Tumor Antigen Escape from CAR T-cell Therapy

Development of an antigen-based approach to noninvasively image CAR T cells in real time and as a predictive tool

CAR T cell therapy has revolutionized the treatment of a spectrum of blood-related malignancies. However, treatment responses vary among cancer types and patients. Accurate monitoring of CAR T cell dynamics is crucial for understanding and evaluating treatment efficacy. Positron emission tomography (PET) offers a comprehensive view of CAR T cell homing, especially in critical organs such as lymphoid structures and bone marrow. This information will help assess treatment response and predict relapse risk. Current PET imaging methods for CAR T require genetic modifications, limiting clinical use. To overcome this, we developed an antigen-based imaging approach enabling whole-body CAR T cell imaging. The probe detects CAR T cells in vivo without affecting their function. In an immunocompetent B cell leukemia model, CAR-PET signal in the spleen predicted early mortality risk. The antigen-based CAR-PET approach allows assessment of CAR T therapy responses without altering established clinical protocols. It seamlessly integrates with FDA-approved and future CAR T cell generations, facilitating broader clinical application.

Electrophilic proximity-inducing synthetic adapters enhance universal T cell function by covalently enforcing immune receptor signaling

Proximity-induction of cell-cell interactions via small molecules represents an emerging field in basic and translational sciences. Covalent anchoring of these small molecules represents a useful chemical strategy to enforce proximity; however, it remains largely unexplored for driving cell-cell interactions. In immunotherapeutic applications, bifunctional small molecules are attractive tools for inducing proximity between immune effector cells like T cells and tumor cells to induce tumoricidal function. We describe a two-component system composed of electrophilic bifunctional small molecules and paired synthetic antigen receptors (SARs) that elicit T cell activation. The molecules, termed covalent immune recruiters (CIRs), were designed to affinity label and covalently engage SARs. We evaluated the utility of CIRs to direct anti-tumor function of human T cells engineered with three biologically distinct classes of SAR. Irrespective of the electrophilic chemistry, tumor-targeting moiety, or SAR design, CIRs outperformed equivalent non-covalent bifunctional adapters, establishing a key role for covalency in maximizing functionality. We determined that covalent linkage enforced early T cell activation events in a manner that was dependent upon each SARs biology and signaling threshold. These results provide a platform to optimize universal SAR-T cell functionality and more broadly reveal new insights into how covalent adapters modulate cell-cell proximity-induction.

Phase 1 study of CAR-37 T cells in patients with relapsed or refractory CD37+ lymphoid malignancies

ABSTRACT

We report a first-in-human clinical trial using chimeric antigen receptor (CAR) T cells targeting CD37, an antigen highly expressed in B- and T-cell malignancies. Five patients with relapsed or refractory CD37+ lymphoid malignancies were enrolled and infused with autologous CAR-37 T cells. CAR-37 T cells expanded in the peripheral blood of all patients and, at peak, comprised >94% of the total lymphocytes in 4 of 5 patients. Tumor responses were observed in 4 of 5 patients with 3 complete responses, 1 mixed response, and 1 patient whose disease progressed rapidly and with relative loss of CD37 expression. Three patients experienced prolonged and severe pancytopenia, and in 2 of these patients, efforts to ablate CAR-37 T cells, which were engineered to coexpress truncated epidermal growth factor receptor, with cetuximab were unsuccessful. Hematopoiesis was restored in these 2 patients after allogeneic hematopoietic stem cell transplantation. No other severe, nonhematopoietic toxicities occurred. We investigated the mechanisms of profound pancytopenia and did not observe activation of CAR-37 T cells in response to hematopoietic stem cells in vitro or hematotoxicity in humanized models. Patients with pancytopenia had sustained high levels of interleukin-18 (IL-18) with low levels of IL-18 binding protein in their peripheral blood. IL-18 levels were significantly higher in CAR-37-treated patients than in both cytopenic and noncytopenic cohorts of CAR-19-treated patients. In conclusion, CAR-37 T cells exhibited antitumor activity, with significant CAR expansion and cytokine production. CAR-37 T cells may be an effective therapy in hematologic malignancies as a bridge to hematopoietic stem cell transplant. This trial was registered at www.ClinicalTrials.gov as #NCT04136275.

Enhanced tumor response to adoptive T cell therapy with PHD2/3-deficient CD8 T cells

While adoptive cell therapy has shown success in hematological malignancies, its potential against solid tumors is hindered by an immunosuppressive tumor microenvironment (TME). In recent years, members of the hypoxia-inducible factor (HIF) family have gained recognition as important regulators of T-cell metabolism and function. The role of HIF signalling in activated CD8 T cell function in the context of adoptive cell transfer, however, has not been explored in full depth. Here we utilize CRISPR-Cas9 technology to delete prolyl hydroxylase domain-containing enzymes (PHD) 2 and 3, thereby stabilizing HIF-1 signalling, in CD8 T cells that have already undergone differentiation and activation, modelling the T cell phenotype utilized in clinical settings. We observe a significant boost in T-cell activation and effector functions following PHD2/3 deletion, which is dependent on HIF-1α, and is accompanied by an increased glycolytic flux. This improvement in CD8 T cell performance translates into an enhancement in tumor response to adoptive T cell therapy in mice, across various tumor models, even including those reported to be extremely resistant to immunotherapeutic interventions. These findings hold promise for advancing CD8 T-cell based therapies and overcoming the immune suppression barriers within challenging tumor microenvironments.

Safety assessment of anti-B cell maturation antigen chimeric antigen receptor T cell therapy: a real-world study based on the FDA adverse event reporting system database

Background

On April 18, 2024, the U.S. Food and Drug Administration officially required updating of the "boxed warning" for T cell malignancies for all chimeric antigen receptor T cell (CAR-T) therapies. Given the clinical significance of these therapies, a rigorous safety assessment is paramount. However, comprehensive real-world safety studies have been lacking for the newly marketed CAR-T products idecabtagene vicleucel (ide-cel) and ciltacabtagene autoleucel (cilta-cel), which target B cell maturation antigen, especially regarding the risk of secondary malignancies. Therefore, we aimed to thoroughly analyze the adverse events (AEs) information in the FDA Adverse Event Reporting System (FAERS) database to comprehensively understand the safety risks of ide-cel and cilta-cel.

Methods

We extracted AE reports related to ide-cel and cilta-cel from the FAERS database (https://fis.fda.gov/extensions/FPD-QDE-FAERS/FPD-QDE-FAERS.html.) from January 1, 2019 to December 31, 2023. Disproportionality analysis and Bayesian analysis were used to identify risk signals across subgroups and specific cases (including for death and secondary malignancies). Weibull distribution analysis was employed to determine the time to AE onset.

Results

A total of 695 AE reports for ide-cel and 848 for cilta-cel were included in the FAERS database. This analysis identified 81 positive signals for ide-cel and 74 for cilta-cel. Notably, comparisons with the drug labels revealed "unexpected signals," including febrile bone marrow aplasia (reporting odds ratio=69.10; confidence interval 39.12-122.03) and plasma cell myeloma (12.45; 8.18-18.95) for ide-cel, and increased serum ferritin (24.98; 8.0-77.58) and large intestine perforation (18.57; 5.98-57.69) for cilta-cel. Both drugs showed a higher AE incidence among male recipients and patients aged ≥65 years, although female recipients faced a greater risk. Most AEs occurred at the early stage of administration. However, secondary malignancies were detected for both drugs, primarily occurring one-year post-administration.

Conclusion

This study provides a foundation for understanding the safety profile of CAR-T cell therapy, particularly in relation to the emergence of secondary malignancies. Such insights are helpful for clinical decision-making and the safe and effective utilization of these therapeutic agents.

Knocking Out CD70 Rescues CD70-Specific NanoCAR T Cells from Antigen-Induced Exhaustion

CD70 is an attractive target for chimeric antigen receptor (CAR) T-cell therapy for the treatment of both solid and liquid malignancies. However, the functionality of CD70-specific CAR T cells is modest. We optimized a CD70-specific VHH-based CAR (nanoCAR). We evaluated the nanoCARs in clinically relevant models in vitro, using co-cultures of CD70-specific nanoCAR T cells with malignant rhabdoid tumor organoids, and in vivo, using a diffuse large B-cell lymphoma patient-derived xenograft (PDX) model. Although the nanoCAR T cells were highly efficient in organoid co-cultures, they showed only modest efficacy in the PDX model. We determined that fratricide was not causing this loss in efficacy but rather CD70 interaction in cis with the nanoCAR-induced exhaustion. Knocking out CD70 in nanoCAR T cells using CRISPR/Cas9 resulted in dramatically enhanced functionality in the diffuse large B-cell lymphoma PDX model. Through single-cell transcriptomics, we obtained evidence that CD70 knockout CD70-specific nanoCAR T cells were protected from antigen-induced exhaustion. In addition, we demonstrated that wild-type CD70-specific nanoCAR T cells already exhibited signs of exhaustion shortly after production. Their gene signature strongly overlapped with gene signatures of exhausted CAR T cells. Conversely, the gene signature of knockout CD70-specific nanoCAR T cells overlapped with the gene signature of CAR T-cell infusion products leading to complete responses in chronic lymphatic leukemia patients. Our data show that CARs targeting endogenous T-cell antigens negatively affect CAR T-cell functionality by inducing an exhausted state, which can be overcome by knocking out the specific target.

Display of Polyvalent Hybrid Antibodies on the Cell Surface for Enhanced Cell Recognition

Cell surface engineering with exogeneous receptors holds great promise for various applications. However, current biological methods face problems with safety, antigen escape, and receptor stoichiometry. The purpose of this study is to develop a biochemical method for displaying polyvalent antibodies (PAbs) on the cell surface. The PAbs are synthesized through the self-assembly of DNA-Ab conjugates under physiological conditions without the involvement of any factors harsh to cells. The data show that PAb-functionalized cells can recognize target cells much more effectively than monovalent controls. Moreover, dual Ab incorporation into the same PAb with a defined stoichiometric ratio leads to the formation of a polyvalent hybrid Ab (DPAb). DPAb-functionalized cells can effectively recognize target cell models with antigen escape, which cannot be achieved by PAbs with one type of Ab. Therefore, this work presents a novel biochemical method for Ab display on the cell surface for enhanced cell recognition.

Advancements and challenges in CAR T cell therapy in autoimmune diseases

Chimeric antigen receptor (CAR) T cells are highly effective at targeting and eliminating cells of the B cell lineage. CAR T cell therapy has become a standard-of-care treatment for patients with relapsed or refractory B cell malignancies. In addition, the administration of genetically modified T cells with the capacity to deplete B cells and/or plasma cells has tremendous therapeutic potential in autoimmune diseases. In the past few years, CD19-based and B cell maturation antigen (BCMA)-based CAR T cell therapies have been applied to various B cell-mediated autoimmune diseases including systemic lupus erythematosus, idiopathic inflammatory myopathy, systemic sclerosis, neuromyelitis optica spectrum disorder, myasthenia gravis and multiple sclerosis. The scientific rationale behind this approach is that deep depletion of B cells, including autoreactive B cell clones, could restore normal immune function, referred to as an immune reset. In this Review, we discuss important aspects of CAR T cell therapy in autoimmune disease, including considerations relating to patient selection, safety, efficacy and medical management. These considerations are based on the early experiences of CAR T cell therapy in autoimmune diseases, and as the field of CAR T cell therapy in autoimmune diseases continues to rapidly evolve, these issues will remain subject to ongoing refinement and adaptation.

Enhancing cellular immunotherapies in cancer by engineering selective therapeutic resistance

Adoptive cell therapies engineered to express chimeric antigen receptors (CARs) or transgenic T cell receptors (TCRs) to recognize and eliminate cancer cells have emerged as a promising approach for achieving long-term remissions in patients with cancer. To be effective, the engineered cells must persist at therapeutically relevant levels while avoiding off-tumour toxicities, which has been challenging to realize outside of B cell and plasma cell malignancies. This Review discusses concepts to enhance the efficacy, safety and accessibility of cellular immunotherapies by endowing cells with selective resistance to small-molecule drugs or antibody-based therapies to facilitate combination therapies with substances that would otherwise interfere with the functionality of the effector cells. We further explore the utility of engineering healthy haematopoietic stem cells to confer resistance to antigen-directed immunotherapies and small-molecule targeted therapies to expand the therapeutic index of said targeted anticancer agents as well as to facilitate in vivo selection of gene-edited haematopoietic stem cells for non-malignant applications. Lastly, we discuss approaches to evade immune rejection, which may be required in the setting of allogeneic cell therapies. Increasing confidence in the tools and outcomes of genetically modified cell therapy now paves the way for rational combinations that will open new therapeutic horizons.

Reshaping the tumor immune microenvironment to improve CAR-T cell-based cancer immunotherapy

In many hematologic malignancies, the adoptive transfer of chimeric antigen receptor (CAR) T cells has demonstrated notable success; nevertheless, further improvements are necessary to optimize treatment efficacy. Current CAR-T therapies are particularly discouraging for solid tumor treatment. The immunosuppressive microenvironment of tumors affects CAR-T cells, limiting the treatment's effectiveness and safety. Therefore, enhancing CAR-T cell infiltration capacity and resolving the immunosuppressive responses within the tumor microenvironment could boost the anti-tumor effect. Specific strategies include structurally altering CAR-T cells combined with targeted therapy, radiotherapy, or chemotherapy. Overall, monitoring the tumor microenvironment and the status of CAR-T cells is beneficial in further investigating the viability of such strategies and advancing CAR-T cell therapy.

CD20-bispecific antibodies improve response to CD19-CAR T cells in lymphoma in vitro and CLL in vivo models

ABSTRACT

Relapse after anti-CD19 chimeric antigen receptor (CD19-CAR) occurs in a substantial proportion of patients with lymphoid malignancies. We assessed the potential benefits of co-administering CD20-targeting bispecific antibodies (CD20-BsAbs) with CD19-CAR T cells with the aim of enhancing immunotherapeutic efficacy. Addition of CD20-BsAbs to cocultures of CD19-CARs and primary samples of B-cell malignancies, comprising malignant B cells and endogenous T cells, significantly improved killing of malignant cells and enhanced the expansion of both endogenous T cells and CD19-CAR T cells. In an immunocompetent mouse model of chronic lymphocytic leukemia, relapse after initial treatment response frequently occurred after CD19-CAR T-cell monotherapy. Additional treatment with CD20-BsAbs significantly enhanced the treatment response and led to improved eradication of malignant cells. Higher efficacy was accompanied by improved T-cell expansion with CD20-BsAb administration and led to longer survival with 80% of the mice being cured with no detectable malignant cell population within 8 weeks of therapy initiation. Collectively, our in vitro and in vivo data demonstrate enhanced therapeutic efficacy of CD19-CAR T cells when combined with CD20-BsAbs in B-cell malignancies. Activation and proliferation of both infused CAR T cells and endogenous T cells may contribute to improved disease control.

Bispecific CAR-T cells targeting CD19/20 in patients with relapsed or refractory B cell non-Hodgkin lymphoma: a phase I/II trial

Non-Hodgkin lymphoma (NHL) is a common malignancy in the hematologic system, and traditional therapy has limited efficacy for people with recurrent/refractory NHL (R/R NHL), especially for patients with diffuse large B cell lymphoma (DLBCL). Chimeric antigen receptor (CAR) T-cell therapy is a novel and effective immunotherapy strategy for R/R hematopoietic malignancies, but relapses can occur due to the loss of CAR-T cells in vivo or the loss of antigen. One strategy to avoid antigen loss after CAR-T cell therapy is to target one more antigen simultaneously. Tandem CAR targeting CD19 and CD22 has demonstrated the reliability of tandem CAR-T cell therapy for R/R B-ALL. This study explores the therapeutic potential of tandem CD19/20 CAR-T in the treatment of R/R B cell NHL. The efficacy and safety of autologous CD19/20 CAR-T cells in eleven R/R B cell NHL adult patients were evaluated in an open-label, single-arm trial. Most patients achieved complete response, exhibiting the efficacy and safety of tandem CD19/20 CAR-T cells. The TCR repertoire diversity of CAR-T cells decreased after infusion. The expanded TCR clones in vivo were mainly derived from TCR clones that had increased expression of genes associated with immune-related signaling pathways from the infusion product (IP). The kinetics of CAR-T cells in vivo were linked to an increase in the expression of genes related to immune response and cytolysis/cytotoxicity.

Beyond CAR-T: The rise of CAR-NK cell therapy in asthma immunotherapy

Asthma poses a major public health burden. While existing asthma drugs manage symptoms for many, some patients remain resistant. The lack of a cure, especially for severe asthma, compels exploration of novel therapies. Cancer immunotherapy successes with CAR-T cells suggest its potential for asthma treatment. Researchers are exploring various approaches for allergic diseases including membrane-bound IgE, IL-5, PD-L2, and CTLA-4 for asthma, and Dectin-1 for fungal asthma. NK cells offer several advantages over T cells for CAR-based immunotherapy. They offer key benefits: (1) HLA compatibility, meaning they can be used in a wider range of patients without the need for matching tissue types. (2) Minimal side effects (CRS and GVHD) due to their limited persistence and cytokine profile. (3) Scalability for "off-the-shelf" production from various sources. Several strategies have been introduced that highlight the superiority and challenges of CAR-NK cell therapy for asthma treatment including IL-10, IFN-γ, ADCC, perforin-granzyme, FASL, KIR, NCRs (NKP46), DAP, DNAM-1, TGF-β, TNF-α, CCL, NKG2A, TF, and EGFR. Furthermore, we advocate for incorporating AI for CAR design optimization and CRISPR-Cas9 gene editing technology for precise gene manipulation to generate highly effective CAR constructs. This review will delve into the evolution and production of CAR designs, explore pre-clinical and clinical studies of CAR-based therapies in asthma, analyze strategies to optimize CAR-NK cell function, conduct a comparative analysis of CAR-T and CAR-NK cell therapy with their respective challenges, and finally present established novel CAR designs with promising potential for asthma treatment.

Finding Your CAR: The Road Ahead for Engineered T Cells

Adoptive cellular therapy using chimeric antigen receptors (CARs) has transformed immunotherapy by engineering T cells to target specific antigens on tumor cells. As the field continues to advance, pathology laboratories will play increasingly essential roles in the complicated multi-step process of CAR T-cell therapy. These include detection of targetable tumor antigens by flow cytometry or immunohistochemistry at the time of disease diagnosis and the isolation and infusion of CAR T cells. Additional roles include: i) detecting antigen loss or heterogeneity that renders resistance to CAR T cells as well as identifying alternative targetable antigens on tumor cells, ii) monitoring the phenotype, persistence, and tumor infiltration properties of CAR T cells and the tumor microenvironment for factors that predict CAR T-cell therapy success, and iii) evaluating side effects and biomarkers of CAR T-cell cytotoxicity such as cytokine release syndrome. This review highlights existing technologies that are applicable to monitoring CAR T-cell persistence, target antigen identification, and loss. Also discussed are emerging technologies that address new challenges such as how to put a brake on CAR T cells. Although pathology laboratories have already provided companion diagnostic tests important in immunotherapy (eg, programmed death-ligand 1, microsatellite instability, and human epidermal growth factor receptor 2 testing), it draws attention to the exciting new translational research opportunities in adoptive cellular therapy.

Synthetic biology approaches for enhancing safety and specificity of CAR-T cell therapies for solid cancers

CAR-T cell therapies have been successful in treating numerous hematologic malignancies as the T cell can be engineered to target a specific antigen associated with the disease. However, translating CAR-T cell therapies for solid cancers is proving more challenging due to the lack of truly tumor-associated antigens and the high risk of off-target toxicities. To combat this, numerous synthetic biology mechanisms are being incorporated to create safer and more specific CAR-T cells that can be spatiotemporally controlled with increased precision. Here, we seek to summarize and analyze the advancements for CAR-T cell therapies with respect to clinical implementation, from the perspective of synthetic biology and immunology. This review should serve as a resource for further investigation and growth within the field of personalized cellular therapies.

FDG-PET/CT is a powerful tool to predict and evaluate response to chimeric antigen receptor (CAR) T-cell therapy in Non-Hodgkin-Lymphoma (NHL)

Chimeric antigen receptor (CAR) T-cell therapy has dramatically shifted the landscape of treatment especially for Non-Hodgkin-Lymphoma (NHL). This study evaluates the role of fluorodeoxyglucose (FDG)-positron emission tomography/computed tomography (PET/CT) in NHL treated with CAR T-cell therapy concerning response assessment and prognosis.We evaluated 34 patients with NHL who received a CAR T-cell therapy between August 2019 and July 2022. All patients underwent a pre-therapeutic FDG-PET/CT (PET-0) 6 days prior and a post-therapeutic FDG-PET/CT (PET-1) 34 days after CAR T-cell therapy. Deauville score (DS) was used for evaluation of response to therapy and compared to a minimum follow-up of 5 months.19/34 (55.9%) patients achieved DS ≤ 3 on PET-1, the remaining 15 (44.1%) patients had DS > 3 on PET-1. 14/19 patients with DS ≤ 3 on PET-1 had no relapsed or refractory (r/r)-disease and were still alive at last follow-up. The other 5 patients had r/r-disease and 4 of these died. Except for two patients who had no r/r-disease, all other patients (13/15) with DS > 3 on PET-1 had r/r-disease and 12 of these subsequently died. Patients with DS ≤ 3 on PET-1 had significantly better progression free survival (PFS; HR: 5.7; p < 0.01) and overall survival (OS; HR: 5.0; p < 0.01) compared to patients with DS > 3 on PET-1. In addition, we demonstrated that patients with DS ≤ 4 on PET-0 tended to have longer PFS (HR: 3.6; p = 0.05).Early FDG-PET/CT using the established DS after CAR T-cell therapy is a powerful tool to evaluate response to therapy.

Image-guided Ablative Procedures

Various image-guided ablative procedures include chemical and thermal ablation techniques and irreversible electroporation. These have been used for curative intent for small tumours and palliative intent for debulking, immunogenicity and pain control. Understanding these techniques is critical to avoiding complications and achieving superior clinical outcomes. Additionally, combination with immunotherapy and chemotherapies is rapidly evolving. There are numerous opportunities in interventional radiology to advance ablation techniques and seamlessly integrate into current treatment regimens for both benign and malignant tumours.

γδ T cells as critical anti-tumor immune effectors

While the effector cells that mediate anti-tumor immunity have historically been attributed to αβ T cells and natural killer cells, γδ T cells are now being recognized as a complementary mechanism mediating tumor rejection. γδ T cells possess a host of functions ranging from antigen presentation to regulatory function and, importantly, have critical roles in eliciting anti-tumor responses where other immune effectors may be rendered ineffective. Recent discoveries have elucidated how these differing functions are mediated by γδ T cells with specific T cell receptors and spatial distribution. Their relative resistance to mechanisms of dysfunction like T cell exhaustion has spurred the development of therapeutic approaches exploiting γδ T cells, and an improved understanding of these cells should enable more effective immunotherapies.

Beyond CAR T cells: exploring alternative cell sources for CAR-like cellular therapies

Chimeric antigen receptor (CAR)-T cell therapy has led to remarkable clinical outcomes in the treatment of hematological malignancies. However, challenges remain, such as limited infiltration into solid tumors, inadequate persistence, systemic toxicities, and manufacturing insufficiencies. The use of alternative cell sources for CAR-based therapies, such as natural killer cells (NK), macrophages (MΦ), invariant Natural Killer T (iNKT) cells, γδT cells, neutrophils, and induced pluripotent stem cells (iPSC), has emerged as a promising avenue. By harnessing these cells' inherent cytotoxic mechanisms and incorporating CAR technology, common CAR-T cell-related limitations can be effectively mitigated. We herein present an overview of the tumoricidal mechanisms, CAR designs, and manufacturing processes of CAR-NK cells, CAR-MΦ, CAR-iNKT cells, CAR-γδT cells, CAR-neutrophils, and iPSC-derived CAR-cells, outlining the advantages, limitations, and potential solutions of these therapeutic strategies.

Scalable process development of NK and CAR-NK expansion in a closed bioreactor

Production of large amounts of functional NK and CAR-NK cells represents one of the bottlenecks for NK-based immunotherapy. In this study, we developed a large-scale, reliable, and practicable NK and CAR-NK production using G-Rex 100M bioreactors, which depend on a gas-permeable membrane technology. This system holds large volumes of medium with enhanced oxygen delivery, creating conditions conducive to large-scale PBNK and CAR-NK expansions for cancer therapy. Both peripheral blood NK cells (PBNKs) and CAR-NKs expanded in these bioreactors retained similar immunophenotypes and exhibited comparable cytotoxicity towards hepatocellular carcinoma (HCC) cells akin to that of NK and CAR-NK cells expanded in G-Rex 6 well bioreactors. Importantly, cryopreservation minimally affected the cytotoxicity of NK cells expanded using the G-Rex 100M bioreactors, establishing a robust platform for scaled-up NK and CAR-NK cell production. This method is promising for the development of "off-the-shelf" NK cells, supporting the future clinical implementation of NK cell immunotherapy.

Recent advances in CAR-T therapy for the treatment of acute myeloid leukemia

Chimeric antigen receptor T-cell (CAR-T) therapy, which has demonstrated notable efficacy against B-cell malignancies and is approved by the US Food and Drug Administration for clinical use in this context, represents a significant milestone in cancer immunotherapy. However, the efficacy of CAR-T therapy for the treatment of acute myeloid leukemia (AML) is poor. The challenges associated with the application of CAR-T therapy for the clinical treatment of AML include, but are not limited to, nonspecific distribution of AML therapeutic targets, difficulties in the production of CAR-T cells, AML blast cell heterogeneity, the immunosuppressive microenvironment in AML, and treatment-related adverse events. In this review, we summarize the recent findings regarding various therapeutic targets for AML (CD33, CD123, CLL1, CD7, etc.) and the results of the latest clinical studies on these targets. Thereafter, we also discuss the challenges related to CAR-T therapy for AML and some promising strategies for overcoming these challenges, including novel approaches such as gene editing and advances in CAR design.

CAR T-cells targeting FGFR4 and CD276 simultaneously show potent antitumor effect against childhood rhabdomyosarcoma

Chimeric antigen receptor (CAR) T-cells targeting Fibroblast Growth Factor Receptor 4 (FGFR4), a highly expressed surface tyrosine receptor in rhabdomyosarcoma (RMS), are already in the clinical phase of development, but tumour heterogeneity and suboptimal activation might hamper their potency. Here we report an optimization strategy of the co-stimulatory and targeting properties of a FGFR4 CAR. We replace the CD8 hinge and transmembrane domain and the 4-1BB co-stimulatory domain with those of CD28. The resulting CARs display enhanced anti-tumor activity in several RMS xenograft models except for an aggressive tumour cell line, RMS559. By searching for a direct target of the RMS core-regulatory transcription factor MYOD1, we identify another surface protein, CD276, as a potential target. Bicistronic CARs (BiCisCAR) targeting both FGFR4 and CD276, containing two distinct co-stimulatory domains, have superior prolonged persistent and invigorated anti-tumor activities compared to the optimized FGFR4-specific CAR and the other BiCisCAR with the same 4-1BB co-stimulatory domain. Our study thus lays down the proof-of-principle for a CAR T-cell therapy targeting both FGFR4 and CD276 in RMS.

CAR-T cell combination therapies in hematologic malignancies

Chimeric antigen receptor-T cell therapy, a groundbreaking cancer treatment, has achieved remarkable success against hematologic malignancies. However, CAR-T monotherapy faces challenges in certain cases, including treatment tolerance and relapse rates. To overcome these challenges, researchers are investigating combining CAR-T cells with other treatments to enhance therapeutic efficacy. Therefore, this review aims to investigate the progress of research in combining CAR-T cells for hematologic malignancies. It covers the basic principles and clinical applications of CAR-T cell therapy, detailing combinations with chemotherapy, immune checkpoint inhibitors, targeted drugs, radiotherapy, hematopoietic stem cell transplantation, and other treatments. These combinations synergistically enhance the antitumor effects of CAR-T cells and comprehensively target tumors through different mechanisms, improving patient response and survival rates.

CAR memory-like NK cells targeting the membrane proximal domain of mesothelin demonstrate promising activity in ovarian cancer

Epithelial ovarian cancer (EOC) remains one of the most lethal gynecological cancers. Cytokine-induced memory-like (CIML) natural killer (NK) cells have shown promising results in preclinical and early-phase clinical trials. In the current study, CIML NK cells demonstrated superior antitumor responses against a panel of EOC cell lines, increased expression of activation receptors, and up-regulation of genes involved in cell cycle/proliferation and down-regulation of inhibitory/suppressive genes. CIML NK cells transduced with a chimeric antigen receptor (CAR) targeting the membrane-proximal domain of mesothelin (MSLN) further improved the antitumor responses against MSLN-expressing EOC cells and patient-derived xenograft tumor cells. CAR arming of the CIML NK cells subtanstially reduced their dysfunction in patient-derived ascites fluid with transcriptomic changes related to altered metabolism and tonic signaling as potential mechanisms. Lastly, the adoptive transfer of MSLN-CAR CIML NK cells demonstrated remarkable inhibition of tumor growth and prevented metastatic spread in xenograft mice, supporting their potential as an effective therapeutic strategy in EOC.

Preclinical studies show that Co-STARs combine the advantages of chimeric antigen and T cell receptors for the treatment of tumors with low antigen densities

Two types of engineered T cells have been successfully used to treat patients with cancer, one with an antigen recognition domain derived from antibodies [chimeric antigen receptors (CARs)] and the other derived from T cell receptors (TCRs). CARs use high-affinity antigen-binding domains and costimulatory domains to induce T cell activation but can only react against target cells with relatively high amounts of antigen. TCRs have a much lower affinity for their antigens but can react against target cells displaying only a few antigen molecules. Here, we describe a new type of receptor, called a Co-STAR (for costimulatory synthetic TCR and antigen receptor), that combines aspects of both CARs and TCRs. In Co-STARs, the antigen-recognizing components of TCRs are replaced by high-affinity antibody fragments, and costimulation is provided by two modules that drive NF-κB signaling (MyD88 and CD40). Using a TCR-mimic antibody fragment that targets a recurrent p53 neoantigen presented in a common human leukocyte antigen (HLA) allele, we demonstrate that T cells equipped with Co-STARs can kill cancer cells bearing low densities of antigen better than T cells engineered with conventional CARs and patient-derived TCRs in vitro. In mouse models, we show that Co-STARs mediate more robust T cell expansion and more durable tumor regressions than TCRs similarly modified with MyD88 and CD40 costimulation. Our data suggest that Co-STARs may have utility for other peptide-HLA antigens in cancer and other targets where antigen density may limit the efficacy of engineered T cells.

Epigenetic Induction of Cancer-Testis Antigens and Endogenous Retroviruses at Single-Cell Level Enhances Immune Recognition and Response in Glioma

Glioblastoma (GBM) is the most common malignant primary brain tumor and remains incurable. Previous work has shown that systemic administration of Decitabine (DAC) induces sufficient expression of cancer-testis antigens (CTA) in GBM for targeting by adoptive T-cell therapy in vivo. However, the mechanisms by which DAC enhances immunogenicity in GBM remain to be elucidated. Using New York esophageal squamous cell carcinoma 1 (NY-ESO-1) as a representative inducible CTA, we demonstrate in patient tissue, immortalized glioma cells, and primary patient-derived gliomaspheres that basal CTA expression is restricted by promoter hypermethylation in gliomas. DAC treatment of glioma cells specifically inhibits DNA methylation silencing to render NY-ESO-1 and other CTA into inducible tumor antigens at single-cell resolution. Functionally, NY-ESO-1 T-cell receptor-engineered effector cell targeting of DAC-induced antigen in primary glioma cells promotes specific and polyfunctional T-cell cytokine profiles. In addition to induction of CTA, DAC concomitantly reactivates tumor-intrinsic human endogenous retroviruses, interferon response signatures, and MHC-I. Overall, we demonstrate that DAC induces targetable tumor antigen and enhances T-cell functionality against GBM, ultimately contributing to the improvement of targeted immune therapies in glioma.

SIGNIFICANCE

This study dissects the tumor-intrinsic epigenetic and transcriptional mechanisms underlying enhanced T-cell functionality targeting decitabine-induced cancer-testis antigens in glioma. Our findings demonstrate concomitant induction of tumor antigens, reactivation of human endogenous retroviruses, and stimulation of interferon signaling as a mechanistic rationale to epigenetically prime human gliomas to immunotherapeutic targeting.

Altered cancer metabolism and implications for next-generation CAR T-cell therapies

This review critically examines the evolving landscape of chimeric antigen receptor (CAR) T-cell therapy in treating solid tumors, with a particular focus on the metabolic challenges within the tumor microenvironment. CAR T-cell therapy has demonstrated remarkable success in hematologic malignancies, yet its efficacy in solid tumors remains limited. A significant barrier is the hostile milieu of the tumor microenvironment, which impairs CAR T-cell survival and function. This review delves into the metabolic adaptations of cancer cells and their impact on immune cells, highlighting the competition for nutrients and the accumulation of immunosuppressive metabolites. It also explores emerging strategies to enhance CAR T-cell metabolic fitness and persistence, including genetic engineering and metabolic reprogramming. An integrated approach, combining metabolic interventions with CAR T-cell therapy, has the potential to overcome these constraints and improve therapeutic outcomes in solid tumors.

CD37 is a safe chimeric antigen receptor target to treat acute myeloid leukemia

Acute myeloid leukemia (AML) is characterized by the accumulation of immature myeloid cells in the bone marrow and the peripheral blood. Nearly half of the AML patients relapse after standard induction therapy, and new forms of therapy are urgently needed. Chimeric antigen receptor (CAR) T therapy has so far not been successful in AML due to lack of efficacy and safety. Indeed, the most attractive antigen targets are stem cell markers such as CD33 or CD123. We demonstrate that CD37, a mature B cell marker, is expressed in AML samples, and its presence correlates with the European LeukemiaNet (ELN) 2017 risk stratification. We repurpose the anti-lymphoma CD37CAR for the treatment of AML and show that CD37CAR T cells specifically kill AML cells, secrete proinflammatory cytokines, and control cancer progression in vivo. Importantly, CD37CAR T cells display no toxicity toward hematopoietic stem cells. Thus, CD37 is a promising and safe CAR T cell AML target.

CAR-T cell therapy in advanced thyroid cancer: from basic to clinical

The majority of patients with thyroid cancer can attain a favorable prognosis with a comprehensive treatment program based on surgical treatment. However, the current treatment options for advanced thyroid cancer are still limited. In recent years, chimeric antigen receptor-modified T-cell (CAR-T) therapy has received widespread attention in the field of oncology treatment. It has achieved remarkable results in the treatment of hematologic tumors. However, due to the constraints of multiple factors, the therapeutic efficacy of CAR-T therapy for solid tumors, including thyroid cancer, has not yet met expectations. This review outlines the fundamental structure and treatment strategies of CAR-T cells, provides an overview of the advancements in both preclinical investigations and clinical trials focusing on targets associated with CAR-T cell therapy in treating thyroid cancer, and discusses the challenges and solutions to CAR-T cell therapy for thyroid cancer. In conclusion, CAR-T cell therapy is a promising therapeutic approach for thyroid cancer, and we hope that our review will provide a timely and updated study of CAR-T cell therapy for thyroid cancer to advance the field.

Controlling CAR-T cell activity and specificity with synthetic SparX adapters

While conventional chimeric antigen-receptor (CAR)-T therapies have shown remarkable clinical activity in some settings, they can induce severe toxicities and are rarely curative. To address these challenges, we developed a controllable cell therapy where synthetic D-domain-containing proteins (soluble protein antigen-receptor X-linker [SparX]) bind one or more tumor antigens and mark those cells for elimination by genetically modified T cells (antigen-receptor complex [ARC]-T). The chimeric antigen receptor was engineered with a D-domain that specifically binds to the SparX protein via a unique TAG, derived from human alpha-fetoprotein. The interaction is mediated through an epitope on the TAG that is occluded in the native alpha-fetoprotein molecule. In vitro and in vivo data demonstrate that the activation and cytolytic activity of ARC-T cells is dependent on the dose of SparX protein and only occurs when ARC-T cells are engaged with SparX proteins bound to antigen-positive cells. ARC-T cell specificity was also redirected in vivo by changing SparX proteins that recognized different tumor antigens to combat inherent or acquired tumor heterogeneity. The ARC-SparX platform is designed to expand patient and physician access to cell therapy by controlling potential toxicities through SparX dosing regimens and enhancing tumor elimination through sequential or simultaneous administration of SparX proteins engineered to bind different tumor antigens.

GD2-Targeting CAR T-cell Therapy for Patients with GD2+ Medulloblastoma

PURPOSE

Medulloblastoma (MB), the most common childhood malignant brain tumor, has a poor prognosis in about 30% of patients. The current standard of care, which includes surgery, radiation, and chemotherapy, is often responsible for cognitive, neurologic, and endocrine side effects. We investigated whether chimeric antigen receptor (CAR) T cells directed toward the disialoganglioside GD2 can represent a potentially more effective treatment with reduced long-term side effects.

EXPERIMENTAL DESIGN

GD2 expression was evaluated on primary tumor biopsies of MB children by flow cytometry. GD2 expression in MB cells was also evaluated in response to an EZH2 inhibitor (tazemetostat). In in vitro and in vivo models, GD2+ MB cells were targeted by a CAR-GD2.CD28.4-1BBζ (CAR.GD2)-T construct, including the suicide gene inducible caspase-9.

RESULTS

GD2 was expressed in 82.68% of MB tumors. The SHH and G3-G4 subtypes expressed the highest levels of GD2, whereas the WNT subtype expressed the lowest. In in vitro coculture assays, CAR.GD2 T cells were able to kill GD2+ MB cells. Pretreatment with tazemetostat upregulated GD2 expression, sensitizing GD2dimMB cells to CAR.GD2 T cells cytotoxic activity. In orthotopic mouse models of MB, intravenously injected CAR.GD2 T cells significantly controlled tumor growth, prolonging the overall survival of treated mice. Moreover, the dimerizing drug AP1903 was able to cross the murine blood-brain barrier and to eliminate both blood-circulating and tumor-infiltrating CAR.GD2 T cells.

CONCLUSIONS

Our experimental data indicate the potential efficacy of CAR.GD2 T-cell therapy. A phase I/II clinical trial is ongoing in our center (NCT05298995) to evaluate the safety and therapeutic efficacy of CAR.GD2 therapy in high-risk MB patients.

Applications and Opportunities for Immune Cell CAR Engineering in Comparative Oncology

Chimeric antigen receptor (CAR) T-adoptive cell therapy has transformed the treatment of human hematologic malignancies. However, its application for the treatment of solid tumors remains challenging. An exciting avenue for advancing this field lies in the use of pet dogs, in which cancers that recapitulate the biology, immunological features, and clinical course of human malignancies arise spontaneously. Moreover, their large size, outbred genetic background, shared environment with humans, and immunocompetency make dogs ideal for investigating and optimizing CAR therapies before human trials. Here, we will outline how challenges in early clinical trials in patients with canine lymphoma, including issues related to autologous CAR T-cell manufacturing, limited CAR T-cell persistence, and tumor antigen escape, mirrored challenges observed in human CAR T trials. We will then highlight emerging adoptive cell therapy strategies currently under investigation in dogs with hematological and solid cancers, which will provide crucial safety and efficacy data on novel CAR T regimens that can be used to support clinical trials. By drawing from ongoing studies, we will illustrate how canine patients with spontaneous cancer may serve as compelling screening platforms to establish innovative CAR therapy approaches and identify predictive biomarkers of response, with a specific emphasis on solid tumors. With increased funding for canine immunotherapy studies, multi-institutional investigations are poised to generate highly impactful clinical data that should translate into more effective human trials, ultimately benefiting both human and canine cancer patients.

Selective haematological cancer eradication with preserved haematopoiesis

Haematopoietic stem cell (HSC) transplantation (HSCT) is the only curative treatment for a broad range of haematological malignancies, but the standard of care relies on untargeted chemotherapies and limited possibilities to treat malignant cells after HSCT without affecting the transplanted healthy cells1. Antigen-specific cell-depleting therapies hold the promise of much more targeted elimination of diseased cells, as witnessed in the past decade by the revolution of clinical practice for B cell malignancies2. However, target selection is complex and limited to antigens expressed on subsets of haematopoietic cells, resulting in a fragmented therapy landscape with high development costs2-5. Here we demonstrate that an antibody-drug conjugate (ADC) targeting the pan-haematopoietic marker CD45 enables the antigen-specific depletion of the entire haematopoietic system, including HSCs. Pairing this ADC with the transplantation of human HSCs engineered to be shielded from the CD45-targeting ADC enables the selective eradication of leukaemic cells with preserved haematopoiesis. The combination of CD45-targeting ADCs and engineered HSCs creates an almost universal strategy to replace a diseased haematopoietic system, irrespective of disease aetiology or originating cell type. We propose that this approach could have broad implications beyond haematological malignancies.

Advances in research on factors affecting chimeric antigen receptor T-cell efficacy

Chimeric antigen receptor T-cell (CAR-T) therapy is becoming an effective technique for the treatment of patients with relapsed/refractory hematologic malignancies. After analyzing patients with tumor progression and sustained remission after CAR-T cell therapy, many factors were found to be associated with the efficacy of CAR-T therapy. This paper reviews the factors affecting the effect of CAR-T such as tumor characteristics, tumor microenvironment and immune function of patients, CAR-T cell structure, construction method and in vivo expansion values, lymphodepletion chemotherapy, and previous treatment, and provides a preliminary outlook on the corresponding therapeutic strategies.

CAR-T cell therapy: a game-changer in cancer treatment and beyond

In recent years, cancer has become one of the primary causes of mortality, approximately 10 million deaths worldwide each year. The most advanced, chimeric antigen receptor (CAR) T cell immunotherapy has turned out as a promising treatment for cancer. CAR-T cell therapy involves the genetic modification of T cells obtained from the patient's blood, and infusion back to the patients. CAR-T cell immunotherapy has led to a significant improvement in the remission rates of hematological cancers. CAR-T cell therapy presently limited to hematological cancers, there are ongoing efforts to develop additional CAR constructs such as bispecific CAR, tandem CAR, inhibitory CAR, combined antigens, CRISPR gene-editing, and nanoparticle delivery. With these advancements, CAR-T cell therapy holds promise concerning potential to improve upon traditional cancer treatments such as chemotherapy and radiation while reducing associated toxicities. This review covers recent advances and advantages of CAR-T cell immunotherapy.

Allogeneic CD19/CD22 CAR T-Cell Therapy for B-Cell Acute Lymphoblastic Leukemia

This case series reports durable remissions in 2 patients with relapsed/refractory B-cell acute lymphoblastic leukemia treated with allogeneic bispecific CD19/CD22-targeting chimeric antigen receptor T cells.

Extracellular domains of CARs reprogramme T cell metabolism without antigen stimulation

Metabolism is an indispensable part of T cell proliferation, activation and exhaustion, yet the metabolism of chimeric antigen receptor (CAR)-T cells remains incompletely understood. CARs are composed of extracellular domains-often single-chain variable fragments (scFvs)-that determine ligand specificity and intracellular domains that trigger signalling following antigen binding. Here, we show that CARs differing only in the scFv variously reprogramme T cell metabolism. Even without exposure to antigens, some CARs increase proliferation and nutrient uptake in T cells. Using stable isotope tracers and mass spectrometry, we observed basal metabolic fluxes through glycolysis doubling and amino acid uptake overtaking anaplerosis in CAR-T cells harbouring a rituximab scFv, unlike other similar anti-CD20 scFvs. Disparate rituximab and 14G2a-based anti-GD2 CAR-T cells are similarly hypermetabolic and channel excess nutrients to nitrogen overflow metabolism. Modest overflow metabolism of CAR-T cells and metabolic compatibility between cancer cells and CAR-T cells are identified as features of efficacious CAR-T cell therapy.

Recent progress in chimeric antigen receptor therapy for acute myeloid leukemia

Although CAR-T cell therapy has been particularly successful as a treatment for B cell malignancies, effectively treating acute myeloid leukemia with CAR remains a greater challenge. Multiple preclinical studies and clinical trials are underway, including on AML-related surface markers that CAR-T cells can target, such as CD123, CD33, NKG2D, CLL1, CD7, FLT3, Lewis Y and CD70, all of which provide opportunities for developing CAR-T therapies with improved specificity and efficacy. We also explored specific strategies for CAR-T cell treatment of AML, including immune checkpoints, suicide genes, dual targeting, genomic tools and the potential for universal CAR. In addition, CAR-T cell therapy for AML still has certain risks and challenges, including cytokine release syndrome (CRS) and haematotoxicity. Despite these challenges, as a new targeting method for AML treatment, CAR-T cell therapy still has great prospects. Ongoing research aims to further optimize this treatment mode.

Precision off-the-shelf natural killer cell therapies for oncology with logic-gated gene circuits

Acute myeloid leukemia (AML) is an aggressive disease with a poor prognosis (5-year survival rate of 30.5% in the United States). Designing cell therapies to target AML is challenging because no single tumor-associated antigen (TAA) is highly expressed on all cancer subpopulations. Furthermore, TAAs are also expressed on healthy cells, leading to toxicity risk. To address these targeting challenges, we engineer natural killer (NK) cells with a multi-input gene circuit consisting of chimeric antigen receptors (CARs) controlled by OR and NOT logic gates. The OR gate kills a range of AML cells from leukemic stem cells to blasts using a bivalent CAR targeting FLT3 and/or CD33. The NOT gate protects healthy hematopoietic stem cells (HSCs) using an inhibitory CAR targeting endomucin, a protective antigen unique to healthy HSCs. NK cells with the combined OR-NOT gene circuit kill multiple AML subtypes and protect primary HSCs, and the circuit also works in vivo.

Selective refueling of CAR T cells using ADA1 and CD26 boosts antitumor immunity

Chimeric antigen receptor (CAR) T cell therapy is hindered in solid tumor treatment due to the immunosuppressive tumor microenvironment and suboptimal T cell persistence. Current strategies do not address nutrient competition in the microenvironment. Hence, we present a metabolic refueling approach using inosine as an alternative fuel. CAR T cells were engineered to express membrane-bound CD26 and cytoplasmic adenosine deaminase 1 (ADA1), converting adenosine to inosine. Autocrine secretion of ADA1 upon CD3/CD26 stimulation activates CAR T cells, improving migration and resistance to transforming growth factor β1 suppression. Fusion of ADA1 with anti-CD3 scFv further boosts inosine production and minimizes tumor cell feeding. In mouse models of hepatocellular carcinoma and non-small cell lung cancer, metabolically refueled CAR T cells exhibit superior tumor reduction compared to unmodified CAR T cells. Overall, our study highlights the potential of selective inosine refueling to enhance CAR T therapy efficacy against solid tumors.

CD19-immunoPET for noninvasive visualization of CD19 expression in B-cell lymphoma patients

Cell- and antibody-based CD19-directed therapies have demonstrated great potential for treating B-cell non-Hodgkin lymphoma (B-NHL). However, all these approaches suffer from limited response rates and considerable toxicity. Until now, therapy decisions have been routinely based on histopathological CD19 staining of a single lesion at initial diagnosis or relapse, disregarding heterogeneity and temporal alterations in antigen expression. To visualize in vivo CD19 expression noninvasively, we radiolabeled anti-human CD19 monoclonal antibodies with copper-64 (64Cu-αCD19) for positron emission tomography (CD19-immunoPET). 64Cu-αCD19 specifically bound to subcutaneous Daudi xenograft mouse models in vivo. Importantly, 64Cu-αCD19 did not affect the anti-lymphoma cytotoxicity of CD19 CAR-T cells in vitro. Following our preclinical validation, 64Cu-αCD19 was injected into four patients with follicular lymphoma, diffuse large B-cell lymphoma or mantle zone lymphoma. We observed varying 64Cu-αCD19 PET uptake patterns at different lymphoma sites, both within and among patients, correlating with ex vivo immunohistochemical CD19 expression. Moreover, one patient exhibited enhanced uptake in the spleen compared to that in patients with prior B-cell-depleting therapy, indicating that 64Cu-αCD19 is applicable for identifying B-cell-rich organs. In conclusion, we demonstrated the specific targeting and visualization of CD19+ B-NHL in mice and humans by CD19-immunoPET. The intra- and interindividual heterogeneous 64Cu-αCD19 uptake patterns of lymphoma lesions indicate variability in CD19 expression, suggesting the potential of CD19-immunoPET as a novel tool to guide CD19-directed therapies.

Charting new paradigms for CAR-T cell therapy beyond current Achilles heels

Chimeric antigen receptor-T (CAR-T) cell therapy has made remarkable strides in treating hematological malignancies. However, the widespread adoption of CAR-T cell therapy is hindered by several challenges. These include concerns about the long-term and complex manufacturing process, as well as efficacy factors such as tumor antigen escape, CAR-T cell exhaustion, and the immunosuppressive tumor microenvironment. Additionally, safety issues like the risk of secondary cancers post-treatment, on-target off-tumor toxicity, and immune effector responses triggered by CAR-T cells are significant considerations. To address these obstacles, researchers have explored various strategies, including allogeneic universal CAR-T cell development, infusion of non-activated quiescent T cells within a 24-hour period, and in vivo induction of CAR-T cells. This review comprehensively examines the clinical challenges of CAR-T cell therapy and outlines strategies to overcome them, aiming to chart pathways beyond its current Achilles heels.

Photothermal Prussian blue nanoparticles generate potent multi-targeted tumor-specific T cells as an adoptive cell therapy

Prussian blue nanoparticle-based photothermal therapy (PBNP-PTT) is an effective tumor treatment capable of eliciting an antitumor immune response. Motivated by the ability of PBNP-PTT to potentiate endogenous immune responses, we recently demonstrated that PBNP-PTT could be used ex vivo to generate tumor-specific T cells against glioblastoma (GBM) cell lines as an adoptive T cell therapy (ATCT). In this study, we further developed this promising T cell development platform. First, we assessed the phenotype and function of T cells generated using PBNP-PTT. We observed that PBNP-PTT facilitated CD8+ T cell expansion from healthy donor PBMCs that secreted IFNγ and TNFα and upregulated CD107a in response to engagement with target U87 cells, suggesting specific antitumor T cell activation and degranulation. Further, CD8+ effector and effector memory T cell populations significantly expanded after co-culture with U87 cells, consistent with tumor-specific effector responses. In orthotopically implanted U87 GBM tumors in vivo, PBNP-PTT-derived T cells effectively reduced U87 tumor growth and generated long-term survival in >80% of tumor-bearing mice by Day 100, compared to 0% of mice treated with PBS, non-specific T cells, or T cells expanded from lysed U87 cells, demonstrating an enhanced antitumor efficacy of this ATCT platform. Finally, we tested the generalizability of our approach by generating T cells targeting medulloblastoma (D556), breast cancer (MDA-MB-231), neuroblastoma (SH-SY5Y), and acute monocytic leukemia (THP-1) cell lines. The resulting T cells secreted IFNγ and exerted increased tumor-specific cytolytic function relative to controls, demonstrating the versatility of PBNP-PTT in generating tumor-specific T cells for ATCT.

High-multiplex single-cell imaging analysis reveals tumor immune contexture associated with clinical outcomes after CAR T cell therapy

Chimeric antigen receptor (CAR) T cell therapy has made great progress in treating lymphoma, yet patient outcomes still vary greatly. The lymphoma microenvironment may be an important factor in the efficacy of CAR T therapy. In this study, we designed a highly multiplexed imaging mass cytometry (IMC) panel to simultaneously quantify 31 biomarkers from 13 patients with relapsed/refractory diffuse large B cell lymphoma (DLBCL) who received CAR19/22 T cell therapy. A total of 20 sections were sampled before CAR T cell infusion or after infusion when relapse occurred. A total of 35 cell clusters were identified, annotated, and subsequently redefined into 10 metaclusters. The CD4+ T cell fraction was positively associated with remission duration. Significantly higher Ki67, CD57, and TIM3 levels and lower CD69 levels in T cells, especially the CD8+/CD4+ Tem and Te cell subsets, were seen in patients with poor outcomes. Cellular neighborhood containing more immune cells was associated with longer remission. Fibroblasts and vascular endothelial cells resided much closer to tumor cells in patients with poor response and short remission after CAR T therapy. Our work comprehensively and systematically dissects the relationship between cell composition, state, and spatial arrangement in the DLBCL microenvironment and the outcomes of CAR T cell therapy, which is beneficial to predict CAR T therapy efficacy.

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.

Adoptive cell immunotherapy for breast cancer: harnessing the power of immune cells

Breast cancer is the most prevalent malignant neoplasm worldwide, necessitating the development of novel therapeutic strategies owing to the limitations posed by conventional treatment modalities. Immunotherapy is an innovative approach that has demonstrated significant efficacy in modulating a patient's innate immune system to combat tumor cells. In the era of precision medicine, adoptive immunotherapy for breast cancer has garnered widespread attention as an emerging treatment strategy, primarily encompassing cellular therapies such as tumor-infiltrating lymphocyte therapy, chimeric antigen receptor T/natural killer/M cell therapy, T cell receptor gene-engineered T cell therapy, lymphokine-activated killer cell therapy, cytokine-induced killer cell therapy, natural killer cell therapy, and γδ T cell therapy, among others. This treatment paradigm is based on the principles of immune memory and antigen specificity, involving the collection, processing, and expansion of the patient's immune cells, followed by their reintroduction into the patient's body to activate the immune system and prevent tumor recurrence and metastasis. Currently, multiple clinical trials are assessing the feasibility, effectiveness, and safety of adoptive immunotherapy in breast cancer. However, this therapeutic approach faces challenges associated with tumor heterogeneity, immune evasion, and treatment safety. This review comprehensively summarizes the latest advancements in adoptive immunotherapy for breast cancer and discusses future research directions and prospects, offering valuable guidance and insights into breast cancer immunotherapy.

Current Landscape of Cancer Immunotherapy: Harnessing the Immune Arsenal to Overcome Immune Evasion

Cancer immune evasion represents a leading hallmark of cancer, posing a significant obstacle to the development of successful anticancer therapies. However, the landscape of cancer treatment has significantly evolved, transitioning into the era of immunotherapy from conventional methods such as surgical resection, radiotherapy, chemotherapy, and targeted drug therapy. Immunotherapy has emerged as a pivotal component in cancer treatment, harnessing the body's immune system to combat cancer and offering improved prognostic outcomes for numerous patients. The remarkable success of immunotherapy has spurred significant efforts to enhance the clinical efficacy of existing agents and strategies. Several immunotherapeutic approaches have received approval for targeted cancer treatments, while others are currently in preclinical and clinical trials. This review explores recent progress in unraveling the mechanisms of cancer immune evasion and evaluates the clinical effectiveness of diverse immunotherapy strategies, including cancer vaccines, adoptive cell therapy, and antibody-based treatments. It encompasses both established treatments and those currently under investigation, providing a comprehensive overview of efforts to combat cancer through immunological approaches. Additionally, the article emphasizes the current developments, limitations, and challenges in cancer immunotherapy. Furthermore, by integrating analyses of cancer immunotherapy resistance mechanisms and exploring combination strategies and personalized approaches, it offers valuable insights crucial for the development of novel anticancer immunotherapeutic strategies.

State of the Art in CAR-T Cell Therapy for Solid Tumors: Is There a Sweeter Future?

Chimeric antigen receptor (CAR)-T cell therapy has proven to be a powerful treatment for hematological malignancies. The situation is very different in the case of solid tumors, for which no CAR-T-based therapy has yet been approved. There are many factors contributing to the absence of response in solid tumors to CAR-T cells, such as the immunosuppressive tumor microenvironment (TME), T cell exhaustion, or the lack of suitable antigen targets, which should have a stable and specific expression on tumor cells. Strategies being developed to improve CAR-T-based therapy for solid tumors include the use of new-generation CARs such as TRUCKs or bi-specific CARs, the combination of CAR therapy with chemo- or radiotherapy, the use of checkpoint inhibitors, and the use of oncolytic viruses. Furthermore, despite the scarcity of targets, a growing number of phase I/II clinical trials are exploring new solid-tumor-associated antigens. Most of these antigens are of a protein nature; however, there is a clear potential in identifying carbohydrate-type antigens associated with tumors, or carbohydrate and proteoglycan antigens that emerge because of aberrant glycosylations occurring in the context of tumor transformation.