Chimeric receptors with 4-1BB signaling capacity provoke potent cytotoxicity against acute lymphoblastic leukemia

In silico and in vivo analysis reveal impact of c-Myc tag in FMC63 scFv-CD19 protein interface and CAR-T cell efficacy

Anti-CD19 CAR-T cell therapy represents a breakthrough in the treatment of B-cell malignancies, and it is expected that this therapy modality will soon cover a range of solid tumors as well. Therefore, a universal cheap and sensitive method to detect CAR expression is of foremost importance. One possibility is the use of epitope tags such as c-Myc, HA or FLAG tags attached to the CAR extracellular domain, however, it is important to determine whether these tags can influence binding of the CAR with its target molecule. Here, we conducted in-silico structural modelling of an FMC63-based anti-CD19 single-chain variable fragment (scFv) with and without a c-Myc peptide tag added to the N-terminus portion and performed molecular dynamics simulation of the scFv with the CD19 target. We show that the c-Myc tag presence in the N-terminus portion does not affect the scFv's structural equilibrium and grants more stability to the scFv. However, intermolecular interaction potential (IIP) analysis reveals that the tag can approximate the complementarity-determining regions (CDRs) present in the scFv and cause steric impediment, potentially disturbing interaction with the CD19 protein. We then tested this possibility with CAR-T cells generated from human donors in a Nalm-6 leukemia model, showing that CAR-T cells with the c-Myc tag have overall worse antitumor activity, which was also observed when the tag was added to the C-terminus position. Ultimately, our results suggest that tag addition is an important aspect of CAR design and can influence CAR-T cell function, therefore its use should be carefully considered.

Fratricide-resistant CD7-CAR T cells in T-ALL

T cell acute lymphoblastic leukemia (T-ALL) is difficult to treat when it relapses after therapy or is chemoresistant; the prognosis of patients with relapsed or refractory T-ALL is generally poor. We report a case series of 17 such patients who received autologous chimeric antigen receptor (CAR) T cells expressing an anti-CD7 CAR and an anti-CD7 protein expression blocker (PEBL), which prevented CAR T cell fratricide. Despite high leukemic burden and low CAR T cell dosing, 16 of the 17 patients attained minimal residual disease-negative complete remission within 1 month. The remaining patient had CD7- T-ALL cells before infusion, which persisted after infusion. Toxicities were mild: cytokine release syndrome grade 1 in ten patients and grade 2 in three patients; immune effector cell-associated neurotoxicity syndrome grade 1 in two patients. Eleven patients remained relapse-free (median follow-up, 15 months), including all nine patients who received an allotransplant. The first patient is in remission 55 months after infusion without further chemotherapy or transplantation; circulating CAR T cells were detectable for 2 years. T cells regenerating after lymphodepletion lacked CD7 expression, were polyclonal and responded to SARS-CoV-2 vaccination; CD7+ immune cells reemerged concomitantly with CAR T cell disappearance. In conclusion, autologous anti-CD7 PEBL-CAR T cells have powerful antileukemic activity and are potentially an effective option for the treatment of T-ALL.

TALEN-edited allogeneic inducible dual CAR T cells enable effective targeting of solid tumors while mitigating off-tumor toxicity

Adoptive cell therapy using chimeric antigen receptor (CAR) T cells has proven to be lifesaving for many cancer patients. However, its therapeutic efficacy has been limited in solid tumors. One key factor for this is cancer-associated fibroblasts (CAFs) that modulate the tumor microenvironment (TME) to inhibit T cell infiltration and induce "T cell dysfunction." Additionally, the sparsity of tumor-specific antigens (TSA) and expression of CAR-directed tumor-associated antigens (TAA) on normal tissues often results in "on-target off-tumor" cytotoxicity, raising safety concerns. Using TALEN-mediated gene editing, we present here an innovative CAR T cell engineering strategy to overcome these challenges. Our allogeneic "Smart CAR T cells" are designed to express a constitutive CAR, targeting FAP+ CAFs in solid tumors. Additionally, a second CAR targeting a TAA such as mesothelin is specifically integrated at a TCR signaling-inducible locus like PDCD1. FAPCAR-mediated CAF targeting induces expression of the mesothelin CAR, establishing an IF/THEN-gated circuit sensitive to dual antigen sensing. Using this approach, we observe enhanced anti-tumor cytotoxicity, while limiting "on-target off-tumor" toxicity. Our study thus demonstrates TALEN-mediated gene editing capabilities for design of allogeneic IF/THEN-gated dual CAR T cells that efficiently target immunotherapy-recalcitrant solid tumors while mitigating potential safety risks, encouraging clinical development of this strategy.

A synthetic cytotoxic T cell platform for rapidly prototyping TCR function

Current tools for functionally profiling T cell receptors with respect to cytotoxic potency and cross-reactivity are hampered by difficulties in establishing model systems to test these proteins in the contexts of different HLA alleles and against broad arrays of potential antigens. We have implemented a granzyme-activatable sensor of T cell cytotoxicity in a universal prototyping platform which enables facile recombinant expression of any combination of TCR-, peptide-, and class I MHC-coding sequences and direct assessment of resultant responses. This system consists of an engineered cell platform based on the immortalized natural killer cell line, YT-Indy, and the MHC-null antigen-presenting cell line, K562. These cells were engineered to furnish the YT-Indy/K562 pair with appropriate protein domains required for recombinant TCR expression and function in a non-T cell chassis, integrate a fluorescence-based target-centric early detection reporter of cytotoxic function, and deploy a set of protective genetic interventions designed to preserve antigen-presenting cells for subsequent capture and downstream characterization. Our data show successful reconstitution of the surface TCR complex in the YT-Indy cell line at biologically relevant levels. We also demonstrate successful induction and highly sensitive detection of antigen-specific response in multiple distinct model TCRs. Additionally, we monitored destruction of targets in co-culture and found that our survival-optimized system allowed for complete preservation after 24 h exposure to cytotoxic effectors. With this bioplatform, we anticipate investigators will be empowered to rapidly express and characterize T cell receptor responses, generate knowledge regarding the patterns of T cell receptor recognition, and optimize therapeutic T cell receptors.

Targeting GPC2 on Intraocular and CNS Metastatic Retinoblastomas with Local and Systemic Delivery of CAR T Cells

PURPOSE

Retinoblastoma is the most common intraocular malignancy in children. Although new chemotherapeutic approaches have improved ocular salvage rates, novel therapies are required for patients with refractory intraocular and metastatic disease. Chimeric antigen receptor (CAR) T cells targeting glypican-2 (GPC2) are a potential new therapeutic strategy.

EXPERIMENTAL DESIGN

GPC2 expression and its regulation by the E2F1 transcription factor were studied in retinoblastoma patient samples and cellular models. In vitro, we performed functional studies comparing GPC2 CAR T cells with different costimulatory domains (4-1BB and CD28). In vivo, the efficacy of local and systemic administration of GPC2 CAR T cells was evaluated in intraocular and leptomeningeal human retinoblastoma xenograft models.

RESULTS

Retinoblastoma tumors, but not healthy retinal tissues, expressed cell surface GPC2, and this tumor-specific expression was driven by E2F1. GPC2-directed CARs with 4-1BB costimulation (GPC2.BBz) were superior to CARs with CD28 stimulatory domains (GPC2.28z), efficiently inducing retinoblastoma cell cytotoxicity and enhancing T-cell proliferation and polyfunctionality. In vivo, GPC2.BBz CARs had enhanced persistence, which led to significant tumor regression compared with either control CD19 or GPC2.28z CARs. In intraocular models, GPC2.BBz CAR T cells efficiently trafficked to tumor-bearing eyes after intravitreal or systemic infusions, significantly prolonging ocular survival. In central nervous system (CNS) retinoblastoma models, intraventricular or systemically administered GPC2.BBz CAR T cells were activated in retinoblastoma-involved CNS tissues, resulting in robust tumor regression with substantially extended overall mouse survival.

CONCLUSIONS

GPC2-directed CAR T cells are effective against intraocular and CNS metastatic retinoblastomas.

Chimeric antigen receptor T-cells: a review on current status and future directions for relapsed/refractory multiple myeloma

Although multiple myeloma is an incurable disease, the past decade has witnessed significant improvement in patient outcomes. This was brought about by the development of T-cell redirection therapies such as chimeric antigen receptor (CAR) T-cells, which can leverage the natural ability of the immune system to fight myeloma cells. The approval of the B-cell maturation antigen (BCMA)-directed CAR T, idecabtagene vicleucel (ide-cel), and ciltacabtagene autoleucel (cilta-cel) has resulted in a paradigm shift in the treatment of relapsed/refractory multiple myeloma. Overall response rates ranging from 73 to 97% are currently achievable. However, the limitations of KarMMa-1 and CARTITUDE-1 studies spurred the generation of real-world data to provide some insights into the effectiveness of ide-cel and cilta-cel among patients who were excluded from clinical trials, particularly those who received prior BCMA-targeted or other T-cell redirection therapies. Despite their unprecedented clinical efficacy in heavily pretreated patients, responses to CAR T remain non-durable. Although the underlying mechanisms of resistance to these agents haven't been fully elucidated, studies have suggested that resistance patterns could be multifaceted, implicating T-cell exhaustion and tumor intrinsic mechanisms such as BCMA target loss, upregulation of gamma-secretase, and others. Herein, we provide a succinct overview of the development of CAR T-cells, manufacturing process, and associated toxicities/complications. In this review, we also recapitulate the existing literature pertaining MM CAR-T as well as emerging data from some of the ongoing clinical trials designed to mitigate the shortcomings of these agents, and improve the clinical efficacy of CAR T, especially in the relapsed/refractory setting.

T cell dysfunction and therapeutic intervention in cancer

Recent advances in immunotherapy have affirmed the curative potential of T cell-based approaches for treating relapsed and refractory cancers. However, the therapeutic efficacy is limited in part owing to the ability of cancers to evade immunosurveillance and adapt to immunological pressure. In this Review, we provide a brief overview of cancer-mediated immunosuppressive mechanisms with a specific focus on the repression of the surveillance and effector function of T cells. We discuss CD8+ T cell exhaustion and functional heterogeneity and describe strategies for targeting the molecular checkpoints that restrict T cell differentiation and effector function to bolster immunotherapeutic effects. We also delineate the emerging contributions of the tumor microenvironment to T cell metabolism and conclude by highlighting discovery-based approaches for developing future cellular therapies. Continued exploration of T cell biology and engineering hold great promise for advancing therapeutic interventions for cancer.

Chick Embryo Chorioallantoic Membrane as a Platform for Assessing the In Vivo Efficacy of Chimeric Antigen Receptor T-cell Therapy in Solid Tumors

The fertilized chicken egg chorioallantoic membrane (CAM), a highly vascularized membrane nourishing the developing embryo, also supports rapid growth of three-dimensional vascularized tumors from engrafted cells and tumor explants. Because murine xenograft models suffer limitations of time, cost, and scalability, we propose CAM tumors as a rapid, efficient screening tool for assessing anti-tumor efficacy of chimeric Ag receptor (CAR) T cells against solid tumors. We tested the efficacy of human epidermal growth factor receptor 2 (HER2)-specific CAR T cells against luminescent, HER2-expressing (FaDu, SCC-47) or HER2-negative (MDA-MB-468) CAM-engrafted tumors. Three days after tumor engraftment, HER2-specific CAR T cells were applied to tumors grown on the CAM. Four days post-CAR T cell treatment, HER2-expressing FaDu and SCC-47 tumors treated with CAR T showed reduced viable cancer cells as assessed by luciferase activity. This reduction in viable tumor cells was confirmed by histology, with lower Ki-67 staining observed in CAR T cell-treated tumors relative to T cell-treated controls. Persistence of CAR T in CAM and tumor tissue 4 days post-treatment was confirmed by CD3 staining. Altogether, our findings support further development of the chick CAM as an in vivo system for rapid, scalable screening of CAR T cell efficacy against human solid tumors.

GLUT1 overexpression enhances CAR T cell metabolic fitness and anti-tumor efficacy

The tumor microenvironment presents many obstacles to effective chimeric antigen receptor (CAR) T cell therapy, including glucose competition from tumor and myeloid cells. Using mouse models of acute lymphoblastic leukemia (ALL), renal cell carcinoma (RCC), and glioblastoma (GBM), we show that enforced expression of the glucose transporter GLUT1 enhances anti-tumor efficacy and promotes favorable CAR-T cell phenotypes for two clinically relevant CAR designs, 19-28z and IL13Rα2-BBz. In the NALM6 ALL model, 19-28z-GLUT1 promotes T stem cell-like memory formation and prolongs survival. RNA sequencing of these CAR-T cells reveals that the overexpression of GLUT1, but not GLUT3, enriches for genes involved in glycolysis, mitochondrial respiration, and memory precursor phenotypes. Extending these data, 19-28z-GLUT1 CAR-T cells improve tumor control and response to rechallenge in an RCC patient-derived xenograft model. Furthermore, IL13Rα2-BBz CAR-T cells overexpressing GLUT1 prolong the survival of mice bearing orthotopic GBMs and exhibit decreased exhaustion markers. This novel engineering approach can offer a competitive advantage to CAR-T cells in harsh tumor environments where glucose is limiting.

Overcoming the challenges of primary resistance and relapse after CAR-T cell therapy

INTRODUCTION

While CAR T-cell therapy has led to remarkable responses in relapsed B-cell hematologic malignancies, only 50% of patients ultimately have a complete, sustained response. Understanding the mechanisms of resistance and relapse after CAR T-cell therapy is crucial to future development and improving outcomes.

AREAS COVERED

We review reasons for both primary resistance and relapse after CAR T-cell therapies. Reasons for primary failure include CAR T-cell manufacturing problems, suboptimal fitness of autologous T-cells themselves, and intrinsic features of the underlying cancer and tumor microenvironment. Relapse after initial response to CAR T-cell therapy may be antigen-positive, due to CAR T-cell exhaustion or limited persistence, or antigen-negative, due to antigen-modulation on the target cells. Finally, we discuss ongoing efforts to overcome resistance to CAR T-cell therapy with enhanced CAR constructs, manufacturing methods, alternate cell types, combinatorial strategies, and optimization of both pre-infusion conditioning regimens and post-infusion consolidative strategies.

EXPERT OPINION

There is a continued need for novel approaches to CAR T-cell therapy for both hematologic and solid malignancies to obtain sustained remissions. Opportunities for improvement include development of new targets, optimally combining existing CAR T-cell therapies, and defining the role for adjunctive immune modulators and stem cell transplant in enhancing long-term survival.

Challenges and innovations in CAR-T cell therapy: a comprehensive analysis

Recent years have seen a marked increase in research on chimeric antigen receptor T (CAR-T) cells, with specific relevance to the treatment of hematological malignancies. Here, the structural principles, iterative processes, and target selection of CAR-T cells for therapeutic applications are described in detail, as well as the challenges faced in the treatment of solid tumors and hematological malignancies. These challenges include insufficient infiltration of cells, off-target effects, cytokine release syndrome, and tumor lysis syndrome. In addition, directions in the iterative development of CAR-T cell therapy are discussed, including modifications of CAR-T cell structures, improvements in specificity using multi-targets and novel targets, the use of Boolean logic gates to minimize off-target effects and control toxicity, and the adoption of additional protection mechanisms to improve the durability of CAR-T cell treatment. This review provides ideas and strategies for the development of CAR-T cell therapy through an in-depth exploration of the underlying mechanisms of action of CAR-T cells and their potential for innovative modification.

Comparison of seven CD19 CAR designs in engineering NK cells for enhancing anti-tumour activity

Chimeric antigen receptor-natural killer (CAR-NK) cell therapy is emerging as a promising cancer treatment, with notable safety and source diversity benefits over CAR-T cells. This study focused on optimizing CAR constructs for NK cells to maximize their therapeutic potential. We designed seven CD19 CAR constructs and expressed them in NK cells using a retroviral system, assessing their tumour-killing efficacy and persistence. Results showed all constructs enhanced tumour-killing and prolonged survival in tumour-bearing mice. In particular, CAR1 (CD8 TMD-CD3ζ SD)-NK cells showed superior efficacy in treating tumour-bearing animals and exhibited enhanced persistence when combined with OX40 co-stimulatory domain. Of note, CAR1-NK cells were most effective at lower effector-to-target ratios, while CAR4 (CD8 TMD-OX40 CD- FcεRIγ SD) compromised NK cell expansion ability. Superior survival rates were noted in mice treated with CAR1-, CAR2 (CD8 TMD- FcεRIγ SD)-, CAR3 (CD8 TMD-OX40 CD- CD3ζ SD)- and CAR4-NK cells over those treated with CAR5 (CD28 TMD- FcεRIγ SD)-, CAR6 (CD8 TMD-4-1BB CD-CD3ζ 1-ITAM SD)- and CAR7 (CD8 TMD-OX40 CD-CD3ζ 1-ITAM SD)-NK cells, with CAR5-NK cells showing the weakest anti-tumour activity. Increased expression of exhaustion markers, especially in CAR7-NK cells, suggests that combining CAR-NK cells with immune checkpoint inhibitors might improve anti-tumour outcomes. These findings provide crucial insights for developing CAR-NK cell products for clinical applications.

Chimeric antigen receptor T-cell therapy for T-cell acute lymphoblastic leukemia

Chimeric antigen receptor (CAR) T-cell therapy is a new and effective treatment for patients with hematologic malignancies. Clinical responses to CAR T cells in leukemia, lymphoma, and multiple myeloma have provided strong evidence of the antitumor activity of these cells. In patients with refractory or relapsed B-cell acute lymphoblastic leukemia (ALL), the infusion of autologous anti-CD19 CAR T cells is rapidly gaining standard-of-care status and might eventually be incorporated into frontline treatment. In T-ALL, however, leukemic cells generally lack surface molecules recognized by established CAR, such as CD19 and CD22. Such deficiency is particularly important, as outcome is dismal for patients with T-ALL that is refractory to standard chemotherapy and/or hematopoietic stem cell transplant. Recently, CAR T-cell technologies directed against T-cell malignancies have been developed and are beginning to be tested clinically. The main technical obstacles stem from the fact that malignant and normal T cells share most surface antigens. Therefore, CAR T cells directed against T-ALL targets might be susceptible to self-elimination during manufacturing and/or have suboptimal activity after infusion. Moreover, removing leukemic cells that might be present in the cell source used for CAR T-cell manufacturing might be problematic. Finally, reconstitution of T cells and natural killer cells after CAR T-cell infusion might be impaired. In this article, we discuss potential targets for CAR T-cell therapy of T-ALL with an emphasis on CD7, and review CAR configurations as well as early clinical results.

Synthetic dual co-stimulation increases the potency of HIT and TCR-targeted cell therapies

Chimeric antigen receptor T cells have dramatically improved the treatment of hematologic malignancies. T cell antigen receptor (TCR)-based cell therapies are yet to achieve comparable outcomes. Importantly, chimeric antigen receptors not only target selected antigens but also reprogram T cell functions through the co-stimulatory pathways that they engage upon antigen recognition. We show here that a fusion receptor comprising the CD80 ectodomain and the 4-1BB cytoplasmic domain, termed 80BB, acts as both a ligand and a receptor to engage the CD28 and 4-1BB pathways, thereby increasing the antitumor potency of human leukocyte antigen-independent TCR (HIT) receptor- or TCR-engineered T cells and tumor-infiltrating lymphocytes. Furthermore, 80BB serves as a switch receptor that provides agonistic 4-1BB co-stimulation upon its ligation by the inhibitory CTLA4 molecule. By combining multiple co-stimulatory features in a single antigen-agnostic synthetic receptor, 80BB is a promising tool to sustain CD3-dependent T cell responses in a wide range of targeted immunotherapies.

Non-viral delivery of RNA for therapeutic T cell engineering

Adoptive T cell transfer has shown great success in treating blood cancers, resulting in a growing number of FDA-approved therapies using chimeric antigen receptor (CAR)-engineered T cells. However, the effectiveness of this treatment for solid tumors is still not satisfactory, emphasizing the need for improved T cell engineering strategies and combination approaches. Currently, CAR T cells are mainly manufactured using gammaretroviral and lentiviral vectors due to their high transduction efficiency. However, there are concerns about their safety, the high cost of producing them in compliance with current Good Manufacturing Practices (cGMP), regulatory obstacles, and limited cargo capacity, which limit the broader use of engineered T cell therapies. To overcome these limitations, researchers have explored non-viral approaches, such as membrane permeabilization and carrier-mediated methods, as more versatile and sustainable alternatives for next-generation T cell engineering. Non-viral delivery methods can be designed to transport a wide range of molecules, including RNA, which allows for more controlled and safe modulation of T cell phenotype and function. In this review, we provide an overview of non-viral RNA delivery in adoptive T cell therapy. We first define the different types of RNA therapeutics, highlighting recent advancements in manufacturing for their therapeutic use. We then discuss the challenges associated with achieving effective RNA delivery in T cells. Next, we provide an overview of current and emerging technologies for delivering RNA into T cells. Finally, we discuss ongoing preclinical and clinical studies involving RNA-modified T cells.

Treatment Options for Hepatocellular Carcinoma Using Immunotherapy: Present and Future

Hepatocellular carcinoma (HCC) is a common cancer, and the body's immune responses greatly affect its progression and the prognosis of patients. Immunological suppression and the maintenance of self-tolerance in the tumor microenvironment are essential responses, and these form part of the theoretical foundations of immunotherapy. In this review, we first discuss the tumor microenvironment of HCC, describe immunosuppression in HCC, and review the major biomarkers used to track HCC progression and response to treatment. We then examine antibody-based therapies, with a focus on immune checkpoint inhibitors (ICIs), monoclonal antibodies that target key proteins in the immune response (programmed cell death protein 1, anti-cytotoxic T-lymphocyte associated protein 4, and programmed death-ligand 1) which have transformed the treatment of HCC and other cancers. ICIs may be used alone or in conjunction with various targeted therapies for patients with advanced HCC who are receiving first-line treatments or subsequent treatments. We also discuss the use of different cellular immunotherapies, including T cell receptor (TCR) T cell therapy and chimeric antigen receptor (CAR) T cell therapy. We then review the use of HCC vaccines, adjuvant immunotherapy, and oncolytic virotherapy, and describe the goals of future research in the development of treatments for HCC.

A new vision of the efficacy of both CAR-NK and CAR-T cells in treating cancers and autoimmune diseases

Chimeric Antigen Receptor (CAR) based therapies are becoming increasingly important in treating patients. CAR-T cells have been shown to be highly effective in the treatment of hematological malignancies. However, harmful therapeutic barriers have been identified, such as the potential for graft-versus-host disease (GVHD), neurotoxicity, and cytokine release syndrome (CRS). As a result, CAR NK-cell therapy is expected to be a new therapeutic option. NK cells act as cytotoxic lymphocytes, supporting the innate immune response against autoimmune diseases and cancer cells by precisely detecting and eliminating malignant cells. Genetic modification of these cells provides a dual approach to the treatment of AD and cancer. It can be used through both CAR-independent and CAR-dependent mechanisms. The use of CAR-based cell therapies has been successful in treating cancer patients, leading to further investigation of this innovative treatment for alternative diseases, including AD. The complementary roles of CAR T and CAR NK cells have stimulated exploration in this area. Our study examines the latest research on the therapeutic effectiveness of these cells in treating both cancer and ADs.

A Roadmap of CAR-T-Cell Therapy in Glioblastoma: Challenges and Future Perspectives

Glioblastoma (GBM) is the most common primary malignant brain tumor, with a median overall survival of less than 2 years and a nearly 100% mortality rate under standard therapy that consists of surgery followed by combined radiochemotherapy. Therefore, new therapeutic strategies are urgently needed. The success of chimeric antigen receptor (CAR) T cells in hematological cancers has prompted preclinical and clinical investigations into CAR-T-cell treatment for GBM. However, recent trials have not demonstrated any major success. Here, we delineate existing challenges impeding the effectiveness of CAR-T-cell therapy for GBM, encompassing the cold (immunosuppressive) microenvironment, tumor heterogeneity, T-cell exhaustion, local and systemic immunosuppression, and the immune privilege inherent to the central nervous system (CNS) parenchyma. Additionally, we deliberate on the progress made in developing next-generation CAR-T cells and novel innovative approaches, such as low-intensity pulsed focused ultrasound, aimed at surmounting current roadblocks in GBM CAR-T-cell therapy.

Chimeric Antigen Receptor (CAR) T-Cell Therapy in Hematologic Malignancies: Clinical Implications and Limitations

Chimeric antigen receptor (CAR) T-cell therapy has become a powerful treatment option in B-cell and plasma cell malignancies, and many patients have benefited from its use. To date, six CAR T-cell products have been approved by the FDA and EMA, and many more are being developed and investigated in clinical trials. The whole field of adoptive cell transfer has experienced an unbelievable development process, and we are now at the edge of a new era of immune therapies that will have its impact beyond hematologic malignancies. Areas of interest are, e.g., solid oncology, autoimmune diseases, infectious diseases, and others. Although much has been achieved so far, there is still a huge effort needed to overcome significant challenges and difficulties. We are witnessing a rapid expansion of knowledge, induced by new biomedical technologies and CAR designs. The era of CAR T-cell therapy has just begun, and new products will widen the therapeutic landscape in the future. This review provides a comprehensive overview of the clinical applications of CAR T-cells, focusing on the approved products and emphasizing their benefits but also indicating limitations and challenges.

Current challenges and therapeutic advances of CAR-T cell therapy for solid tumors

The application of chimeric antigen receptor (CAR) T cells in the management of hematological malignancies has emerged as a noteworthy therapeutic breakthrough. Nevertheless, the utilization and effectiveness of CAR-T cell therapy in solid tumors are still limited primarily because of the absence of tumor-specific target antigen, the existence of immunosuppressive tumor microenvironment, restricted T cell invasion and proliferation, and the occurrence of severe toxicity. This review explored the history of CAR-T and its latest advancements in the management of solid tumors. According to recent studies, optimizing the design of CAR-T cells, implementing logic-gated CAR-T cells and refining the delivery methods of therapeutic agents can all enhance the efficacy of CAR-T cell therapy. Furthermore, combination therapy shows promise as a way to improve the effectiveness of CAR-T cell therapy. At present, numerous clinical trials involving CAR-T cells for solid tumors are actively in progress. In conclusion, CAR-T cell therapy has both potential and challenges when it comes to treating solid tumors. As CAR-T cell therapy continues to evolve, further innovations will be devised to surmount the challenges associated with this treatment modality, ultimately leading to enhanced therapeutic response for patients suffered solid tumors.

Mechanical force determines chimeric antigen receptor microclustering and signaling

Chimeric antigen receptor (CAR) T cells are activated to trigger the lytic machinery after antigen engagement, and this has been successfully applied clinically as therapy. The mechanism by which antigen binding leads to the initiation of CAR signaling remains poorly understood. Here, we used a set of short double-stranded DNA (dsDNA) tethers with mechanical forces ranging from ∼12 to ∼51 pN to manipulate the mechanical force of antigen tether and decouple the microclustering and signaling events. Our results revealed that antigen-binding-induced CAR microclustering and signaling are mechanical force dependent. Additionally, the mechanical force delivered to the antigen tether by the CAR for microclustering is generated by autonomous cell contractility. Mechanistically, the mechanical-force-induced strong adhesion and CAR diffusion confinement led to CAR microclustering. Moreover, cytotoxicity may have a lower mechanical force threshold than cytokine generation. Collectively, these results support a model of mechanical-force-induced CAR microclustering for signaling.

The preclinical discovery and clinical development of ciltacabtagene autoleucel (Cilta-cel) for the treatment of multiple myeloma

INTRODUCTION

Despite remarkable therapeutic advances over the last two decades, which have resulted in dramatic improvements in patient survival, multiple myeloma (MM) is still considered an incurable disease. Therefore, there is a high need for new treatment strategies. Genetically engineered/redirected chimeric antigen receptor (CAR) T cells may represent the most compelling modality of immunotherapy for cancer treatment in general, and MM in particular. Indeed, unprecedented response rates have led to the recent approvals of the first two BCMA-targeted CAR T cell products idecabtagene-vicleucel ('Ide-cel') and ciltacabtagene-autoleucel ('Cilta-Cel') for the treatment of heavily pretreated MM patients. In addition, both are emerging as a new standard-of-care also in earlier lines of therapy.

AREAS COVERED

This article briefly reviews the history of the preclinical development of CAR T cells, with a particular focus on Cilta-cel. Moreover, it summarizes the newest clinical data on Cilta-cel and discusses strategies to further improve its activity and reduce its toxicity.

EXPERT OPINION

Modern next-generation immunotherapy is continuously transforming the MM treatment landscape. Despite several caveats of CAR T cell therapy, including its toxicity, costs, and limited access, prolonged disease-free survival and potential cure of MM are finally within reach.

Rationally designed approaches to augment CAR-T therapy for solid tumor treatment

Chimeric antigen receptor T cell denoted as CAR-T therapy has realized incredible therapeutic advancements for B cell malignancy treatment. However, its therapeutic validity has yet to be successfully achieved in solid tumors. Different from hematological cancers, solid tumors are characterized by dysregulated blood vessels, dense extracellular matrix, and filled with immunosuppressive signals, which together result in CAR-T cells' insufficient infiltration and rapid dysfunction. The insufficient recognition of tumor cells and tumor heterogeneity eventually causes cancer reoccurrences. In addition, CAR-T therapy also raises safety concerns, including potential cytokine release storm, on-target/off-tumor toxicities, and neuro-system side effects. Here we comprehensively review various targeting aspects, including CAR-T cell design, tumor modulation, and delivery strategy. We believe it is essential to rationally design a combinatory CAR-T therapy via constructing optimized CAR-T cells, directly manipulating tumor tissue microenvironments, and selecting the most suitable delivery strategy to achieve the optimal outcome in both safety and efficacy.

Recent advances on CAR-T signaling pave the way for prolonged persistence and new modalities in clinic

Chimeric antigen receptor T-cell (CAR-T) therapy has revolutionized the treatment of hematological malignancies. The importance of the receptor costimulatory domain for long-term CAR-T cell engraftment and therapeutic efficacy was demonstrated with second-generation CAR-T cells. Fifth generation CAR-T cells are currently in preclinical trials. At the same time, the processes that orchestrate the activation and differentiation of CAR-T cells into a specific phenotype that predisposes them to long-term persistence are not fully understood. This review highlights ongoing research aimed at elucidating the role of CAR domains and T-cell signaling molecules involved in these processes.

Chimeric antigen receptor therapy meets mRNA technology

Genetically engineered immune cells expressing chimeric antigen receptors (CARs) have emerged as a new game changer in cancer immunotherapy. The utility of CAR T cell therapy against hematological malignancies has been validated in clinical practice. Other CAR immune cells are currently under investigation to improve the potency of CAR therapy in solid tumors. As a new class of therapeutic modalities, mRNA-based therapeutics hold enormous potential beyond COVID-19 mRNA vaccines. Arming immune cells with mRNA-encoded CARs represents a new frontier in cancer and beyond, enabling in vivo generation of CAR cells without causing transgene integration. In this review, we summarize recent advances in mRNA-based CAR immunotherapies and highlight their opportunities and challenges for the development of a new generation of living drugs.

Engineering approaches for RNA-based and cell-based osteoarthritis therapies

Osteoarthritis (OA) is a chronic, debilitating disease that substantially impairs the quality of life of affected individuals. The underlying mechanisms of OA are diverse and are becoming increasingly understood at the systemic, tissue, cellular and gene levels. However, the pharmacological therapies available remain limited, owing to drug delivery barriers, and consist mainly of broadly immunosuppressive regimens, such as corticosteroids, that provide only short-term palliative benefits and do not alter disease progression. Engineered RNA-based and cell-based therapies developed with synthetic chemistry and biology tools provide promise for future OA treatments with durable, efficacious mechanisms of action that can specifically target the underlying drivers of pathology. This Review highlights emerging classes of RNA-based technologies that hold potential for OA therapies, including small interfering RNA for gene silencing, microRNA and anti-microRNA for multi-gene regulation, mRNA for gene supplementation, and RNA-guided gene-editing platforms such as CRISPR-Cas9. Various cell-engineering strategies are also examined that potentiate disease-dependent, spatiotemporally regulated production of therapeutic molecules, and a conceptual framework is presented for their application as OA treatments. In summary, this Review highlights modern genetic medicines that have been clinically approved for other diseases, in addition to emerging genome and cellular engineering approaches, with the goal of emphasizing their potential as transformative OA treatments.

Chimeric antigen receptor T-cell therapy in hematologic malignancies: Successes, challenges, and opportunities

The success of chimeric antigen receptor T-cell (CAR-T) therapy in hematologic malignancies has realized a longstanding effort toward harnessing the immune system to fight cancer in a truly personalized fashion. Second generation chimeric antigen receptors (CAR) incorporating co-stimulatory molecules like 4-1BB or CD28 were able to overcome some of the hindrances with initial CAR constructs resulting in efficacious products. Many second-generation CAR-T products have been approved in the treatment of relapsed/refractory hematologic malignancies including multiple myeloma (MM), non-Hodgkin lymphoma (NHL), and acute lymphoblastic leukemia. However, challenges remain in optimizing the manufacturing, timely access, limiting the toxicity from CAR-T infusions and improving sustainability of responses derived with CAR-T therapy. Here, we summarize the clinical trial data leading to approval CAR-T therapies in MM and NHL, discuss the limitations with current CAR-T therapy strategies and review emerging strategies for overcoming these limitations.

De novo-designed minibinders expand the synthetic biology sensing repertoire

Synthetic and chimeric receptors capable of recognizing and responding to user-defined antigens have enabled "smart" therapeutics based on engineered cells. These cell engineering tools depend on antigen sensors which are most often derived from antibodies. Advances in the de novo design of proteins have enabled the design of protein binders with the potential to target epitopes with unique properties and faster production timelines compared to antibodies. Building upon our previous work combining a de novo-designed minibinder of the Spike protein of SARS-CoV-2 with the synthetic receptor synNotch (SARSNotch), we investigated whether minibinders can be readily adapted to a diversity of cell engineering tools. We show that the Spike minibinder LCB1 easily generalizes to a next-generation proteolytic receptor SNIPR that performs similarly to our previously reported SARSNotch. LCB1-SNIPR successfully enables the detection of live SARS-CoV-2, an improvement over SARSNotch which can only detect cell-expressed Spike. To test the generalizability of minibinders to diverse applications, we tested LCB1 as an antigen sensor for a chimeric antigen receptor (CAR). LCB1-CAR enabled CD8+ T cells to cytotoxically target Spike-expressing cells. Our findings suggest that minibinders represent a novel class of antigen sensors that have the potential to dramatically expand the sensing repertoire of cell engineering tools.

Disruption of SUV39H1-Mediated H3K9 Methylation Sustains CAR T-cell Function

Suboptimal functional persistence limits the efficacy of adoptive T-cell therapies. CD28-based chimeric antigen receptors (CAR) impart potent effector function to T cells but with a limited lifespan. We show here that the genetic disruption of SUV39H1, which encodes a histone-3, lysine-9 methyl-transferase, enhances the early expansion, long-term persistence, and overall antitumor efficacy of human CAR T cells in leukemia and prostate cancer models. Persisting SUV39H1-edited CAR T cells demonstrate improved expansion and tumor rejection upon multiple rechallenges. Transcriptional and genome accessibility profiling of repeatedly challenged CAR T cells shows improved expression and accessibility of memory transcription factors in SUV39H1-edited CAR T cells. SUV39H1 editing also reduces expression of inhibitory receptors and limits exhaustion in CAR T cells that have undergone multiple rechallenges. Our findings thus demonstrate the potential of epigenetic programming of CAR T cells to balance their function and persistence for improved adoptive cell therapies.

SIGNIFICANCE

T cells engineered with CD28-based CARs possess robust effector function and antigen sensitivity but are hampered by limited persistence, which may result in tumor relapse. We report an epigenetic strategy involving disruption of the SUV39H1-mediated histone-silencing program that promotes the functional persistence of CD28-based CAR T cells. See related article by López-Cobo et al., p. 120. This article is featured in Selected Articles from This Issue, p. 5.

Beyond FOXP3: a 20-year journey unravelling human regulatory T-cell heterogeneity

The initial idea of a distinct group of T-cells responsible for suppressing immune responses was first postulated half a century ago. However, it is only in the last three decades that we have identified what we now term regulatory T-cells (Tregs), and subsequently elucidated and crystallized our understanding of them. Human Tregs have emerged as essential to immune tolerance and the prevention of autoimmune diseases and are typically contemporaneously characterized by their CD3+CD4+CD25high CD127lowFOXP3+ phenotype. It is important to note that FOXP3+ Tregs exhibit substantial diversity in their origin, phenotypic characteristics, and function. Identifying reliable markers is crucial to the accurate identification, quantification, and assessment of Tregs in health and disease, as well as the enrichment and expansion of viable cells for adoptive cell therapy. In our comprehensive review, we address the contributions of various markers identified in the last two decades since the master transcriptional factor FOXP3 was identified in establishing and enriching purity, lineage stability, tissue homing and suppressive proficiency in CD4+ Tregs. Additionally, our review delves into recent breakthroughs in innovative Treg-based therapies, underscoring the significance of distinct markers in their therapeutic utilization. Understanding Treg subsets holds the key to effectively harnessing human Tregs for immunotherapeutic approaches.

Engineered CAR-T cells: An immunotherapeutic approach for cancer treatment and beyond

Chimeric Antigen Receptor (CAR) T cell therapy is a type of adoptive immunotherapy that offers a promising avenue for enhancing cancer treatment since traditional cancer treatments like chemotherapy, surgery, and radiation therapy have proven insufficient in completely eradicating tumors, despite the relatively positive outcomes. It has been observed that CAR-T cell therapy has shown promising results in treating the majority of hematological malignancies but also have a wide scope for other cancer types. CAR is an extra receptor on the T-cell that helps to increase and accelerate tumor destruction by efficiently activating the immune system. It is made up of three domains, the ectodomain, transmembrane, and the endodomain. The ectodomain is essential for antigen recognition and binding, whereas the co-stimulatory signal is transduced by the endodomain. To date, the Food and Drug Administration (FDA) has granted approval for six CAR-T cell therapies. However, despite its remarkable success, CAR-T therapy is associated with numerous adverse events and has certain limitations. This chapter focuses on the structure and function of the CAR domain, various generations of CAR, and the process of CAR-T cell development, adverse effects, and challenges in CAR-T therapy. CAR-T cell therapy also has scopes in other disease conditions which include systemic lupus erythematosus, multiple sclerosis, and myocardial fibrosis, etc.

Programmable synthetic receptors: the next-generation of cell and gene therapies

Cell and gene therapies hold tremendous promise for treating a range of difficult-to-treat diseases. However, concerns over the safety and efficacy require to be further addressed in order to realize their full potential. Synthetic receptors, a synthetic biology tool that can precisely control the function of therapeutic cells and genetic modules, have been rapidly developed and applied as a powerful solution. Delicately designed and engineered, they can be applied to finetune the therapeutic activities, i.e., to regulate production of dosed, bioactive payloads by sensing and processing user-defined signals or biomarkers. This review provides an overview of diverse synthetic receptor systems being used to reprogram therapeutic cells and their wide applications in biomedical research. With a special focus on four synthetic receptor systems at the forefront, including chimeric antigen receptors (CARs) and synthetic Notch (synNotch) receptors, we address the generalized strategies to design, construct and improve synthetic receptors. Meanwhile, we also highlight the expanding landscape of therapeutic applications of the synthetic receptor systems as well as current challenges in their clinical translation.

Immunotherapy for Pediatric Gliomas: CAR-T Cells Against B7H3: A Review of the Literature

BACKGROUND

B7H3 is a co-stimulatory molecule for immune reactions found on the surface of tumor cells in a wide variety of tumors. Preclinical and clinical studies have reported it as a tumor target towards which various immunotherapy modalities could be directed. So far, good results have been obtained in hematological neoplasms; however, a contrasting situation is evident in solid tumors, including those of the CNS, which show high refractoriness to current treatments. The appearance of cellular immunotherapies has transformed oncology due to the reinforcement of the immune response that is compromised in people with cancer.

OBJECTIVE

This article aims to review the literature to describe the advancement in knowledge on B7H3 as a target of CAR-T cells in pediatric gliomas to consider them as an alternative in the treatment of these patients.

RESULTS

Although B7H3 is considered a suitable candidate as a target agent for various immunotherapy techniques, there are still limitations in using CAR-T cells to achieve the desired success.

CONCLUSION

Results obtained with CAR-T cells can be further improved by the suggested proposals; therefore, more clinical trials are needed to study this new therapy in children with gliomas.

Harnessing Chimeric Antigen Receptor-engineered Invariant Natural Killer T Cells: Therapeutic Strategies for Cancer and the Tumor Microenvironment

Chimeric antigen receptor (CAR)-engineered T (CAR-T) cell therapy has emerged as a revolutionary approach for cancer treatment, especially for hematologic cancers. However, CAR-T therapy has some limitations, including cytokine release syndrome (CRS), immune cellassociated neurologic syndrome (ICANS), and difficulty in targeting solid tumors and delivering allogeneic cell therapy due to graft-versus-host disease (GvHD). Therefore, it is important to explore other cell sources for CAR engineering. Invariant natural killer T (iNKT) cells are a potential target, as they possess powerful antitumor ability and do not recognize mismatched major histocompatibility complexes (MHCs) and protein antigens, thus avoiding the risk of GvHD. CAR-engineered iNKT (CAR-iNKT) cell therapy offers a promising new approach to cancer immunotherapy by overcoming the drawbacks of CAR-T cell therapy while retaining potent antitumor capabilities. This review summarizes the current CAR-iNKT cell products, their functions and phenotypes, and their potential for off-the-shelf cancer immunotherapy.

Evolving CAR-T-Cell Therapy for Cancer Treatment: From Scientific Discovery to Cures

In recent years, chimeric antigen receptor (CAR)-T-cell therapy has emerged as the most promising immunotherapy for cancer that typically uses patients' T cells and genetically engineered them to target cancer cells. Although recent improvements in CAR-T-cell therapy have shown remarkable success for treating hematological malignancies, the heterogeneity in tumor antigens and the immunosuppressive nature of the tumor microenvironment (TME) limits its efficacy in solid tumors. Despite the enormous efforts that have been made to make CAR-T-cell therapy more effective and have minimal side effects for treating hematological malignancies, more research needs to be conducted regarding its use in the clinic for treating various other types of cancer. The main concern for CAR-T-cell therapy is severe toxicities due to the cytokine release syndrome, whereas the other challenges are associated with complexity and immune-suppressing TME, tumor antigen heterogeneity, the difficulty of cell trafficking, CAR-T-cell exhaustion, and reduced cytotoxicity in the tumor site. This review discussed the latest discoveries in CAR-T-cell therapy strategies and combination therapies, as well as their effectiveness in different cancers. It also encompasses ongoing clinical trials; current challenges regarding the therapeutic use of CAR-T-cell therapy, especially for solid tumors; and evolving treatment strategies to improve the therapeutic application of CAR-T-cell therapy.

The Current State of Chimeric Antigen Receptor T Cell Therapy for B Lymphoblastic Leukemia

Over the past decade, CAR T cell therapy has transformed the treatment of relapsed or refractory B-ALL in children and adults. CD19-directed CAR T cells can induce complete remissions in a large majority of patients with B-ALL, and up to half of these patients will go on to maintain durable remissions. However, significant challenges remain for patients who relapse or do not respond. This review will discuss the history of CAR T cell therapy for B-ALL, the treatment considerations for CAR T cell recipients, and current clinical trials and future directions for CAR T cell therapy in B-ALL.

Strategies for modifying the chimeric antigen receptor (CAR) to improve safety and reduce toxicity in CAR T cell therapy for cancer

Immune cell therapy with chimeric antigen receptor (CAR) T cells, which has shown promising efficacy in patients with some hematologic malignancies, has introduced several successfully approved CAR T cell therapy products. Nevertheless, despite significant advances, treatment with these products has major challenges regarding potential toxicity and sometimes fatal adverse effects for patients. These toxicities can result from cytokine release or on-target off-tumor toxicity that targets healthy host tissue following CAR T cell therapy. The present study focuses on the unexpected side effects of targeting normal host tissues with off-target toxicity. Also, recent safety strategies such as replacing or adding different components to CARs and redesigning CAR structures to eliminate the toxic impact of CAR T cells, including T cell antigen coupler (TAC), switch molecules, suicide genes, and humanized monoclonal antibodies in the design of CARs, are discussed in this review.

CAR-modified Cellular Therapies in Chronic Lymphocytic Leukemia: Is the Uphill Road Getting Less Steep?

The clinical development of chimeric antigen receptor (CAR) T-cell therapy has been more challenging for chronic lymphocytic leukemia (CLL) compared to other settings. One of the main reasons is the CLL-associated state of immune dysfunction that specifically involves patient-derived T cells. Here, we provide an overview of the clinical results obtained with CAR T-cell therapy in CLL, describing the identified immunologic reasons for the inferior efficacy. Novel CAR T-cell formulations, such as lisocabtagene maraleucel, administered alone or in combination with the Bruton tyrosine kinase inhibitor ibrutinib, are currently under investigation. These approaches are based on the rationale that improving the quality of the T-cell source and of the CAR T-cell product may deliver a more functional therapeutic weapon. Further strategies to boost the efficacy of CAR T cells should rely not only on the production of CAR T cells with an improved cellular composition but also on additional changes. Such alterations could include (1) the coadministration of immunomodulatory agents capable of counteracting CLL-related immunological alterations, (2) the design of improved CAR constructs (such as third- and fourth-generation CARs), (3) the incorporation into the manufacturing process of immunomodulatory compounds overcoming the T-cell defects, and (4) the use of allogeneic CAR T cells or alternative CAR-modified cellular vectors. These strategies may allow to develop more effective CAR-modified cellular therapies capable of counteracting the more aggressive and still incurable forms of CLL.

Leukapheresis for CAR-T cell production and therapy

Chimeric antigen receptor (CAR) T-cell therapy is an effective, individualized immunotherapy, and novel treatment for hematologic malignancies. Six commercial CAR-T cell products are currently approved for lymphatic malignancies and multiple myeloma. In addition, an increasing number of clinical centres produce CAR-T cells on-site, which enable the administration of CAR-T cells on site. The CAR-T cell products are either fresh or cryopreserved. Manufacturing CAR-T cells is a complicated process that begins with leukapheresis to obtain T cells from the patient's peripheral blood. An optimal leukapheresis product is crucial step for a successful CAR-T cell therapy; therefore, it is imperative to understand the factors that may affect the quality or T cells. The leukapheresis for CAR-T cell production is well tolerated and safe for both paediatric and adult patients and CAR-Τ cell therapy presents high clinical response rate in many studies. CAR-T cell therapy is under continuous improvement, and it has transformed into an almost standard procedure in clinical haematology and stem cell transplantation facilities that provide both autologous and allogeneic stem cell transplantations. In patients suffering from advanced haematological malignancies, CAR-T cell therapy shows incredible antitumor efficacy. Even after a single infusion of autologous CD19-targeting CAR-T cells in patients with relapsed or refractory diffuse large B cell lymphoma (DLBCL) and acute lymphoblastic leukaemia (ALL), long lasting remission is observed, and a fraction of the patients are being cured. Future novel constructs are being developed with better T cell persistence and better expansion. New next-generation CAR-T cells are currently designed to avoid toxicities such as cytokine release syndrome and neurotoxicity.

DIALing-up the preclinical characterization of gene-modified adoptive cellular immunotherapies

The preclinical characterization of gene modified adoptive cellular immunotherapy candidates for clinical development often requires the use of mouse models. Gene-modified lymphocytes (GML) incorporating chimeric antigen receptors (CAR) and T-cell receptors (TCR) into immune effector cells require in vivo characterization of biological activity, mechanism of action, and preclinical safety. Typically, this characterization involves the assessment of dose-dependent, on-target, on-tumor activity in severely immunocompromised mice. While suitable for the purpose of evaluating T cell-expressed transgene function in a living host, this approach falls short in translating cellular therapy efficacy, safety, and persistence from preclinical models to humans. To comprehensively characterize cell therapy products in mice, we have developed a framework called "DIAL". This framework aims to enable an end-to-end understanding of genetically engineered cellular immunotherapies in vivo, from infusion to tumor clearance and long-term immunosurveillance. The acronym DIAL stands for Distribution, Infiltration, Accumulation, and Longevity, compartmentalizing the systemic attributes of gene-modified cellular therapy and providing a platform for optimization with the ultimate goal of improving therapeutic efficacy. This review will discuss both existent and emerging examples of DIAL characterization in mouse models, as well as opportunities for future development and optimization.

A Synthetic Cytotoxic T cell Platform for Rapidly Prototyping TCR Function

Current tools for functionally profiling T cell receptors with respect to cytotoxic potency and cross-reactivity are hampered by difficulties in establishing model systems to test these proteins in the contexts of different HLA alleles and against broad arrays of potential antigens. We have implemented and validated a granzyme-activatable sensor of T cell cytotoxicity in a novel universal prototyping platform which enables facile recombinant expression of any combination of TCR-, peptide-, and class I MHC-coding sequences and direct assessment of resultant responses. This system consists of an engineered cell platform based on the immortalized natural killer cell line, YT-Indy, and the MHC-null antigen-presenting cell line, K562. These cells were engineered using contemporary gene-editing techniques to furnish the YT-Indy/K562 pair with appropriate protein domains required for recombinant TCR expression and function in a non-T cell chassis, integrate a fluorescence-based target-centric early detection reporter of cytotoxic function, and deploy a set of protective genetic interventions designed to preserve antigen-presenting cells for subsequent capture and downstream characterization. Our data show successful reconstitution of the surface TCR complex in the YT-Indy cell line at biologically relevant levels. We also demonstrate successful induction and highly sensitive detection of antigen-specific response in multiple distinct model TCRs, with significant responses (p < 0.05 and Cohen's d >1.9) in all cases. Additionally, we monitored destruction of targets in co-culture and found that our survival-optimized system allowed for complete preservation after 24-hour exposure to cytotoxic effectors. With this bioplatform, we anticipate investigators will be empowered to rapidly express and characterize T cell receptor responses, generate new knowledge regarding the patterns of T cell receptor recognition, and optimize novel therapeutic T cell receptors for improved cytotoxic potential and reduced cross-reactivity to undesired antigenic targets.

CAR-T-Cell Therapy in Multiple Myeloma: B-Cell Maturation Antigen (BCMA) and Beyond

Significant progress has been achieved in the realm of therapeutic interventions for multiple myeloma (MM), leading to transformative shifts in its clinical management. While conventional modalities such as surgery, radiotherapy, and chemotherapy have improved the clinical outcomes, the overarching challenge of effecting a comprehensive cure for patients afflicted with relapsed and refractory MM (RRMM) endures. Notably, adoptive cellular therapy, especially chimeric antigen receptor T-cell (CAR-T) therapy, has exhibited efficacy in patients with refractory or resistant B-cell malignancies and is now also being tested in patients with MM. Within this context, the B-cell maturation antigen (BCMA) has emerged as a promising candidate for CAR-T-cell antigen targeting in MM. Alternative targets include SLAMF7, CD38, CD19, the signaling lymphocyte activation molecule CS1, NKG2D, and CD138. Numerous clinical studies have demonstrated the clinical efficacy of these CAR-T-cell therapies, although longitudinal follow-up reveals some degree of antigenic escape. The widespread implementation of CAR-T-cell therapy is encumbered by several barriers, including antigenic evasion, uneven intratumoral infiltration in solid cancers, cytokine release syndrome, neurotoxicity, logistical implementation, and financial burden. This article provides an overview of CAR-T-cell therapy in MM and the utilization of BCMA as the target antigen, as well as an overview of other potential target moieties.

Adoptive NK Cell Therapy - a Beacon of Hope in Multiple Myeloma Treatment

Major advances in the treatment of multiple myeloma (MM) have been achieved by effective new agents such as proteasome inhibitors, immunomodulatory drugs, or monoclonal antibodies. Despite significant progress, MM remains still incurable and, recently, cellular immunotherapy has emerged as a promising treatment for relapsed/refractory MM. The emergence of chimeric antigen receptor (CAR) technology has transformed immunotherapy by enhancing the antitumor functions of T cells and natural killer (NK) cells, leading to effective control of hematologic malignancies. Recent advancements in gene delivery to NK cells have paved the way for the clinical application of CAR-NK cell therapy. CAR-NK cell therapy strategies have demonstrated safety, tolerability, and substantial efficacy in treating B cell malignancies in various clinical settings. However, their effectiveness in eliminating MM remains to be established. This review explores multiple approaches to enhance NK cell cytotoxicity, persistence, expansion, and manufacturing processes, and highlights the challenges and opportunities associated with CAR-NK cell therapy against MM. By shedding light on these aspects, this review aims to provide valuable insights into the potential of CAR-NK cell therapy as a promising approach for improving the treatment outcomes of MM patients.

CAR-T cell therapy for hematological malignancies: History, status and promise

For many years, the methods of cancer treatment are usually surgery, chemotherapy and radiation therapy. Although these methods help to improve the condition, most tumors still have a poor prognosis. In recent years, immunotherapy has great potential in tumor treatment. Chimeric antigen receptor T-cell immunotherapy (CAR-T) uses the patient's own T cells to express chimeric antigen receptors. Chimeric antigen receptor (CAR) recognizes tumor-associated antigens and kills tumor cells. CAR-T has achieved good results in the treatment of hematological tumors. In 2017, the FDA approved the first CAR-T for the treatment of B-cell acute lymphoblastic leukemia (ALL). In October of the same year, the FDA approved CAR-T to treat B-cell lymphoma. In order to improve and enhance the therapeutic effect, CAR-T has become a research focus in recent years. The structure of CAR, the targets of CAR-T treatment, adverse reactions and improvement measures during the treatment process are summarized. This review is an attempt to highlight recent and possibly forgotten findings of advances in chimeric antigen receptor T cell for treatment of hematological tumors.

Harnessing the power of artificial intelligence to advance cell therapy

Cell therapies are powerful technologies in which human cells are reprogrammed for therapeutic applications such as killing cancer cells or replacing defective cells. The technologies underlying cell therapies are increasing in effectiveness and complexity, making rational engineering of cell therapies more difficult. Creating the next generation of cell therapies will require improved experimental approaches and predictive models. Artificial intelligence (AI) and machine learning (ML) methods have revolutionized several fields in biology including genome annotation, protein structure prediction, and enzyme design. In this review, we discuss the potential of combining experimental library screens and AI to build predictive models for the development of modular cell therapy technologies. Advances in DNA synthesis and high-throughput screening techniques enable the construction and screening of libraries of modular cell therapy constructs. AI and ML models trained on this screening data can accelerate the development of cell therapies by generating predictive models, design rules, and improved designs.

Advanced Materials and Delivery Systems for Enhancement of Chimeric Antigen Receptor Cells

Chimeric antigen receptor (CAR) cell therapy is a great success and breakthrough in immunotherapy. However, there are still lots of barriers to its wide use in clinical, including long time consumption, high cost, and failure against solid tumors. For these challenges, researches are deplored to explore CAR cells to more appliable products in clinical. This minireview focuses on the advanced non-viral materials for CAR-T transfection ex vivo with better performance, delivery systems combined with other therapy for enhancement of CAR-T therapy in solid tumors. In addition, the targeted delivery platform for CAR cells in vivo generation as a breakthrough technology as its low cost and convenience. In the end, the prospective direction and future of CAR cell therapy are discussed.

Charging CAR by electrostatic power

Chimeric antigen receptor (CAR)-T cell therapy has emerged as a promising approach for cancer treatment. CAR is a synthetic immune receptor that recognizes tumor antigen and activates T cells through multiple signaling pathways. However, the current CAR design is not as robust as T cell receptor (TCR), a natural antigen receptor with high sensitivity and efficiency. TCR signaling relies on specific molecular interactions, and thus electrostatic force, the major force of molecular interactions, play critical roles. Understanding how electrostatic charge regulates TCR/CAR signaling events will facilitate the development of next-generation T cell therapies. This review summarizes recent findings on the roles of electrostatic interactions in both natural and synthetic immune receptor signaling, specifically that in CAR clustering and effector molecule recruitments, and highlights potential strategies for engineering CAR-T cell therapy by leveraging charge-based interactions.

NKG2D-CAR memory T cells target pediatric T-cell acute lymphoblastic leukemia in vitro and in vivo but fail to eliminate leukemia initiating cells

Introduction

Refractory/relapsed pediatric acute leukemia are still clinically challenging and new therapeutic strategies are needed. Interactions between Natural Killer Group 2D (NKG2D) receptor, expressed in cytotoxic immune cells, and its ligands (NKG2DL), which are upregulated in leukemic blasts, are important for anti-leukemia immunosurveillance. Nevertheless, leukemia cells may develop immunoescape strategies as NKG2DL shedding and/or downregulation.

Methods

In this report, we analyzed the anti-leukemia activity of NKG2D chimeric antigen receptor (CAR) redirected memory (CD45RA-) T cells in vitro and in a murine model of T-cell acute lymphoblastic leukemia (T-ALL). We also explored in vitro how soluble NKG2DL (sNKG2DL) affected NKG2D-CAR T cells' cytotoxicity and the impact of NKG2D-CAR T cells on Jurkat cells gene expression and in vivo functionality.

Results

In vitro, we found NKG2D-CAR T cells targeted leukemia cells and showed resistance to the immunosuppressive effects exerted by sNKG2DL. In vivo, NKG2D-CAR T cells controlled T cell leukemia burden and increased survival of the treated mice but failed to cure the animals. After CAR T cell treatment, Jurkat cells upregulated genes related to proliferation, survival and stemness, and in vivo, they exhibited functional properties of leukemia initiating cells.

Discussion

The data here presented suggest, that, in combination with other therapeutic approaches, NKG2D-CAR T cells could be a novel treatment for pediatric T-ALL.

Innovative Strategies of Reprogramming Immune System Cells by Targeting CRISPR/Cas9-Based Genome-Editing Tools: A New Era of Cancer Management

The recent developments in the study of clustered regularly interspaced short palindromic repeats/associated protein 9 (CRISPR/Cas9) system have revolutionized the art of genome-editing and its applications for cellular differentiation and immune response behavior. This technology has further helped in understanding the mysteries of cancer progression and possible designing of novel antitumor immunotherapies. CRISPR/Cas9-based genome-editing is now often used to engineer universal T-cells, equipped with recombinant T-cell receptor (TCR) or chimeric antigen receptor (CAR). In addition, this technology is used in cytokine stimulation, antibody designing, natural killer (NK) cell transfer, and to overcome immune checkpoints. The innovative potential of CRISPR/Cas9 in preparing the building blocks of adoptive cell transfer (ACT) immunotherapy has opened a new window of antitumor immunotherapy and some of them have gained FDA approval. The manipulation of immunogenetic regulators has opened a new interface for designing, implementation and interpretation of CRISPR/Cas9-based screening in immuno-oncology. Several cancers like lymphoma, melanoma, lung, and liver malignancies have been treated with this strategy, once thought to be impossible. The safe and efficient delivery of CRISPR/Cas9 system within the immune cells for the genome-editing strategy is a challenging task which needs to be sorted out for efficient immunotherapy. Several targeting approaches like virus-mediated, electroporation, microinjection and nanoformulation-based methods have been used, but each procedure offers some limitations. Here, we elaborate the recent updates of cancer management through immunotherapy in partnership with CRISPR/Cas9 technology. Further, some innovative methods of targeting this genome-editing system within the immune system cells for reprogramming them, as a novel strategy of anticancer immunotherapy is elaborated. In addition, future prospects and clinical trials are also discussed.