An NK-like CAR T cell transition in CAR T cell dysfunction

Rodent models for dry eye syndrome (DES)

Dry eye syndrome (DES) is a range of ophthalmic conditions characterized by compromised tear film homeostasis, resulting from various pathological factors and primarily manifesting as ocular discomfort and impaired ocular surface integrity. With the rise in screen time due to modern lifestyles, the prevalence of DES is increasing annually, posing a significant global public health challenge. Pathophysiologically, DES involves damage to the lacrimal functional unit (LFU), including the lacrimal glands, meibomian glands, and corneoconjunctival epithelium, highlighting its multifactorial etiology. Current treatments mainly focus on artificial tears for moisture replacement and anti-inflammatory therapies, but both are limited. Consequently, animal models are crucial for understanding the complex pathological mechanisms of DES and identifying potential therapeutic agents. Rodent eyes, with their structural and physiological similarities to human eyes and cost-effectiveness, have become widely used in DES research. This manuscript reviews the current understanding of DES pathogenesis and rodent models, discussing their strengths, weaknesses, and relevant genetic models. The aim is to furnish critical insights and provide a scholarly resource to propel future investigative endeavors into the pathogenesis of and therapy for DES.

(CAR-)T cell dynamics following chimeric antigen receptor T cells for large B cell lymphoma: a translational tale

Chimeric antigen receptor (CAR) T-cell therapy represents a breakthrough in the treatment of B-cell malignancies. CAR-T cells infusion generally follows a chemotherapy regimen whose lymphodepleting properties create a favorable environment for the expansion of engineered T cells. While this process appears straightforward, emerging evidence reveals that complex mechanisms, collectively representing immune dynamics following CAR-T cell infusion, influence CAR-T cells behavior. In advance of infusion, a final-product enriched with less stressed CAR-T cells can improve their expansion and persistence, providing a biological rationale for early apheresis and administration. Following infusion, the emergence of dysfunctional CAR-T subpopulations, like regulatory or NK-like CAR-T cells, can impair efficacy. The recovery of non-CAR transduced T cells adds further complexity, as these cells could either impact outcomes or exacerbate complications, such as infections or prolonged cytopenia. In this review, we summarize the latest advances in understanding the immune dynamics following CAR-T cell infusion for large B-cell lymphomas, with a focus on both CAR-engineered and native T cell populations, and their impact on treatment efficacy and patient outcomes.

Library-based single-cell analysis of CAR signaling reveals drivers of in vivo persistence

The anti-tumor function of engineered T cells expressing chimeric antigen receptors (CARs) is dependent on signals transduced through intracellular signaling domains (ICDs). Different ICDs are known to drive distinct phenotypes, but systematic investigations into how ICD architectures direct T cell function-particularly at the molecular level-are lacking. Here, we use single-cell sequencing to map diverse signaling inputs to transcriptional outputs, focusing on a defined library of clinically relevant ICD architectures. Informed by these observations, we functionally characterize transcriptionally distinct ICD variants across various contexts to build comprehensive maps from ICD composition to phenotypic output. We identify a unique tonic signaling signature associated with a subset of ICD architectures that drives durable in vivo persistence and efficacy in liquid, but not solid, tumors. Our findings work toward decoding CAR signaling design principles, with implications for the rational design of next-generation ICD architectures optimized for in vivo function.

Quadruple adenine base-edited allogeneic CAR T cells outperform CRISPR/Cas9 nuclease-engineered T cells

Genome-editing technologies have enabled the clinical development of allogeneic cellular therapies, yet the optimal gene-editing modality for multiplex editing of therapeutic T cell product manufacturing remains elusive. In this study, we conducted a comprehensive comparison of CRISPR/Cas9 nuclease and adenine base editor (ABE) technologies in generating allogeneic chimeric antigen receptor (CAR) T cells, utilizing extensive in vitro and in vivo analyses. Both methods achieved high editing efficiencies across four target genes, critical for mitigating graft-versus-host disease and allograft rejection: TRAC or CD3E, B2M, CIITA, and PVR. Notably, ABE demonstrated higher manufacturing yields and distinct off-target profiles compared to Cas9, with translocations observed exclusively in Cas9-edited products. Functionally, ABE-edited CAR T cells exhibited superior in vitro effector functions under continuous antigen stimulation, including enhanced proliferative capacity and increased surface CAR expression. Transcriptomic analysis revealed that ABE editing resulted in reduced activation of p53 and DNA damage response pathways at baseline, along with sustained activation of metabolic pathways during antigen stress. Consistently, Assay for Transposase-Accessible Chromatin using sequencing data indicated that Cas9-edited, but not ABE-edited, CAR T cells showed enrichment of chromatin accessibility peaks associated with double-strand break repair and DNA damage response pathways. In a preclinical leukemia model, ABE-edited CAR T cells demonstrated improved tumor control and extended overall survival compared to their Cas9-edited counterparts. Collectively, these findings position ABE as superior to Cas9 nucleases for multiplex gene editing of therapeutic T cells.

Deciphering the role of histone modifications in memory and exhausted CD8 T cells

Exhausted CD8 T cells (TEX) arising during chronic infections and cancer have reduced functional capacity and limited fate flexibility that prevents optimal disease control and response to immunotherapies. Compared to memory (TMEM) cells, TEX have a unique open chromatin landscape underlying a distinct gene expression program. How TEX transcriptional and epigenetic landscapes are regulated through histone post-translational modifications (hPTMs) remains unclear. Here, we profiled key activating (H3K27ac and H3K4me3) and repressive (H3K27me3 and H3K9me3) histone modifications in naive CD8 T cells (TN), TMEM and TEX. We identified H3K27ac-associated super-enhancers that distinguish TN, TMEM and TEX, along with key transcription factor networks predicted to regulate these different transcriptional landscapes. Promoters of some key genes were poised in TN, but activated in TMEM or TEX whereas other genes poised in TN were repressed in TMEM or TEX, indicating that both repression and activation of poised genes may enforce these distinct cell states. Moreover, narrow peaks of repressive H3K9me3 were associated with increased gene expression in TEX, suggesting an atypical role for this modification. These data indicate that beyond chromatin accessibility, hPTMs differentially regulate specific gene expression programs of TEX compared to TMEM through both activating and repressive pathways.

Characterization of the aryl hydrocarbon receptor as a potential candidate to improve cancer T cell therapies

The efficacy of T-cell-based cancer therapies can be limited by the tumor microenvironment which can lead to T cell dysfunction. Multiple studies, particularly in murine models, have demonstrated the capacity of the aryl hydrocarbon receptor (AHR) to negatively regulate antitumor T cell functions. AHR is a cytoplasmic receptor and transcription factor that was originally identified as a xenobiotic sensor, but has since been shown to play a significant role in the gene regulation of various immune cells, including T cells. Given the insights from murine studies, AHR emerges as a promising candidate to invalidate for optimizing T cell-based cancer therapies. However, the controversial role of AHR in human T cells underscores the need for a more comprehensive characterization of AHR expressing T cells. This study aims to investigate the regulatory mechanisms of AHR in human T cell biology to better understand its impact on reducing antitumor immune responses. Here, we knocked-out AHR in human T cells using CRISPR-Cas9 technology to characterize AHR's function in an in vitro chronic stimulation model. Engineered T cells exhibited enhanced effector- and memory-like profiles and expressed reduced amount of CD39 and TIGIT. AHR knockout enhanced human CAR-T cells' functionality and persistence upon tumor chronic stimulation. Collectively, these results highlight the role of AHR in human CAR-T cells efficiency.

From concept to cure: The evolution of CAR-T cell therapy

Chimeric antigen receptor (CAR)-T cell therapy has revolutionized cancer immunotherapy in the 21st century, providing innovative solutions and life-saving therapies for previously untreatable diseases. This approach has shown remarkable success in treating various hematological malignancies and is now expanding into clinical trials for solid tumors, such as prostate cancer and glioblastoma, as well as infectious and autoimmune diseases. CAR-T cell therapy involves harvesting a patient's T cells, genetically engineering them with viral vectors to express CARs targeting specific antigens and reinfusing the modified cells into the patient. These CAR-T cells function independently of major histocompatibility complex (MHC) antigen presentation, selectively identifying and eliminating target cells. This review highlights the key milestones in CAR-T cell evolution, from its invention to its clinical applications. It outlines the historical timeline leading to the invention of CAR-T cells, discusses the major achievements that have transformed them into a breakthrough therapy, and addresses remaining challenges, including high manufacturing costs, limited accessibility, and toxicity issues such as cytokine release syndrome and immune effector cell-associated neurotoxicity syndrome. Additionally, the review explores future directions and advances in the field, such as developing next-generation CAR-T cells aiming to maximize efficacy, minimize toxicity, and broaden therapeutic applications.

High-dimensional temporal mapping of CAR T cells reveals phenotypic and functional remodeling during manufacturing

Despite the notable success of chimeric antigen receptor (CAR) T cell therapies in hematological malignancies, clinical outcomes remain variable, making it critical to understand how manufacturing influences product composition and function. We developed a 36-marker spectral flow cytometry panel enabling integrated profiling of phenotypic, metabolic, and functional attributes across CAR T cell production. Mid-expansion products (day 5) retained stem-like, metabolically active CD4+ Th1 subsets with high proliferative capacity, whereas prolonged culture (day 10) enriched terminally differentiated CD8+ Tc1 cells and NK-like T cell populations. CAR+ and CAR- T cells showed similar differentiation trajectories, suggesting that culture conditions may have a larger impact on phenotypic remodeling than CAR integration. Upon antigen encounter and restimulation, day 5 and day 10 products showed comparable cytotoxicity, while differing in their activation and checkpoint profiles. Cryopreservation modestly affected stem cell memory, activation, and metabolic markers but preserved overall phenotype and cytotoxic function. These findings establish a high-dimensional framework for mapping CAR T cell dynamics to support manufacturing optimization and next-generation cell therapy design.

MUC18-Directed chimeric antigen receptor T cells for the treatment of mucosal melanoma

PURPOSE

Mucosal melanoma, a highly aggressive form of skin cancer, remains challenging to manage due to the lack of effective therapies. Mucin 18 (MUC18) is overexpressed in both primary and metastatic lesions of melanoma but rarely in normal tissues. The expression profile makes MUC18 a potential target for development of therapeutic antibodies or chimeric antigen receptor-T (CAR-T) cell therapy. This study aims to generate an effective CAR-T targeting MUC18-positive melanoma and evaluate its preclinical antitumor activity.

EXPERIMENTAL DESIGN

A humanized anti-MUC18 single chain antibody fragment (scFv) was used to construct CAR-T with various designs of the hinge, transmembrane, co-stimulatory, and CD3ζ domains. The antitumor efficacy of MUC18 CAR-T cells was assessed in vitro, in MUC18-positive primary and rechallenged xenograft models, as well as in patient-derived xenograft (PDX) models of human mucosal melanoma.

RESULTS

The humanized scFv selectively bound to MUC18 with high affinity. Various MUC18 CAR-T cells specifically killed MUC18-positive melanoma cells and could proliferate as a result of exposure to antigen. Among them, CAR-T cells containing an IgG4-derived hinge domain and a CD28 co-stimulatory domain demonstrated superior antitumor efficiency. Robust tumor regression and CAR-T cell expansion were observed in multiple MUC18-positive xenograft models after treatment with the IgG4 hinge and CD28 empowered CAR-T cells.

CONCLUSIONS

This study demonstrated the development of a novel CAR-T therapy for mucosal melanoma, MUC18 CAR-T, that showed strong potency in tumor eradication and inhibition of tumor relapse. This candidate CAR-T therapy could provide a promising strategy for the treatment of the refractory melanoma.

Modulation of anti-tumour immunity by XPO1 inhibitors

Exportin-1 (XPO1) is a nuclear export protein that, when overexpressed, can facilitate cancer cell proliferation and survival and is frequently overexpressed or mutated in cancer patients. As such, selective inhibitors of XPO1 (XPO1i) function have been developed to inhibit cancer cell proliferation and induce apoptosis. This review outlines the evidence for the immunomodulatory properties of XPO1 inhibition and discusses the potential for combining and sequencing XPO1i with immunotherapy to improve the treatment of patients with cancer. Selinexor is a first-in-class XPO1i that is FDA-approved for the treatment of patients with relapsed and refractory (RR) multiple myeloma and RR diffuse large B cell lymphoma. In addition to the cancer cell intrinsic pro-apoptotic activity, increasing evidence suggests that XPO1 inhibition has immunomodulatory properties. In this review, we describe how XPO1i can lead to a skewing of macrophage polarisation, inhibition of neutrophil extracellular traps, modulation of immune checkpoint expression, blockade of myeloid-derived suppressor cells (MDSCs) and sensitisation of cancer cells to T cell and NK (natural killer) cell immunosurveillance. As such, there is an opportunity for selinexor to enhance immunotherapy efficacy and thus a need for clinical trials assessing selinexor in combination with immunotherapies such as immune checkpoint inhibitors, direct targeting monoclonal antibodies, chimeric antigen receptor (CAR)-T cells and cereblon E3 ligase modulators (CELMoDs).

Machine learning-based prognostic modelling of NK cells in PAAD for immunotherapy guidance

Pancreatic cancer's high incidence and mortality rates are underscored by ineffective treatments, particularly immunotherapy's poor performance. This could stem from an unclear immune microenvironment, where NK cells may play a unique role. Analyzing the NK cell-differentially expressed genes (NKDEGs) from the PAAD_GSE162708 single-cell dataset and utilizing the TCGA-PAAD and ICGC-PACA-AU datasets, we identified 11 NKDEGs linked to pancreatic adenocarcinoma (PAAD) prognosis and developed a prognostic model. This model's risk scores significantly outperformed traditional grading and TNM staging systems, validated through clinical and pathological analyses. Functional enrichment analysis pointed to the Neuroactive ligand-receptor interaction and MAPK signaling pathways, suggesting NK cells' distinctive role in PAAD. High-risk groups showed decreased overall NK cells but increased activated NK cells, which may mediate adverse inflammatory responses. NK cells exhibit synergistic interactions with plasma cells and macrophages and negative regulation by monocytes and naive B cells. Our model accurately predicts immunotherapy responses, indicating potential for targeted drugs to enhance treatment. Additionally, we introduced an NKDEGs-based immunotyping approach for personalized medicine and clinical decision-making in PAAD. This study emphasizes NK cells' potential in PAAD treatment, offering precise patient stratification and therapeutic targets for immunotherapy.

Overcoming extracellular vesicle-mediated fratricide improves CAR T cell treatment against solid tumors

The efficacy of chimeric antigen receptor (CAR) T cells against solid tumors is limited. The molecular mechanisms underlying CAR T cell resistance are yet to be elucidated and new strategies need to be developed to improve treatment outcomes. Here we report that solid tumors respond to CAR T cells by upregulating the secretion of small extracellular vesicles carrying tumor antigens, which are horizontally transferred to CAR T cells, leading to antigen recognition and CAR T cell fratricide. Engineered CAR T cells armored with Serpin B9, a major granzyme B inhibitor, show decreased fratricide and increased vitality, tumor infiltration, and antitumor activity in female mice. Moreover, Serpin B9-armored CAR T cells show higher efficacy than parental CAR T cells in treating solid tumors when combined with the anti-programmed death 1 antibody. Our study demonstrates a mechanism that limits CAR T cell function and suggests an improved strategy in tumor treatment.

Epigenetic landscapes drive CAR-T cell kinetics and fate decisions: Bridging persistence and resistance

Chimeric antigen receptor-T (CAR-T) cell therapy has revolutionized the treatment paradigm for B-cell malignancies and holds promise for solid tumor immunotherapy. However, CAR-T-cell therapy still faces many challenges, especially primary and secondary resistance. Some mechanisms of resistance, including CAR-T-cell dysfunction, an inhibitory tumor microenvironment, and tumor-intrinsic resistance, have been identified in previous studies. As insights into CAR-T-cell biology have increased, the role of epigenetic reprogramming in influencing the clinical effectiveness of CAR-T cells has become increasingly recognized. An increasing number of direct and indirect epigenetic targeting methods are being developed in combination with CAR-T-cell therapy. In this review, we emphasize the broad pharmacological links between epigenetic therapies and CAR-T-cell therapy, not only within CAR-T cells but also involving tumors and the tumor microenvironment. To elucidate the mechanisms through which epigenetic therapies promote CAR-T-cell therapy, we provide a comprehensive overview of the epigenetic basis of CAR-T-cell kinetics and differentiation, tumor-intrinsic factors and the microenvironment. We also describe some epigenetic strategies that have implications for CAR-T-cell therapy in the present and future. Because targeting epigenetics can have pleiotropic effects, developing more selective and less toxic targeting strategies and determining the optimal administration strategy in clinical trials are the focus of the next phase of research. In summary, we highlight the possible mechanisms and clinical potential of epigenetic regulation in CAR-T-cell therapy.

ID3 enhances PD-L1 expression by restructuring MYC to promote colorectal cancer immune evasion

The inhibitor of DNA binding protein ID3 has been associated with the progression of colorectal cancer (CRC). Despite its significance, its specific role in the immune evasion strategies utilized by CRC remains unclear. RNA-seq analysis revealed that ID3 was positively associated with the PD-L1 immune checkpoint. We further demonstrated that tumor cell-expressed ID3 enhanced PD-L1 expression, suppressed the infiltration and activation of CD8+ T cells, and facilitated the immune evasion of CRC cells. Additionally, we found that knockdown of ID3 significantly enhanced the effectiveness of PD-L1 antibody blockade treatment in combating CRC, reduced the upregulation of PD-L1 induced by the antibody, and altered the immune microenvironment within CRC. Mechanistically, ID3 interacted with the transcription factor MYC and reconstructed the four-dimensional structure of MYC, thereby enhancing its binding affinity to the PD-L1 promoter and augmenting PD-L1 transcriptional activity. By integrating analysis of ChIP-seq, RNA-seq, and ImmPort gene sets, we found that ID3's DNA-assisted binding function was widespread and could either enhance or suppress gene transcription, not only affecting tumor immune escape through immune checkpoints but also regulating various cytokines and immune cells involved in tumor immunity. In conclusion, our study uncovers a mechanism by which ID3 promotes immune evasion in CRC and implicates that targeting ID3 may improve the efficacy of anti-PD-1/PD-L1 immunotherapy.

Recurrent Composite Markers of Cell Types and States

Biological function is mediated by the hierarchical organization of cell types and states within tissue ecosystems. Identifying interpretable composite marker sets that both define and distinguish hierarchical cell identities is essential for decoding biological complexity, yet remains a major challenge. Here, we present RECOMBINE, an algorithm that identifies recurrent composite marker sets to define hierarchical cell identities. Validation using both simulated and biological datasets demonstrates that RECOMBINE achieves higher accuracy in identifying discriminative markers compared to existing approaches, including differential gene expression analysis. When applied to single-cell data and validated with spatial transcriptomics data from the mouse visual cortex, RECOMBINE identified key cell type markers and generated a robust gene panel for targeted spatial profiling. It also uncovered markers of CD8+; T cell states, including GZMK+;HAVCR2-; effector memory cells associated with anti-PD-1 therapy response, and revealed a rare intestinal subpopulation with composite markers in mice. Finally, using data from the Tabula Sapiens project, RECOMBINE identified composite marker sets across a broad range of human tissues. Together, these results highlight RECOMBINE as a robust, data-driven framework for optimized marker selection, enabling the discovery and validation of hierarchical cell identities across diverse tissue contexts.

Beyond the blood: expanding CAR T cell therapy to solid tumors

Chimeric antigen receptor (CAR) T cell therapy stands as a transformative advancement in immunotherapy, triumphing against hematological malignancies and, increasingly, autoimmune disorders. After a decade of relatively modest results for solid tumors, recent clinical trials and patient reports have also started to yield promising outcomes in glioblastoma and other challenging solid tumor entities. This Perspective seeks to explore the reasons behind these latest achievements and discusses how they can be sustained and expanded through different strategies involving CAR engineering and synthetic biology. Furthermore, we critically analyze how these breakthroughs can be leveraged to maintain momentum and broaden the therapeutic impact of CAR T cells across a variety of solid tumor landscapes.

Revolutionising Cancer Immunotherapy: Advancements and Prospects in Non-Viral CAR-NK Cell Engineering

The recent advancements in cancer immunotherapy have spotlighted the potential of natural killer (NK) cells, particularly chimeric antigen receptor (CAR)-transduced NK cells. These cells, pivotal in innate immunity, offer a rapid and potent response against cancer cells and pathogens without the need for prior sensitization or recognition of peptide antigens. Although NK cell genetic modification is evolving, the viral transduction method continues to be inefficient and fraught with risks, often resulting in cytotoxic outcomes and the possibility of insertional mutagenesis. Consequently, there has been a surge in the development of non-viral transfection technologies to overcome these challenges in NK cell engineering. Non-viral approaches for CAR-NK cell generation are becoming increasingly essential. Cutting-edge techniques such as trogocytosis, electroporation, lipid nanoparticle (LNP) delivery, clustered regularly interspaced short palindromic repeats-associated protein 9 (CRISPR-Cas9) gene editing and transposons not only enhance the efficiency and safety of CAR-NK cell engineering but also open new avenues for novel therapeutic possibilities. Additionally, the infusion of technologies already successful in CAR T-cell therapy into the CAR-NK paradigm holds immense potential for further advancements. In this review, we present an overview of the potential of NK cells in cancer immunotherapies, as well as non-viral transfection technologies for engineering NK cells.

CAR T cells re-directed by a rationally designed human peptide tag demonstrate efficacy in preclinical models

Currently, only a few chimeric antigen receptor (CAR) T cell therapies have been approved by the Food and Drug Administration and European Medicines Agency for the treatment of B-cell malignancies. To enable broader application of the CAR T cell technology in other indications, improved control and flexible targeting of multiple tumor antigens are required. Here, we developed a novel adapter CAR (AdCAR) T cell platform for flexible targeting of multiple tumor antigens. This platform is based on a short peptide tag derived from an interdomain region of fibroblast growth factor receptor 2 (FGFR2), commonly mutated in cancer. To select AdCARs specific for mutated FGFR2-derived peptide tags, a multistep pooled screening approach in primary T cells was employed, incorporating MACS separation and next-generation sequencing. The resulting AdCAR was highly specific for the FGFR2-derived peptide tag. Using different in vitro and in vivo model systems, the activity of AdCAR T cells was shown to be strictly dependent on the presence of the adapter and corresponding target antigen. Moreover, AdCAR T cells could be redirected to different target antigens by the addition of respective adapter molecules (AM). Finally, in situ expression of functional AM in primary T cells under control of a drug-inducible promoter system was demonstrated, highlighting the potential for controlling the activity of AdCAR T cells by cellular micropharmacies.

Harnessing the potential of gene-editing technology to overcome the current bottlenecks of CAR-T cell therapy in T-cell malignancies

T-cell malignancies (TCMs) include a diverse spectrum of hematologic cancers marked by complex biology and aggressive nature. Treating TCMs remains a critical unmet need in oncology with poor response to standard therapies. Chimeric antigen receptor (CAR)-T cell therapy is one of the most successful types of immunotherapy that has revolutionized cancer treatment, as evidenced by various approved products for CD19 B-cell malignancies and multiple myeloma. Nonetheless, due to some unique hurdles, such as the risk of CAR-T cell fratricide, product contamination with malignant cells, and severe T-cell aplasia, the translation of this treatment approach to TCMs has not been particularly successful. Moreover, irrespective of the type of treated cancer, CAR-T cell therapy can also present some complexities and potential side effects, such as cumbersome and costly manufacturing processes, impaired in vivo function, cytokine release syndrome (CRS), neurotoxicity, and leukemic transformation of CAR-T cells. Recent groundbreaking advances in gene-editing technology and the evolution of precise gene-editing tools such as the CRISPR/Cas9 system and its derivatives have opened a new way to overcoming the mentioned bottlenecks and paving the way for CAR-T cell therapy in TCMs. This review sheds light on how gene editing is being incorporated into CAR-T cell therapy to address current hurdles, enhance therapeutic efficacy, and improve the safety profile of CAR-T cell therapy in TCMs. Ongoing/conducted clinical trials are also discussed to provide a comprehensive view of the evolving landscape of genome-edited CAR-T cell therapy for TCMs.

Immunophenotype of CAR T cells and apheresis products predicts response in CD22 CAR T cell trial for B cell acute lymphoblastic leukemia

Although CAR T cell therapy is increasingly used to treat relapsed B cell acute lymphoblastic leukemia (ALL), 20%-30% of patients do not respond, and few clinical predictors of response have been established, especially in the pediatric population. A deeper analysis of CAR T cell infusion products, along with the apheresis product used as the starting material for CAR T cell manufacturing, provides valuable insights for predicting clinical outcomes. We analyzed infusion products and CD4/8-selected T cell starting materials from pediatric and young adult patients on a single-center study with relapsed/refractory B cell ALL who were undergoing treatment with CD22 CAR T cells and evaluated differences between T cells from responders and non-responders (NCT023215612). We found that CAR T cells from non-responders had a more differentiated T cell phenotype and overexpressed genes associated with cytotoxicity and exhaustion compared with those of responders. Furthermore, we found that these differences could be tracked back to the apheresis materials prior to CAR T cell manufacturing. Using flow cytometry-based immunophenotypic markers, we developed a scoring system that distinguished non-responders based on T cell phenotype at the time of apheresis. These findings can help inform outcomes for patients and providers as well as provide insights into targeted manufacturing changes to optimize CAR T cell efficacy.

Epigenetic enhancement of adoptive T cell immunotherapy

Isshiki et al. and Porazzi et al. report that inhibiting enhancer of zeste homolog 1 (EZH1) and EZH2 enhances chimeric antigen receptor (CAR)/T cell receptor (TCR)-based therapies by reprogramming tumors to be more immunogenic and improving T cell phenotype and demonstrate the efficacy of this combination in preclinical models across hematologic and solid cancers. Clinical trials are ongoing to evaluate its safety and therapeutic potential.

Establishing a GMP-compliant manufacturing process and phase-appropriate analytics for early development of a FiCAR T-cell product with a novel CAR spacer

There is a growing demand for chimeric antigen receptor (CAR) -T cells for clinical trials. Consequently, new centers capable of manufacturing advanced therapy medicinal products (ATMPs) are needed. In this study, we established a good manufacturing practice -compliant manufacturing process and phase-appropriate analytics for a novel autologous CD19-targeted CAR T-cell product, 19-FiCART. We evaluated the stability of fresh, healthy donor-derived leukapheresis products (LPs), produced 19-FiCART using a 12-day semi-automated process with CD4/CD8-positive cell enrichment and lentiviral transduction, and evaluated the in vivo efficacy of 19-FiCART in a xenograft mouse lymphoma model. The optimal hold time and temperature to maintain LP stability were up to 73 h at 2-8 °C. The 19-FiCART manufacturing process consistently yielded more than 2 × 109 highly viable CAR+ T cells, which is considered sufficient for a clinical product. The 19-FiCART products also demonstrated potent anti-tumor activity both in vitro and in vivo. This paper provides a detailed description of the manufacturing process and analytics for 19-FiCART and provides insights into the development of a release strategy for novel CAR T-cell products intended for early clinical studies. Additionally, we present data on LP stability, which has broader implications for the development of various immune cell-based ATMPs.

Current state and perspectives of CAR T cell therapy in central nervous system diseases

B cell-directed CAR T cell therapy has fundamentally changed the treatment of haematological malignancies, and its scope of application is rapidly expanding to include other diseases such as solid tumours or autoimmune disorders. Therapy-refractoriness remains an important challenge in various inflammatory and non-inflammatory disorders of the CNS. The reasons for therapy failure are diverse and include the limited access current therapies have to the CNS, as well as enormous inter- and intra-individual disease heterogeneity. The tissue-penetrating properties of CAR T cells make them a promising option for overcoming this problem and tackling pathologies directly within the CNS. First application of B cell-directed CAR T cells in neuromyelitis optica spectrum disorder and multiple sclerosis patients has recently revealed promising outcomes, expanding the potential of CAR T cell therapy to encompass CNS diseases. Additionally, the optimization of CAR T cells for the therapy of gliomas is a growing field. As a further prospect, preclinical data reveal the potential benefits of CAR T cell therapy in the treatment of primary neurodegenerative diseases such as Alzheimer's disease. Considering the biotechnological optimizations in the field of T cell engineering, such as extension to target different antigens or variation of the modified T cell subtype, new and promising fields of CAR T cell application are rapidly opening up. These innovations offer the potential to address the complex pathophysiological properties of CNS diseases. To use CAR T cell therapy optimally to treat CNS diseases in the future while minimizing therapy risks, further mechanistic research and prospective controlled trials are needed to assess seriously the disease and patient-specific risk-benefit ratio.

Analyze the Diversity and Function of Immune Cells in the Tumor Microenvironment From the Perspective of Single-Cell RNA Sequencing

BACKGROUND

Cancer development is closely associated with complex alterations in the tumor microenvironment (TME). Among these, immune cells within the TME play a huge role in personalized tumor diagnosis and treatment.

OBJECTIVES

This review aims to summarize the diversity of immune cells in the TME, their impact on patient prognosis and treatment response, and the contributions of single-cell RNA sequencing (scRNA-seq) in understanding their functional heterogeneity.

METHODS

We analyzed recent studies utilizing scRNA-seq to investigate immune cell populations in the TME, focusing on their interactions and regulatory mechanisms.

RESULTS

ScRNA-seq reveals the functional heterogeneity of immune cells, enhances our understanding of their role in tumor antibody responses, and facilitates the construction of immune cell interaction networks. These insights provide guidance for the development of cancer immunotherapies and personalized treatment approaches.

CONCLUSION

Applying scRNA-seq to immune cell analysis in the TME offers a novel pathway for personalized cancer treatment. Despite its promise, several challenges remain, highlighting the need for further advancements to fully integrate scRNA-seq into clinical applications.

Generation of allogeneic CAR-NKT cells from hematopoietic stem and progenitor cells using a clinically guided culture method

Cancer immunotherapy with autologous chimeric antigen receptor (CAR) T cells faces challenges in manufacturing and patient selection that could be avoided by using 'off-the-shelf' products, such as allogeneic CAR natural killer T (AlloCAR-NKT) cells. Previously, we reported a system for differentiating human hematopoietic stem and progenitor cells into AlloCAR-NKT cells, but the use of three-dimensional culture and xenogeneic feeders precluded its clinical application. Here we describe a clinically guided method to differentiate and expand IL-15-enhanced AlloCAR-NKT cells with high yield and purity. We generated AlloCAR-NKT cells targeting seven cancers and, in a multiple myeloma model, demonstrated their antitumor efficacy, expansion and persistence. The cells also selectively depleted immunosuppressive cells in the tumor microenviroment and antagonized tumor immune evasion via triple targeting of CAR, TCR and NK receptors. They exhibited a stable hypoimmunogenic phenotype associated with epigenetic and signaling regulation and did not induce detectable graft versus host disease or cytokine release syndrome. These properties of AlloCAR-NKT cells support their potential for clinical translation.

Personalized, autologous neoantigen-specific T cell therapy in metastatic melanoma: a phase 1 trial

New treatment approaches are warranted for patients with advanced melanoma refractory to immune checkpoint blockade (ICB) or BRAF-targeted therapy. We designed BNT221, a personalized, neoantigen-specific autologous T cell product derived from peripheral blood, and tested this in a 3 + 3 dose-finding study with two dose levels (DLs) in patients with locally advanced or metastatic melanoma, disease progression after ICB, measurable disease (Response Evaluation Criteria in Solid Tumors version 1.1) and, where appropriate, BRAF-targeted therapy. Primary and secondary objectives were evaluation of safety, highest tolerated dose and anti-tumor activity. We report here the non-pre-specified, final results of the completed monotherapy arm consisting of nine patients: three at DL1 (1 × 108-1 × 109 cells) and six at DL2 (2 × 109-1 × 1010 cells). Drug products (DPs) were generated for all enrolled patients. BNT221 was well tolerated across both DLs, with no dose-limiting toxicities of grade 3 or higher attributed to the T cell product observed. Specifically, no cytokine release, immune effector cell-associated neurotoxicity or macrophage activation syndromes were reported. A dose of 5.0 × 108-1.0 × 1010 cells was identified for further study conduct. Six patients showed stable disease as best overall response, and tumor reductions (≤20%) were reported for four of these patients. In exploratory analyses, multiple mutant-specific CD4+ and CD8+ T cell responses were generated in each DP. These were cytotoxic, polyfunctional and expressed T cell receptors with broad functional avidities. Neoantigen-specific clonotypes were detected after treatment in blood and tumor. Our results provide key insights into this neoantigen-specific adoptive T cell therapy and demonstrate proof of concept for this new therapeutic approach. ClinicalTrials.gov registration: NCT04625205 .

T cells in the microenvironment of solid pediatric tumors: the case of neuroblastoma

Neuroblastoma (NB) is an immunologically "cold" tumor with poor or no inflamed substrates as most of solid pediatric tumors (SPT). Consistent data indicate that NB tumor microenvironment (TME) is dominated by myeloid cells, with little (but variable) T cell infiltration. The obstacles to lymphocyte infiltration and to their anti-tumor activity are due to different tumor immune evasion strategies, including loss of HLA Class I molecules, high expression of immune checkpoint molecular ligands leading to exhaustion of T effector (and NK) cells, induction of T regulatory, myeloid and stromal cells and secretion of immunosuppressive mediators. In odds with adult solid tumors, NB displays weak immunogenicity caused by intrinsic low mutational burden and scant expression of neoepitopes in the context of MHC-class I antigens which, in turn, are particularly poorly expressed on NB cells, thus inducing low anti-tumor T cell responses. In addition, NB is generated from embryonal cells and is the result of transcriptional abnormalities and not of the accumulation of genetic mutations over time, thus further explaining the low immunogenicity. The poor expression of immunogenic molecules on tumor cells is associated with the high production of immunosuppressive factors which further downregulate lymphocyte infiltration and activity, thus explaining the limited efficacy of new drugs in NB, as immune checkpoint inhibitors. This review is focused on examining the role of T effector and regulatory cells infiltrating TME of NB, taking into account their repertoire, phenotype, function, plasticity and, importantly, predictive value for defining novel targets for therapy.

Single-cell analysis of aplastic anemia reveals a convergence of NK and NK-like CD8+ T cells with a disease-associated TCR signature

Immune aplastic anemia (AA) is a life-threatening bone marrow failure disorder driven by an autoimmune T cell attack against hematopoietic stem and progenitor cells (HSPCs). However, the exact autoantigen targets and role of other immune cells in the pathogenesis of AA are unknown. Here, we analyzed a cohort of 218 patients with AA using single-cell RNA and T cell receptor (TCR) αβ sequencing, TCRβ sequencing, flow cytometry, and plasma cytokine profiling. We identified natural killer (NK) cells and CD8+ terminally differentiated effector T (TEMRA) cells expressing NK receptors with AA-associated TCRβ motifs as the most dysregulated immune cell populations in AA bone marrow. Functional coculture experiments using primary HSPCs and immune cells showed that NK cells cannot kill HSPCs alone but may sensitize HSPCs to CD8+ T cell-mediated killing through production of interferons. Furthermore, HSPCs induced activation of T cell clones with CD8+ TEMRA NK-like phenotype in coculture. Our results reveal a convergent phenotype of innate and adaptive immune cells that may drive AA.

Novel role of the SOX4/CSNK2A1 axis in regulating TOP2A phosphorylation in breast cancer progression

This study examines the critical role of DNA topoisomerase II alpha (TOP2A) phosphorylation in breast cancer progression, regulated by the SRY-box transcription factor 4 (SOX4)/Casein kinase II subunit alpha 1 (CSNK2A1) axis. Using integrated transcriptomic and proteomic analyses, data were sourced from the Clinical Proteomic Tumor Analysis Consortium (CPTAC) and The Cancer Genome Atlas (TCGA) databases. To explore the dataset, differential analysis, kinase-substrate enrichment analysis (KSEA), and weighted gene co-expression network analysis (WGCNA) were performed. Immune profiling, combined with survival analysis, revealed the prognosis linked to different immune profiles in breast cancer patients. In vitro experiments assessed the effect of SOX4 on CSNK2A1 promoter activity through real-time quantitative polymerase chain reaction (RT-qPCR), Western blot, dual-luciferase reporter assays, and chromatin immunoprecipitation (ChIP). The phosphorylation level of TOP2A was also measured. Cell proliferation, migration, and invasion were evaluated using cell counting kit-8 (CCK-8), colony formation, and Transwell assays. In vivo studies extended to mouse models, where the effect of SOX4 on CSNK2A1-TOP2A phosphorylation was analyzed about tumor growth and metastasis. The results showed that upregulation of SOX4 increases CSNK2A1 transcription, which in turn promotes TOP2A phosphorylation and accelerates breast cancer progression. The clinical analysis identified three immune profiles, with the intermediate profile associated with a poorer prognosis, possibly due to enhanced TOP2A phosphorylation mediated by SOX4/CSNK2A1. Silencing SOX4 significantly reduced cell proliferation, migration, invasion, and tumor growth in vivo by lowering CSNK2A1-TOP2A phosphorylation. These findings highlight the therapeutic potential of targeting the SOX4/CSNK2A1 axis in breast cancer and provide insight into its mechanism through TOP2A phosphorylation.

Dissecting the role of CAR signaling architectures on T cell activation and persistence using pooled screens and single-cell sequencing

Chimeric antigen receptor (CAR) T cells offer a promising cancer treatment, yet challenges such as limited T cell persistence hinder efficacy. Given its critical role in modulating T cell responses, it is crucial to understand how the CAR signaling architecture influences T cell function. Here, we designed a combinatorial CAR signaling domain library and performed repeated antigen stimulation assays, pooled screens, and single-cell sequencing to systematically investigate the impact of modifying CAR signaling domains on T cell activation and persistence. Our data reveal the predominant influence of membrane-proximal domains in driving T cell phenotype. Notably, CD40 costimulation was crucial for fostering robust and lasting T cell responses. Furthermore, we correlated in vitro generated CAR T cell phenotypes with clinical outcomes in patients treated with CAR T therapy, establishing the foundation for a clinically informed screening approach. This work deepens our understanding of CAR T cell biology and may guide future CAR engineering efforts.

Microfluidic technologies for enhancing the potency, predictability and affordability of adoptive cell therapies

The development and wider adoption of adoptive cell therapies is constrained by complex and costly manufacturing processes and by inconsistent efficacy across patients. Here we discuss how microfluidic and other fluidic devices can be implemented at each stage of cell manufacturing for adoptive cell therapies, from the harvesting and isolation of the cells to their editing, culturing and functional selection. We suggest that precise and controllable microfluidic systems can streamline the development of these therapies by offering scalability in cell production, bolstering the efficacy and predictability of the therapies and improving their cost-effectiveness and accessibility for broader populations of patients with cancer.

CD70 CAR T cells secreting an anti-CD33/anti-CD3 dual-targeting antibody overcome antigen heterogeneity in AML

ABSTRACT

CD70 has emerged as a promising target in acute myeloid leukemia (AML), and we have previously demonstrated the potency of an optimized CD70-targeted ligand-based chimeric antigen receptor (CAR). However, here, we identify in vivo CD70 antigen escape as a limitation of single-antigen targeting. Combination targeting of CD70 and CD33 may overcome AML antigen heterogeneity. We hypothesized that modifying our CD70 CAR platform to secrete a bispecific T-cell engaging antibody molecule (TEAM) targeting CD33 (7033) would create a therapeutic window whereby AML heterogeneity could be addressed without increasing tissue toxicity. We found that CD33 TEAMs mediated specific cytotoxicity across AML cell lines, including CD33 or CD70 single-antigen knockout tumors. 7033 CAR T cells eradicated tumor in an in vivo mixed tumor model of CD70 antigen escape and outperformed the previously optimized CD70 CAR in a patient-derived xenograft. In vivo gene expression profiling of CAR T cells revealed enhanced 7033 CAR T-cell pathway scoring for persistence, activation, and T-cell receptor signaling. Additionally, CD33 TEAMs successfully redirected T cells isolated from patients with AML to activate, secrete cytokines, and kill tumor targets despite exposure to substantial prior cytotoxic therapies. In summary, our findings demonstrate the feasibility of our 7033 CAR to overcome AML heterogeneity and leverage the bystander T cells of patients; this approach warrants further study in patients with this dire clinical need.

Genetic disruption of Blimp-1 drastically augments the antitumor efficacy of BCMA-targeting CAR T cells

ABSTRACT

Chimeric antigen receptor (CAR) T cells directed against B-cell maturation antigen (BCMA) are an effective treatment for multiple myeloma (MM), but short persistence and frequent relapses are challenges for this immunotherapy. This lack of durability has been attributed to the premature terminal differentiation of CAR T cells, which prevents the formation of long-lived memory cells that maintain antitumor responses. To improve long-term efficacy, we used CRISPR/CRISPR-associated protein 9-mediated gene editing to ablate the expression of the transcription factor Blimp-1. Blimp-1 knockout (KO) CAR T cells displayed a memory-like phenotype compared with control (Mock) CAR T cells, but had reduced effector function, with a striking loss of granzyme B. However, in a murine model of advanced MM, Blimp-1 KO CAR T cells effectively slowed or even prevented disease progression, significantly outperforming Mock CAR T cells in improving survival (P = .006). To understand this enhanced in vivo effectiveness, Blimp-1 KO CAR T cells were characterized after being repeatedly challenged with tumor cells in vitro. In this setting, Blimp-1 KO CAR T cells maintained a highly active state with high expression of memory markers, but, crucially, demonstrated enhanced effector function and increased energetic capacity. RNA-sequencing analysis of tumor-exposed Blimp-1 KO CAR T cells confirmed the presence of a memory-like transcriptomic signature and, additionally, revealed enhanced ribosome biogenesis and repressed CAR T-cell dysfunction as mechanisms that could contribute to improved antitumor activity. Put together, our findings show that dampening Blimp-1 expression altered the phenotype and function of anti-BCMA CAR T cells, leading to augmented therapeutic efficacy in MM.

Trogocytosis-mediated immune evasion in the tumor microenvironment

Trogocytosis is a dynamic cellular process characterized by the exchange of the plasma membrane and associated cytosol during cell-to-cell interactions. Unlike phagocytosis, this transfer maintains the surface localization of transferred membrane molecules. For example, CD4 T cells engaging with antigen-presenting cells undergo trogocytosis, which facilitates the transfer of antigen-loaded major histocompatibility complex (MHC) class II molecules from antigen-presenting cells to CD4 T cells. This transfer results in the formation of antigen-loaded MHC class II molecule-dressed CD4 T cells. These "dressed" CD4 T cells subsequently participate in antigen presentation to other CD4 T cells. Additionally, trogocytosis enables the acquisition of immune-regulatory molecules, such as CTLA-4 and Tim3, in recipient cells, thereby modulating their anti-tumor immunity. Concurrently, donor cells undergo plasma membrane loss, and substantial loss can trigger trogocytosis-mediated cell death, termed trogoptosis. This review aims to explore the trogocytosis-mediated transfer of immune regulatory molecules and their implications within the tumor microenvironment to elucidate the underlying mechanisms of immune evasion in cancers.

Improving molecular subtypes and prognosis of pancreatic cancer through multi group analysis and machine learning

BACKGROUND

Pancreatic cancer (PAC) has a complex tumor immune microenvironment, and currently, there is a lack of accurate personalized treatment. Establishing a novel consensus machine learning driven signature (CMLS) that offers a unique predictive model and possible treatment targets for this condition was the goal of this study.

METHODS

This study integrated multiple omics data of PAC patients, applied ten clustering techniques and ten machine learning approaches to construct molecular subtypes for PAC, and created a new CMLS.

RESULTS

Using multi-omics clustering, we discovered two cancer subtypes (CSs) associated with prognosis, among which CS1 exhibited poor prognostic outcomes. Subsequently, 13 central genes were identified through screening, constituting CMLS with a significant prognostic ability. The low CMLS group had a better prognosis and was more likely to possess a "hot" tumor phenotype. The prognosis for the high CMLS group was dismal. Still, the tumor mutation burden (TMB) and tumor neoantigen burden (TNB) levels in this group of patients were higher than in the low CMLS group, which were more favorable for immune therapy response.

CONCLUSION

This study emphasizes that CMLS provides a beneficial instrument for early prediction of patient prognosis and screening of probable patients appropriate for immunotherapy and has broad implications for clinical practice.

Defining an NK Cell-enriched Rejection-like Phenotype in Liver Transplant Biopsies From the INTERLIVER Study

BACKGROUND

Initial analysis of liver transplant biopsies in the INTERLIVER study (ClinicalTrials.gov; unique identifier NCT03193151) using rejection-associated transcripts failed to find an antibody-mediated rejection state (ie, rich in natural killer [NK] cells and with interferon-gamma effects). We recently developed an optimization strategy in lung transplants that isolated an NK cell-enriched rejection-like (NKRL) state that was molecularly distinct from T cell-mediated rejection (TCMR). Here we apply the same strategy to a liver transplant biopsy population.

METHODS

We used this strategy to search for a molecular NKRL state in 765 consented liver transplant biopsies collected at participating international centers for gold-standard histology and molecular assessment by genome-wide microarrays. Validation through a training set-test set approach of an optimized selection of variables as inputs into unsupervised rejection classification identified an NKRL state in livers.

RESULTS

The full model classified 765 biopsies into the following molecular phenotypes, characterized by their gene expression: no-rejection 54%, TCMR 16%, NKRL 13%, and injury 16%. Top TCMR transcripts were expressed in effector T cells; top NKRL transcripts were almost exclusively expressed in NK cells; and both had increased interferon-γ-inducible transcripts, which were more pronounced in TCMR. Most TCMR biopsies had significant parenchymal injury, molecular fibrosis, and abnormal biochemistry. NKRL biopsies had no excess of injury, fibrosis, or biochemistry abnormalities.

CONCLUSIONS

Optimized rejection algorithms indicate that some liver transplants manifest an NKRL state that is well tolerated in the short term postbiopsy and with minimal injury and relatively normal biochemistry, while also underscoring the potential of TCMR to produce extensive parenchymal injury.

Interleukin-15-armoured GPC3 CAR T cells for patients with solid cancers

Interleukin-15 (IL-15) promotes the survival of T lymphocytes and enhances the antitumour properties of chimeric antigen receptor (CAR) T cells in preclinical models of solid neoplasms in which CAR T cells have limited efficacy1-4. Glypican-3 (GPC3) is expressed in a group of solid cancers5-10, and here we report the evaluation in humans of the effects of IL-15 co-expression on GPC3-expressing CAR T cells (hereafter GPC3 CAR T cells). Cohort 1 patients ( NCT02905188 and NCT02932956 ) received GPC3 CAR T cells, which were safe but produced no objective antitumour responses and reached peak expansion at 2 weeks. Cohort 2 patients ( NCT05103631 and NCT04377932 ) received GPC3 CAR T cells that co-expressed IL-15 (15.CAR), which mediated significantly increased cell expansion and induced a disease control rate of 66% and antitumour response rate of 33%. Infusion of 15.CAR T cells was associated with increased incidence of cytokine release syndrome, which was controlled with IL-1/IL-6 blockade or rapidly ameliorated by activation of the inducible caspase 9 safety switch. Compared with non-responders, tumour-infiltrating 15.CAR T cells from responders showed repression of SWI/SNF epigenetic regulators and upregulation of FOS and JUN family members, as well as of genes related to type I interferon signalling. Collectively, these results demonstrate that IL-15 increases the expansion, intratumoural survival and antitumour activity of GPC3 CAR T cells in patients.

Interleukin 15-Presenting Nanovesicles with Doxorubicin-Loaded Ferritin Cores for Cancer Immunochemotherapy

Interleukin 15 (IL15) is crucial for fostering the survival and proliferation of nature killer (NK) cells and cytotoxic T lymphocytes (CTLs), playing a pivotal role in tumor control. However, IL15 supplementary therapy encounters challenges such as systemic inflammation and non-specific stimulation of cancer cells. Herein, a nanovesicle termed DoxFILN, comprising a membrane presenting IL15/IL15 receptor α complexes (IL15c) and a core of doxorubicin-loaded ferritin (Dox-Fn) are reported. The DoxFILN significantly enhances the densities and activities of intratumoral CTLs and NK cells. Mechanistically, DoxFILN undergoes deshelling in the acidic tumor microenvironment, releasing Dox-Fn and membrane-bound IL15c. Dox-Fn selectively target transferrin receptors on cancerous cells, facilitating intracellular Dox release and inducing immunogenic cell death. Concurrently, membrane-bound IL15c recognizes and activates IL15 receptor β/γc heterodimers, leading to a remarkable increase in the proliferation and activation of CTLs (16-fold and 28-fold) and NK cells (37-fold and 50-fold). The IL15-displaying nanovesicle introduced here holds promise as a potential platform for immunochemotherapy in the treatment of cancer.

Optimising CAR T therapy for the treatment of solid tumors

INTRODUCTION

Adoptive immunotherapy using chimeric antigen receptor (CAR)-engineered T cells has proven transformative in the management of B cell and plasma cel derived malignancies. However, solid tumors have largely proven to be resistant to this therapeutic modality. Challenges include the paucity of safe target antigens, heterogeneity of target expression within the tumor, difficulty in delivery of CAR T cells to the site of disease, poor penetration within solid tumor deposits and inability to circumvent the array of immunosuppressive and biophysical barriers imposed by the solid tumor microenvironment.

AREAS COVERED

Literature was reviewed on the PubMed database, excluding occasional papers which were not available as open access publications or through other means.

EXPERT OPINION

Here, we have surveyed the large body of technological advances that have been made in the quest to bridge the gap toward successful deployment of CAR T cells for the treatment of solid tumors. These encompass the development of more sophisticated targeting strategies to engage solid tumor cells safely and comprehensively, improved drug delivery solutions, design of novel CAR architectures that achieve improved functional persistence and which resist physical, chemical and biological hurdles present in tumor deposits. Prospects for combination therapies that incorporate CAR T cells are also considered.

The power and the promise of CAR-mediated cell immunotherapy for clinical application in pancreatic cancer

BACKGROUND

Pancreatic cancer, referred to as the "monarch of malignancies," is a neoplastic growth mostly arising from the epithelial cells of the pancreatic duct and acinar cells. This particular neoplasm has a highly unfavorable prognosis due to its marked malignancy, inconspicuous initial manifestation, challenging early detection, rapid advancement, and limited survival duration. Cellular immunotherapy is the ex vivo culture and expansion of immune effector cells, granting them the capacity to selectively target malignant cells using specialized techniques. Subsequently, these modified cells are reintroduced into the patient's organism with the purpose of eradicating tumor cells and providing therapeutic intervention for cancer.

PRESENT SITUATION

Presently, the primary cellular therapeutic modalities employed in the treatment of pancreatic cancer encompass CAR T-cell therapy, TCR T-cell therapy, NK-cell therapy, and CAR NK-cell therapy.

AIM OF REVIEW

This review provides a concise overview of the mechanisms and primary targets associated with various cell therapies. Additionally, we will explore the prospective outlook of cell therapy in the context of treating pancreatic cancer.

A bibliometric and knowledge-map study on the treatment of hematological malignancies with CAR-T cells from 2012 to 2023

Recently, CAR-T cell therapy in hematological malignancies has received extensive attention. The objective of this study is to gain a comprehensive understanding of the current research status, development trends, research hotspots, and emerging topics pertaining to CAR-T cells in the treatment of hematological malignancies. Articles pertaining to CAR-T cell therapy for hematological malignancies from the years 2012 to 2023 were obtained and assessed from the Web of Science Core Collection (WoSCC). A bibliometric approach was employed to conduct a scientific, comprehensive, and objective quantitative analysis, as well as a visual analysis, of this particular research domain. A comprehensive analysis was conducted on a corpus of 3643 articles, which were collaboratively authored by 72 countries and various research institutions. CAR-T cell research in treating hematological malignancies shows an increasing trend each year. Notably, the study identified the countries and institutions displaying the highest level of activity, the journals with the most citations and output, as well as the authors who garnered the highest frequency of citations and co-citations. Furthermore, the analysis successfully identified the research hotspots and highlighted six emerging topics within this domain. This study conducted a comprehensive exploration and analysis of the research status, development trends, research hotspots, and emerging topics about CAR-T cells in the treatment of hematological malignancies from 2012 to 2023. The findings of this study will serve as a valuable reference and guide for researchers seeking to delve deeper into this field and determine the future direction of their research.

Miltefosine reinvigorates exhausted T cells by targeting their bioenergetic state

T cell exhaustion presents a major challenge for the efficacy of both immune checkpoint inhibitors (ICBs) and chimeric antigen receptor T (CAR-T) cell immunotherapies. To address this issue, we generate hypofunctional CAR-T cells that imitate the exhaustion state. By screening a Food and Drug Administration (FDA)-approved small molecule library using this model, we identify miltefosine as a potent molecule that restores the impaired function of CAR-T cells in a PD-1/PD-L1-independent manner. Impressively, in the terminally exhausted state where PD-1 antibody treatment is ineffective, miltefosine still enhances CAR-T cell activity. Single-cell sequencing analysis reveals that miltefosine treatment significantly increases the population of effector cells. Mechanistically, miltefosine improves impaired glycolysis and oxidative phosphorylation in hypofunctional CAR-T cells. In both allogeneic and syngeneic tumor models, miltefosine effectively enhances the solid tumor clearance ability of CAR-T cells and T cells, demonstrating its potential as an effective immunotherapeutic drug.

Acute Myeloid Leukemia Skews Therapeutic WT1-specific CD8 TCR-T Cells Towards an NK-like Phenotype that Compromises Function and Persistence

Acute myeloid leukemia (AML) that is relapsed and/or refractory post-allogeneic hematopoietic cell transplantation (HCT) is usually fatal. In a prior study, we demonstrated that AML relapse in high-risk patients was prevented by post-HCT immunotherapy with Epstein-Barr virus (EBV)-specific donor CD8+ T cells engineered to express a high-affinity Wilms Tumor Antigen 1 (WT1)-specific T-cell receptor (TTCR-C4). However, in the present study, infusion of EBV- or Cytomegalovirus (CMV)-specific TTCR-C4 did not clearly improve outcomes in fifteen patients with active disease post-HCT. TCRC4-transduced EBV-specific T cells persisted longer post-transfer than CMV-specific T cells. Persisting TTCR-C4 skewed towards dysfunctional natural killer-like terminal differentiation, distinct from the dominant exhaustion programs reported for T-cell therapies targeting solid tumors. In one patient with active AML post-HCT, a sustained TTCR-C4 effector-memory profile correlated with long-term TTCR-C4 persistence and disease control. These findings reveal complex mechanisms underlying AML-induced T-cell dysfunction, informing future therapeutic strategies for addressing post-HCT relapse.

Baseline immune state and T-cell clonal kinetics are associated with durable response to CAR-T therapy in large B-cell lymphoma

ABSTRACT

Engineered cellular therapy with CD19-targeting chimeric antigen receptor T cells (CAR-Ts) has revolutionized outcomes for patients with relapsed/refractory large B-cell lymphoma (LBCL), but the cellular and molecular features associated with response remain largely unresolved. We analyzed serial peripheral blood samples ranging from the day of apheresis (day -28/baseline) to 28 days after CAR-T infusion from 50 patients with LBCL treated with axicabtagene ciloleucel by integrating single-cell RNA and T-cell receptor sequencing, flow cytometry, and mass cytometry to characterize features associated with response to CAR-T. Pretreatment patient characteristics associated with response included the presence of B cells and increased absolute lymphocyte count to absolute monocyte count ratio (ALC/AMC). Infusion products from responders were enriched for clonally expanded, highly activated CD8+ T cells. We expanded these observations to 99 patients from the ZUMA-1 cohort and identified a subset of patients with elevated baseline B cells, 80% of whom were complete responders. We integrated B-cell proportion ≥0.5% and ALC/AMC ≥1.2 into a 2-factor predictive model and applied this model to the ZUMA-1 cohort. Estimated progression-free survival at 1 year in patients meeting 1 or both criteria was 65% vs 31% for patients meeting neither criterion. Our results suggest that patients' immunologic state at baseline affects the likelihood of response to CAR-T through both modulation of the T-cell apheresis product composition and promoting a more favorable circulating immune compartment before therapy. These baseline immunologic features, measured readily in the clinical setting before CAR-T, can be applied to predict response to therapy.

Phase separation of chimeric antigen receptor promotes immunological synapse maturation and persistent cytotoxicity

Major challenges of chimeric antigen receptor (CAR)-T cell therapy include poor antigen sensitivity and cell persistence. Here, we report a solution to these issues by exploiting CAR phase separation. We found that incorporation of an engineered T cell receptor CD3ε motif, EB6I, into the conventional 28Z or BBZ CAR induced self-phase separation through cation-π interactions. EB6I CAR formed a mature immunological synapse with the CD2 corolla to transduce efficient antigen and costimulatory signaling, although its tonic signaling remained low. Functionally, EB6I CAR-T cells exhibited improved signaling and cytotoxicity against low-antigen tumor cells and persistent tumor-killing function. In multiple primary and relapsed murine tumor models, EB6I CAR-T cells exerted better antitumor functions than conventional CAR-T cells against blood and solid cancers. This study thus unveils a CAR engineering strategy to improve CAR-T cell immunity by leveraging molecular condensation and signaling integration.

Integrating binding affinity and tonic signaling enables a rational CAR design for augmented T cell function

BACKGROUND

The success of chimeric antigen receptor (CAR) T cell therapy for hematological malignancies has not yet translated into long-term elimination of solid tumors indicating the need for adequately tuning CAR T cell functionality.

METHODS

We leveraged a translational pipeline including biophysical characterization and structural prediction of the CAR binding moiety, evaluation of cellular avidity, synapse formation, T cell motility, and functional capacities under repetitive target challenge and in sustained tumor control.

RESULTS

As an example of clinical relevance, we derived a panel of anti-Her2 CARs covering a 4-log affinity range, all expected to target the same Her2 epitope. The same scFv mutations increased both antigen-specific affinity, cellular avidity, and antigen-independent "tonic" signaling; above a minimum threshold, raise in affinity translated into functional avidity in a non-linear fashion. In this case, replacement by amino acids of higher hydrophobicity within the scFv coincidentally augmented affinity, non-specific binding, spontaneous CAR clustering, and tonic signaling, all together relating to T cell functionality in an integrated fashion.

CONCLUSIONS

Data emphasize that tonic signaling is not always due to the positive charge but can be driven by hydrophobic interactions of the scFv. CAR binding affinity above the threshold and tonic signaling are required for sustained T cell functionality in antigen rechallenge and long-term tumor control.

A convenient viral transduction based method for advanced multi-engineering of primary human (CAR) T-cells

The past decades have illustrated the power of T-cell engineering in the development of new and successful cell therapies, such as chimeric antigen receptor (CAR) T-cells. Despite clinical success in hematological malignancies, it also becomes increasingly clear that additional T-cell engineering will be required to improve efficacy and safety and expand the application to solid tumors. Engineering is most often achieved by viral delivery of transgenes, however, viral vector capacity limitations make efficient and reproducible generation of multi transgene expressing T-cell therapeutics technically challenging. We here describe a convenient and efficient method for the delivery of up to three γ-retroviral CAR vectors in T-cells. We achieved this using virus vector mixtures that are simultaneously produced at high titers by double- or triple- transduced stable virus producer cells. We show that this method is superior in overall efficiency and reproducibility to conventional double or triple CAR transductions, in which separate viral batches are used. Due to its robustness, this method can facilitate the research and the development for advanced T-cell engineering towards more effective and safe therapies.

Leucine zipper-based immunomagnetic purification of CAR T cells displaying multiple receptors

Resistance to chimaeric antigen receptor (CAR) T cell therapy develops through multiple mechanisms, most notably antigen loss and tumour-induced immune suppression. It has been suggested that T cells expressing multiple CARs may overcome the resistance of tumours and that T cells expressing receptors that switch inhibitory immune-checkpoint signals into costimulatory signals may enhance the activity of the T cells in the tumour microenvironment. However, engineering multiple features into a single T cell product is difficult because of the transgene-packaging constraints of current gene-delivery vectors. Here we describe a cell-sorting method that leverages leucine zippers for the selective single-step immunomagnetic purification of cells co-transduced with two vectors. Such 'Zip sorting' facilitated the generation of T cells simultaneously expressing up to four CARs and coexpressing up to three 'switch' receptors. In syngeneic mouse models, T cells with multiple CARs and multiple switch receptors eliminated antigenically heterogeneous populations of leukaemia cells coexpressing multiple inhibitory ligands. By combining diverse therapeutic strategies, Zip-sorted multi-CAR multi-switch-receptor T cells can overcome multiple mechanisms of CAR T cell resistance.

T cell landscape in the microenvironment of human solid tumors

T cells are the main effectors involved in anti-tumor immunity, mediating most of the adaptive response towards cancer. After priming in lymph nodes, tumor antigens-specific naïve T lymphocytes proliferate and differentiate into effector CD4+ and CD8+ T cells that migrate from periphery into tumor sites aiming to eliminate cancer cells. Then while most effector T cells die, a small fraction persists and recirculates as long-lived memory T cells which generate enhanced immune responses when re-encountering the same antigen. A number of T (and non-T) cell subsets, stably resides in non-lymphoid peripheral tissues and may provide rapid immune response independently of T cells recruited from blood, against the reemergence of cancer cells. When tumor grows, however, tumor cells have evaded immune surveillance of effector cells (NK and CTL cells) which are exhausted, thus favoring the local expansion of T (and non-T) regulatory cells. In this review, the current knowledge of features of T cells present in the tumor microenvironment (TME) of solid adult and pediatric tumors, the mechanisms upregulating immune-checkpoint molecules and transcriptional and epigenetic landscapes leading to dysfunction and exhaustion of T effector cells are reviewed. The interaction of T cells with cancer- or TME non-neoplastic cells and their secreted molecules shape the T cell profile compromising the intrinsic plasticity of T cells and, therefore, favoring immune evasion. In this phase regulatory T cells contribute to maintain a high immunosuppressive TME thus facilitating tumor cell proliferation and metastatic spread. Despite the advancements of cancer immunotherapy, many tumors are unresponsive to immune checkpoint inhibitors, or therapeutical vaccines or CAR T cell-based adoptive therapy: some novel strategies to improve these T cell-based treatments are lastly proposed.

T cell receptor-centric perspective to multimodal single-cell data analysis

The T cell receptor (TCR), despite its importance, is underutilized in single-cell analysis, with gene expression features solely driving current strategies. Here, we argue for a TCR-first approach, more suited toward T cell repertoires. To this end, we curated a large T cell atlas from 12 prominent human studies, containing in total 500,000 T cells spanning multiple diseases, including melanoma, head and neck cancer, blood cancer, and lung transplantation. Here, we identified severe limitations in cell-type annotation using unsupervised approaches and propose a more robust standard using a semi-supervised method or the TCR arrangement. We showcase the utility of a TCR-first approach through application of the STEGO.R tool for the identification of treatment-related dynamics and previously unknown public T cell clusters with potential antigen-specific properties. Thus, the paradigm shift to a TCR-first can highlight overlooked key T cell features that have the potential for improvements in immunotherapy and diagnostics.