CD155, an onco-immunologic molecule in human tumors

CD155 blockade enhances allogeneic natural killer cell-mediated antitumor response against osteosarcoma

Background

Allogeneic bone marrow transplant (alloBMT) is curative for hematologic malignancies through the graft-versus-tumor (GVT) effect but has been ineffective for solid tumors like osteosarcoma (OS). OS expresses CD155 which interacts strongly with inhibitory receptors TIGIT and CD96 but also binds to activating receptor DNAM-1 on natural killer (NK) cells. CD155 has never been targeted after alloBMT. Combining adoptively transferred allogeneic NK (alloNK) cells with CD155 blockade after alloBMT may enhance a GVT effect against OS.

Methods

Murine NK cells were activated and expanded ex vivo with soluble IL-15/IL-15Rα. AlloNK and syngeneic NK (synNK) cell phenotype, cytotoxicity, cytokine production, and degranulation against CD155-expressing murine OS cell line K7M2 were assessed in vitro. Mice bearing pulmonary OS metastases underwent alloBMT and alloNK cell infusion with anti-CD155 either before or after tumor induction, with select groups receiving anti-DNAM-1 pretreated alloNK cells. Tumor growth, GVHD and survival were monitored, and differential gene expression of lung tissue was assessed by RNA microarray.

Results

AlloNK cells exhibited superior cytotoxicity against CD155-expressing OS compared to synNK cells, and this activity was enhanced by CD155 blockade. CD155 blockade increased alloNK cell degranulation and interferon gamma production through DNAM-1. In vivo, CD155 blockade with alloNK infusion increased survival when treating OS that relapsed after alloBMT. No benefit was seen for treating established OS before alloBMT. Treatment with combination CD155 and anti-DNAM-1 pretreated alloNK ameliorated survival and tumor control benefits seen with CD155 blockade alone. RNA microarray showed mice treated with alloNK and CD155 blockade had increased expression of cytotoxicity genes and the NKG2D ligand H60a, whereas mice treated with anti-DNAM-1 pretreated alloNK cells resulted in upregulation of NK cell inhibitory receptor genes. Whereas blocking DNAM-1 on alloNK abrogated cytotoxicity, blocking NKG2D had no effect, implying DNAM-1:CD155 engagement drives alloNK activation against OS.

Conclusions

These results demonstrate the safety and efficacy of infusing alloNK cells with CD155 blockade to mount a GVT effect against OS and show benefits are in part through DNAM-1. Defining the hierarchy of receptors that govern alloNK responses is critical to translating alloNK cell infusions and immune checkpoint inhibition for solid tumors treated with alloBMT.

WHAT IS ALREADY KNOWN ON THIS TOPIC

Allogeneic bone marrow transplant (alloBMT) has yet to show efficacy in treating solid tumors, such as osteosarcoma (OS). CD155 is expressed on OS and interacts with natural killer (NK) cell receptors, such as activating receptor DNAM-1 and inhibitory receptors TIGIT and CD96 and has a dominant inhibitory effect on NK cell activity. Targeting CD155 interactions on allogeneic NK cells could enhance anti-OS responses, but this has not been tested after alloBMT.

WHAT THIS STUDY ADDS

CD155 blockade enhances allogeneic natural killer cell-mediated cytotoxicity against OS and improved event-free survival after alloBMT in an in vivo mouse model of metastatic pulmonary OS. Addition of DNAM-1 blockade abrogated CD155 blockade-enhanced allogeneic NK cell antitumor responses.

HOW THIS STUDY MIGHT AFFECT RESEARCH PRACTICE OR POLICY

These results demonstrate efficacy of allogeneic NK cells combined with CD155 blockade to mount an antitumor response against CD155-expressing OS. Translation of combination adoptive NK cell and CD155 axis modulation offers a platform for alloBMT treatment approaches for pediatric patients with relapsed and refractory solid tumors.

CD155 as an emerging target in tumor immunotherapy

CD155 is an immunoglobulin-like protein overexpressed in almost all the tumor cells, which not only promotes proliferation, adhesion, invasion, and migration of tumor cells, but also regulates immune responses by interacting with TIGIT, CD226 or CD96 receptors expressed on several immune cells, thereby modulating the functionality of these cellular subsets. As a novel immune checkpoint, the inhibition of CD155/TIGIT, either as a standalone treatment or in conjunction with other immune checkpoint inhibitors, has demonstrated efficacy in managing advanced solid malignancies. In this review, we summarize the intricate relationship between on tumor surface CD155 and its receptors, with further discussion on how they regulate the occurrence of tumor immune escape. In addition, novel therapeutic strategies and clinical trials targeting CD155 and its receptors are summarized, providing a strong rationale and way forward for the development of next-generation immunotherapies.

Molecular insights and promise of oncolytic virus based immunotherapy

Discovering a therapeutic that can counteract the aggressiveness of this disease's mechanism is crucial for improving survival rates for cancer patients and for better understanding the most different types of cancer. In recent years, using these viruses as an anticancer therapy has been thought to be successful. They mostly work by directly destroying cancer cells, activating the immune system to fight cancer, and expressing exogenous effector genes. For the treatment of tumors, oncolytic viruses (OVs), which can be modified to reproduce only in tumor tissues and lyse them while preserving the healthy non-neoplastic host cells and reinstating antitumor immunity which present a novel immunotherapeutic strategy. OVs can exist naturally or be created in a lab by altering existing viruses. These changes heralded the beginning of a new era of less harmful virus-based cancer therapy. We discuss three different types of oncolytic viruses that have already received regulatory approval to treat cancer as well as clinical research using oncolytic adenoviruses. The primary therapeutic applications, mechanism of action of oncolytic virus updates, future views of this therapy will be covered in this chapter.

Identification and clinical value of a new ceRNA axis (TIMP3/hsa-miR-181b-5p/PAX8-AS1) in thyroid cancer

Background

Thyroid cancer (TC) is a prevalent and increasingly common malignant tumor. In most cases, TC progresses slowly and runs a virtually benign course. However, challenges remain with the treatment of refractory TC, which does not respond to traditional management or is subject to relapse or metastasis. Therefore, new therapeutic regimens for TC patients with poor outcomes are urgently needed.

Methods

The differentially expressed RNAs were identified from the expression profile data of RNA from TC downloaded from The Cancer Genome Atlas database. Multiple databases were utilized to investigate the regulatory relationship among RNAs. Subsequently, a competitive endogenous RNA (ceRNA) network was established to elucidate the ceRNA axis that is responsible for the clinical prognosis of TC. To understand the potential mechanism of ceRNA axis in TC, location analysis, functional enrichment analysis, and immune-related analysis were conducted.

Results

A ceRNA network of TC was constructed, and the TIMP3/hsa-miR-181b-5p/PAX8-AS1 ceRNA axis associated with the prognosis of TC was successfully identified. Our results showed that the axis might influence the prognosis of TC through its regulation of regulating tumor immunity.

Conclusions

Our findings provide evidence that TIMP3/hsa-miR-181b-5p/PAX8-AS1 axis is significantly related to the prognosis of TC. The molecules involved in this axis may serve as novel therapeutic approaches for TC treatment.

Breakthrough of solid tumor treatment: CAR-NK immunotherapy

As the latest and most anticipated method of tumor immunotherapy, CAR-NK therapy has received increasing attention in recent years, and its safety and high efficiency have irreplaceable advantages over CAR-T. Current research focuses on the application of CAR-NK in hematological tumors, while there are fewer studies on solid tumor. This article reviews the process of constructing CAR-NK, the effects of hypoxia and metabolic factors, NK cell surface receptors, cytokines, and exosomes on the efficacy of CAR-NK in solid tumor, and the role of CAR-NK in various solid tumor. The mechanism of action and the research status of the potential of CAR-NK in the treatment of solid tumor in clinical practice, and put forward the advantages, limitations and future problems of CAR-NK in the treatment of solid tumor.

Targeting TIGIT for cancer immunotherapy: recent advances and future directions

As a newly identified checkpoint, T cell immunoreceptor with immunoglobulin and tyrosine-based inhibitory motif (ITIM) domain (TIGIT) is highly expressed on CD4+ T cells, CD8+ T cells, natural killer (NK) cells, regulatory T cells (Tregs), and tumor-infiltrating lymphocytes (TILs). TIGIT has been associated with NK cell exhaustion in vivo and in individuals with various cancers. It not only modulates NK cell survival but also mediates T cell exhaustion. As the primary ligand of TIGIT in humans, CD155 may be the main target for immunotherapy due to its interaction with TIGIT. It has been found that the anti-programmed cell death protein 1 (PD-1) treatment response in cancer immunotherapy is correlated with CD155 but not TIGIT. Anti-TIGIT alone and in combination with anti-PD-1 agents have been tested for cancer immunotherapy. Although two clinical studies on advanced lung cancer had positive results, the TIGIT-targeted antibody, tiragolumab, recently failed in two new trials. In this review, we highlight the current developments on TIGIT for cancer immunotherapy and discuss the characteristics and functions of TIGIT.

A Novel Natural Killer Cell-related Gene Signature for Improving the Prediction of Prognosis and Immunotherapy Response in Bladder Cancer

BACKGROUND

Bladder cancer (BLCA) is a commonly diagnosed cancer worldwide that exhibits high rates of recurrence and metastasis. Immunotherapy is increasingly being recognised in the clinical management of bladder cancer. In addition, the prospect of developing Natural Killer (NK) cell-related immunotherapy is promising in BLCA.

METHODS

We established and verified a prognostic signature based on NK cell-related gene expression. We then calculated the NKscore of BLCA samples and correlated it with the clinical outcomes, molecular subtypes of BLCA, tumour microenvironment (TME), and predicted efficacy of immune checkpoint inhibitors (ICI) and chemotherapy drugs to thoroughly explore the implications of the NKscore. Finally, the role of the NK signature gene HECTD1 in BLCA was verified by Quantitative Real-time PCR, Cell Counting Kit-8 Assay (CCK-8), Transwell Assay and Colony Formation Experiment.

RESULTS

We analysed NK cell-associated genes and identified six genes with significant prognostic relevance. A high NK score significantly represents a worse prognosis. NKscore was significantly correlated with seven types of classical molecular subtype classifications of BLCA. In addition, NKscore positively correlates with NK-related immune checkpoints, suggesting that emerging NK cell immune checkpoint inhibitors, such as monalizumab, may have potential therapeutic promise for patients with high NKscore. The results of the T cell inflamed score (TIS) and tumour immune dysfunction exclusion (TIDE) score confirmed the suitability of immunotherapy for patients with a high NK score. Likewise, patients with a high NK score may be more suitable for several significant chemotherapeutic drugs. Functional experiments showed that the knockdown of HECTD1 significantly attenuated the proliferation, migration, and invasion ability of tumour cells.

CONCLUSION

To sum up, the capability of our signature to predict prognosis and immunotherapy response was robust. Hopefully, these results will provide new insights for BLCA research and patient immunotherapy.

Poliovirus receptor inhibition in breast cancer cells induces antitumor immunity via T cell activation

Radiotherapy (RT) is a commonly used treatment option for patients with cancer because it can effectively control tumor growth and kill tumor cells. However, the impact of RT goes beyond direct tumor cell killing because it can change the tumor microenvironment by altering surrounding tissues and infiltrating cells and modulating the expression of immune checkpoints. Poliovirus receptor (PVR, cluster of differentiation (CD)155), a member of the nectin-like molecule family, is overexpressed in many human cancers. However, its role in the tumor growth and T-cell immune responses of triple-negative breast cancer (TNBC) remains unclear. In the present study, we observe that radiation exposure increases PVR expression in MDA-MB-231 and BT549 cells. Silencing PVR not only inhibited the proliferation of breast cancer cells but also significantly enhanced the cytotoxicity of cytotoxic T lymphocytes (CTLs) compared with the control or RT groups. Treatment of T cells with PVR decreased CD8+ T cells, increased CD4+ T cells, and induced PVR ligands such as T cell immunoreceptor with immunoglobulin and ITIM domain, CD226, and CD96. However, after treatment with PVR, CTL responses decreased and secretion of interferon-γ, tumor necrosis factor-α, interleukin (IL)-2, IL-6, and IL-10 was significantly inhibited. In contrast, PVR knockdown increased the production of these cytokines, illustrating the immunosuppressive function of PVR. Suppression of PVR using an anti-PVR antibody inhibited 4T1 tumor growth by increasing immune cell infiltration. These results provide new insights into the role of PVR in TNBC and highlight its potential as a target for T cell-mediated immunotherapy in breast cancer.

Prognostic factors of resected pathological stage I lung adenocarcinoma: evaluating subtypes and PD-L1/CD155 expression

We aimed to compare the prognostic impacts of adenocarcinoma subtypes, programmed death-ligand I (PD-L1), and CD155 expression on patients with resected pathological stage (p-stage) I lung adenocarcinoma. In total, 353 patients with completely resected p-stage I lung adenocarcinomas were retrospectively reviewed. The expression levels of PD-L1 and CD155 in tumour cells from each adenocarcinoma subtype were evaluated using several clinicopathological and histological features, such as the presence of a micropapillary pattern. A total of 52 patients (14.7%) had PD-L1-positive tumours, whereas 128 patients (36.3%) had CD155-positive tumours, with a tumour proportion score of 5% for both PD-L1 and CD155 expression. Compared with patients with other adenocarcinoma subtypes, those with solid-predominant adenocarcinomas were significantly more positive for PD-L1 and CD155. Multivariate analysis showed that PD-L1 expression status was significantly associated with progression-free survival and overall survival, whereas CD155 expression and the presence of a micropapillary pattern were not significantly associated with either parameter. Patients with PD-L1-positive tumours had poorer prognoses than those with CD155-positive tumours. Moreover, PD-L1 and CD155 were significantly expressed in solid-predominant adenocarcinomas. The results of this study suggest that immune checkpoint inhibitors can be used as adjuvants in the treatment of patients with p-stage I adenocarcinoma.

Advancements and challenges in oncolytic virus therapy for gastrointestinal tumors

BACKGROUND

Tumors of the gastrointestinal tract impose a substantial healthcare burden due to their prevalence and challenging prognosis.

METHODS

We conducted a review of peer-reviewed scientific literature using reputable databases (PubMed, Scopus, Web of Science) with a focus on oncolytic virus therapy within the context of gastrointestinal tumors. Our search covered the period up to the study's completion in June 2023.

INCLUSION AND EXCLUSION CRITERIA

This study includes articles from peer-reviewed scientific journals, written in English, that specifically address oncolytic virus therapy for gastrointestinal tumors, encompassing genetic engineering advances, combined therapeutic strategies, and safety and efficacy concerns. Excluded are articles not meeting these criteria or focusing on non-primary gastrointestinal metastatic tumors.

RESULTS

Our review revealed the remarkable specificity of oncolytic viruses in targeting tumor cells and their potential to enhance anti-tumor immune responses. However, challenges related to safety and efficacy persist, underscoring the need for ongoing research and improvement.

CONCLUSION

This study highlights the promising role of oncolytic virus therapy in enhancing gastrointestinal tumor treatments. Continued investigation and innovative combination therapies hold the key to reducing the burden of these tumors on patients and healthcare systems.

Enhancing T cell anti-tumor efficacy with a PD1-TIGIT chimeric immune-checkpoint switch receptor

Chimeric antigen receptor (CAR) T cell immunotherapy has demonstrated success in the treatment of hematological malignancies; however, its efficacy and applications in solid tumors remain limited. Immunosuppressive factors, particularly inhibitory checkpoint molecules, restrict CAR T cell activity inside solid tumors. The modulation of checkpoint pathways has emerged as a promising approach to promote anti-tumor responses in CAR T cells. Programmed cell death protein 1 (PD1) and T cell immunoreceptor with Ig and ITIM domains (TIGIT) are two critical immune-checkpoint molecules that suppress anti-tumor activity in T cells. Simultaneous targeting of these two inhibitory molecules could be an efficient checkpoint modulation strategy. Here, we developed a PD1-TIGIT chimeric immune-checkpoint switch receptor (CISR) that enhances the efficacy of CAR T cell immunotherapy by reversing the inhibitory checkpoint signals of PD1/PDL1 and/or TIGIT/CD155. In addition to neutralizing PDL1 and CD155, this chimeric receptor is engineered with the transmembrane region and intracellular domain of CD28, thereby effectively enhancing T cell survival and tumor-targeting functions. Notably, under simultaneous stimulation of PDL1 and CD155, CISR-CAR T cells demonstrate superior performance in terms of cell survival, proliferation, cytokine release, and cytotoxicity in vitro, compared with conventional CAR T cells. Experiments utilizing both cell line- and patient-derived xenotransplantation tumor models showed that CISR-CAR T cells exhibit robust infiltration and anti-tumor efficiency in vivo. Our results highlight the potential for the CISR strategy to enhance T cell anti-tumor efficacy and provide an alternative approach for T cell-based immunotherapies.

MicroRNA-326 negatively regulates CD155 expression in lung adenocarcinoma

Treatment with immune checkpoint inhibitors induces a durable response in some patients with non-small-cell lung cancer, but eventually gives rise to drug resistance. Upregulation of CD155 expression is implicated as one mechanism of resistance to programmed death receptor-1 (PD-1)/PD-1 ligand (PD-L1) inhibitors, and it is therefore important to characterize the mechanisms underlying regulation of CD155 expression in tumor cells. The aim of this study was to identify microRNAs (miRNAs) that might regulate CD155 expression at the posttranscriptional level in lung cancer. Comprehensive miRNA screening with target prediction programs and a dual-luciferase reporter assay identified miR-346, miR-328-3p, miR-326, and miR-330-5p as miRNAs that bind to the 3'-UTR of CD155 mRNA. Forced expression of these miRNAs suppressed CD155 expression in lung cancer cell lines. Immunohistochemical staining of CD155 in tissue specimens from 57 patients with lung adenocarcinoma revealed the median tumor proportion score for CD155 to be 68%. The abundance of miR-326 in these specimens with a low level of CD155 expression was significantly greater than in specimens with a high level (p < 0.005). Our results thus suggest that miR-326 negatively regulates CD155 expression in lung adenocarcinoma and might therefore play a role in the development of resistance to PD-1/PD-L1 inhibitors.

Poliovirus receptor (PVR) mediates carboplatin-induced PD-L1 expression in non-small-cell lung cancer cells

Programmed death-ligand-1 (PD-L1) is an immune suppressor that inhibits T cell based immunity. Anti-PD-L1/PD-1 immunotherapy benefits those patients receiving platinum-based combinational chemotherapy. However, the underlying mechanism is still largely unknown. In this study, we found that carboplatin could induce PD-L1 expression in NSCLC H292, A549 and H1299 cells in a dose-dependent manner. mRNA sequencing and the subsequent validation assays found that carboplatin significantly induced PVR expression, which is considered as an immuno-adhesion molecule. Mechanistically, PVR knockdown significantly abrogated carboplatin-induced PD-L1 expression. Functionally, knockdown of PVR significantly reversed the CD3+ T cells proliferation inhibition caused by carboplatin increased PD-L1. Moreover, the carboplatin-induced PVR and subsequent up-regulation of PD-L1 might be mediated via the EGFR, PI3K/AKT, and ERK signaling pathways. Immunohistochemical staining results showed that the PD-L1 expression was positively associated with PVR expression in clinical NSCLC samples. Our study reveals a novel regulatory mechanism of PD-L1 expression, provides evidence that carboplatin inhibits tumor immune response by up-regulating PD-L1 expression and explains the rationale for combining platinum-based chemotherapy with PD-L1/PD-1 inhibitors.

The role of bone marrow microenvironment (BMM) cells in acute myeloid leukemia (AML) progression: immune checkpoints, metabolic checkpoints, and signaling pathways

Acute myeloid leukemia (AML) comprises a multifarious and heterogeneous array of illnesses characterized by the anomalous proliferation of myeloid cells in the bone marrow microenvironment (BMM). The BMM plays a pivotal role in promoting AML progression, angiogenesis, and metastasis. The immune checkpoints (ICs) and metabolic processes are the key players in this process. In this review, we delineate the metabolic and immune checkpoint characteristics of the AML BMM, with a focus on the roles of BMM cells e.g. tumor-associated macrophages, natural killer cells, dendritic cells, metabolic profiles and related signaling pathways. We also discuss the signaling pathways stimulated in AML cells by BMM factors that lead to AML progression. We then delve into the roles of immune checkpoints in AML angiogenesis, metastasis, and cell proliferation, including co-stimulatory and inhibitory ICs. Lastly, we discuss the potential therapeutic approaches and future directions for AML treatment, emphasizing the potential of targeting metabolic and immune checkpoints in AML BMM as prognostic and therapeutic targets. In conclusion, the modulation of these processes through the use of directed drugs opens up new promising avenues in combating AML. Thereby, a comprehensive elucidation of the significance of these AML BMM cells' metabolic and immune checkpoints and signaling pathways on leukemic cells can be undertaken in the future investigations. Additionally, these checkpoints and cells should be considered plausible multi-targeted therapies for AML in combination with other conventional treatments in AML. Video Abstract.

Genetically Engineered-Cell-Membrane Nanovesicles for Cancer Immunotherapy

The advent of immunotherapy has marked a new era in cancer treatment, offering significant clinical benefits. Cell membrane as drug delivery materials has played a crucial role in enhancing cancer therapy because of their inherent biocompatibility and negligible immunogenicity. Different cell membranes are prepared into cell membrane nanovesicles (CMNs), but CMNs have limitations such as inefficient targeting ability, low efficacy, and unpredictable side effects. Genetic engineering has deepened the critical role of CMNs in cancer immunotherapy, enabling genetically engineered-CMN (GCMN)-based therapeutics. To date, CMNs that are surface modified by various functional proteins have been developed through genetic engineering. Herein, a brief overview of surface engineering strategies for CMNs and the features of various membrane sources is discussed, followed by a description of GCMN preparation methods. The application of GCMNs in cancer immunotherapy directed at different immune targets is addressed as are the challenges and prospects of GCMNs in clinical translation.

Clinical significance of CD155 expression and correlation with cellular components of tumor microenvironment in gastric adenocarcinoma

Introduction

CD155 is recently emerging as a promising target in malignancies. However, the relationship between CD155 expression and tumor microenvironment (TME) cell infiltration in gastric adenocarcinoma (GAC) has rarely been clarified.

Methods

We measured CD155 expression in specimens of gastric precancerous disease and GAC by immunohistochemistry. The association of CD155 expression with GAC progression and cells infiltration in TME was evaluated through 268 GAC tissues and public dataset analysis.

Results

We showed that the expression of CD155 was positively correlated with the pathological development of gastric precancerous disease (r = 0.521, P < 0.0001). GAC patients with high CD155 expression had a poorer overall survival (P = 0.033). Moreover, CD155 expression correlated with aggressive clinicopathological features including tumor volume, tumor stage, lymph node involvement, and cell proliferation (P <0.05). Remarkably, CD155 expression positively related to the infiltration of CD68+ macrophages in TME (P = 0.011). Meanwhile, the positive correlation was observed between CD155 and CD31 (P = 0.026). In addition, patients with high CD155 expression combined with low CD3, CD4, CD8, IL-17, IFN-γ or CD19 expression as well as those with high CD155 and α-SMA expression showed significantly worse overall survival (P < 0.05).

Conclusions

CD155 may play a pivotal role in the development of GAC through both immunological and non-immunological mechanisms and be expected to become a novel target of immunotherapy in GAC patients.

Checkpoint Inhibitors in Acute Myeloid Leukemia

The prognosis of acute myeloid leukemia (AML) remains unsatisfactory. Among the reasons for the poor response to therapy and high incidence of relapse, there is tumor cell immune escape, as AML blasts can negatively influence various components of the immune system, mostly weakening T-cells. Since leukemic cells can dysregulate immune checkpoints (ICs), receptor-based signal transductors that lead to the negative regulation of T-cells and, eventually, to immune surveillance escape, the inhibition of ICs is a promising therapeutic strategy and has led to the development of so-called immune checkpoint inhibitors (ICIs). ICIs, in combination with conventional chemotherapy, hypomethylating agents or targeted therapies, are being increasingly tested in cases of AML, but the results reported are often conflicting. Here, we review the main issues concerning the immune system in AML, the main pathways leading to immune escape and the results obtained from clinical trials of ICIs, alone or in combination, in newly diagnosed or relapsed/refractory AML.

DNAM-1 chimeric receptor-engineered NK cells: a new frontier for CAR-NK cell-based immunotherapy

DNAM-1 is a major NK cell activating receptor and, together with NKG2D and NCRs, by binding specific ligands, strongly contributes to mediating the killing of tumor or virus-infected cells. DNAM-1 specifically recognizes PVR and Nectin-2 ligands that are expressed on some virus-infected cells and on a broad spectrum of tumor cells of both hematological and solid malignancies. So far, while NK cells engineered for different antigen chimeric receptors (CARs) or chimeric NKG2D receptor have been extensively tested in preclinical and clinical studies, the use of DNAM-1 chimeric receptor-engineered NK cells has been proposed only in our recent proof-of-concept study and deserves further development. The aim of this perspective study is to describe the rationale for using this novel tool as a new anti-cancer immunotherapy.

Bispecific anti-CD3×anti-CD155 antibody mediates T-cell immunotherapy in human haematologic malignancies

T cells are important components in the cell-mediated antitumour response. In recent years, bispecific antibodies (Bi-Abs) have become promising treatments because of their ability to recruit T cells that kill tumours. Here, we demonstrate that CD155 is expressed in a wide range of human haematologic tumours and report on the ability of the bispecific antibody anti-CD3 x anti-CD155 (CD155Bi-Ab) to activate T cells targeting malignant haematologic cells. The specific cytolytic effect of T cells armed with CD155Bi-Ab was evaluated by quantitative luciferase assay, and the results showed that the cytolytic effect of these cells was accompanied by an increase in the level of the cell-killing mediator perforin. Moreover, compared with their unarmed T-cell counterparts, CD155Bi-Ab-armed T cells induced significant cytotoxicity in CD155-positive haematologic tumour cells, as indicated by lactate dehydrogenase assays, and these results were accompanied by increased granzyme B secretion. Furthermore, CD155Bi-Ab-armed T cells produced more T-cell-derived cytokines, including TNF-α, IFN-γ, and IL-2. In conclusion, CD155Bi-Ab enhances the ability of T cells to kill haematologic tumour cells, and therefore, CD155 may serve as a novel target for immunotherapy against haematologic malignancies.

Ablation of CD226 on CD4+ T cells modulates asthma progress associated with altered IL-10 response and gut microbiota

To investigate the role of the costimulatory molecule CD226 in asthma pathogenesis, we produced a CD4⁺ T-cell-specific CD226 knockout mice model (Cd226^ΔCD4) and induced airway allergic inflammation by administering ovalbumin (OVA). Our results revealed alleviated lung inflammation, decreased levels of OVA-specific IgE, and increased levels of IL-10 in the serum of Cd226^ΔCD4 mice (P < 0.05). Moreover, IL-10 levels in CD4⁺ T cells were significantly elevated in the mediastinal lymph node, spleen, and Peyer's patches in the Cd226^ΔCD4 mice compared with those in controls (P < 0.05 to P < 0.01). Notably, there was a significantly higher IL-10 mRNA levels in the large intestine of the mice (P < 0.05). The protective effect of CD226 deficiency is also associated with the accumulation of gut TCRγδ⁺ intraepithelial lymphocytes and reversion of the gut microbiome dysbiosis. The Bacteroidetes-to-Firmicutes ratio and the abundance of Akkermansia increased in the absence of CD226 after OVA treatment. Our data reveal the synchronous changes in the lung and intestine in OVA-treated CD226-knockout mice, supporting the gut-lung axis concept and providing evidence for novel therapeutic approaches for asthma.

Oncolytic virotherapy: basic principles, recent advances and future directions

Oncolytic viruses (OVs) have attracted growing awareness in the twenty-first century, as they are generally considered to have direct oncolysis and cancer immune effects. With the progress in genetic engineering technology, OVs have been adopted as versatile platforms for developing novel antitumor strategies, used alone or in combination with other therapies. Recent studies have yielded eye-catching results that delineate the promising clinical outcomes that OVs would bring about in the future. In this review, we summarized the basic principles of OVs in terms of their classifications, as well as the recent advances in OV-modification strategies based on their characteristics, biofunctions, and cancer hallmarks. Candidate OVs are expected to be designed as "qualified soldiers" first by improving target fidelity and safety, and then equipped with "cold weapons" for a proper cytocidal effect, "hot weapons" capable of activating cancer immunotherapy, or "auxiliary weapons" by harnessing tactics such as anti-angiogenesis, reversed metabolic reprogramming and decomposing extracellular matrix around tumors. Combinations with other cancer therapeutic agents have also been elaborated to show encouraging antitumor effects. Robust results from clinical trials using OV as a treatment congruously suggested its significance in future application directions and challenges in developing OVs as novel weapons for tactical decisions in cancer treatment.

MD Simulation Reveals Regulation of Mechanical Force and Extracellular Domain 2 on Binding of DNAM-1 to CD155

Two extracellular domains of the adhesive receptor DNAM-1 are involved in various cellular biological processes through binding to ligand CD155, usually under a mechano-microenvironment. The first extracellular domain (D1) plays a key role in recognition, but the function of the second extracellular domain (D2) and effects of force on the interaction of DNAM-1 with CD155 remain unclear. We herein studied the interaction of DNAM-1 with CD155 by performing steered molecular dynamics (MD) simulations, and observed the roles of tensile force and D2 on the affinity of DNAM-1 to CD155. The results showed that D2 improved DNAM-1 affinity to CD155; the DNAM-1/CD155 complex had a high mechanical strength and a better mechanical stability for its conformational conservation either at pulling with constant velocity or under constant tensile force (≤100 pN); the catch-slip bond transition governed CD155 dissociation from DNAM-1; and, together with the newly assigned key residues in the binding site, force-induced conformation changes should be responsible for the mechanical regulation of DNAM-1's affinity to CD155. This work provided a novel insight in understanding the mechanical regulation mechanism and D2 function in the interaction of DNAM-1 with CD155, as well as their molecular basis, relevant transmembrane signaling, and cellular immune responses under a mechano-microenvironment.

Nectin Family Ligands Trigger Immune Effector Functions in Health and Autoimmunity

The superfamily of immunoglobulin cell-adhesion molecules (IgCAMs) is a well-known family of cell-adhesion molecules used for immune-cell extravasation and cell–cell interaction. Amongst others, this family includes DNAX accessory molecule 1 (DNAM-1/CD226), class-I-restricted T-cell-associated molecule (CRTAM/CD355), T-cell-activated increased late expression (Tactile/CD96), T-cell immunoreceptor with Ig and ITIM domains (TIGIT), Nectins and Nectin-like molecules (Necls). Besides using these molecules to migrate towards inflammatory sites, their interactions within the immune system can support the immunological synapse with antigen-presenting cells or target cells for cytotoxicity, and trigger diverse effector functions. Although their role is generally described in oncoimmunity, this review emphasizes recent advances in the (dys)function of Nectin-family ligands in health, chronic inflammatory conditions and autoimmune diseases. In addition, this review provides a detailed overview on the expression pattern of Nectins and Necls and their ligands on different immune-cell types by focusing on human cell systems.

Tumor Cell-Intrinsic CD96 Mediates Chemoresistance and Cancer Stemness by Regulating Mitochondrial Fatty Acid β-Oxidation

Targeting CD96 that originates in immune cells has shown potential for cancer therapy. However, the role of intrinsic CD96 in solid tumor cells remains unknown. Here, it is found that CD96 is frequently expressed in tumor cells from clinical breast cancer samples and is correlated with poor long-term prognosis in these patients. The CD96⁺ cancer cell subpopulations exhibit features of both breast cancer stem cells and chemoresistance. In vivo inhibition of cancer cell-intrinsic CD96 enhances the chemotherapeutic response in a patient-derived tumor xenograft model. Mechanistically, CD96 enhances mitochondrial fatty acid β-oxidation via the CD155-CD96-Src-Stat3-Opa1 pathway, which subsequently promotes chemoresistance in breast cancer stem cells. A previously unknown role is identified for tumor cell-intrinsic CD96 and an attractive target in improving the chemotherapeutic response.

T cell-derived interleukin-22 drives the expression of CD155 by cancer cells to suppress NK cell function and promote metastasis

Although T cells can exert potent anti-tumor immunity, a subset of T helper (Th) cells producing interleukin-22 (IL-22) in breast and lung tumors is linked to dismal patient outcome. Here, we examined the mechanisms whereby these T cells contribute to disease. In murine models of lung and breast cancer, constitutional and T cell-specific deletion of Il22 reduced metastases without affecting primary tumor growth. Deletion of the IL-22 receptor on cancer cells decreases metastasis to a degree similar to that seen in IL-22-deficient mice. IL-22 induced high expression of CD155, which bound to the activating receptor CD226 on NK cells. Excessive activation led to decreased amounts of CD226 and functionally impaired NK cells, which elevated the metastatic burden. IL-22 signaling was also associated with CD155 expression in human datasets and with poor patient outcomes. Taken together, our findings reveal an immunosuppressive circuit activated by T cell-derived IL-22 that promotes lung metastasis.

CD96 as a Potential Immune Regulator in Cancers

The discovery of CTLA-4 and PD-1 checkpoints has prompted scientific researchers and the pharmaceutical industry to develop and conduct extensive research on tumor-specific inhibitors. As a result, the list of potential immune checkpoint molecules is growing over time. Receptors for nectin and nectin-like proteins have recently emerged as promising targets for cancer immunotherapy. Potential immune checkpoints, including CD226, TIGIT, and CD96, belong to this receptor class. Among them, CD96 has received little attention. In this mini-review, we aim to discuss the basic biology of CD96 as well as the most recent relevant research on this as a promising candidate for cancer immunotherapy.

Advances in therapeutic targeting of immune checkpoints receptors within the CD96-TIGIT axis: clinical implications and future perspectives

INTRODUCTION

The development of therapeutic antibodies targeting immune checkpoint molecules (ICMs) that induce long-term remissions in cancer patients has revolutionized cancer immunotherapy. However, a major drawback is that relapse after an initial response may be attributed to innate and acquired resistance. Additionally, these treatments are not beneficial to all patients. Therefore, the discovery and targeting of novel ICMs and their combination with other immunotherapeutics are urgently needed.

AREAS COVERED

There has been increasing evidence of the CD96-TIGIT axis as ICMs in cancer immunotherapy in the last five years. This review will highlight and discuss the current knowledge about the role of CD96 and TIGIT in hematological and solid tumor immunotherapy in the context of empirical studies and clinical trials, and provide a comprehensive list of ongoing cancer clinical trials on the blockade of these ICMs, as well as the rationale behind combinational therapies with anti-PD-1/PD-L1 agents, chemotherapy drugs, and radiotherapy. Moreover, we share our perspectives on anti-CD96/TIGIT-related combination therapies.

EXPERT OPINION

CD96-TIGIT axis regulates anti-tumor immune responses. Thus, the receptors within this axis are the potential candidates for cancer immunotherapy. Combining the inhibition of CD96-TIGIT with anti-PD-1/PD-L1 mAbs and chemotherapy drugs has shown relatively effective results in the context of preclinical studies and tumor models.

The Dual Blockade of the TIGIT and PD-1/PD-L1 Pathway as a New Hope for Ovarian Cancer Patients

The prognosis for ovarian cancer (OC) patients is poor and the five-year survival rate is only 47%. Immune checkpoints (ICPs) appear to be the potential targets in up-and-coming OC treatment. However, the response of OC patients to immunotherapy based on programmed cell death pathway (PD-1/PD-L1) inhibitors totals only 6-15%. The promising approach is a combined therapy, including other ICPs such as the T-cell immunoglobulin and ITIM domain/CD155/DNAX accessory molecule-1 (TIGIT/CD155/DNAM-1) axis. Preclinical studies in a murine model of colorectal cancer showed that the dual blockade of PD-1/PD-L1 and TIGIT led to remission in the whole studied group vs. the regression of the tumors with the blockade of a single pathway. The approach stimulates the effector activity of T cells and NK cells, and redirects the immune system activity against the tumor. The understanding of the synergistic action of the TIGIT and PD-1/PD-L1 blockade is, however, poor. Thus, the aim of this review is to summarize the current knowledge about the mode of action of the dual TIGIT and PD-1/PD-L1 blockade and its potential benefits for OC patients. Considering the positive impact of this combined therapy in malignancies, including lung and colorectal cancer, it appears to be a promising approach in OC treatment.

Immunotherapy targeting inhibitory checkpoints: The role of NK and other innate lymphoid cells

Monoclonal antibodies that target specific ligand-receptor signaling pathways and act as immune checkpoint inhibitors have been designed to remove the brakes in T cells and restore strong and long-term antitumor-immunity. Of note, many of these inhibitory receptors are also expressed by Innate Lymphoid Cells (ILCs), suggesting that also blockade of inhibitory pathways in innate lymphocytes has a role in the response to the treatment with checkpoint inhibitors. ILCs comprise cytotoxic NK cells and "helper" subsets and are important cellular components in the tumor microenvironment. In addition to killing tumor cells, ILCs release inflammatory cytokines, thus contributing to shape adaptive cell activation in the context of immunotherapy. Therefore, ILCs play both a direct and indirect role in the response to checkpoint blockade. Understanding the impact of ILC-mediated response on the treatment outcome would contribute to enhance immunotherapy efficacy, as still numerous patients resist or relapse.

Preliminary Analysis of Cervical Cancer Immunotherapy

Cervical cancer is one of the most common gynecologically malignancies worldwide. Although vaccine and cervical cancer screening including human papillomavirus testing, cytology testing, and colposcopy have developed rapidly in recent years, effectively reducing cervical cancer mortality, cervical cancer remains a malignancy with higher female fatality rates worldwide and has a high risk for socioeconomically disadvantaged groups. The combination of platinum-paclitaxel and chemotherapy, possibly with the addition of bevacizumab, is currently the treatment of choice for advanced cervical cancer, but it only has remission purposes. Therefore, new therapeutic strategies are needed for both locally advanced and metastatic cervical cancer. Here, we make a preliminary analysis of cervical cancer immunotherapy.

Prognostic and clinicopathological significance of CD155 expression in cancer patients: a meta-analysis

Background

It has been previously reported that CD155 is often over-expressed in a variety of cancer types. In fact, it is known to be involved in cancer development, and its role in cancer has been widely established. However, clinical and mechanistic studies involving CD155 yielded conflicting results. Thus, the present study aimed to evaluate overall prognostic value of CD155 in cancer patients, using a comprehensive analysis.

Methods

Online databases were searched, data was collected, and clinical value of CD155 was evaluated by combining hazard ratios (HRs) or odds ratios (ORs).

Results

The present study involved meta-analysis of 26 previous studies that involved 4325 cancer patients. These studies were obtained from 25 research articles. The results of the study revealed that increased CD155 expression was significantly associated with reduced OS in patients with cancer as compared to low CD155 expression (pooled HR = 1.772, 95% CI = 1.441–2.178, P < 0.001). Furthermore, subgroup analysis demonstrated that the level of CD155 expression was significantly associated with OS in patients with digestive system cancer (pooled HR = 1.570, 95% CI = 1.120–2.201, P = 0.009), hepatobiliary pancreatic cancer (pooled HR = 1.677, 95% CI = 1.037–2.712, P = 0.035), digestive tract cancer (pooled HR = 1.512, 95% CI = 1.016–2.250, P = 0.042), breast cancer (pooled HR = 2.137, 95% CI = 1.448–3.154, P < 0.001), lung cancer (pooled HR = 1.706, 95% CI = 1.193–2.440, P = 0.003), head and neck cancer (pooled HR = 1.470, 95% CI = 1.160–1.862, P = 0.001). Additionally, a significant correlation was observed between enhanced CD155 expression and advanced tumor stage (pooled OR = 1.697, 95% CI = 1.217–2.366, P = 0.002), LN metastasis (pooled OR = 1.953, 95% CI = 1.253–3.046, P = 0.003), and distant metastasis (pooled OR = 2.253, 95% CI = 1.235–4.110, P = 0.008).

Conclusion

Altogether, the results of the present study revealed that CD155 acted as an independent marker of prognosis in cancer patients, and it could provide a new and strong direction for cancer treatment.

Fcγ receptor-mediated cross-linking codefines the immunostimulatory activity of anti-human CD96 antibodies

New strategies that augment T cell responses are required to broaden the therapeutic arsenal against cancer. CD96, TIGIT, and CD226 are receptors that bind to a communal ligand, CD155, and transduce either inhibitory or activating signals. The function of TIGIT and CD226 is established, whereas the role of CD96 remains ambiguous. Using a panel of engineered antibodies, we discovered that the T cell stimulatory activity of anti-CD96 antibodies requires antibody cross-linking and is potentiated by Fcγ receptors. Thus, soluble "Fc silent" anti-CD96 antibodies failed to stimulate human T cells, whereas the same antibodies were stimulatory after coating onto plastic surfaces. Remarkably, the activity of soluble anti-CD96 antibodies was reinstated by engineering the Fc domain to a human IgG1 isotype, and it was dependent on antibody trans-cross-linking by FcγRI. In contrast, neither human IgG2 nor variants with increased Fcγ receptor IIB binding possessed stimulatory activity. Anti-CD96 antibodies acted directly on T cells and augmented gene expression networks associated with T cell activation, leading to proliferation, cytokine secretion, and resistance to Treg suppression. Furthermore, CD96 expression correlated with survival in HPV+ head and neck squamous cell carcinoma, and its cross-linking activated tumor-infiltrating T cells, thus highlighting the potential of anti-CD96 antibodies in cancer immunotherapy.

Opportunities for Nitric Oxide in Potentiating Cancer Immunotherapy

Despite nearly 30 years of development and recent highlights of nitric oxide (NO) donors and NO delivery systems in anticancer therapy, the limited understanding of exogenous NO's effects on the immune system has prevented their advancement into clinical use. In particular, the effects of exogenously delivered NO differing from that of endogenous NO has obscured how the potential and functions of NO in anticancer therapy may be estimated and exploited despite the accumulating evidence of NO's cancer therapy-potentiating effects on the immune system. After introducing their fundamentals and characteristics, this review discusses the current mechanistic understanding of NO donors and delivery systems in modulating the immunogenicity of cancer cells as well as the differentiation and functions of innate and adaptive immune cells. Lastly, the potential for the complex modulatory effects of NO with the immune system to be leveraged for therapeutic applications is discussed in the context of recent advancements in the implementation of NO delivery systems for anticancer immunotherapy applications. SIGNIFICANCE STATEMENT: Despite a 30-year history and recent highlights of nitric oxide (NO) donors and delivery systems as anticancer therapeutics, their clinical translation has been limited. Increasing evidence of the complex interactions between NO and the immune system has revealed both the potential and hurdles in their clinical translation. This review summarizes the effects of exogenous NO on cancer and immune cells in vitro and elaborates these effects in the context of recent reports exploiting NO delivery systems in vivo in cancer therapy applications.

V-Set and immunoglobulin domain containing (VSIG) proteins as emerging immune checkpoint targets for cancer immunotherapy

The development of immune checkpoint inhibitors is becoming a promising approach to fight cancers. Antibodies targeting immune checkpoint proteins such as CTLA-4 and PD-1 can reinvigorate endogenous antitumor T-cell responses and bring durable advantages to several malignancies. However, only a small subset of patients benefit from these checkpoint inhibitors. Identification of new immune checkpoints with the aim of combination blockade of multiple immune inhibitory pathways is becoming necessary to improve efficiency. Recently, several B7 family-related proteins, TIGIT, VSIG4, and VSIG3, which belong to the VSIG family, have attracted substantial attention as coinhibitory receptors during T-cell activation. By interacting with their corresponding ligands, these VSIG proteins inhibit T-cell responses and maintain an immune suppressive microenvironment in tumors. These results indicated that VSIG family members are becoming putative immune checkpoints in cancer immunotherapy. In this review, we summarized the function of each VSIG protein in regulating immune responses and in tumor progression, thus providing an overview of our current understanding of VSIG family members.

Generating Anti-TIGIT and CD155 Monoclonal Antibodies for Tumor Immunotherapy

Many studies have confirmed that the human poliovirus receptor (PVR; CD155) is related to tumor cell migration, invasion, and thus tumor progression. A PVR receptor binds its ligand T cell Ig and the ITIM domain (TIGIT) to inhibit the function of T and NK cells, thereby allowing tumors to evade immune surveillance. In this study, two IgG1 monoclonal antibodies, anti-CD155 and anti-TIGIT, were expressed by the mammalian transient transfection system, then, antibody-dependent cell-mediated cytotoxicity, antibody-binding affinity, and antitumor efficacy were evaluated subsequently in vitro. In this work, protein A affinity chromatography was used for antibodies' purification. Analysis methods included Western blot, enzyme-linked immunosorbent assay, and flow cytometry. Our data suggested that both the two monoclonal antibodies have a purity of higher than 90%, and bound tightly to the antigen with dissociation constant (K d) and 50% effective concentrations (EC50) below micromolar range. Most notably, these antibodies promote antitumor activity of immune cells in vitro. Therefore, our study laid down the foundation for subsequent in vivo experiments for further evaluation.

Sequential Single-Cell Transcriptional and Protein Marker Profiling Reveals TIGIT as a Marker of CD19 CAR-T Cell Dysfunction in Patients with Non-Hodgkin Lymphoma

Chimeric antigen receptor T-cell (CAR-T cell) therapy directed at CD19 produces durable remissions in the treatment of relapsed/refractory non-Hodgkin lymphoma (NHL). Nonetheless, many patients receiving CD19 CAR-T cells fail to respond for unknown reasons. To reveal changes in 4-1BB-based CD19 CAR-T cells and identify biomarkers of response, we used single-cell RNA sequencing and protein surface marker profiling of patient CAR-T cells pre- and postinfusion into patients with NHL. At the transcriptional and protein levels, we note the evolution of CAR-T cells toward a nonproliferative, highly differentiated, and exhausted state, with an enriched exhaustion profile in CAR-T cells of patients with poor response marked by TIGIT expression. Utilizing in vitro and in vivo studies, we demonstrate that TIGIT blockade alone improves the antitumor function of CAR-T cells. Altogether, we provide evidence of CAR-T cell dysfunction marked by TIGIT expression driving a poor response in patients with NHL.

SIGNIFICANCE

This is the first study investigating the mechanisms linked to CAR-T patient responses based on the sequential analysis of manufactured and infused CAR-T cells using single-cell RNA and protein expression data. Furthermore, our findings are the first to demonstrate an improvement of CAR-T cell efficacy with TIGIT inhibition alone. This article is highlighted in the In This Issue feature, p. 1825.

DNAM-1-chimeric receptor-engineered NK cells, combined with Nutlin-3a, more effectively fight neuroblastoma cells in vitro: a proof-of-concept study

Adoptive transfer of engineered NK cells, one of clinical approaches to fight cancer, is gaining great interest in the last decade. However, the development of new strategies is needed to improve clinical efficacy and safety of NK cell-based immunotherapy. NK cell-mediated recognition and lysis of tumor cells are strictly dependent on the expression of ligands for NK cell-activating receptors NKG2D and DNAM-1 on tumor cells. Of note, the PVR/CD155 and Nectin-2/CD112 ligands for DNAM-1 are expressed primarily on solid tumor cells and poorly expressed in normal tissue cells. Here, we generated human NK cells expressing either the full length DNAM-1 receptor or three different DNAM-1-based chimeric receptor that provide the expression of DNAM-1 fused to a costimulatory molecule such as 2B4 and CD3ζ chain. Upon transfection into primary human NK cells isolated from healthy donors, we evaluated the surface expression of DNAM-1 and, as a functional readout, we assessed the extent of degranulation, cytotoxicity and the production of IFNγ and TNFα in response to human leukemic K562 cell line. In addition, we explored the effect of Nutlin-3a, a MDM2-targeting drug able of restoring p53 functions and known to have an immunomodulatory effect, on the degranulation of DNAM-1-engineered NK cells in response to human neuroblastoma (NB) LA-N-5 and SMS-KCNR cell lines. By comparing NK cells transfected with four different plasmid vectors and through blocking experiments, DNAM-1-CD3ζ-engineered NK cells showed the strongest response. Furthermore, both LA-N-5 and SMS-KCNR cells pretreated with Nutlin-3a were significantly more susceptible to DNAM-1-engineered NK cells than NK cells transfected with the empty vector. Our results provide a proof-of-concept suggesting that the combined use of DNAM-1-chimeric receptor-engineered NK cells and Nutlin-3a may represent a novel therapeutic approach for the treatment of solid tumors, such as NB, carrying dysfunctional p53.

CD155 in tumor progression and targeted therapy

CD155, also known as the poliovirus receptor (PVR), has received considerable attention in recent years because of its intrinsic and extrinsic roles in tumor progression. Although barely expressed in host cells, CD155 is upregulated in tumor-infiltrating myeloid cells. High expression of CD155 in tumor cells across multiple cancer types is common and associated with poor patient outcomes. The intrinsic functions of CD155 in tumor cells promote tumor progression and metastasis, whereas its extrinsic immunoregulatory functions in the tumor microenvironment (TME) involve interaction with the upregulated inhibitory immune cell receptor and checkpoint TIGIT, suggesting that CD155 and CD155 pathways are promising tumor immunotherapy targets. Preclinical studies demonstrate that targeting CD155 and its receptor (anti-TIGIT) using a single treatment or in combination with anti-PD-1 can improve immune-mediated tumor control. However, there is still a limited understanding of CD155 and its associated targeting strategies, especially antibody and immune cell editing-related strategies of CD155 in cancer. Here, we review the role of CD155 in host and tumor cells in controlling tumor progression and discuss the potential of targeting CD155 for tumor therapy.

Tumor-Derived Membrane Vesicles: A Promising Tool for Personalized Immunotherapy

Tumor-derived membrane vesicles (TDMVs) are non-invasive, chemotactic, easily obtained characteristics and contain various tumor-borne substances, such as nucleic acid and proteins. The unique properties of tumor cells and membranes make them widely used in drug loading, membrane fusion and vaccines. In particular, personalized vectors prepared using the editable properties of cells can help in the design of personalized vaccines. This review focuses on recent research on TDMV technology and its application in personalized immunotherapy. We elucidate the strengths and challenges of TDMVs to promote their application from theory to clinical practice.

Circulating tumor cells from melanoma patients show phenotypic plasticity and metastatic potential in xenograft NOD.CB17 mice

Background

Innovative therapies have improved the overall survival in melanoma, although a high number of patients still experience disease progression or recurrence. Ex-vivo culture of circulating tumour cells (CTCs) represents a valuable laboratory resource for in-depth characterization of rare cell populations responsible for disease progression.

Methods

CTCs from patients with metastatic melanoma were in-vitro established. Their stemness was demonstrated by both phenotypic and genotypic assays, as well as by functional studies. Xenograft experiments in NOD.CB17 mice injected with CTCs from a single patient were completed. Data were analysed by Student’s test and results expressed as mean ± SEM.

Results

CTCs share the mutational profile with primary cells, an intermediate epithelial-mesenchymal transition (EMT) phenotype and high expression of the immunosuppressive factors. A subclonal CTC population exhibited stem cell properties as high aldehyde dehydrogenase 1 activity, melanosphere-forming ability, and expression of major stemness transcription factors. Xenograft experiments confirmed the CTC ability to generate melanoma in-vivo and revealed enhanced metastatic propensity.

Conclusions

CTCs play a relevant role in melanoma and may actively contribute to drive the disease progression and metastasis. Thus, they are a unique potential tool for pharmacogenomic studies to guide treatment strategies in advanced disease.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09829-1.

CD155 promotes radioresistance and malignancy of esophageal cancer by regulating Hippo-YAP pathway

The expression of CD155 has been observed to increase in various human cancers, but its role in the development of esophageal cancer (EC) is unclear. Radiotherapy is one of the primary therapeutic options for EC. However, radioresistance is still a severe issue in EC treatment. In this study, Oncomine database mining, immunohistochemistry, and survival analysis showed that higher expression of CD155 in patients with EC than in healthy controls. In vitro and in vivo, we found for the first time that irradiation increased the expression of CD155 in EC cells. CD155 knockdown inhibited cell proliferation and migration and tumor formation, and significantly increased radiosensitivity in EC. The in vivo model with high CD155 expression significantly promoted the proliferation and migration of EC cells. Furthermore, increased CD155 expression was associated with poor prognosis in patients with EC. CD155 regulated the Hippo-Yap pathway, influencing cell proliferation and migration. Therefore, CD155 is essential for the proliferation, migration, and radioresistance of EC. CD155 inhibition may be a viable strategy for improving radiation treatment efficacy in individuals with EC.

Clinical significance of signal regulatory protein alpha and T cell immunoreceptor with immunoglobulin and immunoreceptor tyrosine-based inhibition motif domain expression in undifferentiated pleomorphic sarcoma

PURPOSE

Undifferentiated pleomorphic sarcoma (UPS) is associated with poor prognosis. Recently, signal regulatory protein alpha (SIRPα), which is the immune checkpoint of macrophages, and T cell immunoreceptor with immunoglobulin and immunoreceptor tyrosine-based inhibition motif domains (TIGIT), which is the immune checkpoint of T cells and natural killer cells, have been considered as potential targets for cancer immunotherapy. This study aimed to assess the value of SIRPα and TIGIT as prognostic factors of UPS.

MATERIALS AND METHODS

The cBio Cancer Genomics Portal was used to analyze mRNA expression data of 50 UPS cases in the Cancer Genome Atlas. We retrieved 49 UPS cases and performed immunohistochemistry (IHC) to detect programmed death ligand 1 (PD-L1), SIRPα, CD68, CD163, TIGIT, CD155, and CD8.

RESULTS

SIRPα was positively associated with CD163 (Pearson's r = 0.51, p = 0.0002) as per open access data and IHC of the cohort (p = 0.002), which revealed that SIRPα-positive macrophage infiltration was higher in UPS cells with ≥ 1% PD-L1 expression than that in UPS cells with < 1% PD-L1 expression (p = 0.047). TIGIT was positively correlated with PD-L1 (r = 0.54, p < 0.0001) and CD8A (r = 0.98, p < 0.0001). In 35 of 49 cases, IHC revealed high levels of TIGIT expression on tumor cells. Furthermore, TIGIT expression on tumor cells was negatively correlated with CD155-positive (p = 0.0144) and CD8-positive (p = 0.0487) cell infiltration. Survival analysis showed that the high degree of SIRPα-positive macrophage infiltration was associated with poor overall survival and metastasis (p < 0.0001, p = 0.0006, respectively).

CONCLUSION

SIRPα-positive macrophages infiltrated UPS cells, which predicted poor prognosis. High TIGIT expression on tumor cells was associated with decreased levels of tumor-infiltrating macrophages in UPS.

Update in TIGIT Immune-Checkpoint Role in Cancer

The in-depth characterization of cross-talk between tumor cells and T cells in solid and hematological malignancies will have to be considered to develop new therapeutical strategies concerning the reactivation and maintenance of patient-specific antitumor responses within the patient tumor microenvironment. Activation of immune cells depends on a delicate balance between activating and inhibitory signals mediated by different receptors. T cell immunoreceptor with immunoglobulin and ITIM domain (TIGIT) is an inhibitory receptor expressed by regulatory T cells (Tregs), activated T cells, and natural killer (NK) cells. TIGIT pathway regulates T cell-mediated tumor recognition in vivo and in vitro and represents an exciting target for checkpoint blockade immunotherapy. TIGIT blockade as monotherapy or in combination with other inhibitor receptors or drugs is emerging in clinical trials in patients with cancer. The purpose of this review is to update the role of TIGIT in cancer progression, looking at TIGIT pathways that are often upregulated in immune cells and at possible therapeutic strategies to avoid tumor aggressiveness, drug resistance, and treatment side effects. However, in the first part, we overviewed the role of immune checkpoints in immunoediting, the TIGIT structure and ligands, and summarized the key immune cells that express TIGIT.

TIGIT as a Promising Therapeutic Target in Autoimmune Diseases

Co-inhibitory receptors (IRs) are molecules that protect host against autoimmune reactions and maintain peripheral self-tolerance, playing an essential role in maintaining immune homeostasis. In view of the substantial clinical progresses of negative immune checkpoint blockade in cancer treatment, the role of IRs in autoimmune diseases is also obvious. Several advances highlighted the substantial impacts of T cell immunoglobulin and ITIM domain (TIGIT), a novel IR, in autoimmunity. Blockade of TIGIT pathway exacerbates multiple autoimmune diseases, whereas enhancement of TIGIT function has been shown to alleviate autoimmune settings in mice. These data suggested that TIGIT pathway can be manipulated to achieve durable tolerance to treat autoimmune disorders. In this review, we provide an overview of characteristics of TIGIT and its role in autoimmunity. We then discuss recent approaches and future directions to leverage our knowledge of TIGIT as therapeutic target in autoimmune diseases.

Tumor FAK orchestrates immunosuppression in ovarian cancer via the CD155/TIGIT axis

High-grade serous ovarian cancer (HGSOC) is a lethal malignancy characterized by an immunosuppressive tumor microenvironment containing few tumor infiltrating lymphocytes (TILs) and an insensitivity to checkpoint inhibitor immunotherapies. Gains in the PTK2 gene encoding focal adhesion kinase (FAK) at Chr8 q24.3 occur in ∼70% of HGSOC tumors, and elevated FAK messenger RNA (mRNA) levels are associated with poor patient survival. Herein, we show that active FAK, phosphorylated at tyrosine-576 within catalytic domain, is significantly increased in late-stage HGSOC tumors. Active FAK costained with CD155, a checkpoint receptor ligand for TIGIT (T cell immunoreceptor with immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domains), in HGSOC tumors and a selective association between FAK and TIGIT checkpoint ligands were supported by patient transcriptomic database analysis. HGSOC tumors with high FAK expression were associated with low CD3 mRNA levels. Accordingly, late-stage tumors showed elevated active FAK staining and significantly lower levels of CD3+ TILs. Using the KMF (Kras, Myc, FAK) syngeneic ovarian tumor model containing spontaneous PTK2 (FAK) gene gains, the effects of tumor intrinsic genetic or oral small molecule FAK inhibitior (FAKi; VS-4718) were evaluated in vivo. Blocking FAK activity decreased tumor burden, suppressed ascites KMF-associated CD155 levels, and increased peritoneal TILs. The combination of FAKi with blocking TIGIT antibody (1B4) maintained elevated TIL levels and reduced TIGIT+ T regulatory cell levels, prolonged host survival, increased CXCL13 levels, and led to the formation of omental tertiary lymphoid structures. Collectively, our studies support FAK and TIGIT targeting as a rationale immunotherapy combination for HGSOC.

CD155 expression and its clinical significance in non‑small cell lung cancer

CD155 serves an important role in tumor progression by promoting cell proliferation and migration. CD155 is also involved in the immune evasion of tumor cells, which may cause the development and progression of tumors. Accordingly, CD155 has emerged as a novel target in cancer immunotherapy; however, its expression in lung cancer remains unclear. To assess CD155 expression and its prognostic significance, 96 patients with completely resected pathologic stage I adenocarcinoma of the lung were retrospectively reviewed. Immunohistochemical staining was performed to evaluate CD155 expression on tumor cells. Expression levels of programmed death-ligand 1 (PD-L1), another molecule participating in immune evasion, were also evaluated immunohistochemically. CD155 expression was positive in 37 patients (38.5%). CD155-positivity was associated with aggressive tumor behavior, such as pleural invasion and vascular invasion. In addition, CD155-positivity was a significant factor to predict a poor prognosis (5-year overall survival (OS) rate, 63.3% for CD155-positive patients vs. 93.1% for CD155-negative patients; P<0.001). Patients harboring tumors with positive CD155 and PD-L1 expression showed the poorest prognosis (5-year OS rate, 44.4% for both-positive patients vs. 85.4% for the other patients; P<0.001). The positive expression status of both CD155 and PD-L1 was a significant and independent unfavorable prognostic factor (hazard ratio, 3.86; 95% confidence interval, 1.51-9.89; P=0.004; in a multivariate analysis). In conclusion, CD155-positivity was associated with aggressive tumor behavior, and was a factor to predict a poor prognosis. Its prognostic impact was enhanced when combined with PD-L1 expression status. These results should be validated in a large-scale study.

Spatial proteomics finds CD155 and Endophilin-A1 as mediators of growth and invasion in medulloblastoma

The composition of the plasma membrane (PM)-associated proteome of tumor cells determines cell-cell and cell-matrix interactions and the response to environmental cues. Whether the PM-associated proteome impacts the phenotype of Medulloblastoma (MB) tumor cells and how it adapts in response to growth factor cues is poorly understood. Using a spatial proteomics approach, we observed that hepatocyte growth factor (HGF)-induced activation of the receptor tyrosine kinase c-MET in MB cells changes the abundance of transmembrane and membrane-associated proteins. The depletion of MAP4K4, a pro-migratory effector kinase downstream of c-MET, leads to a specific decrease of the adhesion and immunomodulatory receptor CD155 and of components of the fast-endophilin-mediated endocytosis (FEME) machinery in the PM-associated proteome of HGF-activated MB cells. The decreased surface expression of CD155 or of the fast-endophilin-mediated endocytosis effector endophilin-A1 reduces growth and invasiveness of MB tumor cells in the tissue context. These data thus describe a novel function of MAP4K4 in the control of the PM-associated proteome of tumor cells and identified two downstream effector mechanisms controlling proliferation and invasiveness of MB cells.

Oncolytic viruses in melanoma

Malignant melanoma recurrence remains heterogeneous in presentation, ranging from locoregional disease (i.e., local recurrence, satellites, in transit disease) to distant dermal and visceral metastases. This diverse spectrum of disease requires a personalized approach to management and has resulted in the development of both local (e.g., surgery, radiation, intralesional injection) and systemic (intravenous or oral) treatment strategies. Intralesional agents such as oncolytic viruses may also evoke local immune stimulation to induce and enhance the antitumor immune response. Further, it is hypothesized that these oncolytic viruses may convert immunologically "cold" tumors to more reactive "hot" tumor microenvironments and thereby overcome anti-PD-1 therapy resistance. Currently, talimogene laherparepvec (T-VEC), a modified herpes virus, is FDA-approved in this population, with many other oncolytic viruses under investigation in both preclinical and trial settings. Herein, we detail the scientific rationale, current landscape, and future directions of oncolytic viruses in melanoma.

High serum soluble CD155 level predicts poor prognosis and correlates with an immunosuppressive tumor microenvironment in hepatocellular carcinoma

Background

Hepatocellular carcinoma (HCC) is one of the most prevalent malignancies with poor prognosis. There is no research about the clinical significance of serum soluble CD155 (sCD155) level for HCC. We aim to explore the prognostic and diagnostic value of sCD155 in HCC patients undergoing curative resection.

Methods

Serum sCD155 level in HCC patients was determined by enzyme‐linked immunosorbent assay. The prognostic significance of sCD155 was evaluated by Cox regression and Kaplan–Meier analyses. CD155 expression and biomarkers of immune cells in HCC tissues were detected by immunohistochemistry staining. The diagnostic significance of sCD155 was evaluated using receiver operating characteristic curve.

Results

Serum sCD155 level was significantly increased in HCC patients and predicted poor prognosis. The prognostic value of sCD155 remained in low recurrent risk subgroups of HCC. Serum sCD155 level was positively related to CD155 expression in HCC tissues. High serum sCD155 level was associated with decreased numbers of CD8⁺T cells and CD56⁺NK cells and increased number of CD163⁺M2 macrophages. Serum sCD155 level had better performance in distinguishing HCC patients from healthy donors and patients with chronic liver conditions than α‐fetoprotein. Among patients with α‐fetoprotein ≤ 20 ng/ml, serum sCD155 level could differentiate HCC patients from non‐HCC patients.

Conclusion

Serum sCD155 level represents a promising biomarker for diagnosis and prognosis of HCC. High serum sCD155 level may reflect an immunosuppressive tumor microenvironment in HCC.

CD155/TIGIT signaling regulates the effector function of tumor-infiltrating CD8+ T cell by NF-κB pathway in colorectal cancer

BACKGROUND AND AIM

CD155/T-cell immunoglobulin and ITIM domain (TIGIT) suppressed anti-cancer immunity in several cancers, but its roles in colorectal cancer (CRC) were not clear. Here, we investigated its roles in CRC.

METHODS

The percentages of CD8⁺ T cells expressing TIGIT and secreting cytokines (IL-2, TNF-α, and IFNγ) were evaluated by flow cytometry. The expression level of CD155 was determined by western blot and immunohistochemistry. The levels of cytokines were determined by enzyme-linked immunosorbent assay. The activation of the nuclear factor-kappa B (NF-κB) pathway was examined by western blot and immunofluorescent assay.

RESULTS

T-cell immunoglobulin and ITIM domain was overexpressed on CD8⁺ T cells of CRC patients and mice. CD155 was overexpressed in mice CRC tissues and cells. The addition of CD155 recombinant protein could decrease the percentages of CD8⁺ T cells secreting cytokines. Blocking TIGIT could increase the percentages of cytokine-secreting CD8⁺ T cells. Coculturing with CD155-knockdown CRC cells could upregulate the percentages of CD8⁺ T cells secreting cytokines. Blocking TIGIT partially counteracted the effect of the knockdown of CD155. Besides, coculturing with CD155-knockdown CRC cells could promote the secretion of cytokines, activate the NF-κB pathway, and enhance the nuclear translocation of p65. And these effects were counteracted by the application of an NF-κB inhibitor. Finally, blocking TIGIT played anti-cancer roles such as suppression of tumor growth, increasing the percentages of cytokine-secreting CD8⁺ T cells and activation of the NF-κB signaling pathway.

CONCLUSION

Suppressing CD155/TIGIT exerted anti-cancer effects against CRC, and our findings provided a potential therapeutic approach to treat CRC.