Glycan-directed CAR-T cells

The dilemmas and possible solutions for CAR-T cell therapy application in solid tumors

Chimeric antigen receptor T (CAR-T) cell therapy, as an adoptive immunotherapy, is playing an increasingly important role in the treatment of malignant tumors. CAR-T cells are referred to as "living drugs" as they not only target tumor cells directly, but also induce long-term immune memory that has the potential to provide long-lasting protection. CD19.CAR-T cells have achieved complete response rates of over 90 % for acute lymphoblastic leukemia and over 60 % for non-Hodgkin's lymphoma. However, the response rate of CAR-T cells in the treatment of solid tumors remains extremely low and the side effects potentially severe. In this review, we discuss the limitations that the solid tumor microenvironment poses for CAR-T application and the solutions that are being developed to address these limitations, in the hope that in the near future, CAR-T cell therapy for solid tumors can attain the same success rates as are now being seen clinically for hematological malignancies.

Tumor glucose metabolism and the T cell glycocalyx: implication for T cell function

The T cell is an immune cell subset highly effective in eliminating cancer cells. Cancer immunotherapy empowers T cells and occupies a solid position in cancer treatment. The response rate, however, remains relatively low (<30%). The efficacy of immunotherapy is highly dependent on T cell infiltration into the tumor microenvironment (TME) and the ability of these infiltrated T cells to sustain their function within the TME. A better understanding of the inhibitory impact of the TME on T cells is crucial to improve cancer immunotherapy. Tumor cells are well described for their switch into aerobic glycolysis (Warburg effect), resulting in high glucose consumption and a metabolically distinct TME. Conversely, glycosylation, a predominant posttranslational modification of proteins, also relies on glucose molecules. Proper glycosylation of T cell receptors influences the immunological synapse between T cells and tumor cells, thereby affecting T cell effector functions including their cytolytic and cytostatic activities. This review delves into the complex interplay between tumor glucose metabolism and the glycocalyx of T cells, shedding light on how the TME can induce alterations in the T cell glycocalyx, which can subsequently influence the T cell's ability to target and eliminate tumor cells.

Synthetic biology approaches for improving the specificity and efficacy of cancer immunotherapy

Immunotherapy has shown robust efficacy in treating a broad spectrum of hematological and solid cancers. Despite the transformative impact of immunotherapy on cancer treatment, several outstanding challenges remain. These challenges include on-target off-tumor toxicity, systemic toxicity, and the complexity of achieving potent and sustainable therapeutic efficacy. Synthetic biology has emerged as a promising approach to overcome these obstacles, offering innovative tools for engineering living cells with customized functions. This review provides an overview of the current landscape and future prospects of cancer immunotherapy, particularly emphasizing the role of synthetic biology in augmenting its specificity, controllability, and efficacy. We delineate and discuss two principal synthetic biology strategies: those targeting tumor surface antigens with engineered immune cells and those detecting intratumoral disease signatures with engineered gene circuits. This review concludes with a forward-looking perspective on the enduring challenges in cancer immunotherapy and the potential breakthroughs that synthetic biology may contribute to the field.

Identification of drug responsible glycogene signature in liver carcinoma from meta-analysis using RNA-seq data

Glycans have attracted much attention in cancer therapeutic strategies, and cell surface proteins and lipids with glycans are known to be altered during the carcinogenic process. However, our understanding of how the glycogenes profile responds to drug stimulation remains incomplete. In this study, we search public databases for Sequence Read Archive data on drug-treated liver cancer cells, with the aim to comprehensively analyze the drug responses of glycogenes via bioinformatic meta-analysis. The study comprised 86 datasets, encompassing eight distinct liver cancer cell lines and 13 different drugs. Differentially expressed genes were quantified, and 399 glycogenes were identified. The glycogenes signature was then analyzed using bioinformatics methodologies. In the Protein-protein interaction network analysis, we identified drug-responsive glycogenes such as Beta-1,4-Galactosyltransferase 1, GDP-Mannose 4,6-Dehydratase, UDP-Glucose Ceramide Glucosyltransferase, and Solute Carrier Family 2 Member 4 as key glycan biomarkers. In the enrichment analysis using the pathway list of glycogenes, the results also demonstrated that drug stimulation resulted in alterations to glycopathway-related genes involved in several processes, namely O-Mannosylation, POMGNT2 Type, Capping, Heparan Sulfate Sulfation, and Glucuronidation pathways. These genes and pathways commonly exhibit variable expression across multiple liver cancer cells in response to the same drug, making them potential targets for new cancer therapies. In addition to their primary roles, drugs may also participate in the regulation of glycans. The insights from this study could pave the way for the development of liver cancer therapies that target the regulation of gene profiles involved in the biosynthesis of glycans.

Advances and prospects of mRNA vaccines in cancer immunotherapy

Cancer vaccines, designed to activate the body's own immune system to fight against tumors, are a current trend in cancer treatment and receiving increasing attention. Cancer vaccines mainly include oncolytic virus vaccine, cell vaccine, peptide vaccine and nucleic acid vaccine. Over the course of decades of research, oncolytic virus vaccine T-VEC, cellular vaccine sipuleucel-T, various peptide vaccines, and DNA vaccine against HPV positive cervical cancer have brought encouraging results for cancer therapy, but are losing momentum in development due to their respective shortcomings. In contrast, the advantages of mRNA vaccines such as high safety, ease of production, and unmatched efficacy are on full display. In addition, advances in technology such as pseudouridine modification have cracked down the bottleneck for developing mRNA vaccines including instability, innate immunogenicity, and low efficiency of in vivo delivery. Several cancer mRNA vaccines have achieved promising results in clinical trials, and their usage in conjunction with other immune checkpoint inhibitors (ICIs) has further boosted the efficiency of anti-tumor immune response. We expect a rapid development of mRNA vaccines for cancer immunotherapy in the near future. This review provides a brief overview of the current status of mRNA vaccines, highlights the action mechanism of cancer mRNA vaccines, their recent advances in clinical trials, and prospects for their clinical applications.

The functional roles of protein glycosylation in human maternal-fetal crosstalk

BACKGROUND

The establishment of maternal-fetal crosstalk is vital to a successful pregnancy. Glycosylation is a post-translational modification in which glycans (monosaccharide chains) are attached to an organic molecule. Glycans are involved in many physiological and pathological processes. Human endometrial epithelium, endometrial gland secretions, decidual immune cells, and trophoblasts are highly enriched with glycoconjugates and glycan-binding molecules important for a healthy pregnancy. Aberrant glycosylation in the placenta and uterus has been linked to repeated implantation failure and various pregnancy complications, but there is no recent review summarizing the functional roles of glycosylation at the maternal-fetal interface and their associations with pathological processes.

OBJECTIVE AND RATIONALE

This review aims to summarize recent findings on glycosylation, glycosyltransferases, and glycan-binding receptors at the maternal-fetal interface, and their involvement in regulating the biology and pathological conditions associated with endometrial receptivity, placentation and maternal-fetal immunotolerance. Current knowledge limitations and future insights into the study of glycobiology in reproduction are discussed.

SEARCH METHODS

A comprehensive PubMed search was conducted using the following keywords: glycosylation, glycosyltransferases, glycan-binding proteins, endometrium, trophoblasts, maternal-fetal immunotolerance, siglec, selectin, galectin, repeated implantation failure, early pregnancy loss, recurrent pregnancy loss, preeclampsia, and fetal growth restriction. Relevant reports published between 1980 and 2023 and studies related to these reports were retrieved and reviewed. Only publications written in English were included.

OUTCOMES

The application of ultrasensitive mass spectrometry tools and lectin-based glycan profiling has enabled characterization of glycans present at the maternal-fetal interface and in maternal serum. The endometrial luminal epithelium is covered with highly glycosylated mucin that regulates blastocyst adhesion during implantation. In the placenta, fucose and sialic acid residues are abundantly presented on the villous membrane and are essential for proper placentation and establishment of maternal-fetal immunotolerance. Glycan-binding receptors, including selectins, sialic-acid-binding immunoglobulin-like lectins (siglecs) and galectins, also modulate implantation, trophoblast functions and maternal-fetal immunotolerance. Aberrant glycosylation is associated with repeated implantation failure, early pregnancy loss and various pregnancy complications. The current limitation in the field is that most glycobiological research relies on association studies, with few studies revealing the specific functions of glycans. Technological advancements in analytic, synthetic and functional glycobiology have laid the groundwork for further exploration of glycans in reproductive biology under both physiological and pathological conditions.

WIDER IMPLICATIONS

A deep understanding of the functions of glycan structures would provide insights into the molecular mechanisms underlying their involvement in the physiological and pathological regulation of early pregnancy. Glycans may also potentially serve as novel early predictive markers and therapeutic targets for repeated implantation failure, pregnancy loss, and other pregnancy complications.

Decoding glycomics with a suite of methods for differential expression analysis

Glycomics, the comprehensive profiling of all glycan structures in samples, is rapidly expanding to enable insights into physiology and disease mechanisms. However, glycan structure complexity and glycomics data interpretation present challenges, especially for differential expression analysis. Here, we present a framework for differential glycomics expression analysis. Our methodology encompasses specialized and domain-informed methods for data normalization and imputation, glycan motif extraction and quantification, differential expression analysis, motif enrichment analysis, time series analysis, and meta-analytic capabilities, synthesizing results across multiple studies. All methods are integrated into our open-source glycowork package, facilitating performant workflows and user-friendly access. We demonstrate these methods using dedicated simulations and glycomics datasets of N-, O-, lipid-linked, and free glycans. Differential expression tests here focus on human datasets and cancer vs. healthy tissue comparisons. Our rigorous approach allows for robust, reliable, and comprehensive differential expression analyses in glycomics, contributing to advancing glycomics research and its translation to clinical and diagnostic applications.

CRISPR-screen identifies ZIP9 and dysregulated Zn2+ homeostasis as a cause of cancer-associated changes in glycosylation

INTRODUCTION

In epithelial cancers, truncated O-glycans, such as the Thomson-nouveau antigen (Tn) and its sialylated form (STn), are upregulated on the cell surface and associated with poor prognosis and immunological escape. Recent studies have shown that these carbohydrate epitopes facilitate cancer development and can be targeted therapeutically; however, the mechanism underpinning their expression remains unclear.

METHODS

To identify genes directly influencing the expression of cancer-associated O-glycans, we conducted an unbiased, positive-selection, whole-genome CRISPR knockout-screen using monoclonal antibodies against Tn and STn.

RESULTS AND CONCLUSIONS

We show that knockout of the Zn2+-transporter SLC39A9 (ZIP9), alongside the well-described targets C1GALT1 (C1GalT1) and its molecular chaperone, C1GALT1C1 (COSMC), results in surface-expression of cancer-associated O-glycans. No other gene perturbations were found to reliably induce O-glycan truncation. We furthermore show that ZIP9 knockout affects N-linked glycosylation, resulting in upregulation of oligo-mannose, hybrid-type, and α2,6-sialylated structures as well as downregulation of tri- and tetra-antennary structures. Finally, we demonstrate that accumulation of Zn2+ in the secretory pathway coincides with cell-surface presentation of truncated O-glycans in cancer tissue, and that over-expression of COSMC mitigates such changes. Collectively, the findings show that dysregulation of ZIP9 and Zn2+ induces cancer-like glycosylation on the cell surface by affecting the glycosylation machinery.

Targeting Solid Cancers with a Cancer-Specific Monoclonal Antibody to Surface Expressed Aberrantly O-glycosylated Proteins

The lack of antibodies with sufficient cancer selectivity is currently limiting the treatment of solid tumors by immunotherapies. Most current immunotherapeutic targets are tumor-associated antigens that are also found in healthy tissues and often do not display sufficient cancer selectivity to be used as targets for potent antibody-based immunotherapeutic treatments, such as chimeric antigen receptor (CAR) T cells. Many solid tumors, however, display aberrant glycosylation that results in expression of tumor-associated carbohydrate antigens that are distinct from healthy tissues. Targeting aberrantly glycosylated glycopeptide epitopes within existing or novel glycoprotein targets may provide the cancer selectivity needed for immunotherapy of solid tumors. However, to date only a few such glycopeptide epitopes have been targeted. Here, we used O-glycoproteomics data from multiple cell lines to identify a glycopeptide epitope in CD44v6, a cancer-associated CD44 isoform, and developed a cancer-specific mAb, 4C8, through a glycopeptide immunization strategy. 4C8 selectively binds to Tn-glycosylated CD44v6 in a site-specific manner with low nanomolar affinity. 4C8 was shown to be highly cancer specific by IHC of sections from multiple healthy and cancerous tissues. 4C8 CAR T cells demonstrated target-specific cytotoxicity in vitro and significant tumor regression and increased survival in vivo. Importantly, 4C8 CAR T cells were able to selectively kill target cells in a mixed organotypic skin cancer model having abundant CD44v6 expression without affecting healthy keratinocytes, indicating tolerability and safety.

Chemoenzymatic Tagging of Tn/TF/STF Antigens in Living Systems

Truncated mucin-type O-glycans, such as Tn-associated antigens, are aberrantly expressed biomarkers of cancer, but remain challenging to target. Reactive antibodies to these antigens either lack high-affinity or are prone to antigen escape. Here, we have developed a robust chemoenzymatic strategy for the global labeling of Tn-associated antigens, i.e. Tn (GalNAcα-O-Ser/Thr), Thomsen-Friedenreich (Galβ1-3GalNAcα-O-Ser/Thr, TF) and STF (Neu5Acα2-3Galβ1-3GalNAcα-O-Ser/Thr, STF) antigens, in human whole blood with high efficiency and selectivity. This method relies on the use of the O-glycan sialyltransferase ST6GalNAc1 to transfer a sialic acid-functionalized adaptor to the GalNAc residue of these antigens. By tagging, the adaptor functionalized antigens can be easily targeted by customized strategies such as, but not limited to, chimeric antigen receptor T-Cells (CAR-T). We expect this tagging system to find broad applications in cancer diagnostics and targeting in combination with established strategies.

Harnessing the potential of CAR-T cell therapy: progress, challenges, and future directions in hematological and solid tumor treatments

Traditional cancer treatments use nonspecific drugs and monoclonal antibodies to target tumor cells. Chimeric antigen receptor (CAR)-T cell therapy, however, leverages the immune system's T-cells to recognize and attack tumor cells. T-cells are isolated from patients and modified to target tumor-associated antigens. CAR-T therapy has achieved FDA approval for treating blood cancers like B-cell acute lymphoblastic leukemia, large B-cell lymphoma, and multiple myeloma by targeting CD-19 and B-cell maturation antigens. Bi-specific chimeric antigen receptors may contribute to mitigating tumor antigen escape, but their efficacy could be limited in cases where certain tumor cells do not express the targeted antigens. Despite success in blood cancers, CAR-T technology faces challenges in solid tumors, including lack of reliable tumor-associated antigens, hypoxic cores, immunosuppressive tumor environments, enhanced reactive oxygen species, and decreased T-cell infiltration. To overcome these challenges, current research aims to identify reliable tumor-associated antigens and develop cost-effective, tumor microenvironment-specific CAR-T cells. This review covers the evolution of CAR-T therapy against various tumors, including hematological and solid tumors, highlights challenges faced by CAR-T cell therapy, and suggests strategies to overcome these obstacles, such as utilizing single-cell RNA sequencing and artificial intelligence to optimize clinical-grade CAR-T cells.

CAR T-cell therapy: Reprogramming patient's immune cell to treat cancer

Chimeric antigen receptor (CAR)-T cell therapy is a game changer in cancer treatment. Although CAR-T cell therapy has achieved significant clinical responses in specific subgroups of B cell leukaemia or lymphoma, various difficulties restrict CAR-T cell therapy's therapeutic effectiveness in solid tumours and haematological malignancies. Severe life-threatening toxicities, poor anti-tumour effectiveness, antigen escape, restricted trafficking, and limited tumour penetration are all barriers to successful CAR-T cell treatment. Furthermore, CAR-T cell interactions with the host and tumour microenvironment have a significant impact on their activity. Furthermore, developing and implementing these therapies necessitates a complicated staff. Innovative methodologies and tactics to engineering more potent CAR-T cells with greater anti-tumour activity and less toxicity are required to address these important difficulties.

CAR T-Cell Therapy in Children with Solid Tumors

The limited efficacy of traditional cancer treatments, including chemotherapy, radiotherapy, and surgery, emphasize the significance of employing innovative methods. CAR (Chimeric Antigen Receptor) T-cell therapy remains the most revolutionizing treatment of pediatric hematological malignancies and solid tumors. Patient’s own lymphocytes are modified ex-vivo using gene transfer techniques and programmed to recognize and destroy specific tumor cells regardless of MHC receptor, which probably makes CAR-T the most personalized therapy for the patient. With continued refinement and optimization, CAR-T cell therapy has the potential to significantly improve outcomes and quality of life for children with limited treatment options. It has shown remarkable success in treating hematological malignancies, such as acute lymphoblastic leukemia (ALL) and non-Hodgkin lymphoma (NHL). However, its effectiveness in treating solid tumors is still being investigated and remains an area of active research. In this review we focus on solid tumors and explain the concept of CAR modified T cells, and discuss some novel CAR designs that are being considered to enhance the safety of CAR T-cell therapy in under-mentioned cancers. Furthermore, we summarize the most crucial recent reports concerning the solid tumors treatment in children. In the end we provide a short summary of many challenges that limit the therapeutic efficacy of CAR-T in solid tumors, such as antigen escape, immunosuppressive microenvironment, poor trafficking, and tumor infiltration, on-target off-tumor effects and general toxicity.

Glycans as shapers of tumour microenvironment: A sweet driver of T-cell-mediated anti-tumour immune response

Essentially all cells are covered with a dense coat of different glycan structures/sugar chains, giving rise to the so-called glycocalyx. Changes in cellular glycosylation are a hallmark of cancer, affecting most of the pathophysiological processes associated with malignant transformation, including tumour immune responses. Glycans are chief macromolecules that define T-cell development, differentiation, fate, activation and signalling. Thus, the diversity of glycans expressed at the surface of T cells constitutes a fundamental molecular interface with the microenvironment by regulating the bilateral interactions between T-cells and cancer cells, fine-tuning the anti-tumour immune response. In this review, we will introduce the power of glycans as orchestrators of T-cell-mediated immune response in physiological conditions and in cancer. We discuss how glycans modulate the glyco-metabolic landscape in the tumour microenvironment, and whether glycans can synergize with immunotherapy as a way of rewiring T-cell effector functions against cancer cells.

Head and Neck Cancer Immunotherapy: Molecular Biological Aspects of Preclinical and Clinical Research

Breakthrough research in the field of immune checkpoint inhibitors and the development of a human papilloma virus vaccine triggered a plethora of research in the field of cancer immunotherapy. Both had significant effects on the treatment of head and neck squamous cell carcinoma. The advent of preclinical models and multidisciplinary approaches including bioinformatics, genetic engineering, clinical oncology, and immunology helped in the development of tumour-infiltrating lymphocytes (TILs) and chimeric antigen receptor (CAR) T-cell therapy. Here, we discuss different immunotherapies such as adoptive T-cell transfer, immune checkpoint inhibitors, interleukins, and cancer vaccines for the treatment of head and neck cancer. This review showcases the intrinsic relation between the understanding and implementation of basic biology and clinical practice. We also address potential limitations of each immunotherapy approach and the advantages of personalized immunotherapy. Overall, the aim of this review is to encourage further research in the field of immunotherapy for head and neck cancer.

Chimeric Antigen Receptor T-Cell Therapy: Current Perspective on T Cell-Intrinsic, T Cell-Extrinsic, and Therapeutic Limitations

ABSTRACT

Genetically engineered chimeric antigen receptor (CAR) T-cell therapy leverages the ability of the immune system to eliminate tumors and redirects cytotoxic functions toward cells expressing specified tumor-restricted antigens. Although 6 CAR T-cell therapies have received Food and Drug Administration (FDA) approval for the treatment of many hematological malignancies, limitations involving T cell-intrinsic, T cell-extrinsic, and therapeutic factors remain in the treatment of both liquid and solid tumors. Chimeric antigen receptor design, signals from the tumor microenvironment, tumor antigen escape mechanisms, and systemic inflammatory consequences of CAR T-cell infusion all influence the efficacy and feasibility of CAR T-cell therapy in different malignancies. Here, we review the core structure of the CAR, the evolution of different CAR generations, CAR T-cell therapy limitations, and current strategies being investigated to overcome the T cell-intrinsic, T cell-independent, and therapeutic barriers to successful CAR T-cell therapy.

Decoding Strategies to Evade Immunoregulators Galectin-1, -3, and -9 and Their Ligands as Novel Therapeutics in Cancer Immunotherapy

Galectins are a family of ß-galactoside-binding proteins that play a variety of roles in normal physiology. In cancer, their expression levels are typically elevated and often associated with poor prognosis. They are known to fuel a variety of cancer progression pathways through their glycan-binding interactions with cancer, stromal, and immune cell surfaces. Of the 15 galectins in mammals, galectin (Gal)-1, -3, and -9 are particularly notable for their critical roles in tumor immune escape. While these galectins play integral roles in promoting cancer progression, they are also instrumental in regulating the survival, differentiation, and function of anti-tumor T cells that compromise anti-tumor immunity and weaken novel immunotherapies. To this end, there has been a surge in the development of new strategies to inhibit their pro-malignancy characteristics, particularly in reversing tumor immunosuppression through galectin-glycan ligand-targeting methods. This review examines some new approaches to evading Gal-1, -3, and -9-ligand interactions to interfere with their tumor-promoting and immunoregulating activities. Whether using neutralizing antibodies, synthetic peptides, glyco-metabolic modifiers, competitive inhibitors, vaccines, gene editing, exo-glycan modification, or chimeric antigen receptor (CAR)-T cells, these methods offer new hope of synergizing their inhibitory effects with current immunotherapeutic methods and yielding highly effective, durable responses.

Combating challenges in CAR-T cells with engineering immunology

Chimeric antigen receptors (CAR) T cells (CAR-T) mark a significant step towards producing safe and effective personal anticancer treatments. CAR-T strategies engineers the T cells from the patients to allow specific binding to a tumour-specific antigen. CAR-Ts are a second-wave offensive strategy to clear out remaining chemotherapy-resistant tumour cells. Though showing practical antitumor abilities in multiple haematological malignancies and solid tumour cancers, the issues of antigen escape, tumour infiltration/penetration, and toxicity side effects limit the usage of prolonged CAR-T therapies. However, engineering immunology has exploited human stem cell-based CAR-T therapies and the development of CAR-M (macrophage) therapies to combat the disadvantages of conventional CAR-T therapies. In this review, we will highlight the challenges of CAR-T therapies and combat them with engineering immunology for cancer immunotherapy.

Recent findings on chimeric antigen receptor (CAR)-engineered immune cell therapy in solid tumors and hematological malignancies

Advancements in adoptive cell therapy over the last four decades have revealed various new therapeutic strategies, such as chimeric antigen receptors (CARs), which are dedicated immune cells that are engineered and administered to eliminate cancer cells. In this context, CAR T-cells have shown significant promise in the treatment of hematological malignancies. However, many obstacles limit the efficacy of CAR T-cell therapy in both solid tumors and hematological malignancies. Consequently, CAR-NK and CAR-M cell therapies have recently emerged as novel therapeutic options for addressing the challenges associated with CAR T-cell therapies. Currently, many CAR immune cell trials are underway in various human malignancies around the world to improve antitumor activity and reduce the toxicity of CAR immune cell therapy. This review will describe the comprehensive literature of recent findings on CAR immune cell therapy in a wide range of human malignancies, as well as the challenges that have emerged in recent years.

Novel lectin-based chimeric antigen receptors target Gb3-positive tumour cells

The link between cancer and aberrant glycosylation has recently become evident. Glycans and their altered forms, known as tumour-associated carbohydrate antigens (TACAs), are diverse, complex and difficult to target therapeutically. Lectins are naturally occurring glycan-binding proteins  that offer a unique opportunity to recognise TACAs. T cells expressing chimeric antigen receptors (CARs) have proven to be a successful immunotherapy against leukaemias, but so far have shown limited success in solid tumours. We developed a panel of lectin-CARs that recognise the glycosphingolipid globotriaosylceramide (Gb3), which is overexpressed in various cancers, such as Burkitt's lymphoma, colorectal, breast and pancreatic. We have selected the following lectins: Shiga toxin's B-subunit from Shigella dysenteriae, LecA from Pseudomonas aeruginosa, and the engineered lectin Mitsuba from Mytilus galloprovincialis as antigen-binding domains and fused them to a well-known second-generation CAR. The Gb3-binding lectin-CARs have demonstrated target-specific cytotoxicity against Burkitt's lymphoma-derived cell lines as well as solid tumour cells from colorectal and triple-negative breast cancer. Our findings reveal the big potential of lectin-based CARs as therapeutical applications to target Gb3 and other TACAs expressed in haematological malignancies and solid tumours.

Emerging Trends in Immunotherapy for Cancer

Recent advances in cancer immunology have enabled the discovery of promising immunotherapies for various malignancies that have shifted the cancer treatment paradigm. The innovative research and clinical advancements of immunotherapy approaches have prolonged the survival of patients with relapsed or refractory metastatic cancers. Since the U.S. FDA approved the first immune checkpoint inhibitor in 2011, the field of cancer immunotherapy has grown exponentially. Multiple therapeutic approaches or agents to manipulate different aspects of the immune system are currently in development. These include cancer vaccines, adoptive cell therapies (such as CAR-T or NK cell therapy), monoclonal antibodies, cytokine therapies, oncolytic viruses, and inhibitors targeting immune checkpoints that have demonstrated promising clinical efficacy. Multiple immunotherapeutic approaches have been approved for specific cancer treatments, while others are currently in preclinical and clinical trial stages. Given the success of immunotherapy, there has been a tremendous thrust to improve the clinical efficacy of various agents and strategies implemented so far. Here, we present a comprehensive overview of the development and clinical implementation of various immunotherapy approaches currently being used to treat cancer. We also highlight the latest developments, emerging trends, limitations, and future promises of cancer immunotherapy.

Addiction of Cancer Stem Cells to MUC1-C in Triple-Negative Breast Cancer Progression

Triple-negative breast cancer (TNBC) is an aggressive malignancy with limited treatment options. TNBC progression is associated with expansion of cancer stem cells (CSCs). Few insights are available regarding druggable targets that drive the TNBC CSC state. This review summarizes the literature on TNBC CSCs and the compelling evidence that they are addicted to the MUC1-C transmembrane protein. In normal epithelia, MUC1-C is activated by loss of homeostasis and induces reversible wound-healing responses of inflammation and repair. However, in settings of chronic inflammation, MUC1-C promotes carcinogenesis. MUC1-C induces EMT, epigenetic reprogramming and chromatin remodeling in TNBC CSCs, which are dependent on MUC1-C for self-renewal and tumorigenicity. MUC1-C-induced lineage plasticity in TNBC CSCs confers DNA damage resistance and immune evasion by chronic activation of inflammatory pathways and global changes in chromatin architecture. Of therapeutic significance, an antibody generated against the MUC1-C extracellular domain has been advanced in a clinical trial of anti-MUC1-C CAR T cells and in IND-enabling studies for development as an antibody–drug conjugate (ADC). Agents targeting the MUC1-C cytoplasmic domain have also entered the clinic and are undergoing further development as candidates for advancing TNBC treatment. Eliminating TNBC CSCs will be necessary for curing this recalcitrant cancer and MUC1-C represents a promising druggable target for achieving that goal.

Recent advances and future perspectives on carbohydrate-based cancer vaccines and therapeutics

Carbohydrates are abundantly expressed on the surface of both eukaryotic and prokaryotic cells, often as post translational modifications of proteins. Glycoproteins are recognized by the immune system and can trigger both innate and humoral responses. This feature has been harnessed to generate vaccines against polysaccharide-encapsulated bacteria such as Streptococcus pneumoniae, Hemophilus influenzae type b and Neisseria meningitidis. In cancer, glycosylation plays a pivotal role in malignancy development and progression. Since glycans are specifically expressed on the surface of tumor cells, they have been targeted for the discovery of anticancer preventive and therapeutic treatments, such as vaccines and monoclonal antibodies. Despite the various efforts made over the last years, resulting in a series of clinical studies, attempts of vaccination with carbohydrate-based candidates have proven unsuccessful, primarily due to the immune tolerance often associated with these glycans. New strategies are thus deployed to enhance carbohydrate-based cancer vaccines. Moreover, lessons learned from glycan immunobiology paved the way to the development of new monoclonal antibodies specifically designed to recognize cancer-bound carbohydrates and induce tumor cell killing. Herein we provide an overview of the immunological principles behind the immune response towards glycans and glycoconjugates and the approaches exploited at both preclinical and clinical level to target cancer-associated glycans for the development of vaccines and therapeutic monoclonal antibodies. We also discuss gaps and opportunities to successfully advance glycan-directed cancer therapies, which could provide patients with innovative and effective treatments.

Glycosylation and its research progress in endometrial cancer

Endometrial cancer (EC) is one of the most common tumors in the female reproductive system, which seriously threatens women's health, particularly in developed countries. 13% of the patients with EC have a poor prognosis due to recurrence and metastasis. Therefore, identifying good predictive biomarkers and therapeutic targets is critical to enable the early detection of metastasis and improve the prognosis. For decades, extensive studies had focused on glycans and glycoproteins in the progression of cancer. The types of glycans that are covalently attached to the polypeptide backbone, usually via nitrogen or oxygen linkages, are known as N‑glycans or O‑glycans, respectively. The degree of protein glycosylation and the aberrant changes in the carbohydrate structures have been implicated in the extent of tumorigenesis and reported to play a critical role in regulating tumor invasion, metabolism, and immunity. This review summarizes the essential biological role of glycosylation in EC, with a focus on the recent advances in glycomics and glycosylation markers, highlighting their implications in the diagnosis and treatment of EC.

Chimeric Antigen Receptor T-Cells: An Overview of Concepts, Applications, Limitations, and Proposed Solutions

Adaptive immunity, orchestrated by B-cells and T-cells, plays a crucial role in protecting the body from pathogenic invaders and can be used as tools to enhance the body's defense mechanisms against cancer by genetically engineering these immune cells. Several strategies have been identified for cancer treatment and evaluated for their efficacy against other diseases such as autoimmune and infectious diseases. One of the most advanced technologies is chimeric antigen receptor (CAR) T-cell therapy, a pioneering therapy in the oncology field. Successful clinical trials have resulted in the approval of six CAR-T cell products by the Food and Drug Administration for the treatment of hematological malignancies. However, there have been various obstacles that limit the use of CAR T-cell therapy as the first line of defense mechanism against cancer. Various innovative CAR-T cell therapeutic designs have been evaluated in preclinical and clinical trial settings and have demonstrated much potential for development. Such trials testing the suitability of CARs against solid tumors and HIV are showing promising results. In addition, new solutions have been proposed to overcome the limitations of this therapy. This review provides an overview of the current knowledge regarding this novel technology, including CAR T-cell structure, different applications, limitations, and proposed solutions.

Glycoprotein PTGDS promotes tumorigenesis of diffuse large B-cell lymphoma by MYH9-mediated regulation of Wnt-β-catenin-STAT3 signaling

Glycoprotein prostaglandin D2 synthase (PTGDS) is a member of the lipocalin superfamily and plays dual roles in prostaglandins metabolism and lipid transport. PTGDS has been involved in various cellular processes including the tumorigenesis of solid tumors, yet its role in carcinogenesis is contradictory and the significance of PTGDS in hematological malignancies is ill-defined. Here, we aimed to explore the expression and function of PTGDS in diffuse large B-cell lymphoma (DLBCL), especially the potential role of PTGDS inhibitor, AT56, in lymphoma therapy. Remarkable high expression of PTGDS was found in DLBCL, which was significantly correlated with poor prognosis. PTGDS overexpression and rhPTGDS were found to promote cell proliferation. Besides, in vitro and in vivo studies indicated that PTGDS knockdown and AT56 treatment exerted an anti-tumor effect by regulating cell viability, proliferation, apoptosis, cell cycle, and invasion, and enhanced the drug sensitivity to adriamycin and bendamustine through promoting DNA damage. Moreover, the co-immunoprecipitation-based mass spectrum identified the interaction between PTGDS and MYH9, which was found to promote DLBCL progression. PTGDS inhibition led to reduced expression of MYH9, and then declined activation of the Wnt-β-catenin-STAT3 pathway through influencing the ubiquitination and degradation of GSK3-β in DLBCL. The rescue experiment demonstrated that PTGDS exerted an oncogenic role through regulating MYH9 and then the Wnt-β-catenin-STAT3 pathway. Based on point mutation of glycosylation sites, we confirmed the N-glycosylation of PTGDS in Asn51 and Asn78 and found that abnormal glycosylation of PTGDS resulted in its nuclear translocation, prolonged half-life, and enhanced cell proliferation. Collectively, our findings identified for the first time that glycoprotein PTGDS promoted tumorigenesis of DLBCL through MYH9-mediated regulation of Wnt-β-catenin-STAT3 signaling, and highlighted the potential role of AT56 as a novel therapeutic strategy for DLBCL treatment.

Black in Immuno Week: Who We Are, What We Did, and Why It Matters

Our organization, Black in Immuno (@BlackInImmuno), was formed in September 2020 to celebrate, support, and amplify Black voices in immunology when social media campaigns like #BlackInTheIvory illuminated the shared overt and covert issues of systemic racism faced by Black researchers in all facets of science, technology, engineering, art, and mathematics. Black in Immuno was cofounded by a group of Black immunology trainees working at multiple institutions globally: Joël Babdor, E. Evonne Jean, Elaine Kouame, Alexis S. Mobley, Justine C. Noel, and Madina Wane. We devised Black in Immuno Week, held November 22-28, 2020, as a global celebration of Black immunologists. The week was designed to advocate for increased diversity and accessibility in immunology, amplify Black excellence in immunology, and create a community of Black immunologists who can support each other to flourish despite barriers in academia and other job sectors. The week contained live panels and scientific talks, a casual networking mixer, online advocacy and amplification sessions, and a series of wellness events. Our live-streamed programs reached over 300 individuals, and thousands of people kept the conversations going globally using #BlackInImmuno and #BlackInImmunoWeek on social media from five continents. Below, we highlight the events and significant takeaways of the week.

Trends in oligomannosylation and α1,2-mannosidase expression in human cancers

Aberrant protein glycosylation is a prominent cancer feature. While many tumour-associated glycoepitopes have been reported, advances in glycoanalytics continue to uncover new associations between glycosylation and cancer. Guided by a comprehensive literature survey suggesting that oligomannosylation (Man_5–9 GlcNAc₂) is a widespread and often regulated glycosignature in human cancers, we here revisit a valuable compilation of nearly 500 porous graphitized carbon LC-MS/MS N-glycomics datasets acquired across 11 human cancer types to systematically test for oligomannose-cancer associations. Firstly, the quantitative glycomics data obtained across 34 cancerous cell lines demonstrated that oligomannosylation is a pan-cancer feature spanning in a wide abundance range. In keeping with literature, our quantitative glycomics data of tumour and matching control tissues and new MALDI-MS imaging data of tissue microarrays showed a strong cancer-associated elevation of oligomannosylation in both basal cell (p = 1.78 × 10^–12) and squamous cell (p = 1.23 × 10^–11) skin cancer and colorectal cancer (p = 8.0 × 10^–4). The glycomics data also indicated that some cancer types including gastric and liver cancer exhibit unchanged or reduced oligomannose levels, observations also supported by literature and MALDI-MS imaging data. Finally, expression data from public cancer repositories indicated that several α1,2-mannosidases are regulated in tumour tissues suggesting that these glycan-processing enzymes may contribute to the cancer-associated modulation of oligomannosylation. This omics-centric study has compiled robust glycomics and enzyme expression data revealing interesting molecular trends that open avenues to better understand the role of oligomannosylation in human cancers.

Mapping of truncated O-glycans in cancers of epithelial and non-epithelial origin

BACKGROUND

Novel immunotherapies targeting cancer-associated truncated O-glycans Tn (GalNAcα-Ser/Thr) and STn (Neu5Acα2-6GalNacα-Ser/Thr) are promising strategies for cancer treatment. However, no comprehensive, antibody-based mapping of truncated O-glycans in tumours exist to guide drug development.

METHODS

We used monoclonal antibodies to map the expression of truncated O-glycans in >700 tissue cores representing healthy and tumour tissues originating from breast, colon, lung, pancreas, skin, CNS and mesenchymal tissue. Patient-derived xenografts were used to evaluate Tn expression upon tumour engraftment.

RESULTS

The Tn-antigen was highly expressed in breast (57%, n = 64), colorectal (51%, n = 140) and pancreatic (53%, n = 108) tumours, while STn was mainly observed in colorectal (80%, n = 140) and pancreatic (56%, n = 108) tumours. We observed no truncated O-glycans in mesenchymal tumours (n = 32) and low expression of Tn (5%, n = 87) and STn (1%, n = 75) in CNS tumours. No Tn-antigen was found in normal tissue (n = 124) while STn was occasionally observed in healthy gastrointestinal tissue. Surface expression of Tn-antigen was identified across several cancers. Tn and STn expression decreased with tumour grade, but not with cancer stage. Numerous xenografts maintained Tn expression.

CONCLUSIONS

Surface expression of truncated O-glycans is limited to cancers of epithelial origin, making Tn and STn attractive immunological targets in the treatment of human carcinomas.

CAR T cells: Building on the CD19 paradigm

Spearheaded by the therapeutic use of chimeric antigen receptors (CARs) targeting CD19, synthetic immunology has entered the clinical arena. CARs are recombinant receptors for antigen that engage cell surface molecules through the variable region of an antibody and signal through arrayed T-cell activating and costimulatory domains. CARs allow redirection of T-cell cytotoxicity against any antigen of choice, independent of MHC expression. Patient T cells engineered to express CARs specific for CD19 have yielded remarkable outcomes in subjects with relapsed/refractory B- cell malignancies, setting off unprecedented interest in T-cell engineering and cell-based cancer immunotherapy. In this review, we present the challenges to extend the use of CAR T cells to solid tumors and other pathologies. We further highlight progress in CAR design, cell manufacturing, and genome editing, which in aggregate hold the promise of generating safer and more effective genetically instructed immunity. Novel engineered cell types, including innate T-cell types, natural killer (NK) cells, macrophages, and induced pluripotent stem cell-derived immune cells, are on the horizon, as are applications of CAR T cells to treat autoimmunity, severe infections, and senescence-associated pathologies.

Emerging glyco-based strategies to steer immune responses

Glycan structures are common posttranslational modifications of proteins, which serve multiple important structural roles (for instance in protein folding), but also are crucial participants in cell-cell communications and in the regulation of immune responses. Through the interaction with glycan-binding receptors, glycans are able to affect the activation status of antigen-presenting cells, leading either to induction of pro-inflammatory responses or to suppression of immunity and instigation of immune tolerance. This unique feature of glycans has attracted the interest and spurred collaborations of glyco-chemists and glyco-immunologists to develop glycan-based tools as potential therapeutic approaches in the fight against diseases such as cancer and autoimmune conditions. In this review, we highlight emerging advances in this field, and in particular, we discuss on how glycan-modified conjugates or glycoengineered cells can be employed as targeting devices to direct tumor antigens to lectin receptors on antigen-presenting cells, like dendritic cells. In addition, we address how glycan-based nanoparticles can act as delivery platforms to enhance immune responses. Finally, we discuss some of the latest developments in glycan-based therapies, including chimeric antigen receptor (CAR)-T cells to achieve targeting of tumor-associated glycan-specific epitopes, as well as the use of glycan moieties to suppress ongoing immune responses, especially in the context of autoimmunity.

Systems glycobiology for discovering drug targets, biomarkers, and rational designs for glyco-immunotherapy

Cancer immunotherapy has revolutionized treatment and led to an unprecedented wave of immuno-oncology research during the past two decades. In 2018, two pioneer immunotherapy innovators, Tasuku Honjo and James P. Allison, were awarded the Nobel Prize for their landmark cancer immunotherapy work regarding “cancer therapy by inhibition of negative immune regulation” –CTLA4 and PD-1 immune checkpoints. However, the challenge in the coming decade is to develop cancer immunotherapies that can more consistently treat various patients and cancer types. Overcoming this challenge requires a systemic understanding of the underlying interactions between immune cells, tumor cells, and immunotherapeutics. The role of aberrant glycosylation in this process, and how it influences tumor immunity and immunotherapy is beginning to emerge. Herein, we review current knowledge of miRNA-mediated regulatory mechanisms of glycosylation machinery, and how these carbohydrate moieties impact immune cell and tumor cell interactions. We discuss these insights in the context of clinical findings and provide an outlook on modulating the regulation of glycosylation to offer new therapeutic opportunities. Finally, in the coming age of systems glycobiology, we highlight how emerging technologies in systems glycobiology are enabling deeper insights into cancer immuno-oncology, helping identify novel drug targets and key biomarkers of cancer, and facilitating the rational design of glyco-immunotherapies. These hold great promise clinically in the immuno-oncology field.

Tumor-Associated Glycans as Targets for Immunotherapy: The Wistar Institute Experience/Legacy

Tumor cells are characterized by the expression of tumor-specific carbohydrate structures that differ from their normal counterparts. Carbohydrates on tumor cells have phenotypical as well as functional implications, impacting the tumor progression process, from malignant transformation to metastasis formation. Importantly, carbohydrates are structures that play a role in receptor-ligand interaction and elicit the activity of growth factor receptors, integrins, lectins, and other type 1 transmembrane proteins. They have been recognized as biomarkers for cancer diagnosis, and evidence demonstrating their relevance as targets for anticancer therapeutic strategies, including immunotherapy, continues to accumulate. Different approaches targeting carbohydrates include monoclonal antibodies (mAbs), antibody (Ab)-drug conjugates, vaccines, and adhesion antagonists. Development of bispecific antibodies and chimeric antigen receptor (CAR)-modified T cells against tumor-associated carbohydrate antigens (TACAs) as promising cancer immunotherapeutic agents is rapidly evolving. As reviewed here, there are several cancer-associated glycan features that can be leveraged to design rational drug or immune system targets, applying multiple TACA structural and functional features to be targeted as the standard treatment paradigm. Many of the underlying targets were defined by researchers at the Wistar Institute in Philadelphia, Pennsylvania, which provide basis for different immunotherapy approaches.

The Role of Glycosyltransferases in Colorectal Cancer

Colorectal cancer (CRC) is one of the main causes of cancer death in the world. Post-translational modifications (PTMs) have been extensively studied in malignancies due to its relevance in tumor pathogenesis and therapy. This review is focused on the dysregulation of glycosyltransferase expression in CRC and its impact in cell function and in several biological pathways associated with CRC pathogenesis, prognosis and therapeutic approaches. Glycan structures act as interface molecules between cells and their environment and in several cases facilitate molecule function. CRC tissue shows alterations in glycan structures decorating molecules, such as annexin-1, mucins, heat shock protein 90 (Hsp90), β1 integrin, carcinoembryonic antigen (CEA), epidermal growth factor receptor (EGFR), insulin-like growth factor-binding protein 3 (IGFBP3), transforming growth factor beta (TGF-β) receptors, Fas (CD95), PD-L1, decorin, sorbin and SH3 domain-containing protein 1 (SORBS1), CD147 and glycosphingolipids. All of these are described as key molecules in oncogenesis and metastasis. Therefore, glycosylation in CRC can affect cell migration, cell–cell adhesion, actin polymerization, mitosis, cell membrane repair, apoptosis, cell differentiation, stemness regulation, intestinal mucosal barrier integrity, immune system regulation, T cell polarization and gut microbiota composition; all such functions are associated with the prognosis and evolution of the disease. According to these findings, multiple strategies have been evaluated to alter oligosaccharide processing and to modify glycoconjugate structures in order to control CRC progression and prevent metastasis. Additionally, immunotherapy approaches have contemplated the use of neo-antigens, generated by altered glycosylation, as targets for tumor-specific T cells or engineered CAR (Chimeric antigen receptors) T cells.

CAR-T cell therapy: current limitations and potential strategies

Chimeric antigen receptor (CAR)-T cell therapy is a revolutionary new pillar in cancer treatment. Although treatment with CAR-T cells has produced remarkable clinical responses with certain subsets of B cell leukemia or lymphoma, many challenges limit the therapeutic efficacy of CAR-T cells in solid tumors and hematological malignancies. Barriers to effective CAR-T cell therapy include severe life-threatening toxicities, modest anti-tumor activity, antigen escape, restricted trafficking, and limited tumor infiltration. In addition, the host and tumor microenvironment interactions with CAR-T cells critically alter CAR-T cell function. Furthermore, a complex workforce is required to develop and implement these treatments. In order to overcome these significant challenges, innovative strategies and approaches to engineer more powerful CAR-T cells with improved anti-tumor activity and decreased toxicity are necessary. In this review, we discuss recent innovations in CAR-T cell engineering to improve clinical efficacy in both hematological malignancy and solid tumors and strategies to overcome limitations of CAR-T cell therapy in both hematological malignancy and solid tumors.

The role of O-glycosylation in human disease

O-glycosylation is a highly frequent post-translation modification of proteins, with important functional implications in both physiological and disease contexts. The biosynthesis of O-glycans depends on several layers of regulation of the cellular glycosylation machinery, being organ-, tissue- and cell-specific. This review provides insights on the molecular mechanism underlying O-glycan biosynthesis and modification, and highlights illustrative examples of diseases that are triggered or modulated by aberrant cellular O-glycosylation. Particular relevance is given to genetic disorders of glycosylation, infectious diseases and cancer. Finally, we address the potential of O-glycans and their biosynthetic pathways as targets for novel therapeutic strategies.

Aberrant protein glycosylation in cancer: implications in targeted therapy

Aberrant cell surface glycosylation signatures are currently known to actively drive the neoplastic transformation of healthy cells. By disrupting the homeostatic functions of their protein carriers, cancer-associated glycans mechanistically underpin several molecular hallmarks of human malignancy. Furthermore, such aberrant glycan structures play key roles in the acquisition of molecular resistance to targeted therapeutic agents, which compromises their clinical efficacy, by modulating tumour cell aggressiveness and supporting the establishment of an immunosuppressive microenvironment. Recent advances in the study of the tumour cell glycoproteome have unravelled previously elusive molecular mechanisms of therapeutic resistance, guided the rational design of novel personalized therapeutic strategies, and may further improve the clinical performance of currently approved anti-cancer targeted agents. In this review, we highlight the impact of glycosylation in cancer targeted therapy, with particular focus on receptor tyrosine kinase-targeted therapy, immune checkpoints blockade therapy, and current developments on therapeutic strategies directed to glycan-binding proteins and other innovative glycan therapeutic strategies.

Genetic engineering of T cells for immunotherapy

Genetically engineered T cell immunotherapies have provided remarkable clinical success to treat B cell acute lymphoblastic leukaemia by harnessing a patient's own T cells to kill cancer, and these approaches have the potential to provide therapeutic benefit for numerous other cancers, infectious diseases and autoimmunity. By introduction of either a transgenic T cell receptor or a chimeric antigen receptor, T cells can be programmed to target cancer cells. However, initial studies have made it clear that the field will need to implement more complex levels of genetic regulation of engineered T cells to ensure both safety and efficacy. Here, we review the principles by which our knowledge of genetics and genome engineering will drive the next generation of adoptive T cell therapies.

Glycoproteogenomics: Setting the Course for Next-generation Cancer Neoantigen Discovery for Cancer Vaccines

Molecular-assisted precision oncology gained tremendous ground with high-throughput next-generation sequencing (NGS), supported by robust bioinformatics. The quest for genomics-based cancer medicine set the foundations for improved patient stratification, while unveiling a wide array of neoantigens for immunotherapy. Upfront pre-clinical and clinical studies have successfully used tumor-specific peptides in vaccines with minimal off-target effects. However, the low mutational burden presented by many lesions challenges the generalization of these solutions, requiring the diversification of neoantigen sources. Oncoproteogenomics utilizing customized databases for protein annotation by mass spectrometry (MS) is a powerful tool toward this end. Expanding the concept toward exploring proteoforms originated from post-translational modifications (PTMs) will be decisive to improve molecular subtyping and provide potentially targetable functional nodes with increased cancer specificity. Walking through the path of systems biology, we highlight that alterations in protein glycosylation at the cell surface not only have functional impact on cancer progression and dissemination but also originate unique molecular fingerprints for targeted therapeutics. Moreover, we discuss the outstanding challenges required to accommodate glycoproteomics in oncoproteogenomics platforms. We envisage that such rationale may flag a rather neglected research field, generating novel paradigms for precision oncology and immunotherapy.

Towards structure-focused glycoproteomics

Facilitated by advances in the separation sciences, mass spectrometry and informatics, glycoproteomics, the analysis of intact glycopeptides at scale, has recently matured enabling new insights into the complex glycoproteome. While diverse quantitative glycoproteomics strategies capable of mapping monosaccharide compositions of N- and O-linked glycans to discrete sites of proteins within complex biological mixtures with considerable sensitivity, quantitative accuracy and coverage have become available, developments supporting the advancement of structure-focused glycoproteomics, a recognised frontier in the field, have emerged. Technologies capable of providing site-specific information of the glycan fine structures in a glycoproteome-wide context are indeed necessary to address many pending questions in glycobiology. In this review, we firstly survey the latest glycoproteomics studies published in 2018–2020, their approaches and their findings, and then summarise important technological innovations in structure-focused glycoproteomics. Our review illustrates that while the O-glycoproteome remains comparably under-explored despite the emergence of new O-glycan-selective mucinases and other innovative tools aiding O-glycoproteome profiling, quantitative glycoproteomics is increasingly used to profile the N-glycoproteome to tackle diverse biological questions. Excitingly, new strategies compatible with structure-focused glycoproteomics including novel chemoenzymatic labelling, enrichment, separation, and mass spectrometry-based detection methods are rapidly emerging revealing glycan fine structural details including bisecting GlcNAcylation, core and antenna fucosylation, and sialyl-linkage information with protein site resolution. Glycoproteomics has clearly become a mainstay within the glycosciences that continues to reach a broader community. It transpires that structure-focused glycoproteomics holds a considerable potential to aid our understanding of systems glycobiology and unlock secrets of the glycoproteome in the immediate future.

Current Status on Therapeutic Molecules Targeting Siglec Receptors

The sialic acid-binding immunoglobulin-type of lectins (Siglecs) are receptors that recognize sialic acid-containing glycans. In the majority of the cases, Siglecs are expressed on immune cells and play a critical role in regulating immune cell signaling. Over the years, it has been shown that the sialic acid-Siglec axis participates in immunological homeostasis, and that any imbalance can trigger different pathologies, such as autoimmune diseases or cancer. For all this, different therapeutics have been developed that bind to Siglecs, either based on antibodies or being smaller molecules. In this review, we briefly introduce the Siglec family and we compile a description of glycan-based molecules and antibody-based therapies (including CAR-T and bispecific antibodies) that have been designed to therapeutically targeting Siglecs.

Efficient Screening of Glycan-Specific Aptamers Using a Glycosylated Peptide as a Scaffold

Abnormal glycan structures are valuable biomarkers for disease states; the development of glycan-specific binders is thereby significantly important. However, the structural homology and weak immunogenicity of glycans pose major hurdles in the evolution of antibodies, while the poor availability of complex glycans also has extremely hindered the selection of anti-glycan aptamers. Herein, we present a new approach to efficiently screen aptamers toward specific glycans with a complex structure, using a glycosylated peptide as a scaffold. In this method, using peptide-imprinted magnetic nanoparticles (MNPs) as a versatile platform, a glycopeptide tryptically digested from a native glycoprotein was selectively entrapped for positive selection, while a nonglycosylated analogue with an identical peptide sequence was synthesized for negative selection. Alternating positive and negative selection steps were carried out to guide the directed evolution of glycan-binding aptamers. As proof of the principle, the biantennary digalactosylated disialylated N-glycan A2G2S2, against which there have been no antibodies and lectins so far, was employed as the target. With the glycoprotein transferrin as a source of target glycan, two satisfied anti-A2G2S2 aptamers were selected within seven rounds. Since A2G2S2 is upregulated in cancerous liver cells, carboxyfluorescein (FAM)-labeled aptamers were prepared as fluorescent imaging reagents, and successful differentiation of cancerous liver cells over normal liver cells was achieved, which demonstrated the application feasibility of the selected aptamers. This approach obviated a tedious glycan preparation process and allowed favorable expose of the intrinsic flexible conformation of natural glycans. Therefore, it holds great promise for developing glycan-specific aptamers for challenging applications such as cancer targeting.

Intestinal epithelial glycosylation in homeostasis and gut microbiota interactions in IBD

Inflammatory bowel disease (IBD) affects 6.8 million people globally. A variety of factors have been implicated in IBD pathogenesis, including host genetics, immune dysregulation and gut microbiota alterations. Emerging evidence implicates intestinal epithelial glycosylation as an underappreciated process that interfaces with these three factors. IBD is associated with increased expression of truncated O-glycans as well as altered expression of terminal glycan structures. IBD genes, glycosyltransferase mislocalization, altered glycosyltransferase and glycosidase expression and dysbiosis drive changes in the glycome. These glycan changes disrupt the mucus layer, glycan-lectin interactions, host-microorganism interactions and mucosal immunity, and ultimately contribute to IBD pathogenesis. Epithelial glycans are especially critical in regulating the gut microbiota through providing bacterial ligands and nutrients and ultimately determining the spatial organization of the gut microbiota. In this Review, we discuss the regulation of intestinal epithelial glycosylation, altered epithelial glycosylation in IBD and mechanisms for how these alterations contribute to disease pathobiology. We hope that this Review provides a foundation for future studies on IBD glycosylation and the emergence of glycan-inspired therapies for IBD.

Identification of Targets to Redirect CAR T Cells in Glioblastoma and Colorectal Cancer: An Arduous Venture

The chimeric antigen receptor (CAR) is an artificial molecule engineered to induce cytolytic T cell reactions in tumors. Generally, this molecule combines an extracellular single-chain variable fragment (scFv) able to recognize tumor-associated epitopes together with the intracellular signaling domains that are required for T cell activation. When expressed by T cells, the CAR enables the recognition and subsequent destruction of cancer cells expressing the complementary antigen on their surface. Although the clinical application for CAR T cells is currently limited to some hematological malignancies, researchers are trying to develop CAR T cell-based therapies for the treatment of solid tumors. However, while in the case of CD19, or other targets restricted to the hematopoietic compartment, the toxicity is limited and manageable, the scarcity of specific antigens expressed by solid tumors and not by healthy cells from vital organs makes the clinical development of CAR T cells in this context particularly challenging. Here we summarize relevant research and clinical trials conducted to redirect CAR T cells to surface antigens in solid tumors and cancer stem cells with a focus on colorectal cancer and glioblastoma. Finally, we will discuss current knowledge of altered glycosylation of CSCs and cancer cells and how these novel epitopes may help to target CAR T cell-based immunotherapy in the future.

Fasten the seat belt: Increasing safety of CAR T-cell therapy

After the recent success and approvals of chimeric antigen receptor (CAR) T cells in haematological malignancies, its efficacy is currently evaluated in a broad spectrum of tumor entities including melanoma. However, severe and potentially life-threatening side effects like cytokine release syndrome, neurologic toxicities, and the competing risk of morbidity and mortality from the treatment itself are still a major limiting factor in the current CAR T-cell landscape. In addition, especially in solid tumors, the lack of ideal target antigens to avoid on-target/off-tumor toxicities also restricts its use. While various groups are working on strategies to boost CAR T-cell efficacy, mechanisms to increase engineered T-cell safety should not move out of focus. Thus, the aim of this article is to summarize and to discuss current and potential future strategies and mechanisms to increase CAR T-cell safety in order to enable the wide use of this promising approach in melanoma and other tumor entities.

Oncofetal Chondroitin Sulfate: A Putative Therapeutic Target in Adult and Pediatric Solid Tumors

Solid tumors remain a major challenge for targeted therapeutic intervention strategies such as antibody-drug conjugates and immunotherapy. At a minimum, clear and actionable solid tumor targets have to comply with the key biological requirement of being differentially over-expressed in solid tumors and metastasis, in contrast to healthy organs. Oncofetal chondroitin sulfate is a cancer-specific secondary glycosaminoglycan modification to proteoglycans expressed in a variety of solid tumors and metastasis. Normally, this modification is found to be exclusively expressed in the placenta, where it is thought to facilitate normal placental implantation during pregnancy. Informed by this biology, oncofetal chondroitin sulfate is currently under investigation as a broad and specific target in solid tumors. Here, we discuss oncofetal chondroitin sulfate as a potential therapeutic target in childhood solid tumors in the context of current knowhow obtained over the past five years in adult cancers.

Human T cell glycosylation and implications on immune therapy for cancer

Glycosylation is an important post-translational modification, giving rise to a diverse and abundant repertoire of glycans on the cell surface, collectively known as the glycome. When focusing on immunity, glycans are indispensable in virtually all signaling and cell-cell interactions. More specifically, glycans have been shown to regulate key pathophysiological steps within T cell biology such as T cell development, thymocyte selection, T cell activity and signaling as well as T cell differentiation and proliferation. They are of major importance in determining the interaction of human T cells with tumor cells. In this review, we will describe the role of glycosylation of human T cells in more depth, elaborate on the importance of glycosylation in the interaction of human T cells with tumor cells and discuss the potential of cancer immunotherapies that are based on manipulating the glycome functions at the tumor immune interface.^1,2