigens are precisely regulated. A fluence of 150 J cm-2 (2 W cm-2 for 75 s) increases dendritic cell maturation and antitumor T cell proliferation, providing valuable clinical insights. The ER stress nano-orchestrator enhances both adjuvanticity and antigenicity via the protein kinase R-like endoplasmic reticulum kinase (PERK)-C/EBP homologousprotein (CHOP) pathway to regulate ICD-induced DAMPs and promote tumor cell apoptosis. These optimized ER stress phototherapeutic dying tumor cells can serve as prophylactic vaccines, achieving a remarkable 100% success rate against tumor rechallenge in vivo. Additionally, the nano-orchestrator shows the potential to develop in situ therapeutic tumor vaccines when combined with anti-PD-L1 treatment, providing important insights into enhancing the efficacy of immune checkpoint regulators by modulating endogenous immune responses.

Rapid turnover of CTLA4 is associated with a complex architecture of reversible ubiquitylation.

The immune checkpoint regulator CTLA4 is an unusually short-lived membrane protein. Here, we show that its lysosomal degradation is dependent on ubiquitylation at lysine residues 203 and 213. Inhibition of the v-ATPase partially restores CTLA4 levels following cycloheximide treatment, but also reveals a fraction that is secreted in exosomes. The endosomal deubiquitylase, USP8, interacts with CTLA4, and its loss enhances CTLA4 ubiquitylation in cancer cells, mouse CD4+ T cells, and cancer cell-derived exosomes. Depletion of the USP8 adapter protein, HD-PTP, but not ESCRT-0 recapitulates this cellular phenotype but shows distinct properties vis-à-vis exosome incorporation. Re-expression of wild-type USP8, but neither a catalytically inactive nor a localization-compromised ΔMIT domain mutant can rescue delayed degradation of CTLA4 or counteract its accumulation in clustered endosomes. UbiCRest analysis of CTLA4-associated ubiquitin chain linkages identifies a complex mixture of conventional Lys63- and more unusual Lys27- and Lys29-linked polyubiquitin chains that may underly the rapidity of protein turnover.

Extracorporeal photopheresis vs. systemic immunosuppression for immune-related adverse events: Interim analysis of a prospective two-arm study

BackgroundCheckpoint inhibitor-induced steroid-refractory (sr) and steroid-dependent (sd) immune-related adverse events (irAE) account for about 11 % of irAE. Although these patients face worse outcomes due to irAE mortality and/or sustained immunosuppression, which impairs anti-tumor response, there is no established second-line treatment based on prospective trial data. MethodsThis prospective comparative study investigates outcomes of extracorporeal photopheresis (ECP), an immunomodulating therapy, versus second-line immunosuppressants (SLI) in sr/sd-irAE. The primary endpoint was longitudinal change in immunophenotype; secondary endpoints were outcome of irAE and tumor response. Patient demographics, quality of life (EORTC QLQ-C30; global health status (GHS/QoL)) and longitudinal blood samples were analyzed at baseline; in weeks 1, 4, 8, and 12. ResultsAt interim analysis, 21 patients (11 ECP, 10 SLI) with 7 different sr/sd-irAE were included. Compared with the SLI group, the ECP group demonstrated a higher clinical response rate of irAE (93 % vs. 80 %; 95 % CI 0.83–1.92; P = 0.54) and a better GHS/QoL score throughout all follow-up visits. ECP patients showed a numerically higher overall survival (23 vs. 12 months; 95 % CI 0.02–3.02; P = 0.27) and lower cancer progression rates (33 % vs. 67 %; 95 % CI 0.09–1.60; P = 0.52). Immunophenotyping revealed changes in immune cell populations and the regulation of immune checkpoints. There were no significant safety issues in either treatment group. ConclusionThis prospective comparative study supports the clinical efficacy of ECP in the treatment of sr/sd-irAE in comparison to the SLI cohort. Thus, ECP represents a potential treatment option for this indication, given its good safety profile while maintaining anti-tumor response. Trial RegistrationClinicalTrials.gov, NCT05700565, https://classic.clinicaltrials.gov/ct2/show/NCT05700565.

Comprehensive analysis of the expression and prognosis for cyclin-dependent protein kinase family in osteosarcoma

Background and Objective Cyclin-dependent protein kinases (CDKs) have been suggested as prospective therapeutic targets because they control processes vital to the survival and growth of cancer cells. However, research on the varied CDK expression profiles and prognostic factors in osteosarcoma is still lacking. Methods The osteosarcoma microRNA (GSE65071) and gene expression profiles were retrieved from the Gene Expression Omnibus (GEO) database (GSE42352). A substantial variation in prognosis was discovered in CDKs using the TARGET database. Cytoscape was used to construct the miRNAs-CDKs network, and functional and pathway enrichment analyses were completed. It was looked at how immune checkpoint genes, m6A-related genes, and CDKs interact. Results In patients with osteosarcoma compared to normal samples, CDK1-5, CDK18, CDK16, and CDK17 gene expression levels were considerably greater, whereas CDK7-9, CDK11B, CDK16, and CDK20 gene expression levels were significantly lower. Patients with osteosarcoma who had low CDK3 and 18 gene levels or high CDK6, 9 gene levels were predicted to have a favorable prognosis and a long-life expectancy. Immune checkpoint genes, m6A-related gene expression, and CDKs expression all showed some connection. Finally, a network of crucial CDKs and miRNAs was constructed. Conclusion According to our research, CDK3, 6, 9, and 18 have been identified as possible therapeutic targets for osteosarcoma, and CDKs may have a role in controlling m6A mutations in tumor cells as well as immune checkpoint regulation.

Expression of immune checkpoint markers in peripheral blood lymphocytes of women with fibroadenoma of the breast

Changes of the immune state in patients with fibroadenoma (FA) or other benign lesions of the breast, as well as the involvement of immune checkpoints in pathogenesis of these lesions, remain underexplored. The aim of this study was to compare the expression level of the key immune checkpoint markers CD279/PD-1, CD274/PD-L1, CD366/TIM3, and CD223/LAG3 in total circulating lymphocytes, T cell population as well as in its CD4 and CD8 subsets in peripheral blood from women with breast FA and healthy controls. Blood samples were taken from 12 women diagnosed with FA of the breast (aged 23-54 years, FA group) and 15 healthy women (aged 22-52 years, control group). Sample uptake was performed immediately before surgery, and samples were further analyzed by multicolor flow cytometry using monoclonal antibodies CD3-VioBlue, CD4/CD8-FITC, PD1-PE, PD-L1-PerCP-Cy.5.5, and TIM3/LAG3-APC. Each sample was incubated with 4 antibody combinations: CD3/CD4/PD1/PD-L1/TIM3, CD3/CD4/PD1/PD-L1/LAG3, CD3/CD8/PD1/PD-L1/TIM3, and CD3/CD8/PD1/PD-L1/LAG3. First, mono-expression of each of the 4 immune checkpoint markers was evaluated in the lymphocyte gate from both investigated groups. In FA samples, a significant increase in PD-L1 expression (assessed as percent of positive cells and fluorescence intensity change) was observed. Regarding expression of immune checkpoints in CD3+ T cells, along with significantly increased %PD-L1+, elevated numbers of PD1+T cells were detected. As for the differences in immune checkpoint expression changes between CD4+ and CD8+ T cell subsets, FA patient group demonstrated a more prominent increase in the amount of CD8+PD1+T cells relative to CD4 subset. The profiles of PD-L1 changes in CD4 and CD8 subpopulations were comparable showing, in both cases, a significant increase in FA sample group. We also analyzed changes in co-expression of any two immune checkpoint markers in CD4+ and CD8+ T cell subsets. The most noticeable was as increase in the prevalence of PD1+PD-L1+ phenotype in both T cell subpopulations from FA patients compared to the controls. With respect to co-expression of 3 checkpoint markers in CD4+ and CD8+ T cells, a significant increase in the percentage of PD1+PD-L1+TIM3+ cells among CD4 T helpers was found in FA. Thus, specific changes of T cell phenotype related to (co-)expression of immune checkpoint regulators may occur in systemic circulation of women with breast FA.

Non-coding RNAs in BRAF-mutant melanoma: targets, indicators, and therapeutic potential.

Melanoma, a highly aggressive skin cancer, is often driven by BRAF mutations, such as the V600E mutation, which promotes cancer growth through the MAPK pathway and contributes to treatment resistance. Understanding the role of non-coding RNAs (ncRNAs) in these processes is crucial for developing new therapeutic strategies. This review aims to elucidate the relationship between ncRNAs and BRAF mutations in melanoma, focusing on their regulatory roles and impact on treatment resistance. We comprehensively reviewed current literature to synthesize evidence on ncRNA-mediated regulation of BRAF-mutant melanoma and their influence on therapeutic responses. Key ncRNAs, including microRNAs and long ncRNAs, were identified as significant regulators of melanoma development and therapy resistance. MicroRNAs such as miR-15/16 and miR-200 families modulate critical pathways like Wnt signaling and melanogenesis. Long ncRNAs like ANRIL and SAMMSON play roles in cell growth, invasion, and drug susceptibility. Specific ncRNAs, such as BANCR and RMEL3, intersect with the MAPK pathway, highlighting their potential as therapeutic targets or biomarkers in BRAF-mutant melanoma. Additionally, ncRNAs involved in drug resistance, such as miR-579-3p and miR-1246, target processes like autophagy and immune checkpoint regulation. This review highlights the pivotal roles of ncRNAs in regulating BRAF-mutant melanoma and their contribution to drug resistance. These findings underscore the potential of ncRNAs as biomarkers and therapeutic targets, paving the way for innovative treatments to improve outcomes for melanoma patients.

The Aryl Hydrocarbon Receptor Controls IFNγ-Induced Immune Checkpoints PD-L1 and IDO via the JAK/STAT Pathway in Lung Adenocarcinoma.

While immunotherapy has shown efficacy in lung adenocarcinoma (LUAD) patients, many respond only partially or not at all. One limitation in improving outcomes is the lack of a complete understanding of immune checkpoint regulation. Here, we investigated a possible link between an environmental chemical receptor implicated in lung cancer and immune regulation, (the aryl hydrocarbon receptor/AhR), a known but counterintuitive mediator of immunosuppression (IFNγ), and regulation of two immune checkpoints (PD-L1 and IDO). AhR gene-edited LUAD cell lines, a syngeneic LUAD mouse model, bulk- and scRNA sequencing of LUADs and tumor-infiltrating leukocytes were used to map out a signaling pathway leading from IFNγ through the AhR to JAK/STAT, PD-L1, IDO, and tumor-mediated immunosuppression. The data demonstrate that: 1) IFNγ activation of the JAK/STAT pathway leading to PD-L1 and IDO1 upregulation is mediated by the AhR in murine and human LUAD cells, 2) AhR-driven IDO1 induction results in the production of Kynurenine (Kyn), an AhR ligand, which likely mediates an AhR→IDO1→Kyn→AhR amplification loop, 3) transplantation of AhR-knockout LUAD cells results in long-term tumor immunity in most recipients. 4) The 23% of AhR-knockout tumors that do grow do so at a much slower pace than controls and exhibit higher densities of CD8+ T cells expressing markers of immunocompetence, increased activity, and increased cell-cell communication. The data definitively link the AhR to IFNγ-induced JAK/STAT pathway and immune checkpoint-mediated immunosuppression and support the targeting of the AhR in the context of LUAD.

Abstract Or120: CD40 is an immune checkpoint regulator that potentiates myocardial inflammation through activation and expansion of CCR2 + macrophages and CD8 T-cells

Novel immune checkpoint therapeutics including CD40 agonists have tremendous promise to elicit antitumor responses in patients resistant to current therapies. Conventional immune checkpoint inhibitors (PD-1/PD-L1, CTLA-4 antagonists) are associated with serious adverse cardiac events including life-threatening myocarditis. However, little is known regarding the potential for CD40 agonists to trigger myocardial inflammation or myocarditis. Here, we leveraged genetic mouse models, single cell sequencing, and cell depletion studies to demonstrate that an anti-CD40 agonist antibody reshapes the cardiac immune landscape through activation of CCR2 + macrophages and subsequent recruitment of effector memory CD8 T-cells. We identify a positive feedback loop between CCR2 + macrophages and CD8 T-cells driven by IL12b, TNF, and IFN-γ signaling that promotes myocardial inflammation and show that prior exposure to CD40 agonists sensitizes the heart to secondary insults and accelerates LV remodeling. Collectively, these findings highlight the potential for CD40 agonists to promote myocardial inflammation and potentiate heart failure pathogenesis.

Targeting of immune checkpoint regulator V-domain Ig suppressor of T-cell activation (VISTA) with 89Zr-labelled CI-8993

BackgroundCI-8993 is a fully human IgG1κ monoclonal antibody (mAb) that binds specifically to immune checkpoint molecule VISTA (V-domain Ig suppressor of T-cell activation). Phase I safety has been established in patients with advanced cancer (NCT02671955). To determine the pharmacokinetics and biodistribution of CI-8993 in patients, we aimed to develop 89Zr-labelled CI-8993 and validate PET imaging and quantitation in preclinical models prior to a planned human bioimaging trial.MethodsCI-8993 and human isotype IgG1 control were conjugated to the metal ion chelator p-isothiocyanatobenzyl-desferrioxamine (Df). Quality of conjugates were assessed by SE-HPLC, SDS-PAGE, and FACS. After radiolabelling with zirconium-89 (89Zr), radioconjugates were assessed for radiochemical purity, immunoreactivity, antigen binding affinity, and serum stability in vitro. [89Zr]Zr-Df-CI-8993 alone (1 mg/kg, 4.6 MBq) or in combination with 30 mg/kg unlabelled CI-8993, as well as isotype control [89Zr]Zr-Df-IgG1 (1 mg/kg, 4.6 MBq) were assessed in human VISTA knock-in female (C57BL/6 N-Vsirtm1.1(VSIR)Geno, huVISTA KI) or control C57BL/6 mice bearing syngeneic MB49 bladder cancer tumours; and in BALB/c nu/nu mice bearing pancreatic Capan-2 tumours.ResultsStable constructs with an average chelator-to-antibody ratio of 1.81 were achieved. SDS-PAGE and SE-HPLC showed integrity of CI-8993 was maintained after conjugation; and ELISA indicated no impact of conjugation and radiolabelling on binding to human VISTA. PET imaging and biodistribution in MB49 tumour-bearing huVISTA KI female mice showed specific localisation of [89Zr]Zr-Df-CI-8993 to VISTA in spleen and tumour tissues expressing human VISTA. Specific tumour uptake was also demonstrated in Capan-2 xenografted BALB/c nu/nu mice.ConclusionsWe radiolabelled and validated [89Zr]Zr-Df-CI-8993 for specific binding to huVISTA in vivo. Our results demonstrate that 89Zr-labelled CI-8993 is now suitable for targeting and imaging VISTA expression in human trials.Graphical

SPP1 could be an immunological and prognostic biomarker: From pan-cancer comprehensive analysis to osteosarcoma validation.

Secreted phosphoprotein 1 (SPP1), also known as osteopontin, is a phosphorylated protein. High SPP1 expression levels have been detected in multiple cancers and are associated with poor prognosis and reduced survival rates. However, only a few pan-cancer analyses have targeted SPP1. We conducted a comprehensive analysis using multiple public databases, including TIMER and TCGA, to investigate the expression levels of SPP1 in 33 different tumor types. In addition, we verified the effect of SPP1 on osteosarcoma. To assess the impact of SPP1 on patient outcomes, we employed univariate Cox regression and Kaplan-Meier survival analyses to analyze overall survival (OS), disease-specific survival (DSS), and progression-free interval (PFI) in these tumor patients. We also explored SPP1 gene alterations in various tumor tissues using cBioPortal. We then examined the relationship between SPP1 and clinical characteristics, TME, immune regulatory genes, immune checkpoints, TMB, and MSI using R language. In addition, we used GSEA to investigate the molecular mechanisms underlying the role of SPP1. Bioinformatics analysis indicated that SPP1 was upregulated in 17 tumors. Overexpression of SPP1 results in poor OS, DSS, and PFI in CESC, ESCA, GBM, LGG, LIHC, PAAD, PRAD, and skin cutaneous melanoma. SPP1 expression was positively associated with immunocyte infiltration, immune regulatory genes, immune checkpoints, TMB, MSI, and drug sensitivity in certain cancers. We found that high expression of SPP1 in osteosarcoma was related to drug resistance and metastasis and further demonstrated that SPP1 can stimulate osteosarcoma cell proliferation via CCND1 by activating the PI3K/Akt pathway. These findings strongly suggest that SPP1 is a potential prognostic marker and novel target for cancer immunotherapy.

Progress of IL-21 and Tfh Mediated Immunotherapy in Non-small Cell Lung Cancer

Non-small cell lung cancer (NSCLC) is a prevalent and aggressive global malignancy. Conventional surgical treatments, radiotherapy, chemotherapy, and targeted therapies often fall short in halting disease progression due to inherent limitations, resulting in suboptimal prognosis. Despite the advent of immunotherapy drugs offering new hope for NSCLC treatment, current efficacy remains insufficient to meet all patient needs. Therefore, actively exploring novel immunotherapeutic approaches to further reduce mortality rates in NSCLC patients has become a crucial focus of NSCLC research. This article aims to systematically review the anti-tumor effects of interleukin-21 and follicular helper T cells in NSCLC immunotherapy by summarizing and analyzing relevant literatures from both domestic and international sources, as well as exploring the potential for enhancing NSCLC treatment prospects through immune checkpoint regulation via immunotherapeutic means. .

SLC16A3 is a Prognostic Marker and Affects Immune Regulation in Bladder Cancer.

Overexpression of SLC16A3 can contribute to the development of various tumors by regulating metabolism, but a systematic analysis of SLC16A3 in bladder cancer (BC) has been rarely reported. We used the BC datasets from public databases to investigate SLC16A3 expression in BC. We first analysed the relationship between SLC16A3 expression and clinical characteristics of 412 bladder cancer patients. After that, gene function analyses and immunocorrelation analyses of SLC16A3 were conducted with the R package. For immunotherapy effect and drug sensitivity analysis, we also used the R package. We also analysed the relation between SLC16A3 expression and 20 m6A modification key genes. Finally, we determined the expression localization of SLC16A3 in bladder cancer by single-cell sequencing analysis using 3,115 BC cells. We further detected the expression of SLC16A3/MCT4 on BC samples by reversed transcriptionquantitative polymerase chain reaction and immunohistochemistry. The SLC16A3 was overexpressed in BC cells, including epithelial cells (p＜0.001). The high SLC16A3 expression level of patients with BC was significantly related to poor prognosis (p＝0.044), and we established a reliable prognosis model for BC patients. Statistically significant associations between SLC16A3 and m6A modification (ALKBH5) gene (p＜0.001), key genes in aerobic glycolysis, M2 macrophage infiltration (p＝0.0058), and immune checkpoint regulation were observed. Overexpression of SLC16A3 is an independent prognostic factor in patients with BC. SLC16A3 may influence the immune infiltration of BC by regulating BC metabolism and m6A methylation, which ultimately can lead to the progress of BC. For the detection and therapy of BC, SLC16A3 may be a potent therapeutic target for BC.

The immunomodulatory ballet of tumour-derived extracellular vesicles and neutrophils orchestrating the dynamic CD73/PD-L1 pathway in cancer.

Head and neck squamous cell carcinoma (HNSCC) is a global cancer burden with a 5-year overall survival rate of around 50%, stagnant for decades. A tumour-induced immunosuppressive microenvironment contributes to HNSCC progression, with the adenosine (ADO) pathway and an upregulated expression of inhibitory immune checkpoint regulators playing a key role in this context. The correlation between high neutrophil-to-lymphocyte ratio (NLR) with advanced tumour staging suggests involvement of neutrophils (NØ) in cancer progression. Interestingly, we associated a high NLR with an increased intracellular PD-L1 localization in primary HNSCC samples, potentially mediating more aggressive tumour characteristics and therefore synergistically favouring tumour progression. Still, further research is needed to harness this knowledge for effective treatments and overcome resistance. Since it is hypothesized that the tumour microenvironment (TME) may be influenced by small extracellular vesicles (sEVs) secreted by tumours (TEX), this study aims to investigate the impact of HNSCC-derived TEX on NØ and blockade of ADO receptors as a potential strategy to reverse the pro-tumour phenotype of NØ. UMSCC47-TEX exhibited CD73 enzymatic activity involved in ADO signalling, as well as the immune checkpoint inhibitor PD-L1. Data revealed that TEX induce chemotaxis of NØ and the sustained interaction promotes a shift into a pro-tumour phenotype, dependent on ADO receptors (P1R), increasing CD170high subpopulation, CD73 and PD-L1 expression, followed by an immunosuppressive secretome. Blocking A3R reduced CD73 and PD-L1 expression. Co-culture experiments with HNSCC cells demonstrated that TEX-modulated NØ increase the CD73/PD-L1 axis, through Cyclin D-CDK4/6 signalling. To support these findings, the CAM model with primary tumour was treated with NØ supernatant. Moreover, these NØ promoted an increase in migration, invasion, and reduced cell death. Targeting P1R on NØ, particularly A3R, exhibited potential therapeutic strategy to counteract immunosuppression in HNSCC. Understanding the TEX-mediated crosstalk between tumours and NØ offers insights into immunomodulation for improving cancer therapies.

Immune checkpoint regulation is critically involved in canine cutaneous histiocytoma regression.

Canine cutaneous histiocytoma (CCH) is a benign tumor frequently occurring in young dogs which is derived from Langerhans cells (LC). Distinguishing features of this tumor are its spontaneous regression following a rapid tumor growth. Impaired control of immune checkpoints during tumor development and progression is a widespread phenomenon which may result in an absent or ineffective immune response. The interaction between the inflammatory response and the expression of immune checkpoint molecules is only partially described in this tumor type. The aim of this study was to identify immune checkpoint molecules and molecules from the interferon-mediated immune response that are involved in the regression of CCH. Forty-eight CCH derived from dogs ≤ 4 years of age were assigned to one of four groups according to the severity and distribution of lymphocyte infiltration. Using immunohistochemistry and whole-slide image scans of consecutive sections the expression of programmed death protein ligand 1 (PD-L1), CD80, CD86, Survivin, forkhead box protein 3, Ki-67, cleaved caspase-3, CD3, and mx1 were investigated. RNA in-situ hybridization was performed for transcripts of mx1 and interferon-γ. Neoplastic cells showed an expression of PD-L1, CD80, CD86, and Survivin. The density of CD80 expressing cells was negatively correlated with regression while the density of cleaved caspase-3 positive cells increased with regression. Mx1 transcripts and protein were predominantly localized in neoplastic cells while interferon-γ transcripts were most frequently detected in T-cells. The expression of the immune checkpoint molecules CD86 and PD-L1 and particularly the reduced expression of CD80 in groups 3 and 4 indicate an influence of the investigated immune checkpoints on tumor regression. In parallel an activation of the apoptotic cascade during regression is suggested. Finally, the detection of mx1 within the neoplasm pinpoints to a yet undisclosed role of anti-cellular signaling in tumor immunity.

Expression of Immune Checkpoint Regulator Cytotoxic T Lymphocyte Antigen 4 (CTLA-4) and Programmed Cell Death Protein Ligand 1 (PD-L1) in Invasive Ductal Carcinoma Breast

Expression of Immune Checkpoint Regulator Cytotoxic T Lymphocyte Antigen 4 (CTLA-4) and Programmed Cell Death Protein Ligand 1 (PD-L1) in Invasive Ductal Carcinoma Breast

The Immune Checkpoint Protein PD-L1 Regulates Ciliogenesis and Hedgehog Signaling.

The primary cilium, an antenna-like sensory organelle that protrudes from the surface of most eukaryotic cell types, has become a signaling hub of growing interest given that defects in its structure and/or function are associated with human diseases and syndromes, known as ciliopathies. With the continuously expanding role of primary cilia in health and diseases, identifying new players in ciliogenesis will lead to a better understanding of the function of this organelle. It has been shown that the primary cilium shares similarities with the immune synapse, a highly organized structure at the interface between an antigen-presenting or target cell and a lymphocyte. Studies have demonstrated a role for known cilia regulators in immune synapse formation. However, whether immune synapse regulators modulate ciliogenesis remains elusive. Here, we find that programmed death ligand 1 (PD-L1), an immune checkpoint protein and regulator of immune synapse formation, plays a role in the regulation of ciliogenesis. We found that PD-L1 is enriched at the centrosome/basal body and Golgi apparatus of ciliated cells and depleting PD-L1 enhanced ciliogenesis and increased the accumulation of ciliary membrane trafficking proteins Rab8a, BBS5, and sensory receptor protein PC-2. Moreover, PD-L1 formed a complex with BBS5 and PC-2. In addition, we found that depletion of PD-L1 resulted in the ciliary accumulation of Gli3 and the downregulation of Gli1. Our results suggest that PD-L1 is a new player in ciliogenesis, contributing to PC-2-mediated sensory signaling and the Hh signaling cascade.