T cells targeting NY-ESO-1 demonstrate efficacy against disseminated neuroblastoma

Identification of Core Techniques That Enhance Genome Editing of Human T Cells Expressing Synthetic Antigen Receptors

Genome editing technologies have seen remarkable progress in recent years, enabling precise regulation of exogenous and endogenous genes. These advances have been extensively applied to the engineering of human T lymphocytes, leading to the development of practice changing therapies for patients with cancer and the promise of synthetic immune cell therapies for a variety of nonmalignant diseases. Many distinct conceptual and technical approaches have been used to edit T-cell genomes, however targeted assessments of which techniques are most effective for manufacturing, gene editing, and transgene expression are rarely reported. Through extensive comparative evaluation, we identified methods that most effectively enhance engineering of research-scale and preclinical T-cell products at critical stages of manufacturing.

Adoptive cell therapy in paediatric extracranial solid tumours: current approaches and future challenges

Immunotherapy has ignited hope to cure paediatric solid tumours that resist traditional therapies. Among the most promising methods is adoptive cell therapy (ACT). Particularly, ACT using T cells equipped with chimeric antigen receptors (CARs) has moved into the spotlight in clinical studies. However, the efficacy of ACT is challenged by ACT-intrinsic factors, like lack of activation or T cell exhaustion, as well as immune evasion strategies of paediatric solid tumours, such as their highly immunosuppressive microenvironment. Novel strategies, including ACT using innate-like lymphocytes, innovative cell engineering techniques, and ACT combination therapies, are being developed and will be crucial to overcome these challenges. Here, we discuss the main classes of ACT for the treatment of paediatric extracranial solid tumours, reflect on the available preclinical and clinical evidence supporting promising strategies, and address the challenges that ACT is still facing. Ultimately, we highlight state-of-the-art developments and opportunities for new therapeutic options, which hold great potential for improving outcomes in this challenging patient population.

Expression Pattern of Tumor-associated Antigens in Neuroblastoma: Association With Cytogenetic Features and Survival

Background/Aim

The prognosis of high-risk and relapsed neuroblastoma (NB) patients remains poor. The identification of tumor-associated markers is important for differential diagnosis, prognosis, and the development of targeted therapies. The aim of the study was to determine the expression profile of nine most common NB antigens and assess their association with clinicopathological characteristics and patient survival.

Patients and Methods

Tumor samples from 86 patients with NB were evaluated for the expression of tumor-associated antigen (TAA) using quantitative PCR. Twenty-one patients with benign tumors and 17 healthy donors were assigned as controls.

Results

Overexpression of tyrosine hydroxylase (TH), PHOX2B, PRAME, GPC2, B7-H3, and Survivin is the most typical for NB. Positive expression of MAGEA3, MAGEA1, and NY-ESO-1 at low levels was detected in 54%, 48%, and 52%, respectively, and was not NB specific. Higher TH expression was observed in samples without MYCN-amplification, while higher expression of Survivin, PHOX2B, and GPC2 was significantly associated with the presence of 1p.36 deletion. Overexpression of TH, PHOX2B, and MAGEA1 was associated with better event-free (EFS) and overall survival (OS). Survivin overexpression was associated with poor EFS but had no impact on OS. Multivariate analysis confirmed Survivin as independent marker for poor survival, and PHOX2B and MAGEA1 for better survival.

Conclusion

High expression of TH, PHOX2B, and MAGEA1 genes are favorable prognostic factors for OS and EFS, whereas high expression of Survivin is associated with an increased risk of relapse or progression.

Immune responses against shared antigens are common in esophago-gastric cancer and can be enhanced using CD40-activated B cells

BACKGROUND

Specific immune response is a hallmark of cancer immunotherapy and shared tumor-associated antigens (TAAs) are important targets. Recent advances using combined cellular therapy against multiple TAAs renewed the interest in this class of antigens. Our study aims to determine the role of TAAs in esophago-gastric adenocarcinoma (EGA).

METHODS

RNA expression was assessed by NanoString in tumor samples of 41 treatment-naïve EGA patients. Endogenous T cell and antibody responses against the 10 most relevant TAAs were determined by FluoroSpot and protein-bound bead assays. Digital image analysis was used to evaluate the correlation of TAAs and T-cell abundance. T-cell receptor sequencing, in vitro expansion with autologous CD40-activated B cells (CD40Bs) and in vitro cytotoxicity assays were applied to determine specific expansion, clonality and cytotoxic activity of expanded T cells.

RESULTS

68.3% of patients expressed ≥5 TAAs simultaneously with coregulated clusters, which were similar to data from The Cancer Genome Atlas (n=505). Endogenous cellular or humoral responses against ≥1 TAA were detectable in 75.0% and 53.7% of patients, respectively. We found a correlation of T-cell abundance and the expression of TAAs and genes related to antigen presentation. TAA-specific T-cell responses were polyclonal, could be induced or enhanced using autologous CD40Bs and were cytotoxic in vitro. Despite the frequent expression of TAAs co-occurrence with immune responses was rare.

CONCLUSIONS

We identified the most relevant TAAs in EGA for monitoring of clinical trials and as therapeutic targets. Antigen-escape rather than missing immune response should be considered as mechanism underlying immunotherapy resistance of EGA.

Neoantigens in precision cancer immunotherapy: from identification to clinical applications

Immunotherapies targeting cancer neoantigens are safe, effective, and precise. Neoantigens can be identified mainly by genomic techniques such as next-generation sequencing and high-throughput single-cell sequencing; proteomic techniques such as mass spectrometry; and bioinformatics tools based on high-throughput sequencing data, mass spectrometry data, and biological databases. Neoantigen-related therapies are widely used in clinical practice and include neoantigen vaccines, neoantigen-specific CD8+ and CD4+ T cells, and neoantigen-pulsed dendritic cells. In addition, neoantigens can be used as biomarkers to assess immunotherapy response, resistance, and prognosis. Therapies based on neoantigens are an important and promising branch of cancer immunotherapy. Unremitting efforts are needed to unravel the comprehensive role of neoantigens in anti-tumor immunity and to extend their clinical application. This review aimed to summarize the progress in neoantigen research and to discuss its opportunities and challenges in precision cancer immunotherapy.

Synergistic Therapeutic Effects of Low Dose Decitabine and NY-ESO-1 Specific TCR-T Cells for the Colorectal Cancer With Microsatellite Stability

Patients of colorectal cancer (CRC) with microsatellite stability (MSS) show poor clinical response and little beneficial result from the immune-checkpoint inhibitors, due to the ‘cold’ tumor microenvironment. Meanwhile, decitabine can drive the ‘cold’ microenvironment towards ‘hot’ in multiple ways, such as upregulating the tumor associated antigen (TAA) and human leukocyte antigen (HLA) molecular. NY-ESO-1, one of the most important TAAs, can be observably induced in tumors by low dose decitabine, and present itself as ideal targets for antigen specific T cell receptor engineered T (TCR-T) cells. We innovatively used a synergistic tactic, combining decitabine and NY-ESO-1 specific TCR-T cells, for fighting the MSS CRC. Firstly, we confirmed the lysing effect of the NY-ESO-1 TCR-T cells on the NY-ESO-1⁺ and HLA-A2⁺ cells in vitro and in vivo. In A375 tumor-bearing mice, the results showed that NY-ESO-1 TCR-T cell therapy could inhibit A375 tumor growth and prolonged the survival time. Furthermore, the synergistic effect of decitabine and NY-ESO-1 TCR-T cells was shown to induce an even higher percentage of tumor cells being lysed in vitro than other control groups, and more potent tumor inhibition and longer survival time were observed in vivo. The innovative synergistic therapeutic strategy of decitabine and TCR-T cells for the CRC with MSS may be also effective in the treatment of other epithelial malignancies. Decitabine may likewise be adopted in combination with other cellular immunotherapies.

Development of Cancer Immunotherapies

Cancer immunotherapy, or the utilization of components of the immune system to target and eliminate cancer, has become a highly active area of research in the past several decades and a common treatment strategy for several cancer types. The concept of harnessing the immune system for this purpose originated over 100 years ago when a physician by the name of William Coley successfully treated several of his cancer patients with a combination of live and attenuated bacteria, later known as "Coley's Toxins", after observing a subset of prior patients enter remission following their diagnosis with the common bacterial infection, erysipelas. However, it was not until late in the twentieth century that cancer immunotherapies were developed for widespread use, thereby transforming the treatment landscape of numerous cancer types. Pivotal studies elucidating molecular and cellular functions of immune cells, such as the discovery of IL-2 and production of monoclonal antibodies, fostered the development of novel techniques for studying the immune system and ultimately the development and approval of several cancer immunotherapies by the United States Food and Drug Association in the 1980s and 1990s, including the tuberculosis vaccine-Bacillus Calmette-Guérin, IL-2, and the CD20-targeting monoclonal antibody. Approval of the first therapeutic cancer vaccine, Sipuleucel-T, for the treatment of metastatic castration-resistant prostate cancer and the groundbreaking success and approval of immune checkpoint inhibitors and chimeric antigen receptor T cell therapy in the last decade, have driven an explosion of interest in and pursuit of novel cancer immunotherapy strategies. A broad range of modalities ranging from antibodies to adoptive T cell therapies is under investigation for the generalized treatment of a broad spectrum of cancers as well as personalized medicine. This chapter will focus on the recent advances, current strategies, and future outlook of immunotherapy development for the treatment of cancer.

NY-ESO-1 as a diagnostic and prognostic marker for myxoid liposarcoma

INTRODUCTION

Myxoid liposarcoma (MLS) is a common lipogenic sarcoma, which is difficult to diagnose in small specimens. New York oesophageal squamous cell carcinoma 1 (NY-ESO-1) is a cancer-testis antigen expressed in neoplastic tissue. In this study, NY-ESO-1 expression was assessed in various soft tissue tumors (STTs), and we also evaluated its diagnostic utility.

METHODS

We included 434 cases of STTs for collection of clinicopathological data. Tissue microarrays were designed, and immunostaining for NY-ESO-1 was examined. We investigated the correlation between NY-ESO-1 expression and various clinicopathological parameters. We also evaluated the role of NY-ESO-1 as a diagnostic marker for MLS and its possible use in prognostication.

RESULTS

Sixty-four of the 434 STTs (14.75%) were immunoreactive for NY-ESO-1, and the most frequent type of tumor in the NY-ESO-1 positive group was MLS (70.3%, 45/64), followed by synovial sarcoma (17.2%, 11/64). MLS showed 72.6% (45/62) immunopositivity for NY-ESO-1. The sensitivity and specificity of NY-ESO-1 expression for the diagnosis of MLS were 84.4% and 100%, respectively, compared to DDIT3 fluorescence in situ hybridization. When restricting analysis to the MLS (n=62), the NY-ESO-1 positive group had a poor overall survival (OS) rate (P=0.039).

CONCLUSION

NY-ESO-1 was substantially and widely expressed in the majority of MLS cases. NY-ESO-1 positivity by IHC staining was also a predictor of a poor OS in patients with MLS. It is possible to use NY-ESO-1 for diagnosis and for predicting a prognosis in patients with MLS, and it may be used as a therapeutic target.

Genetically Modified T Cells for Esophageal Cancer Therapy: A Promising Clinical Application

Esophageal cancer is an exceedingly aggressive and malignant cancer that imposes a substantial burden on patients and their families. It is usually treated with surgery, chemotherapy, radiotherapy, and molecular-targeted therapy. Immunotherapy is a novel treatment modality for esophageal cancer wherein genetically engineered adoptive cell therapy is utilized, which modifies immune cells to attack cancer cells. Using chimeric antigen receptor (CAR) or T cell receptor (TCR) modified T cells yielded demonstrably encouraging efficacy in patients. CAR-T cell therapy has shown robust clinical results for malignant hematological diseases, particularly in B cell-derived malignancies. Natural killer (NK) cells could serve as another reliable and safe CAR engineering platform, and CAR-NK cell therapy could be a more generalized approach for cancer immunotherapy because NK cells are histocompatibility-independent. TCR-T cells can detect a broad range of targeted antigens within subcellular compartments and hold great potential for use in cancer therapy. Numerous studies have been conducted to evaluate the efficacy and feasibility of CAR and TCR based adoptive cell therapies (ACT). A comprehensive understanding of genetically-modified T cell technologies can facilitate the clinical translation of these adoptive cell-based immunotherapies. Here, we systematically review the state-of-the-art knowledge on genetically-modified T-cell therapy and provide a summary of preclinical and clinical trials of CAR and TCR-transgenic ACT.

Chimeric Antigen Receptor (CAR) T Cell Therapy for Metastatic Melanoma: Challenges and Road Ahead

Metastatic melanoma is the most aggressive and difficult to treat type of skin cancer, with a survival rate of less than 10%. Metastatic melanoma has conventionally been considered very difficult to treat; however, recent progress in understanding the cellular and molecular mechanisms involved in the tumorigenesis, metastasis and immune escape have led to the introduction of new therapies. These include targeted molecular therapy and novel immune-based approaches such as immune checkpoint blockade (ICB), tumor-infiltrating lymphocytes (TILs), and genetically engineered T-lymphocytes such as chimeric antigen receptor (CAR) T cells. Among these, CAR T cell therapy has recently made promising strides towards the treatment of advanced hematological and solid cancers. Although CAR T cell therapy might offer new hope for melanoma patients, it is not without its shortcomings, which include off-target toxicity, and the emergence of resistance to therapy (e.g., due to antigen loss), leading to eventual relapse. The present review will not only describe the basic steps of melanoma metastasis, but also discuss how CAR T cells could treat metastatic melanoma. We will outline specific strategies including combination approaches that could be used to overcome some limitations of CAR T cell therapy for metastatic melanoma.

Neoantigen Specific T Cells Derived From T Cell-Derived Induced Pluripotent Stem Cells for the Treatment of Hepatocellular Carcinoma: Potential and Challenges

Immunotherapy has become an indispensable part of the comprehensive treatment of hepatocellular carcinoma (HCC). Immunotherapy has proven effective in patients with early HCC, advanced HCC, or HCC recurrence after liver transplantation. Clinically, the most commonly used immunotherapy is immune checkpoint inhibition using monoclonal antibodies, such as CTLA-4 and PD-1. However, it cannot fundamentally solve the problems of a weakened immune system and inactivation of immune cells involved in killing tumor cells. T cells can express tumor antigen-recognizing T cell receptors (TCRs) or chimeric antigen receptors (CARs) on the cell surface through gene editing to improve the specificity and responsiveness of immune cells. According to previous studies, TCR-T cell therapy is significantly better than CAR-T cell therapy in the treatment of solid tumors and is one of the most promising immune cell therapies for solid tumors so far. However, its application in the treatment of HCC is still being researched. Technological advancements in induction and redifferentiation of induced pluripotent stem cells (iPSCs) allow us to use T cells to induce T cell-derived iPSCs (T-iPSCs) and then differentiate them into TCR-T cells. This has allowed a convenient strategy to study HCC models and explore optimal treatment strategies. This review gives an overview of the major advances in the development of protocols to generate neoantigen-specific TCR-T cells from T-iPSCs. We will also discuss their potential and challenges in the treatment of HCC.

Strategies to Improve Chimeric Antigen Receptor Therapies for Neuroblastoma

Chimeric antigen receptors (CARs) are among the curative immunotherapeutic approaches that exploit the antigen specificity and cytotoxicity function of potent immune cells against cancers. Neuroblastomas, the most common extracranial pediatric solid tumors with diverse characteristics, could be a promising candidate for using CAR therapies. Several methods harness CAR-modified cells in neuroblastoma to increase therapeutic efficiency, although the assessment has been less successful. Regarding the improvement of CARs, various trials have been launched to overcome insufficient capacity. However, the reasons behind the inadequate response against neuroblastoma of CAR-modified cells are still not well understood. It is essential to update the present state of comprehension of CARs to improve the efficiency of CAR therapies. This review summarizes the crucial features of CARs and their design for neuroblastoma, discusses challenges that impact the outcomes of the immunotherapeutic competence, and focuses on devising strategies currently being investigated to improve the efficacy of CARs for neuroblastoma immunotherapy.

Bioengineered tissue models for the development of dynamic immuno-associated tumor models and high-throughput immunotherapy cytotoxicity assays

Cancer immunotherapy is rapidly developing, with numerous therapies approved over the past decade and more therapies expected to gain approval in the future. However, immunotherapy of solid tumors has been less successful because immunosuppressive barriers limit immune cell trafficking and function against cancer cells. Interactions between suppressive immune cells, cytokines, and inhibitory factors are central to cancer immunotherapy approaches. In this review, we discuss recent advances in utilizing microfluidic platforms for understanding cancer-suppressive immune system interactions. Dendritic cell (DC)-mediated tumor models, infiltrated lymphocyte-mediated tumor models [e.g., natural killer (NK) cells, T cells, chimeric antigen receptor (CAR) T cells, and macrophages], monocyte-mediated tumor models, and immune checkpoint blockade (ICB) tumor models are among the various bioengineered immune cell-cancer cell interactions that we reviewed herein.

Metastatic Burden Defines Clinically and Biologically Distinct Subgroups of Stage 4 High-Risk Neuroblastoma

This study aimed to identify the prognostic subgroups of stage 4 high-risk neuroblastoma based on metastatic burden and explore their distinct clinical and genomic features. Patients aged ≥18 months with stage 4 and metaiodobenzylguanidine-avid neuroblastoma were enrolled. One hundred and thirty eligible patients were treated under the tandem high-dose chemotherapy scheme. Prognostic significance of metastatic burden measured by the modified Curie score was analyzed using a competing risk approach, and the optimal cut-point was determined. Metastasis-specific subgroups (cut-point: 26) were compared using clinicopathological variables, and differential gene expression analysis and gene set variation analysis (GSVA) were performed using RNA sequencing (RNA-seq). Metastatic burden at diagnosis showed a progressive association with relapse/progression. After applying the cut-point, patients with high metastatic burden showed >3-fold higher risk of relapse/progression than those with low metastatic burden. Moreover, patients with high metastatic burden showed smaller primary tumors and higher biochemical marker levels than those with low metastatic burden. In the genomic analysis, 51 genes were found to be differentially expressed based on the set criteria. GSVA revealed 55 gene sets, which significantly distinguished patients with high metastatic burden from those with low metastatic burden at a false discovery rate <0.25. The results indicated the prognostic significance of metastatic burden in stage 4 high-risk neuroblastoma, and we identified the distinct clinicopathological and genomic features based on metastatic burden. This study may aid in the better understanding and risk-stratification of stage 4 high-risk neuroblastoma patients.

Nanoformulation of CCL21 greatly increases its effectiveness as an immunotherapy for neuroblastoma

Neuroblastoma is the most commonly diagnosed extracranial solid tumor in children. The patients with aggressive metastatic disease or refractory/relapsed neuroblastoma currently face a dismally low chance of survival. Thus, there is a great need for more effective therapies for this illness. In previous studies, we, as well as others, showed that the immune cell chemoattractant C-C motif chemokine ligand 21 (CCL21) is effective as an intratumoral therapy able to slow the growth of cancers. In this current study, we developed and tested an injectable, slow-release, uniform, and optimally loaded alginate nanoformulation of CCL21 as a means to provide prolonged intratumoral treatment. The alginate-nanoformulated CCL21, when injected intratumorally into mice bearing neuroblastoma lesions, significantly prolonged survival and decreased the tumor growth rate compared to CCL21 alone, empty nanoparticles, or buffer. Notably, we also observed complete tumor clearance and subsequent full protection against tumor rechallenge in 33% of nanoformulated CCL21-treated mice. Greater intratumoral presence of nanoformulated CCL21, compared to free CCL21, at days 1 and 2 after treatment ended was confirmed through fluorescent labeling and tracking. Nanoformulated CCL21-treated tumors exhibited a general pattern of prolonged increases in anti-tumor cytokines and relatively lower levels of pro-tumor cytokines in comparison to tumors treated with CCL21 alone or buffer only. Thus, this novel nanoformulation of CCL21 is an effective treatment for neuroblastoma, and may have potential for the delivery of CCL21 to other types of solid tumors in the future and as a slow-release delivery modality for other immunotherapies.

Antibodies specific for disease-associated antigens (DAA) expressed in non-malignant diseases reveal potential new tumor-associated antigens (TAA) for immunotherapy or immunoprevention

Immune responses to a large number of mutated and non-mutated tumor antigens have been studied in an attempt to unravel the highly complex immune response to cancer. Better understanding of both the effectors and the targets of successful immunosurveillance can inform various immunotherapeutic approaches, which can strengthen or replace natural immunosurveillance that a tumor has managed to escape. In this review we highlight targets of antibodies generated in the context of diseases other than cancer, such as asthma, allergies, autoimmune disorders, inflammation and infections, where the antibody presence correlates either with an increased or a reduced lifetime risk of cancer. We focus on their target antigens, self-molecules abnormally expressed on diseased cells or cross-reactive with exogenous antigens and found on cancer cells as tumor associated antigens (TAA). We refer to them as disease-associated antigens (DAA). We review 4 distinct categories of antibodies according to their target DAA, their origin and their reported impact on cancer risk: natural antibodies, autoantibodies, long-term memory antibodies and allergy-associated antibodies. Increased understanding and focus on their specific targets could enable a more rational choice of antigens for both therapeutic and preventative cancer vaccines and other more effective and less toxic cancer immunotherapies.

Unleashing the immune response to NY-ESO-1 cancer testis antigen as a potential target for cancer immunotherapy

INTRODUCTION

Cancer Immunotherapy has recently emerged as a promising and effective modality to treat different malignancies. Antigenic profiling of cancer tissues and determination of any pre-existing immune responses to cancer antigens may help predict responses to immune intervention in cancer. NY-ESO-1, a cancer testis antigen is the most immunogenic antigen to date. The promise of NY-ESO-1 as a candidate for specific immune recognition of cancer comes from its restricted expression in normal adult tissue but frequent occurrence in multiple tumors including melanoma and carcinomas of lung, esophageal, liver, gastric, prostrate, ovarian, and bladder.

MAIN BODY

This review summarizes current knowledge of NY-ESO-1 as efficient biomarker and target of immunotherapy. It also addresses limitations and challenges preventing a robust immune response to NY-ESO-1 expressing cancers, and describes pre-clinical and clinical observations relevant to NY-ESO-1 immunity, holding potential therapeutic relevance for cancer treatment.

CONCLUSION

NY-ESO-1 induces strong immune responses in cancer patients but has limited objective clinical responses to NY-ESO-1 expressing tumors due to effect of competitive negative signaling from immune-checkpoints and immune-suppressive tumor microenvironment. We propose that combination therapy to increase the efficacy of NY-ESO-1 specific immunotherapeutic interventions should be explored to unleash the immune response against NY-ESO-1 expressing tumors.

Monitoring Immune Responses in Neuroblastoma Patients during Therapy

Neuroblastoma (NBL) is the most common extracranial solid tumor in childhood. Despite intense treatment, children with this high-risk disease have a poor prognosis. Immunotherapy showed a significant improvement in event-free survival in high-risk NBL patients receiving chimeric anti-GD2 in combination with cytokines and isotretinoin after myeloablative consolidation therapy. However, response to immunotherapy varies widely, and often therapy is stopped due to severe toxicities. Objective markers that help to predict which patients will respond or develop toxicity to a certain treatment are lacking. Immunotherapy guided via immune monitoring protocols will help to identify responders as early as possible, to decipher the immune response at play, and to adjust or develop new treatment strategies. In this review, we summarize recent studies investigating frequency and phenotype of immune cells in NBL patients prior and during current treatment protocols and highlight how these findings are related to clinical outcome. In addition, we discuss potential targets to improve immunogenicity and strategies that may help to improve therapy efficacy. We conclude that immune monitoring during therapy of NBL patients is essential to identify predictive biomarkers to guide patients towards effective treatment, with limited toxicities and optimal quality of life.

Genetically engineered T cells for cancer immunotherapy

T cells in the immune system protect the human body from infection by pathogens and clear mutant cells through specific recognition by T cell receptors (TCRs). Cancer immunotherapy, by relying on this basic recognition method, boosts the antitumor efficacy of T cells by unleashing the inhibition of immune checkpoints and expands adaptive immunity by facilitating the adoptive transfer of genetically engineered T cells. T cells genetically equipped with chimeric antigen receptors (CARs) or TCRs have shown remarkable effectiveness in treating some hematological malignancies, although the efficacy of engineered T cells in treating solid tumors is far from satisfactory. In this review, we summarize the development of genetically engineered T cells, outline the most recent studies investigating genetically engineered T cells for cancer immunotherapy, and discuss strategies for improving the performance of these T cells in fighting cancers.

State of the art in immunotherapy of neuroblastoma

Neuroblastoma (NB) is a common and deadly malignancy mostly observed in children. Evolution of therapeutic options for NB led to the addition of immunotherapeutic modalities to the previously recruited chemotherapeutic options. Molecular studies of the NB cells resulted in the discovery of many tumor-associated genes and antigens such as MYCN gene and GD2. MYCN gene and GD2 surface antigen are two of the most practical discoveries regarding immunotherapy of neuroblastoma. The GD2 antigen has been targeted in many animal and human studies including Phase III clinical trials. Even though these antigens have changed the face of pediatric neuroblastoma, they do not take as much credit in immunotherapy of adult-onset neuroblastoma. Monoclonal antibodies have been designed to detect this antigen on the surface of NB tumor cells. Despite bettering the outcomes for NB patients, current therapies still fail in many cases. Studies are underway to discover more specific tumor-associated antigens and more effective treatment options. In the current narrative, immunotherapy of NB - from emerging of this therapeutic backbone in NB to the latest discoveries regarding this malignancy - has been reviewed.

CAR T Cells for Solid Tumors: New Strategies for Finding, Infiltrating, and Surviving in the Tumor Microenvironment

Chimeric antigen receptor (CAR) T cells, T cells that have been genetically engineered to express a receptor that recognizes a specific antigen, have given rise to breakthroughs in treating hematological malignancies. However, their success in treating solid tumors has been limited. The unique challenges posed to CAR T cell therapy by solid tumors can be described in three steps: finding, entering, and surviving in the tumor. The use of dual CAR designs that recognize multiple antigens at once and local administration of CAR T cells are both strategies that have been used to overcome the hurdle of localization to the tumor. Additionally, the immunosuppressive tumor microenvironment has implications for T cell function in terms of differentiation and exhaustion, and combining CARs with checkpoint blockade or depletion of other suppressive factors in the microenvironment has shown very promising results to mitigate the phenomenon of T cell exhaustion. Finally, identifying and overcoming mechanisms associated with dysfunction in CAR T cells is of vital importance to generating CAR T cells that can proliferate and successfully eliminate tumor cells. The structure and costimulatory domains chosen for the CAR may play an important role in the overall function of CAR T cells in the TME, and “armored” CARs that secrete cytokines and third- and fourth-generation CARs with multiple costimulatory domains offer ways to enhance CAR T cell function.

Novel Immunotherapeutic Approaches for Neuroblastoma and Malignant Melanoma

Neuroblastoma (NB) and malignant melanoma (MM), tumors of pediatric age and adulthood, respectively, share a common origin, both of them deriving from the neural crest cells. Although NB and MM have a different behavior, in respect to age of onset, primary tissue involvement and metastatic spread, the prognosis for high stage-affected patients is still poor, in spite of aggressive treatment strategies and the huge amount of new discovered biological knowledge. For these reasons researchers are continuously attempting to find out new treatment options, which in a near future could be translated to the clinical practice. In the last two decades, a strong effort has been spent in the field of translational research of immunotherapy which led to satisfactory results. Indeed, several immunotherapeutic clinical trials have been performed and some of them also resulted beneficial. Here, we summarize preclinical studies based on immunotherapeutic approaches applied in models of both NB and MM.

Immune landscape and in vivo immunogenicity of NY-ESO-1 tumor antigen in advanced neuroblastoma patients

BACKGROUND

Indirect evidence suggesting the immunosensitivity/immunogenicity of neuroblastoma is accumulating. The aims of this study were to investigate the immune landscape of neuroblastoma and to evaluate the in vivo immunogenicity of the NY-ESO-1 tumor antigen in advanced neuroblastoma patients.

METHODS

The immune infiltrating cells of the NY-ESO-1+ tumors from three HLA*A201 patients with metastatic neuroblastoma who relapsed after conventional treatments were evaluated by immunohistochemistry. The patients were vaccinated with the HLA-A*0201-restricted peptide NY-ESO-1_157-165(V). The peptide was emulsified in Montanide ISA51 and given subcutaneously in a phase I pilot study. The immunogenicity of NY-ESO-1 antigen was evaluated by monitoring mononuclear cells in patient peripheral blood, pre- and post-vaccine, by short-term in vitro sensitization, HLA-multimer staining and IFN-γ ELISpot analysis.

RESULTS

Both CD3 T cells and CD163 myeloid cells were present in pre-vaccine tumors and PD-1 and PD-L1 expression was mainly found in the immune infiltrate. Despite the advanced stage of the disease, the vaccination induced systemic NY-ESO-1 specific CD8 T cells releasing IFN-γ in response to activation with the NY-ESO-1 peptide and an HLA-A2 positive neuroblastoma cell line.

CONCLUSIONS

Our results indicate that vaccination with a tumor-associated peptide is able to boost NY-ESO-1-specific, functionally active T cells in advanced neuroblastoma patients with lymphocyte infiltration in their pre-vaccine tumors.

TRIAL REGISTRATION

EudraCT #2006-002859-33.

Adoptive Cell Therapy in Treating Pediatric Solid Tumors

PURPOSE OF REVIEW

This review will discuss the challenges facing adoptive cell techniques in the treatment of solid tumors and examine the therapies that are in development for specifically pediatric solid tumors.

RECENT FINDINGS

Targeting solid tumors with adoptive cell therapy has been limited by the inhibitory tumor microenvironment and heterogeneous expression of targetable antigens. Many creative strategies to overcome these limitations are being developed but still need to be tested clinically. Early phase clinical trials in neuroblastoma with GD2 CAR T cells are promising but results need to be validated on a larger scale. Most research in other pediatric solid tumors is still in early stages. Adoptive cell therapy represents a useful tool to improve the outcomes of many pediatric solid tumors but significant study is still required. Several clinical trials are ongoing to test therapies that have shown promise in the lab.

Systematic identification of cancer-specific MHC-binding peptides with RAVEN

Immunotherapy can revolutionize anti-cancer therapy if specific targets are available. Immunogenic peptides encoded by cancer-specific genes (CSGs) may enable targeted immunotherapy, even of oligo-mutated cancers, which lack neo-antigens generated by protein-coding missense mutations. Here, we describe an algorithm and user-friendly software named RAVEN (Rich Analysis of Variable gene Expressions in Numerous tissues) that automatizes the systematic and fast identification of CSG-encoded peptides highly affine to Major Histocompatibility Complexes (MHC) starting from transcriptome data. We applied RAVEN to a dataset assembled from 2,678 simultaneously normalized gene expression microarrays comprising 50 tumor entities, with a focus on oligo-mutated pediatric cancers, and 71 normal tissue types. RAVEN performed a transcriptome-wide scan in each cancer entity for gender-specific CSGs, and identified several established CSGs, but also many novel candidates potentially suitable for targeting multiple cancer types. The specific expression of the most promising CSGs was validated in cancer cell lines and in a comprehensive tissue-microarray. Subsequently, RAVEN identified likely immunogenic CSG-encoded peptides by predicting their affinity to MHCs and excluded sequence identity to abundantly expressed proteins by interrogating the UniProt protein-database. The predicted affinity of selected peptides was validated in T2-cell peptide-binding assays in which many showed binding-kinetics like a very immunogenic influenza control peptide. Collectively, we provide an exquisitely curated catalogue of cancer-specific and highly MHC-affine peptides across 50 cancer types, and a freely available software (https://github.com/JSGerke/RAVENsoftware) to easily apply our algorithm to any gene expression dataset. We anticipate that our peptide libraries and software constitute a rich resource to advance anti-cancer immunotherapy.

Promoter hypomethylation of NY-ESO-1, association with clinicopathological features and PD-L1 expression in non-small cell lung cancer

Cancer-Testis antigens (CTA) are immunogenic molecules with normal tissue expression restricted to testes but with aberrant expression in up to 30% of non-small cell lung cancers (NSCLCs). Regulation of CTA expression is mediated in part through promoter DNA methylation. Recently, immunotherapy has altered treatment paradigms in NSCLC. Given its immunogenicity and ability to be re-expressed through demethylation, NY-ESO-1 promoter methylation, protein expression and its association with programmed death receptor ligand-1 (PD-L1) expression and clinicopathological features were investigated. Lung cancer cell line demethylation resulting from 5-Aza-2'-deoxycytidine treatment was associated with both NY-ESO-1 and PD-L1 re-expression in vitro but not increased chemosensitivity. NY-ESO-1 hypomethylation was observed in 15/94 (16%) of patient samples and associated with positive protein expression (P < 0.0001). In contrast, PD-L1 expression was observed in 50/91 (55%) but strong expression in only 12/91 (13%) cases. There was no association between NY-ESO-1 and PD-L1 expression, despite resultant re-expression of both by 5-Aza-2'-deoxycytidine. Importantly, NY-ESO-1 hypomethylation was found to be an independent marker of poor prognosis in patients not treated with chemotherapy (HR 3.59, P = 0.003) in multivariate analysis. In patients treated with chemotherapy there were no differences in survival associated with NY-ESO-1 hypomethylation. Collectively, these results provided supporting evidence for the potential use of NY-ESO-1 hypomethylation as a prognostic biomarker in stage 3 NSCLCs. In addition, these data highlight the potential to incorporate demethylating agents to enhance immune activation, in tumours currently devoid of immune infiltrates and expression of immune checkpoint genes.

The Multi-Purpose Tool of Tumor Immunotherapy: Gene-Engineered T Cells

A detailed summary of the published clinical trials of chimeric antigen receptor T cells (CAR-T) and TCR-transduced T cells (TCR-T) was constructed to understand the development trend of adoptive T cell therapy (ACT). In contrast to TCR-T, the number of CAR-T clinical trials has increased dramatically in China in the last three years. The ACT seems to be very prosperous. But, the multidimensional interaction of tumor, tumor associated antigen (TAA) and normal tissue exacerbates the uncontrolled outcome of T cells gene therapy. It reminds us the importance that optimizing treatment security to prevent the fatal serious adverse events. How to balance the safety and effectiveness of the ACT? At least six measures can potentially optimize the safety of ACT. At the same time, with the application of gene editing techniques, more endogenous receptors are disrupted while more exogenous receptors are expressed on T cells. As a multi-purpose tool of tumor immunotherapy, gene-engineered T cells (GE-T) have been given different functional weapons. A network which is likely to link radiation therapy, tumor vaccines, CAR-T and TCR-T is being built. Moreover, more and more evidences indicated that the combination of the ACT and other therapies would further enhance the anti-tumor capacity of the GE-T.

Monocyte lineage-derived IL-6 does not affect chimeric antigen receptor T-cell function

BACKGROUND AIMS

Chimeric antigen receptor (CAR) T-cell therapy targeting CD19 has demonstrated remarkable success in targeting B-cell malignancies but is often complicated by serious systemic toxicity in the form of cytokine release syndrome (CRS). CRS symptoms are primarily mediated by interleukin 6 (IL-6), and clinical management has focused on inhibition of IL-6 signaling. The cellular source and function of IL-6 in CRS remain unknown.

METHODS

Using co-culture assays and data from patients on our clinical CAR T-cell trials, we investigated the cellular source of IL-6, as well as other CRS-associated cytokines, during CAR T-cell activation. We also explored the effect that IL-6 has on T-cell function.

RESULTS

We demonstrated that IL-6 is secreted by monocyte-lineage cells in response to CAR T-cell activation in a contact-independent mechanism upon T-cell engagement of target leukemia. We observed that the presence of antigen-presenting cell-derived IL-6 has no impact on CAR T-cell transcriptional profiles or cytotoxicity. Finally, we confirm that CAR T cells do not secrete IL-6 in vivo during clinical CRS.

DISCUSSION

These findings suggest that IL-6 blockade will not affect CD19 CAR T-cell-driven anti-leukemic cytotoxicity, permitting enhanced control of CRS while maintaining CAR T-cell efficacy.

HLA-E inhibitor enhances the killing of neuroblastoma stem cells by co-cultured dendritic cells and cytokine-induced killer cells loaded with membrane-based microparticles

Neuroblastoma stem cells (NSCs) can cause drug resistance and tumor recurrence. This study aimed to enhance the lytic effect of dendritic cells (DCs) co-cultured with cytokine-induced killer (CIK) cells. NSCs were obtained by suspension culture, and DC-CIK cells were loaded with extracted NSC membrane-based microparticles (MMPs) before evaluating the lytic effect of DC-CIK cells on NSCs. After inhibiting the function or expression of human leukocyte antigen-E (HLA-E) in NSCs by anti-HLA-E monoclonal antibody or siRNA, the DC-CIK cell lytic effect on NSCs was re-assessed. NSC nestin expression was high, but glial fibrillary acid protein expression and class IIIβ-tubulin-1 expression were low. Moreover, NSCs exhibited strong tumorigenic ability in nude mice. Loading DCs with NSC-derived MMPs induced the differentiation of DCs and CIK cells and enhanced the killing of NSCs by DC-CIK cells. Inhibiting the function or expression of HLA-E in NSCs further enhanced the cytolytic capability of DC-CIK cells loaded with NSC-derived MMPs. HLA-E inhibitor can enhance the killing of NSC by DC-CIK cells loaded with NSC-derived MMPs.

Recent advances in T-cell engineering for use in immunotherapy

Adoptive T-cell therapies have shown exceptional promise in the treatment of cancer, especially B-cell malignancies. Two distinct strategies have been used to redirect the activity of ex vivo engineered T cells. In one case, the well-known ability of the T-cell receptor (TCR) to recognize a specific peptide bound to a major histocompatibility complex molecule has been exploited by introducing a TCR against a cancer-associated peptide/human leukocyte antigen complex. In the other strategy, synthetic constructs called chimeric antigen receptors (CARs) that contain antibody variable domains (single-chain fragments variable) and signaling domains have been introduced into T cells. Whereas many reviews have described these two approaches, this review focuses on a few recent advances of significant interest. The early success of CARs has been followed by questions about optimal configurations of these synthetic constructs, especially for efficacy against solid tumors. Among the many features that are important, the dimensions and stoichiometries of CAR/antigen complexes at the synapse have recently begun to be appreciated. In TCR-mediated approaches, recent evidence that mutated peptides (neoantigens) serve as targets for endogenous T-cell responses suggests that these neoantigens may also provide new opportunities for adoptive T-cell therapies with TCRs.