Dendritic Cells Research Articles

CTIM-17. INDIVIDUALIZED MULTIMODAL IMMUNOTHERAPY (IMI) FOR ADULTS WITH DIFFUSE MIDLINE GLIOMA OR DIFFUSE HEMISPHERIC GLIOMA

Abstract Diffuse Midline Glioma (DMG, H3K27 mutant) and Diffuse Hemispheric Glioma (DHG, H3G34 mutant) are rare malignant CNS tumors with dismal prognosis. We retrospectively searched in our database for adults (>18y) with molecularly define DMG/DHG, treated between May 2015 and 2024 with IMI as part of first-line treatment. Amongst 157 IMI-treated malignant glioma patients, four patients fit these restrictions, pointing to scarce experience of IMI for DMG/DHG adult patients. HM (M, 29y) was diagnosed with a DMG in the pons. He received radiochemotherapy, and continued after 2x TMZm with BRAF-MEK-inhibition therapy. He received one IO-Vac® dendritic cell vaccine but showed fast progression thereafter. He died 9 months after diagnosis. GJE (F, 28y) had a DMG at the corpus callosum. She received radiochemotherapy and 6x TMZm, followed by 2x IO-Vac® and 3x maintenance immunogenic cell death (ICD) immunotherapy (NDV injections, sessions of modulated electrohyperthermia), combined with WT1 and H3K27M long-peptide vaccines. She progressed after 20 months, for which a new IO-Vac® and an H3K27M short- and long-peptide vaccine were given. She died 5 months later. Overall Survival (OS) was 26 months after initial diagnosis. JD (F, 27y) was diagnosed with a DMG in C2-C6. She received radiochemotherapy followed by IMI alone, including 2x IO-Vac®, one ICD immunotherapy, and four doses of anti-PD1. She died 17 months later, making OS 27 months after diagnosis. VJ (F, 21y) had a DHG in the left cerebrum. She received radiochemotherapy and 12 cycles of maintenance TMZ (TMZm), between which ICD immunotherapy was inserted each time. Afterwards, she received two IO-Vac®. Finally, she received ICD immunotherapy (6x) combined with checkpoint inhibitors (4x anti-CTLA4, 10x anti-PD1). Thirty months after diagnosis, she is in remission with a stable Health Utility Index of 0.72. IMI might have contributed to a better OS in three out of four DMG/DHG patients, and should be explored further as part of the treatment for these patients.

Molecular hybridization modification improves the stability and immunomodulatory activity of TP5 peptide

Thymopentin (TP5) plays an important role in host immunomodulation, yet its bioavailability is significantly limited by its short half-life. YW12D is a peptide with strong stability but relatively weak immunoactivity. Tuning the physicochemical properties of such molecules may yield synthetic molecules displaying optimal stability, safety and enhanced immunological activity. Here, natural peptides were modified to improve their activity by hybridization strategies. A hybrid peptide YW12D-TP5 (YTP) that combines TP5 and YW12D is designed. The half-life of YTP in plasma is significantly longer than that of YW12D and TP5. YTP also displays an improved ability to protect the host from CTX-induced weight loss and thymus and spleen indices decrease than YW12D and TP5. In addition, YTP promotes dendritic cell maturation and increases the expression of cytokines IL-1β, IL-6, TNF-α and immunoglobulins IgA, IgG, and IgM. A combination of antibody-specific blocking assay, SPR, molecular dynamics simulations and western blotting suggest that the immunomodulatory effect of YTP is associated with its activation of the TLR2-NF-кB signaling axis. In sum, we demonstrate that peptide hybridization is an effective strategy for redirecting biological activity to generate novel bioactive molecules with desired properties.

TMIC-71. ELUCIDATING IMMUNE MICROENVIRONMENTAL DISTINCTIONS BETWEEN IDH-MUTANT ASTROCYTOMA AND OLIGODENDROGLIOMA USING SINGLE-CELL TRANSCRIPTIONAL PROFILING

Abstract Despite exhibiting longer overall survival that IDH-wt counterparts, IDH-mutant gliomas remain uniformly deadly and impact patients in the prime of adult life. The immune microenvironment of IDH-mutant gliomas remains incompletely characterized, particularly with regard to distinctions between IDH-mutant astrocytoma and IDH-mutant, 1p/19q codeleted oligodendroglioma. To address this knowledge gap, we subjected dissociated tumor suspensions derived from 7 astrocytoma and 7 oligodendroglioma clinical samples to flow cytometry-based sorting for the pan-immune marker, CD45, and the microglial marker, P2RY12. This process yielded both microglial and non-microglial immune cell populations, which were then analyzed by scRNA sequencing. This workflow revealed a single large cluster of microglia, characterized by expression of Galectin-1 and lysosomal Lipase A, which was present at a significantly higher level in oligodendroglioma. While the biological significance of this cluster is unclear, gene set enrichment analysis exploring phenotypic differences between microglia in astrocytoma and oligodendroglioma revealed significant increases in expression of gene sets related to antigen presentation in astrocytoma. Parallel analysis of the non-microglial immune fraction showed an increase in the expression of pro-inflammatory gene sets, such as genes related to cytokine secretion, within the CD8 T-cell compartment of astrocytomas. We also observed upregulation of the expression of inflammatory gene sets within the dendritic cells of astrocytomas. Taken together, these changes suggest that the immune compartment of astrocytoma is more active and inflamed, and targeting the immune system in these tumors may represent a potential therapeutic avenue.

Analyzing immune cell infiltrates in skeletal muscle of infantile-onset Pompe disease using bioinformatics and machine learning

Pompe disease, a severe lysosomal storage disorder, is marked by heart problems, muscle weakness, and respiratory difficulties. This study aimed to identify novel markers for infantile-onset Pompe disease by analyzing key genes and immune cells infiltrating affected skeletal muscles, building on existing research linking its progression to the immune cell infiltration. The datasets GSE38680 and GSE159062 were downloaded and differential expression genes (DEGs) were identified. Potential markers were screened using support vector machine recursive feature elimination (SVM-RFE) analysis and least absolute shrinkage and selection operator (LASSO) regression models. To analyze DEGs and immune processes, 22 immune cell types in affected tissues were examined using CIBERSORT. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed significant enrichment in the calcium signaling pathway, phosphatidylinositol signaling system, ubiquitin-mediated proteolysis and JAK-STAT signaling pathway. Machine learning identified GPNMB, CALML6 and TRIM7 as key genes. Immune cell infiltration analysis showed that the expression levels of the above three genes were closely related to immune cells in our target population under study, including T cells regulatory (Tregs), monocytes, macrophages M0, resting and activated dendritic cells, naive and memory B cells. Overall, our study results may provide new clues for exploring markers related to Pompe disease by highlighting key genes and their relationship with immune infiltration, offering insights into the disease’s development. However, previous studies have shown limited evidence of significant immune cell infiltration in muscle biopsies from Pompe patients, and this lack of direct evidence necessitates further investigation and experimental validation in laboratory settings to confirm these associations.

CTIM-13. D2C7-IT IN COMBINATION WITH AN FC-ENGINEERED ANTI-HUMANCD40 MONOCLONAL ANTIBODY (2141-V11) ADMINISTERED INTRATUMORALLY VIA CONVECTION-ENHANCED DELIVERY (CED) FOLLOWED BY CERVICAL PERILYMPHATIC INJECTIONS (CPLIS) OF 2141-V11 IN PATIENTS WITH RECURRENT GLIOBLASTOMA (RGBM)

Abstract BACKGROUND The combination of D2C7-IT, an antibody toxin conjugate, and anti-mouseCD40 via CED generates robust antitumor immunity by killing tumor cells, activating microglia, reversing glioma-associated microglia and macrophage (GAMM)-mediated immune suppression, and empowering polyfunctional tumor antigen-specific CD8 T cells in glioma models. In addition to reprogramming GAMMs, anti-CD40 also activated dendritic cells and induced glioma-specific T cell responses in tumor draining lymph nodes. After establishing the phase 2 dose of the combination of D2C7-IT+2141-V11 when infused via CED, we initiated an assessment of the safety and efficacy of the combination of D2C7-IT+2141-V11 CED followed by repeated subcutaneous CPLIs of 2141-V11 ipsilateral to the tumor in patients with rGBM, IDH wild-type (NCT04547777). METHODS Eligible are adult patients with solitary supratentorial rGBM; ≥4weeks after chemotherapy, bevacizumab, or investigational agent; adequate organ function; and KPS ≥70%. Patients are treated with D2C7-IT (166μg) and 2141-V11 (3mg), both infused via CED, followed by CPLI of 2141-V11 at 2mg at weeks 2 and 4 post D2C7-IT+2141-V11 CED, followed by every 3 weeks for 1 year and then every 4-6 weeks. RESULTS As of May 22, 2024, 18 patients with rGBM (median age of 54) were treated with D2C7-IT+2141-V11 CED followed by CPLIs of 2141-V11. 83% patients remain alive (range 3.3-14.8 months from start of D2C7-IT CED infusion) with a median of 8 CPLIs of 2141-V11 received (range 3-19). No study related grade 4 or 5 adverse events (AEs) were observed. Grade 3 AEs related to D2C7-IT and/or 2141-V11 include one each of hydrocephalus, headache, seizure, and cerebral edema. AEs related exclusively to CPLIs of 2141-V11 consist of grade 1 injection site reaction (n=16). CONCLUSIONS The addition of CPLIs of 2141-V11 post CED of D2C7-IT+2141-V11 is feasible and has shown an acceptable toxicity profile. The safety and efficacy results will be updated.

Discovery of the First-in-Class Dual-Target ROCK/HDAC Inhibitor with Potent Antitumor Efficacy in Vivo That Trigger Antitumor Immunity.

Triple-negative breast cancer (TNBC) represents a highly aggressive and heterogeneous malignancy. Currently, multitarget drug approaches present a promising therapeutic approach for TNBC. Utilizing a combinatorial chemistry strategy to construct a virtual screening database, dual ROCK/HDAC-targeting benzothiophene compounds were identified. Notably, compound 10h effectively inhibits ROCK1/2 and HDAC1/2/3/6/8 while demonstrating potent antiproliferative activity against breast cancer cells. In an orthotopic mouse model of breast cancer, 10h significantly suppressed tumor growth without apparent toxicity. Importantly, 10h induced immunogenic cell death (ICD), promoted dendritic cells (DCs) maturation, and activated T cells, thereby initiating antitumor immunity. In conclusion, compound 10h is a novel dual-target ROCK/HDAC inhibitor that represents a promising treatment strategy for TNBC.

4E-BP3 deficiency impairs dendritic cell activation and CD4+ T cell differentiation and attenuates α-myosin-specific T cell-mediated myocarditis in mice.

Immune checkpoint inhibitor (ICI)-associated myocarditis is a rare but potentially fatal immune-related adverse event. Previously, we reported a case of ICI-associated myocarditis with elevated autoantibodies to 4E-binding protein 3 (4E-BP3). Recent studies have suggested that 4E-BP3 may play an important role in tumor development. However, its role in cardiac diseases including myocarditis is unknown. We investigated the role of 4E-BP3 in an autoimmune myocarditis mouse model. Myocarditis was induced in wild-type and 4E-BP3 knockout mice by immunization with murine α-myosin peptide. 4E-BP3 gene expression was upregulated in the heart of myocarditis mouse. We found that genetic deletion of 4E-BP3 attenuated myocardial inflammation, reduced fibrosis area, and improved cardiac function in myocarditis mice. Studies in bone marrow-chimeric mice demonstrated that immune cell-derived 4E-BP3 plays a pivotal role in the pathogenesis of myocarditis. Immune cell transfer experiments revealed that 4E-BP3 deficiency in dendritic cells and CD4+ T cells decreased disease severity in recipient mice. Furthermore, dendritic cells that were deficient in 4E-BP3 exhibited a diminished capacity to produce IL-6 and IL-1β. Naive CD4+ T cells lacking 4E-BP3 had a reduced ability to differentiate into T-helper (Th)1 and Th17 cells. These findings suggest that 4E-BP3 in dendritic cells and CD4+ T cells may be critically involved in the pathogenesis of α-myosin-specific T cell-mediated myocarditis. Thus, 4E-BP3 could be a possible therapeutic target for myocarditis.

Characterization of HTLV-1 Infectious Molecular Clone Isolated from Patient with HAM/TSP and Immortalization of Human Primary T-Cell Lines

Human T-cell leukemia virus (HTLV-1) is the etiological agent of lymphoproliferative diseases such as adult T-cell leukemia and T-cell lymphoma (ATL) and a neurodegenerative disease known as HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). While several molecular clones of HTLV-1 have been published, all were isolated from samples derived from patients with adult T-cell leukemia. Here, we report the characterization of an HTLV-1 infectious molecular clone isolated from a sample of a patient with HAM/TSP disease. Genetic comparative analyses of the HAM/TSP molecular clone (pBST) revealed unique genetic alterations and specific viral mRNA expression patterns. Interestingly, our clone also harbors characteristics previously published to favor the development of HAM/TSP disease. The molecular clone is capable of infection and immortalization of human primary T cells in vitro. Our studies further demonstrate that the HTLV-1 virus produced from primary T cells transfected with pBST or ACH molecular clones cannot sustain long-term expansion, and cells cease to proliferate after 3–4 months in culture. In contrast, long-term proliferation and immortalization were achieved if the virus was transmitted from dendritic cells to primary T cells, and secondary infection of 729B cells in vitro was demonstrated. In both primary T cells and 729B cells, pBST and ACH were latent, and only hbz viral RNA was detected. This study suggests that HTLV-1 transmission from DC to T cells favors the immortalization of latently infected cells.

Synthesis of SulfoCy5‐ and SulfoCy7‐αGalCer Probes as Chemical Tools for Investigating the Uptake of Liposomal αGalCer Conjugates by Antigen Presenting Cells

Abstractα‐Galactosylceramide (αGalCer) is a synthetic glycolipid that, when loaded into the CD1d receptor of antigen presenting cells, activates iNKT cells to coordinate the generation of both innate and adaptive immune responses. In vaccines, the αGalCer adjuvant is generally delivered in liposomes, but interestingly, little is known about the intracellular fate of αGalCer‐antigen conjugates resulting in the absence of clear “design rules” for this type of compounds and their formulations. To unravel the uptake mechanism of liposomal αGalCer conjugates and understand the fate of its components, we synthesized sulfoCy7‐αGalCer 1 and sulfoCy5‐αGalCer 2. The fluorescent probes were obtained from a linker‐functionalized αGalCer, which was then modified with sulfoCy7/sulfoCy5. After formulation in liposomes, the cellular presentation was studied in a murine dendritic cell line using fluorescence imaging and flow cytometry. Imaging indicates that liposomes loaded with sulfoCy5‐αGalCer are taken up by DC2.4 cells in a heterogeneous and concentration‐dependent manner. Additionally, fluorescence antibody staining confirms that αGalCer is ultimately presented by CD1d receptors, but importantly is cleaved from sulfoCy5 before reaching the cell surface. These results validate our synthetic probes as useful in mechanistic studies of the uptake of αGalCer‐antigen conjugates as shown here for DC2.4 cells.

Biomimetic Dual‐Driven Heterojunction Nanomotors for Targeted Catalytic Immunotherapy of Glioblastoma

AbstractThe existence of the blood–brain barrier (BBB) and the characteristics of the immunosuppressive microenvironment in glioblastoma (GBM) present significant challenges for targeted GBM therapy. To address this, a biomimetic hybrid cell membrane‐modified dual‐driven heterojunction nanomotor (HM@MnO2‐AuNR‐SiO2) is proposed for targeted GBM treatment. These nanomotors are designed to bypass the BBB and target glioma regions by mimicking the surface characteristics of GBM and macrophage membranes. More importantly, the MnO2‐AuNR‐SiO2 heterojunction structure enables dual‐driven propulsion through near‐infrared‐II (NIR‐II) light and oxygen bubbles, allowing effective treatment at deep tumor sites. Meanwhile, the plasmonic AuNR‐MnO2 heterostructure facilitates the separation of electron–hole pairs and generates reactive oxygen species (ROS), inducing immunogenic tumor cell death under NIR‐II laser irradiation. Furthermore, MnO2 in the tumor microenvironment reacts to release Mn2+ ions, activating the cGAS‐STING pathway and enhancing antitumor immunity. In vitro and in vivo experiments demonstrate that these dual‐driven biomimetic nanomotors achieve active targeting and deep tumor infiltration, promoting M1 macrophage polarization, dendritic cell maturation, and effector T‐cell activation, thereby enhancing GBM catalysis and immunotherapy through ROS production and STING pathway activation.

Combination CXCR4 and PD1 blockade enhances intratumoral dendritic cell activation and immune responses against hepatocellular carcinoma.

Immune checkpoint inhibitors (ICIs) have revolutionized the treatment of unresectable hepatocellular carcinoma (HCC), but their impressive efficacy is seen in just a fraction of patients. One key mechanism of immunotherapy resistance is the paucity of dendritic cells (DCs) in liver malignancies. Here, we tested combination blockade of programmed death receptor 1 (PD1) and CXCR4, a receptor for CXCL12, a pleiotropic factor that mediates immunosuppression in tumors. Using orthotopic grafted and autochthonous HCC models with underlying liver damage, we evaluated treatment feasibility and efficacy. In addition, we examined the effects of treatment using immunofluorescence, flow cytometric analysis of DCs in vivo and in vitro, and RNA-sequencing. Combination anti-CXCR4 and anti-PD1therapy was safe and significantly inhibited tumor growth and prolonged survival in all murine preclinical models of HCC tested. The combination treatment successfully reprogrammed antigen-presenting cells, revealing the potential role of conventional type 1 DCs (cDC1s) in the HCC microenvironment. Moreover, DC reprogramming enhanced anticancer immunity by facilitating CD8+ T-cell accumulation and activation in the HCC tissue. The effectiveness of anti-CXCR4/PD1 therapy was compromised entirely in Batf3-KO mice deficient in cDC1s. Thus, combined CXCR4/PD1 blockade can reprogram intra-tumoral cDC1s and holds the potential to potentiate antitumor immune response against HCC.

Causal relationship between immune cells and hypopituitarism: bidirectional Mendelian randomization study

Hypopituitarism, one or more pituitary hormones inefficiently produced by the anterior pituitary or released from the posterior pituitary to adapt to the needs of the organism. Existing epidemiological data show that immune-mediated diffuse infiltration of the anterior pituitary is important in the development of hypopituitarism. However, the precise connection between immune cells and hypopituitarism remains unclear. This study aimed to elucidate the potential causal links between the 731 immune cell types and hypopituitarism risk. Based on data from a genome-wide association study (GWAS), a bidirectional two-sample Mendelian Randomization (MR) analysis was performed using five methods to explore the potential influence of immune cell phenotypes on hypopituitarism. Sensitivity analyses were conducted to examine the robustness of these findings. Our findings support that B cells, T cells, Tregs, dendritic cells, monocytes, and myeloid cells each have a bidirectional influence on hypopituitarism. One B-cell phenotype was associated with increased hypopituitarism risk, while two B-cell phenotypes play a protective role in hypopituitarism. Moreover, seven T-cell phenotypes demonstrate significant protective properties on hypopituitarism. Seven Tregs were associated with increased hypopituitarism risk. Furthermore, one monocyte was identified to be significantly associated with hypopituitarism risk. In addition, reverse MR analysis revealed that hypopituitarism was positively associated with 30 additional immune cell phenotypes and negatively associated with 17 immune cells. Our investigation shed light on the intricate potential relationship between immune cells and hypopituitarism via genetic methods, underscoring the immune-mediated pathway in hypopituitarism pathogenesis, thereby offering valuable insights for future clinical investigations.

Exogenous or in situ vaccination to trigger clinical responses in pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDA) is a lethal disease for which remarkable therapeutic resistance is the norm. Conventional immunotherapies, like immune checkpoint inhibitors, show limited efficacy in PDA due to a remarkably immunosuppressive tumor microenvironment (TME) and systemic inflammation. This review discusses the potential of both exogenous and in situ vaccination strategies to overcome these barriers and enhance anti-tumor immunity in PDA. Exogenous vaccines, including whole-cell, dendritic cell, peptide, and nucleic acid-based vaccines, have shown varying degrees of promise but face challenges related to antigen selection, production complexities, and patient-specific factors. In contrast, in situ vaccination strategies leverage conventional cytotoxic therapies, such as chemotherapy and radiation therapy, to induce immunogenic cell death and modulate the TME with the aim to stimulate anti-tumor immunity. While preclinical studies support the use of in situ vaccination, balancing the stimulatory and inhibitory effects is likely fundamental to eliciting productive anti-tumor responses in patients. Ongoing research seeks to identify new innovative strategies that can harness the endogenous immune response and trigger in situ vaccination. Overall, while both vaccination approaches offer significant potential, further research and clinical trials will be needed to optimize these strategies for improving patient outcomes in PDA.

Randomized Phase II Study of Durvalumab with or without Tremelimumab in Patients with Metastatic Castration Resistant Prostate Cancer.

Programmed death-ligand 1 (PD-L1) is overexpressed by dendritic cells in patients with metastatic castration-resistant prostate cancer (mCRPC) progressing on androgen receptor pathway inhibitors. We tested whether checkpoint blockade could enhance antitumor activity in mCRPC. In a multicenter open-label non-comparative randomized phase II study, patients with mCRPC treated with £ 1 prior cytotoxic chemotherapy, with measurable disease and progression on abiraterone and/or enzalutamide were randomized to durvalumab (D) 1500mg IV Q4 weeks ± 4 doses of tremelimumab (T) 75mg IV. The primary endpoint was objective response (OR) by iRECIST using a Simon 2-stage design. Correlative testing included PD-L1/CD8 immunohistochemistry on baseline tumour biopsies and deep targeted sequencing of plasma cell-free DNA. 52 patients were enrolled. Median age was 70 years (range, 50-83 years) and 52% had prior taxane therapy for mCRPC. In stage 1, 13 patients were randomized to D with no OR observed. D+T advanced to stage 2 with 39 patients enrolled (receiving a median 3 cycles, range 1-53). D+T related adverse events (AEs) were mainly £ grade 2 but led to discontinuation in 7 patients . There were seven OR (19.4% [95% confidence interval: 8.2-36.0%]; intention to treat (ITT) 17.9% [95% confidence interval: 7.5-33.5%]). Five responding tumours were PD-L1 positive and two exhibited DNA damage repair defects. Responses were observed without high tumour mutational burden or other genomic indices of immunotherapy sensitivity. D+T is active in mCRPC but patient selection remains a challenge. Further studies to develop predictive biomarkers are warranted.

Recent advances in immunometabolism in rheumatic diseases.

Aberrant autoreactive innate and adaptive immune responses cause systemic autoimmune diseases. Autoimmunity has been linked to abnormal metabolic states, and immunometabolism has emerged as a critical field in understanding the pathogenesis of rheumatic diseases. We aimed to explore the latest research on metabolic reprogramming in various immune cell types, including T cells, B cells, neutrophils, dendritic cells, monocytes, and macrophages, in the context of rheumatic diseases. Each immune cell utilizes preferred metabolic pathways, and the cell activation dramatically modifies metabolic status. The inhibition of these pathways alters cell survival, differentiation, proliferation, and cytokine production - all of which contribute to rheumatic disease progression. Targeting metabolic pathways or introducing anti-inflammatory metabolites, such as itaconate, could be novel therapeutic strategies for rheumatic diseases. Further research should focus on strategies for translating basic research findings to bedside applications.

Low‒Dose Cyclophosphamide Enhances the Tumoricidal Effects of 5-Day Spacing Stereotactic Ablative Radiotherapy by Boosting Antitumor Immunity.

To investigate the potential role of low‒dose cyclophosphamide (Cy) as a radiosensitizer by evaluating its impact on the immune response and the abscopal effect of stereotactic ablative radiotherapy (SABR) through preclinical models. CT26 tumors (immunologically hot) and 4T1 tumors (immunologically cold), grown in immunocompetent BALB/c and immunodeficient BALB/c‒nude mice, were irradiated with 20 Gy in two fractions with 5‒day spacing followed by intraperitoneal injections of 9 mg/kg Cy every 3 days. Immunological changes in CT26 tumors caused by the treatments were assessed using flow cytometry. Changes in the expression of HIF‒1α in tumors were also assessed. Splenocytes and bone marrow‒derived dendritic cells (DCs) were exposed to various concentrations of Cy to assess T cell proliferation and DC differentiation. The combination of Cy with RT (RT+Cy) significantly suppressed tumor growth compared to RT alone in immunocompetent mice, while that effect was not observed in immunodeficient mice. Additionally, RT+Cy effectively induced abscopal effects in hot and cold tumors, with increased CD8+ T cells in blood and tumors. Significantly higher expression levels of Granzyme B, IFN‒γ, and TNF‒α were observed in RT+Cy group compared to the RT alone group. In vitro data indicated that low‒dose Cy promotes DC differentiation. Low‒dose Cy suppressed the radiation‒induced upregulation of HIF‒1α in the tumors. Low‒dose Cy enhances tumoricidal effects of 5‒day spacing high‒dose RT by increasing anti-tumor immune responses.

Potent Amphiphilic Poly(Amino Acid) Nanoadjuvant Delivers Biomineralized Ovalbumin for Photothermal-Augmented Immunotherapy.

Cancer nanovaccines have emerged as an indispensable weapon for tumor treatment. However, insufficient immunogenicity and immunosuppression hamper the therapeutic effects of nanovaccines. Here, biodegradable nanovaccines (OMPP) composed of ovalbumin (OVA)-manganese oxide nanoparticles, amphiphilic poly(γ-glutamic acid) (γ-PGA), and ε-polylysine (PL) are constructed to realize enhanced cancer immunotherapy. Interestingly, amphiphilic γ-PGA and PL could serve as both carriers and immunoadjuvants to promote the cytosolic delivery of antigens and enhance the maturation of dendritic cells. Additionally, taking advantage of the photothermal property of OMPP, immunogenic cell death and in situ release of tumor-associated antigens can be triggered under near-infrared light irradiation for personalized tumor treatment. Moreover, OMPP nanovaccines can efficiently alleviate tumor hypoxia and downregulate programmed death-ligand 1 expression to reprogram the immunosuppressive tumor microenvironment. OMPP-mediated therapy has been shown to provoke robust immune responses to suppress B16-OVA melanoma and prevent postsurgical tumor recurrence. This work presents a facile strategy for the fabrication of nanovaccines by integrating carrier and adjuvant while exploring the inherent properties to promote antigen release and modulate immunosuppression, which demonstrates great potential for effective cancer immunotherapy.

Cell damage shifts the microRNA content of small extracellular vesicles into a Toll-like receptor 7-activating cargo capable to propagate inflammation and immunity

BackgroundThe physiological relevance of cell-to-cell communication mediated by small extracellular vesicle-encapsulated microRNAs (sEV-miRNAs) remains debated because of the limiting representativity of specific miRNAs within the extracellular pool. We hypothesize that sEV-miRNA non-canonical function consisting of the stimulation of Toll-like receptor 7 (TLR7) may rely on a global shift of the sEV cargo rather than on the induction of one or few specific miRNAs. Psoriasis represents an ideal model to test such hypothesis as it is driven by overt activation of TLR7-expressing plasmacytoid dendritic cells (pDCs) following keratinocyte damage.MethodsTo mimic the onset of psoriasis, keratinocytes were treated with a cocktail of psoriatic cytokines or UV-irradiated. SmallRNA sequencing was performed on sEVs released by healthy and UV-treated keratinocytes. sEV-miRNAs were analyzed for nucleotide composition as well as for the presence of putative TLR7-binding triplets. Primary human pDCs where stimulated with sEVs +/- inhibitors of TLR7 (Enpatoran), of sEV release (GW4869 + manumycin) and of TLR7-mediated pDC activation (anti-BDCA-2 antibody). Secretion of type I IFNs and activation of CD8+T cells were used as readouts. qPCR on psoriatic and healthy skin biopsies was conducted to identify induced miRNAs.ResultssEV-miRNAs released by damaged keratinocytes revealed a significantly higher content of TLR7-activating sequences than healthy cells. As expected, differential expression analysis confirmed the presence of miRNAs upregulated in psoriatic skin, including miR203a. More importantly, 76.5% of induced miRNAs possessed TLR7-binding features and among these we could detect several previously demonstrated TLR7 ligands. In accordance with this in silico analysis, sEVs from damaged keratinocytes recapitulated key events of psoriatic pathogenesis by triggering pDCs to release type I interferon and activate cytotoxic CD8+T cells in a TLR7- and sEV-dependent manner.DiscussionOur results demonstrate that miR203a is just one paradigmatic TLR7-activating miRNA among the hundreds released by UV-irradiated keratinocytes, which altogether trigger pDC activation in psoriatic conditions. This represents the first evidence that cell damage shifts the miRNA content of sEVs towards a TLR7-activating cargo capable to propagate inflammation and immunity, offering strong support to the physiological role of systemic miRNA-based cell-to-cell communication.

An in vitro investigation into the cytotoxic impact of antigen-presenting dendritic cell-tumor infiltrating lymphocytes on ovarian cancer cells

ObjectiveThe objective of this study is to develop a novel therapeutic approach for the treatment of ovarian cancer while investigating the role of tumor-infiltrating lymphocytes (TILs) in the context of ovarian cancer therapy. The primary aim is to establish a technical procedure for the isolation of tumor cells, lymphocytes, and dendritic cells (DCs) derived from ovarian cancer tissues or ascites. Subsequently, the focus lies on the generation of dendritic cell-tumor infiltrating lymphocytes (DC-TILs) exhibiting specific cytotoxic capabilities aimed at targeted therapeutic interventions. The cytotoxic impact of DC-TIL interactions on tumor cells was investigated through in vitro experimentation. This research aims to provide fundamental experimental insights for the future clinical advancement of TIL therapy in ovarian cancer.MethodsThe experimental samples included fresh surgical specimens and ascites specimens procured from three patients (ranging in age from 32 to 75), sourced from the Department of Gynecology at the Third Bethune Hospital of Jilin University. TILs were extracted through in vitro isolation from solid tumor tissues, while primary tumor cells and DCs were obtained from ascites specimens. Tumor-specific antigens derived from patient tumor cells were utilized to stimulate the maturation of DCs. TILs were subsequently co-cultured with antigen-stimulated DC cells. Subsequently, TILs with specific killing effects were obtained, and the cytotoxic impact of DC-TILs on tumor cells was detected in vitro.Results(1) TILs were successfully obtained through expansion from the tumor tissue of a patient diagnosed with ovarian cancer. (2) DCs were successfully induced from ascites cells harvested from patients diagnosed with ovarian cancer. (3) TILs significantly enhanced the cytotoxicity of tumor cells following DC stimulation.ConclusionTILs have the capacity to augment the cytotoxicity directed towards tumor cells following DC stimulation.

A single-cell transcriptomic map of the murine and human multiple myeloma immune microenvironment across disease stages

BackgroundThe long-term effectiveness of immunotherapies against Multiple Myeloma (MM) remains elusive, demonstrated by the inevitable relapse in patients. This underscores the urgent need for an in-depth analysis of the MM tumor-immune microenvironment (TME). Hereto, a representative immunocompetent MM mouse model can offer a valuable approach to study the dynamic changes within the MM-TME and to uncover potential resistance mechanisms hampering effective and durable therapeutic strategies in MM.MethodsWe generated a comprehensive single-cell RNA-sequencing atlas of the MM-TME in bone marrow and spleen encompassing different stages of disease, using the immunocompetent 5T33MM mouse model. Through comparative analysis, we correlated our murine dataset with the pathogenesis in MM patients by reanalyzing publicly available datasets of human bone marrow samples across various disease stages. Using flow cytometry, we validated the dynamic changes upon disease progression in the 5T33MM model. Furthermore, interesting target populations, as well as the immune-boosting anti-CD40 agonist (αCD40) therapy were tested ex vivo on murine and human primary samples and in vivo using the 5T33MM model.ResultsIn this study, we identified the heterogenous and dynamic changes within the TME of murine and human MM. We found that the MM-TME was characterized by an increase in T cells, accompanied with an exhausted phenotype. Although neutrophils appeared to be rather innocuous at early disease stages, they acquired a pro-tumorigenic phenotype during MM progression. Moreover, conventional dendritic cells (cDCs) showed a less activated phenotype in MM, underscoring the potential of immune-boosting therapies such as αCD40 therapy. Importantly, we provided the first pre-clinical evaluation of αCD40 therapy and demonstrated successful induction of cDC- and T-cell activation, accompanied by a significant short-term anti-tumor response.ConclusionsThis resource provides a comprehensive and detailed immune atlas of the evolution in human and murine MM disease progression. Our findings can contribute to immune-based patient stratification and facilitate the development of novel and durable (immune) therapeutic strategies in MM.