Immune checkpoint reprogramming via sequential nucleic acid delivery strategy optimizes systemic immune responses for gastrointestinal cancer immunotherapy.

Monoclonal antibodies targeting immune checkpoints have been widely applied in gastrointestinal cancer immunotherapy. However, systemic administration of various monoclonal antibodies does not often result in sustained effects in reversing the immunosuppressive tumor microenvironment (TME), which may be due to the spatiotemporal dynamic changes of immune checkpoints. Herein, we reported a novel immune checkpoint reprogramming strategy for gastrointestinal cancer immunotherapy. It was achieved by the sequential delivery of siPD-L1 (siRNA for programmed cell death ligand 1) and pOX40L (plasmid for OX40 ligand), which were complexed with two cationic polymer brush-grafted carbon nanotubes (dense short (DS) and dense long (DL)) designed based on the structural characteristics of nucleic acids and brush architectures. Upon administrating DL/pOX40L for the first three dosages, then followed by DS/siPD-L1 for the next three dosages to the TME, it upregulated the stimulatory checkpoint OX40L on dendritic cells (DCs) and downregulated inhibitory checkpoint PD-L1 on tumor cells and DCs in a sequential reprogramming manner. Compared with other combination treatments, this sequential strategy drastically boosted the DCs maturation, and CD8+ cytotoxic T lymphocytes infiltration in tumor site. Furthermore, it could augment the local antitumor response and improve the T cell infiltration in tumor-draining lymph nodes to reverse the peripheral immunosuppression. Our study demonstrated that sequential nucleic acid delivery strategy via personalized nanoplatforms effectively reversed the immunosuppression status in both tumor microenvironment and peripheral immune landscape, which significantly enhanced the systemic antitumor immune responses and established an optimal immunotherapy strategy against gastrointestinal cancer.

Uncovering the Expression Pattern of the Costimulatory Receptors ICOS, 4-1BB, and OX-40 in Exhausted Peripheral and Tumor-Infiltrating Natural Killer Cells from Patients with Cervical Cancer.

Cervical cancer (CC) poses a significant health burden, particularly in low- and middle-income countries. NK cells play a crucial role against CC; however, they can become exhausted and lose their cytotoxic capacity. This work explores the expression of costimulatory receptors (ICOS, 4-1BB, OX-40) in exhausted NK cells from CC patients. Peripheral blood and tumor biopsies were collected, and flow cytometry was used to evaluate the expression of costimulatory receptors in exhausted NK cells. There is an increase of peripheral exhausted NK cells (PD-1+TIGIT+) in CC patients; this subpopulation has a selectively increased expression of the costimulatory receptors ICOS and 4-1BB. An exhausted population is also highly increased in tumor-infiltrating NK cells, and it shows a dramatically increased expression of the costimulatory receptors ICOS (>15×) and 4-1BB (>10×) compared to peripheral NK cells. The exhausted cells, both in the periphery and in the tumor infiltrating lymphocytes (TILs), are also more likely than non-exhausted NK cell populations (PD-1-TIGIT-) to express these costimulatory receptors; increases ranging from 2.0× ICOS, 2.4× 4-1BB, and 2.6× OX-40 in CD56dim PBMCs to 1.5× ICOS, 5× 4-1BB, and 10× OX-40 in TILs were found. Our study demonstrates for the first time the increased expression of the costimulatory receptors ICOS, 4-1BB, and OX-40 in peripheral CD56dim, CD56bright, and tumor-infiltrating NK cells in CC. Targeting these receptors for stimulation could reverse exhaustion and be a promising immunotherapy strategy.

NK Cell Degranulation Triggered by Rituximab Identifies Potential Markers of Subpopulations with Enhanced Cytotoxicity toward Malignant B Cells.

A promising strategy in cancer immunotherapy is to restore or enhance the cytotoxicity of NK cells, among others, by activating the mechanism of antibody-dependent cellular cytotoxicity (ADCC). Monoclonal antibodies targeting tumor antigens, such as rituximab (targeting CD20), induce NK cell-mediated ADCC and have been used to treat B cell malignancies, such as non-Hodgkin lymphoma, but not always successfully. The aim of this study was to analyze the gene expression profile of the NK cells involved in the cytolytic response stimulated by rituximab. NK cells were co-cultured with rituximab-opsonized Raji cells. Sorting into responder and non-responder groups was based on the presence of CD107a, which is a degranulation marker. RNA-seq results showed that the KIT and TNFSF4 genes were strongly down-regulated in the degranulating population of NK cells (responders); this was further confirmed by qRT-PCR. Both genes encode surface proteins with cellular signaling abilities, namely c-KIT and the OX40 ligand. Consistent with our findings, c-KIT was previously reported to correlate inversely with cytokine production by activated NK cells. The significance of these findings for cancer immunotherapy seems essential, as the pharmacological inhibition of c-KIT and OX40L, or gene ablation, could be further tested for the enhancement of the anti-tumor activity of NK cells in response to rituximab.

Association between OX40L polymorphism and type 2 diabetes mellitus in Iranians.

INTRODUCTION: Diabetes mellitus (DM) is one of the leading causes of morbidity and mortality worldwide. It is a multifactorial disease that genetic and environmental factors contribute to its development. The aim of the study was to investigate the association of OX40L promoter gene polymorphisms with type 2 diabetes mellitus (T2DM) in Iranians. MATERIALS AND METHODS: Three hundred and sixty-eight subjects including 184 healthy subjects and 184 T2DM patients were enrolled in our study. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was applied to detect genotype and allele frequencies of rs3850641, rs1234313 and rs10912580. In addition, SNPStats web tool was applied to estimate haplotype frequency and linkage disequilibrium (LD). RESULTS: The distribution of tested polymorphisms was statistically different between the T2DM patients and healthy subjects (P < 0.01). rs1234313 AG (OR = 0.375, 95% CI = 0.193-0.727, P = 0.004) and rs10912580 AG (OR = 0.351, 95% CI = 0.162-0.758, P = 0.008) genotypes were associated with the decreased risk of T2DM in Iranians. Moreover, our prediction revealed that AAG (OR = 0.46, 95% CI= (0.28-0.76), P = 0.0028) and GAG (OR = 0.24, 95% CI= (0.13-0.45), P < 0.0001) haplotypes were related to the reduced risk of the disease. However, the tested polymorphisms had no effect on biochemical parameters and body mass index (BMI) in the patient group (P > 0.05). CONCLUSION: Our findings revealed that OX40L promoter gene polymorphisms are associated with T2DM. Moreover, genotype and allelic variations were related to the decreased risk of T2DM in Iranians. Further studies are recommended to show whether these polymorphic variations could affect OX40/OX40L interaction or OX40L phenotype.

Non-viral-mediated gene transfer of OX40 ligand for tumor immunotherapy.

Background: Immune checkpoint blockade (ICB) is rapidly becoming a standard of care in the treatment of many cancer types. However, the subset of patients who respond to this type of therapy is limited. Another way to promote antitumoral immunity is the use of immunostimulatory molecules, such as cytokines or T cell co-stimulators. The systemic administration of immunotherapeutics leads to significant immune-related adverse events (irAEs), therefore, the localized antitumoral action is needed. One way to achieve this is intratumoral non-viral gene-immune therapy, which allows for prolonged and localized gene expression, and multiple drug administration. In this study, we combined the previously described non-viral gene delivery system, PEG-PEI-TAT copolymer, PPT, with murine OX40L-encoding plasmid DNA. Methods: The resulting OX40L/PPT nanoparticles were characterized via gel mobility assay, dynamic light scattering analysis and in vitro transfection efficiency evaluation. The antitumoral efficacy of intratumorally (i.t.) administered nanoparticles was estimated using subcutaneously (s.c.) implanted CT26 (colon cancer), B16F0 (melanoma) and 4T1 (breast cancer) tumor models. The dynamics of stromal immune cell populations was analyzed using flow cytometry. Weight loss and cachexia were used as irAE indicators. The effect of combination of i.t. OX40L/PPT with intraperitoneal PD-1 ICB was estimated in s.c. CT26 tumor model. Results: The obtained OX40L/PPT nanoparticles had properties applicable for cell transfection and provided OX40L protein expression in vitro in all three investigated cancer models. We observed that OX40L/PPT treatment successfully inhibited tumor growth in B16F0 and CT26 tumor models and showed a tendency to inhibit 4T1 tumor growth. In B16F0 tumor model, OX40L/PPT treatment led to the increase in antitumoral effector NK and T killer cells and to the decrease in pro-tumoral myeloid cells populations within tumor stroma. No irAE signs were observed in all 3 tumor models, which indicates good treatment tolerability in mice. Combining OX40L/PPT with PD-1 ICB significantly improved treatment efficacy in the CT26 subcutaneous colon cancer model, providing protective immunity against CT26 colon cancer cells. Conclusion: Overall, the anti-tumor efficacy observed with OX40L non-viral gene therapy, whether administered alone or in combination with ICB, highlights its potential to revolutionize cancer gene therapy, thus paving the way for unprecedented advancements in the cancer therapy field.

The role of OX40 ligand/OX40 axis signalling in atopic dermatitis.

Atopic dermatitis (AD) is a heterogeneous inflammatory condition involving multiple immune pathways mediated by pathogenic T cells. OX40 ligand (OX40L) and OX40 are costimulatory immune checkpoint molecules that regulate effector and memory T-cell activity and promote sustained immune responses in multiple immunological pathways, including T helper (Th)2, Th1, Th17 and Th22. As such, OX40L/OX40 signalling between antigen-presenting cells (APCs) and activated T cells postantigen recognition promotes pathogenic T-cell proliferation and survival. Under inflammatory conditions, OX40L is upregulated on APCs, enhancing the magnitude of antigen-specific T-cell responses and secretion of proinflammatory cytokines. In AD, OX40L/OX40 signalling contributes to the amplification and chronic persistence of T-cell-mediated inflammation. Recent therapeutic success in clinical trials has highlighted the importance of the OX40L/OX40 axis as a promising target for the treatment of AD. Here, we discuss the many factors that are involved in the expression of OX40L and OX40, including the cytokine milieu, antigen presentation, the inflammatory environment in AD, and the therapeutic direction influenced by this costimulatory pathway.

Atopic dermatitis (AD) (also known as atopic eczema) is a common skin disease caused by inflammation, and affects 2­3 of every 10 people worldwide. AD affects people of all ages and can cause a range of symptoms, including dry thickened skin, itchiness, rashes and pain. Despite the recent addition of new targeted treatment options, there is still a need for new treatments for people with moderate-to-severe AD. New drugs are being studied that target two important signalling molecules in the immune system, called OX40 ligand (OX40L) and OX40. OX40L and OX40 bind together to continue the cycle of immune system activation, leading to increasing symptoms of AD. Blocking the OX40L and OX40 interaction may ease or stop symptoms of AD. This review outlines what is currently known about the causes of AD, including the role played by the immune system and specifically the role of OX40L and OX40. We also highlight the development of new treatments that target the OX40L and OX40 interaction to treat AD, and suggest what the future may hold for managing AD.

High-mannose glycans from Schistosoma mansoni eggs are important for priming of Th2 responses via Dectin-2 and prostaglandin E2.

The parasitic helminth Schistosoma mansoni is a potent inducer of type 2 immune responses by stimulating dendritic cells (DCs) to prime T helper 2 (Th2) responses. We previously found that S. mansoni soluble egg antigens (SEA) promote the synthesis of Prostaglandin E2 (PGE2) by DCs through ERK-dependent signaling via Dectin-1 and Dectin-2 that subsequently induces OX40L expression, licensing them for Th2 priming, yet the ligands present in SEA involved in driving this response and whether specific targeting of PGE2 synthesis by DCs could affect Th2 polarization are unknown. We here show that the ability of SEA to bind Dectin-2 and drive ERK phosphorylation, PGE2 synthesis, OX40L expression, and Th2 polarization is impaired upon cleavage of high-mannose glycans by Endoglycosidase H treatment. This identifies high-mannose glycans present on glycoproteins in SEA as important drivers of this signaling axis. Moreover, we find that OX40L expression and Th2 induction are abrogated when microsomal prostaglandin E synthase-1 (mPGES) is selectively inhibited, but not when a general COX-1/2 inhibitor is used. This shows that the de novo synthesis of PGE2 is vital for the Th2 priming function of SEA-stimulated DCs as well as points to the potential existence of other COX-dependent lipid mediators that antagonize PGE2-driven Th2 polarization. Lastly, specific PGE2 inhibition following immunization with S. mansoni eggs dampened the egg-specific Th cell response. In summary, our findings provide new insights in the molecular mechanisms underpinning Th2 induction by S. mansoni and identify druggable targets for potential control of helminth driven-Th2 responses.

Expression patterns of novel immunotherapy targets in intermediate- and high-grade lung neuroendocrine neoplasms.

BACKGROUND: Advancements in immunotherapeutic approaches only had a modest impact on the therapy of lung neuroendocrine neoplasms (LNENs). Our multicenter study aimed to investigate the expression patterns of novel immunotherapy targets in intermediate- and high-grade LNENs. METHODS: The expressions of V-domain Ig suppressor of T cell activation (VISTA), OX40L, Glucocorticoid-induced TNF receptor (GITR), and T cell immunoglobulin and mucin domain 3 (TIM3) proteins were measured by immunohistochemistry in surgically resected tumor samples of 26 atypical carcinoid (AC), 49 large cell neuroendocrine lung cancer (LCNEC), and 66 small cell lung cancer (SCLC) patients. Tumor and immune cells were separately scored. RESULTS: Tumor cell TIM3 expression was the highest in ACs (p < 0.001), whereas elevated tumor cell GITR levels were characteristic for both ACs and SCLCs (p < 0.001 and p = 0.011, respectively). OX40L expression of tumor cells was considerably lower in ACs (vs. SCLCs; p < 0.001). Tumor cell VISTA expression was consistently low in LNENs, with no significant differences across histological subtypes. ACs were the least immunogenic tumors concerning immune cell abundance (p < 0.001). Immune cell VISTA and GITR expressions were also significantly lower in these intermediate-grade malignancies than in SCLCs or in LCNECs. Immune cell TIM3 and GITR expressions were associated with borderline prognostic significance in our multivariate model (p = 0.057 and p = 0.071, respectively). CONCLUSIONS: LNEN subtypes have characteristic and widely divergent VISTA, OX40L, GITR, and TIM3 protein expressions. By shedding light on the different expression patterns of these immunotherapy targets, the current multicenter study provides support for the future implementation of novel immunotherapeutic approaches.

Blockade of OX40/OX40L signaling using anti-OX40L alleviates murine lupus nephritis.

Genetic variants of the OX40 ligand (OX40L) locus are associated with the risk of systemic lupus erythematosus (SLE), it is unclear how the OX40L blockade delays the lupus phenotype. Therefore, we examined the effects of an anti-OX40L antibody in MRL/Lpr mice. Next, we investigated the effect of anti-OX40L on immunosuppression in keyhole limpet hemocyanin-immunized C57BL/6J mice. In vitro treatment of anti-OX40L in CD4+ T and B220+ B cells was used to explore the role of OX40L in the pathogenesis of SLE. Anti-OX40L alleviated murine lupus nephritis, accompanied by decreased production of anti-dsDNA and proteinuria, as well as lower frequencies of splenic T helper (Th) 1 and T-follicular helper cells (Tfh). In keyhole limpet hemocyanin-immunized mice, decreased levels of immunoglobulins and plasmablasts were observed in the anti-OX40L group. Anti-OX40L reduced the number and area of germinal centers. Compared with the control IgG group, anti-OX40L downregulated CD4+ T-cell differentiation into Th1 and Tfh cells and upregulated CD4+ T-cell differentiation into regulatory T cells in vitro. Furthermore, anti-OX40L inhibited toll-like receptor 7-mediated differentiation of antibody-secreting cells and antibody production through the regulation of the SPIB-BLIMP1-XBP1 axis in B cells. These results suggest that OX40L is a promising therapeutic target for SLE.

Single-cell profiling of response to neoadjuvant chemo-immunotherapy in surgically resectable esophageal squamous cell carcinoma.

BACKGROUND: The efficacy of neoadjuvant chemo-immunotherapy (NAT) in esophageal squamous cell carcinoma (ESCC) is challenged by the intricate interplay within the tumor microenvironment (TME). Unveiling the immune landscape of ESCC in the context of NAT could shed light on heterogeneity and optimize therapeutic strategies for patients. METHODS: We analyzed single cells from 22 baseline and 24 post-NAT treatment samples of stage II/III ESCC patients to explore the association between the immune landscape and pathological response to neoadjuvant anti-PD-1 combination therapy, including pathological complete response (pCR), major pathological response (MPR), and incomplete pathological response (IPR). RESULTS: Single-cell profiling identified 14 major cell subsets of cancer, immune, and stromal cells. Trajectory analysis unveiled an interesting link between cancer cell differentiation and pathological response to NAT. ESCC tumors enriched with less differentiated cancer cells exhibited a potentially favorable pathological response to NAT, while tumors enriched with clusters of more differentiated cancer cells may resist treatment. Deconvolution of transcriptomes in pre-treatment tumors identified gene signatures in response to NAT contributed by specific immune cell populations. Upregulated genes associated with better pathological responses in CD8 + effector T cells primarily involved interferon-gamma (IFNγ) signaling, neutrophil degranulation, and negative regulation of the T cell apoptotic process, whereas downregulated genes were dominated by those in the immune response-activating cell surface receptor signaling pathway. Natural killer cells in pre-treatment tumors from pCR patients showed a similar upregulation of gene expression in response to IFNγ but a downregulation of genes in the neutrophil-mediated immunity pathways. A decreased cellular contexture of regulatory T cells in ESCC TME indicated a potentially favorable pathological response to NAT. Cell-cell communication analysis revealed extensive interactions between CCL5 and its receptor CCR5 in various immune cells of baseline pCR tumors. Immune checkpoint interaction pairs, including CTLA4-CD86, TIGIT-PVR, LGALS9-HAVCR2, and TNFSF4-TNFRSF4, might serve as additional therapeutic targets for ICI therapy in ESCC. CONCLUSIONS: This pioneering study unveiled an intriguing association between cancer cell differentiation and pathological response in esophageal cancer patients, revealing distinct subgroups of tumors for which neoadjuvant chemo-immunotherapy might be effective. We also delineated the immune landscape of ESCC tumors in the context of clinical response to NAT, which provides clinical insights for better understanding how patients respond to the treatment and further identifying novel therapeutic targets for ESCC patients in the future.