Expression of anti-HVEM single-chain antibody on tumor cells induces tumor-specific immunity with long-term memory

Herpesvirus Entry Mediator as an Immune Checkpoint Target and a Potential Prognostic Biomarker in Myeloid and Lymphoid Leukemia

Herpesvirus entry mediator (HVEM) is a molecular switch that can modulate immune responses against cancer. The significance of HVEM as an immune checkpoint target and a potential prognostic biomarker in malignancies is still controversial. This study aims to determine whether HVEM is an immune checkpoint target with inhibitory effects on anti-tumor CD4+ T cell responses in vitro and whether HVEM gene expression is dysregulated in patients with acute lymphocytic leukemia (ALL). HVEM gene expression in tumor cell lines and peripheral blood mononuclear cells (PBMCs) from ALL patients and healthy controls was measured using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Tumor cells were left untreated (control) or were treated with an HVEM blocker before co-culturing with CD4+ T cells in vitro in a carboxyfluorescein succinimidyl ester (CFSE)-dependent proliferation assay. HVEM expression was upregulated in the chronic myelogenous leukemia cell line (K562) (FC = 376.3, p = 0.086) compared with normal embryonic kidney cells (Hek293). CD4+ T cell proliferation was significantly increased in the HVEM blocker-treated K562 cells (p = 0.0033). Significant HVEM differences were detected in ALL PBMCs compared with the controls, and these were associated with newly diagnosed ALL (p = 0.0011) and relapsed/refractory (p = 0.0051) B cell ALL (p = 0.0039) patients. A significant differentiation between malignant ALL and the controls was observed in a receiver operating characteristic (ROC) curve analysis with AUC = 0.78 ± 0.092 (p = 0.014). These results indicate that HVEM is an inhibitory molecule that may serve as a target for immunotherapy and a potential ALL biomarker.

A novel disulfidptosis-related immune checkpoint genes signature: forecasting the prognosis of hepatocellular carcinoma

BACKGROUND

HCC is an extremely malignant tumor with a very poor prognosis. In 2023, a brand-new kind of cell death known as disulfidptosis was identified. Although, the prognosis as well as expression of immune checkpoints that are closely connected with it in HCC remain unknown.

METHODS

In this work, we identified 49 genes with abnormal expression in liver cancer and normal liver tissue, with 23 of them being differentially expressed genes. To create a signature, we classified all HCC cases into three subtypes and used the TCGA database to evaluate each relevant gene's prognostic value for survival.

RESULTS

Five gene signatures were identified using the LASSO Cox regression approach, while those diagnosed with HCC were split into either low- or high-risk groups. Patients having low-risk HCC showed a much greater likelihood of surviving than those with high risk (p < 0.05). Through immune cell infiltration analysis, it was found that immune-related genes were abundant in high-risk groups and had reduced immune status.

CONCLUSION

In conclusion, immune checkpoint genes highly associated with disulfidptosis contribute to tumor immunity and can be used to evaluate HCC prognosis. When it comes to predicting overall survival (OS) time in HCC, risk score has been set to be a separate predictor. Through immune cell infiltration analysis, it was found that immune-related genes were abundant in high-risk groups and had reduced immune status. It is possible to measure the prognosis of HCC based on immune checkpoints genes strongly linked to disulfidptosis.

Current Approaches of Immune Checkpoint Therapy in Chronic Lymphocytic Leukemia

OPINION STATEMENT

Increasing understanding of the complex interaction between leukemic and immune cells, which is responsible for tumor progression and immune evasion, has paved the way for the development of novel immunotherapy approaches in chronic lymphocytic leukemia (CLL). One of the well-known immune escape mechanisms of tumor cells is the up-regulation of immune checkpoint molecules. In recent years, targeting immune checkpoint receptors is the most clinically effective immunotherapeutic strategy for cancer treatment. In this regard, various immune checkpoint blockade (ICB) drugs are currently been investigating for their potential effects on improving anti-tumor immune response and clinical efficacy in the hematological malignancies; however, their effectiveness in patients with CLL has shown less remarkable success, and ongoing research is focused on identifying strategies to enhance the efficacy of ICB in CLL.

The Implementation of TNFRSF Co-Stimulatory Domains in CAR-T Cells for Optimal Functional Activity

The Tumor Necrosis Factor Receptor Superfamily (TNFRSF) is a large and important immunoregulatory family that provides crucial co-stimulatory signals to many if not all immune effector cells. Each co-stimulatory TNFRSF member has a distinct expression profile and a unique functional impact on various types of cells and at different stages of the immune response. Correspondingly, exploiting TNFRSF-mediated signaling for cancer immunotherapy has been a major field of interest, with various therapeutic TNFRSF-exploiting anti-cancer approaches such as 4-1BB and CD27 agonistic antibodies being evaluated (pre)clinically. A further application of TNFRSF signaling is the incorporation of the intracellular co-stimulatory domain of a TNFRSF into so-called Chimeric Antigen Receptor (CAR) constructs for CAR-T cell therapy, the most prominent example of which is the 4-1BB co-stimulatory domain included in the clinically approved product Kymriah. In fact, CAR-T cell function can be clearly influenced by the unique co-stimulatory features of members of the TNFRSF. Here, we review a select group of TNFRSF members (4-1BB, OX40, CD27, CD40, HVEM, and GITR) that have gained prominence as co-stimulatory domains in CAR-T cell therapy and illustrate the unique features that each confers to CAR-T cells.

Blockade of HVEM for Prostate Cancer Immunotherapy in Humanized Mice

Simple Summary

Current immune checkpoint inhibitors have shown limitations for immunotherapy of prostate cancer. Thus, it is crucial to investigate other immune checkpoints to prevent disease progression in patients with prostate cancer. Here, we first show that the HVEM/BTLA immune checkpoint is associated with disease progression in patients. We then show that immunotherapy aimed at targeting HVEM reduced tumor growth twofold in vivo in a humanized mouse model of the pathology. The mode of action of the therapy was dependent on CD8⁺ T cells and is associated with improved T cell activation and reduced exhaustion. Finally, we demonstrated that HVEM expressed by the tumor negatively regulated the anti-tumor immune response. Our results indicate that targeting HVEM might be an attractive option for patients with prostate cancer.

Abstract

The herpes virus entry mediator (HVEM) delivers a negative signal to T cells mainly through the B and T lymphocyte attenuator (BTLA) molecule. Thus, HVEM/BTLA may represent a novel immune checkpoint during an anti-tumor immune response. However, a formal demonstration that HVEM can represent a target for cancer immunotherapy is still lacking. Here, we first showed that HVEM and BTLA mRNA expression levels were associated with a worse progression-free interval in patients with prostate adenocarcinomas, indicating a detrimental role for the HVEM/BTLA immune checkpoint during prostate cancer progression. We then showed that administration of a monoclonal antibody to human HVEM resulted in a twofold reduction in the growth of a prostate cancer cell line in NOD.SCID.gc-null mice reconstituted with human T cells. Using CRISPR/Cas9, we showed that the therapeutic effect of the mAb depended on HVEM expression by the tumor, with no effect on graft vs. host disease or activation of human T cells in the spleen. In contrast, the proliferation and number of tumor-infiltrating leukocytes increased following treatment, and depletion of CD8⁺ T cells partly alleviated treatment’s efficacy. The expression of genes belonging to various T cell activation pathways was enriched in tumor-infiltrating leukocytes, whereas genes associated with immuno-suppressive pathways were decreased, possibly resulting in modifications of leukocyte adhesion and motility. Finally, we developed a simple in vivo assay in humanized mice to directly demonstrate that HVEM expressed by the tumor is an immune checkpoint for T cell-mediated tumor control. Our results show that targeting HVEM is a promising strategy for prostate cancer immunotherapy.

MiR-29c downregulates tumor-expressed B7-H3 to mediate the antitumor NK-cell functions in ovarian cancer

OBJECTIVE

B7-H3 is a member of the B7 family of immune checkpoint molecule. Although B7-H3 has been shown to regulate T cell-mediated peripheral immune response, whether it also correlated with NK cell exhaustion in ovarian cancer remains unclear. The purpose of this study was to explore the mechanism of B7-H3 regulating NK-cell proliferation and function.

MATERIAL AND METHODS

To investigate the relationship between B7-H3 expression and the NK-cell function in ovarian cancer, human ovarian tumor tissues and cell lines were first examined the protein and mRNA expression of B7-H3 by quantitative real-time PCR (qRT-PCR), Immunohistochemistry and Western-blot assays. Then we established B7-H3 knockout cell lines and measured the cytotoxicity of NK cells on these cells by LDH release assay and Flow Cytometry. In addition, we analyzed B7-H3 in the regulation of glycolysis and glycolysis-related proteins by Glycolysis Stress Test, Glucose Consumption Assay and Western-blot. Moreover, luciferase reporter assay was used to confirm the directly regulation of miR-29c to B7-H3. Finally, we carried out in vivo experiments.

RESULTS

We observed that tumor-expressed B7-H3 inhibits NK-cell function in vitro and in vivo, and is associated with glycolysis of ovarian cancer cell. Therapeutically, B7-H3 blockade prolonged the survival of SKOV3 tumor-bearing mice. In addition, miR-29c improved the anti-tumor efficacy of NK-cell by directly targeting B7-H3 in vitro were observed, but not in vivo.

CONCLUSION

Our results demonstrate that miR-29c downregulates B7-H3 to inhibit NK-cell exhaustion and associated with glycolysis, which suggest that NK cells may be a new target of anti-B7-H3 therapy in ovarian cancer patients.

An Update on Anti-CD137 Antibodies in Immunotherapies for Cancer

The selective expression of CD137 on cells of the immune system (e.g., T and DC cells) and oncogenic cells in several types of cancer leads this molecule to be an attractive target to discover cancer immunotherapy. Therefore, specific antibodies against CD137 are being studied and developed aiming to activate and enhance anti-cancer immune responses as well as suppress oncogenic cells. Accumulating evidence suggests that anti-CD137 antibodies can be used separately to prevent tumor in some cases, while in other cases, these antibodies need to be co-administered with other antibodies or drugs/vaccines/regents for a better performance. Thus, in this work, we aim to update and discuss current knowledge about anti-cancer effects of anti-CD137 antibodies as mono- and combined-immunotherapies.

Chimeric Antigen Receptor T Cell Bearing Herpes Virus Entry Mediator Co-stimulatory Signal Domain Exhibits High Functional Potency

Chimeric antigen receptor (CAR) is a hybrid molecule consisting of an antigen-binding domain and a signal transduction domain. The artificial T cells expressing CAR (CAR-T cells) are expected to be a useful tool for treatment of various diseases, such as cancer. The addition of a co-stimulatory signal domain (CSSD) to CAR is shown to be critical for modulating CAR-T cell activities. However, the interplay among types of CSSDs, effector functions, and characteristics of CAR-T cells is largely unknown. To elucidate the interplay, we analyzed effector functions, differentiation to memory T cell subsets, exhaustion, and energy metabolism of the CAR-T cells with different CSSDs. Comparing to the CAR-T cells bearing a CD28- or 4-1BB-derived CSSD, which are currently used for CAR-T cell development, we found that the CAR-T cells with a herpes virus entry mediator (HVEM)-derived CSSD exhibited enhanced effector functions and efficient and balanced differentiation to both central and effector memory subsets, associated with an elevated energy metabolism and a reduced level of exhaustion. Thus, we developed the CAR-T cells bearing the CSSD derived from HVEM with high functional potency. The HVEM-derived CSSD may be useful for developing effective CAR-T cells.

The TNF-TNFR Family of Co-signal Molecules

Costimulatory signals initiated by the interaction between the tumor necrosis factor (TNF) ligand and cognate TNF receptor (TNFR) superfamilies promote clonal expansion, differentiation, and survival of antigen-primed CD4⁺ and CD8⁺ T cells and have a pivotal role in T-cell-mediated adaptive immunity and diseases. Accumulating evidence in recent years indicates that costimulatory signals via the subset of the TNFR superfamily molecules, OX40 (TNFRSF4), 4-1BB (TNFRSF9), CD27, DR3 (TNFRSF25), CD30 (TNFRSF8), GITR (TNFRSF18), TNFR2 (TNFRSF1B), and HVEM (TNFRSF14), which are constitutive or inducible on T cells, play important roles in protective immunity, inflammatory and autoimmune diseases, and tumor immunotherapy. In this chapter, we will summarize the findings of recent studies on these TNFR family of co-signaling molecules regarding their function at various stages of the T-cell response in the context of infection, inflammation, and cancer. We will also discuss how these TNFR co-signals are critical for immune regulation and have therapeutic potential for the treatment of T-cell-mediated diseases.

Therapeutic potential of anti-CD137 (4-1BB) monoclonal antibodies

INTRODUCTION

4-1BB (CD137) is an important T-cell stimulating molecule. The 4-1BB mAb or its variants have shown remarkable therapeutic activity against autoimmunity, viral infections, and cancer. Antibodies to 4-1BB have recently entered clinical trials for the treatment of cancer with favorable toxicity profile. In this article, we present a review documenting the efficacy and pitfalls of 4-1BB therapy.

AREAS COVERED

An extensive literature search has been made on 4-1BB, spanning two decades, and a comprehensive report is presented here highlighting the origins, biological effects, therapeutic potential, and mechanistic basis of targeting 4-1BB as well as the side effects associated with such therapy.

EXPERT OPINION

Research so far indicates that 4-1BB is highly protective against various pathological conditions including cancer. However, a few important side effects of 4-1BB therapy such as liver toxicity, thrombocytopenia, anemia, and suppressive effects on certain immune competent cells should be taken into consideration before it is used for human therapy.

Targeting tumor-necrosis factor receptor pathways for tumor immunotherapy

With the success of ipilimumab and promise of programmed death-1 pathway-targeted agents, the field of tumor immunotherapy is expanding rapidly. Newer targets for clinical development include select members of the tumor necrosis factor receptor (TNFR) family. Agonist antibodies to these co-stimulatory molecules target both T and B cells, modulating T-cell activation and enhancing immune responses. In vitro and in vivo preclinical data have provided the basis for continued development of 4-1BB, OX40, glucocorticoid-induced TNFR-related gene, herpes virus entry mediator, and CD27 as potential therapies for patients with cancer. In this review, we summarize the immune response to tumors, consider preclinical and early clinical data on select TNFR family members, discuss potential translational challenges and suggest possible combination therapies with the aim of inducing durable antitumor responses.

Combining antibody-directed presentation of IL-15 and 4-1BBL in a trifunctional fusion protein for cancer immunotherapy

Influencing the cytokine receptor network that modulates the immune response holds great potential for cancer immunotherapy. Although encouraging results have been obtained by focusing on individual members of the common γ-chain (γc) receptor family and TNF receptor superfamily so far, combination strategies might be required to further improve the effectiveness of the antitumor response. Here, we propose the combination of interleukin (IL)-15 and 4-1BBL in a single, tumor-directed molecule. Therefore, a trifunctional antibody fusion protein was generated, composed of a tumor-specific recombinant antibody, IL-15 linked to a fragment of the IL-15Rα chain (RD) and the extracellular domain of 4-1BBL. In soluble and targeted forms, the trifunctional antibody fusion protein RD_IL-15_scFv_4-1BBL was shown to stimulate activated T-cell proliferation and induce T-cell cytotoxicity to a similar degree as the bifunctional scFv_RD_IL-15 fusion protein. On the other hand, in targeted form, the trifunctional fusion protein was much more effective in inducing T-cell proliferation and IFN-γ release of unstimulated peripheral blood mononuclear cells (PBMC). Here, the additional signal enhancement could be attributed to the costimulatory activity of 4-1BBL, indicating a clear benefit for the simultaneous presentation of IL-15 and 4-1BBL in one molecule. Furthermore, the trifunctional antibody fusion protein was more effective than the corresponding bifunctional fusion proteins in reducing metastases in a tumor mouse model in vivo. Hence, the targeted combination of IL-15 and 4-BBL in the form of a trifunctional antibody-fusion protein is a promising new approach for cancer immunotherapy.

Targeting costimulatory molecules to improve antitumor immunity

The full activation of T cells necessitates the concomitant activation of two signals, the engagement of T-cell receptor by peptide/major histocompatibility complex II and an additional signal delivered by costimulatory molecules. The best characterized costimulatory molecules belong to B7/CD28 and TNF/TNFR families and play crucial roles in the modulation of immune response and improvement of antitumor immunity. Unfortunately, tumors often generate an immunosuppressive microenvironment, where T-cell response is attenuated by the lack of costimulatory molecules on the surface of cancer cells. Thus, targeting costimulatory pathways represent an attractive therapeutic strategy to enhance the antitumor immunity in several human cancers. Here, latest therapeutic approaches targeting costimulatory molecules will be described.