Targeting a CAR to the TRAC locus with CRISPR/Cas9 enhances tumour rejection

Cost-effective strategies for CAR-T cell therapy manufacturing

CAR-T cell therapy has revolutionized cancer treatment, with approvals for conditions like acute B-leukemia, large B cell lymphoma (LBCL), follicular lymphoma (FL), mantle cell lymphoma (MCL), and multiple myeloma. However, its high costs limit accessibility. Key factors driving these costs include the need for personalized, autologous treatments, transportation to specialized facilities, reliance on viral vectors requiring advanced laboratories, and lengthy cell expansion processes. To address these challenges, alternative strategies aim to simplify and reduce production complexity. Non-viral vectors, such as Sleeping Beauty, piggyBac, and CRISPR, delivered via nanoparticles or electroporation, present promising solutions. These methods could streamline manufacturing, eliminate the need for viral vectors, and reduce associated costs. Furthermore, shortening cell expansion periods and optimizing protocols could significantly accelerate production. An emerging approach involves using genetically edited T cells from healthy donors to create universal CAR-T products capable of treating multiple patients. Finally, decentralized point-of-care (POC) manufacturing of CAR-T cells minimize logistical expenses, eliminating the need for complex infrastructure, and enabling localized production closer to patients. This innovative strategy holds potential for broadening access and reducing costs, representing a step toward democratizing CAR-T therapy. Combined, these advances could make this groundbreaking treatment more feasible for healthcare systems worldwide.

Gentle and efficient engineering of primary human NK cells by photoporation with polydopamine nanosensitizers

Over the past several years, adoptive T cell therapies have accounted for great success in treating diverse malignancies. More recently, however, NK cells are being investigated as a promising alternative. Due to the innate antiviral properties of NK cells, viral engineering has proven to be challenging, prompting the development of non-viral transfection technologies. In this work, we evaluated photoporation with polydopamine nanosensitizers as a notable upcoming transfection technology for the engineering of NK cells and compared its performance to Nucleofection. Our results demonstrated the successful transfection of NK cells with eGFP mRNA and gene editing with Cas9 ribonucleoproteins (RNPs) for knock-out of the KLRC1 gene, encoding for the inhibitory NK cell receptor NKG2A. Importantly, no alterations to the phenotype of the cells (e.g. expression of surface markers and release of cytokines) could be detected, nor was the proliferation or cytolytic capacity of the cells influenced by either of the treatments. Overall, our findings highlight the potential of polydopamine-sensitized photoporation as a gentle and efficient transfection technology for NK cell engineering.

Non-viral, high throughput genetic engineering of primary immune cells using nanostraw-mediated transfection

Transfection of proteins, mRNA, and chimeric antigen receptor (CAR) transgenes into immune cells remains a critical bottleneck in cell manufacturing. Current methods, such as viruses and bulk electroporation, are hampered by low transfection efficiency, unintended transgene integration, and significant cell perturbation. The Nanostraw Electro-actuated Transfection (NExT) technology offers a solution by using high aspect-ratio nanostraws and localized electric fields to precisely deliver biomolecules into cells with minimal disruption. We demonstrate that NExT can deliver proteins, polysaccharides, and mRNA into primary human CD8+ and CD4+ T cells, and achieve CRISPR/Cas9 gene knockout of CXCR4 and TRAC in CD8+ T cells. We showcase NExT's versatility across a range of primary human immune cells, including CD4+ T cells, γδ-T cells, dendritic cells, NK cells, Treg cells, macrophages, and neutrophils. Finally, we developed a scalable, high-throughput multiwell NExT system capable of transfecting over 14 million cells and delivering diverse cargoes into multiple cell types from various donors simultaneously. This technology holds promise for streamlining high-throughput screening of allogeneic donors and reducing optimization costs for large-scale CAR-immune cell transfection.

Revolutionising cancer intervention: the repercussions of CAR-T cell therapy on modern oncology practices

Chimeric Antigen Receptor T-cell (CAR-T) therapy represents a groundbreaking advance in oncology, leveraging patient-specific immune cells to target malignant tumours precisely. By equipping T cells with synthetic receptors, CAR-T therapy achieves remarkable antitumor effects and offers hope for durable cancer control. However, several limitations persist, including antigen scarcity, immunosuppressive tumour microenvironments, and T-cell exhaustion. CRISPR-Cas9 gene editing has enhanced CAR-T potency by knocking out immune checkpoints (PD-1, CTLA-4) and improving persistence, while RNA interference (RNAi) silences immune-evasion genes (e.g. SOCS1). Nanozyme-based delivery systems enable precise CRISPR-Cas9 delivery (> 70% editing efficiency) and tumour targeting, overcoming instability and off-target effects. Innovations like SUPRA CARs, armoured CAR-T cells (e.g. IL-12/IL-21-secreting TRUCKs), and dual checkpoint inhibition synergize to reprogram the tumour microenvironment, reducing relapse by 40% in trials. Despite progress, high costs, manufacturing hurdles, and ethical concerns (e.g. germline editing risks) remain critical barriers. Emerging solutions include universal off-the-shelf CAR-Ts, hybrid nano-CRISPR systems, and AI-driven design, paving the way for scalable, personalised immunotherapy. This review highlights breakthroughs in CRISPR, RNAi, and nanotechnology, underscoring CAR-T therapy's transformative potential while addressing translational challenges for broader clinical adoption.

HPV-driven cancers: a looming threat and the potential of CRISPR/Cas9 for targeted therapy

Cervical and other anogenital malignancies are largely caused by E6 and E7 oncogenes of high-risk human papillomaviruses (HPVs), which inhibit important tumor suppressors like p53 and pRb when they are persistently activated. The main goal of traditional treatments is to physically or chemically kill cancer cells, but they frequently only offer temporary relief, have serious side effects, and have a high risk of recurrence. Exploring the efficacy and accuracy of CRISPR-Cas9 gene editing in both inducing death in HPV-infected cancer cells and restoring the activity of tumor suppressors is our main goal. In this study, we propose a novel precision oncology strategy that targets and inhibits the detrimental effects of the E6 and E7 oncogenes using the CRISPR-Cas9 gene editing system. In order to do this, we create unique guide RNAs that target the integrated HPV DNA and reactivate p53 and pRb. Reactivation is meant to halt aberrant cell development and restart the cell's natural dying pathways. This review discusses the potential of CRISPR/Cas9 in targeting HPV oncogenes, with a focus on studies that have demonstrated its promise in cancer treatment. Given the absence of a definitive treatment for papillomavirus infection and its subsequent association with various cancers, future clinical trials and experimental investigations appear essential to establish and evaluate the therapeutic potential of CRISPR-based approaches. This approach provides a less invasive alternative to conventional treatments and opens the door to personalized care that considers the genetic makeup of each patient's tumor.

Efficient and Precise Integration of Large DNA Sequences Using Precise Interstrand Cross-Linking of Long ssDNA and sgRNA

Homology-directed repair (HDR) allows the precise introduction of functional constructs into the human genome through nonviral gene-editing reagents. However, its application in large DNA sequence gene editing remains limited due to challenges such as low efficiency and the off-target effect. To address these limitations, a new method named AOLP was developed to synthesize chemically modified long single-stranded DNA (lssDNA) as the template donor for Cas9-based gene editing, which has been proven to be more stable than that prepared using the commercial phosphorylation method. We propose a novel strategy involving precise ligation-based interstrand cross-linking between lssDNA and sgRNA using cyanovinylcarbazole nucleoside (CNVK), enhancing the upregulation of the HDR pathway for DSB repair induced by Cas9. The light-activated ligation between Cas9/sgRNA and lssDNA improves the knock-in (KI) efficiency, overcomes the challenges of low KI efficiency, and surpasses the low off-target effect accompanied by the lssDNA donor. Moreover, the interstrand cross-linking of lssDNA and sgRNA can subtly control the ligation sites and the degree of cross-linking of lssDNA and sgRNA to enhance the KI accuracy of HDR. Our approach improves the KI efficiency of lssDNA in K562, HEK293T, and HepG2 cells by 4- to 12-fold relative to conventional lssDNA donors prepared using the phosphorylation method. Furthermore, the KI accuracy of HDR pathway in HEK293T cells is enhanced by >4.7-fold relative to previous commercial lssDNA. Leveraging this approach, we achieved an unprecedented KI rate of approximately 36% for a gene-sized 1.4 kilobase lssDNA insertion in HEK293T cells.

CD97-directed CAR-T cells with enhanced persistence eradicate acute myeloid leukemia in diverse xenograft models

Chimeric antigen receptor (CAR)-T therapy on acute myeloid leukemia (AML) is hindered by the absence of a suitable tumor-specific antigen. Here, we propose CD97 as a potential target for CAR-T therapy against AML based on its broader and higher expression on AML cells compared to normal hematopoietic stem and progenitor cells (HSPCs). To resolve the fratricide problem caused by CD97 expression on T cells, we knock out CD97 in CAR-T cells using CRISPR-Cas9. Our CD97KO CAR-T cells eliminate both AML cell lines and primary AML cells effectively while showing tolerable toxicity to HSPCs. Furthermore, we mutate the CD3ζ domain of the CAR and find that the optimized CD97 CAR-T cells exhibit persistent anti-tumor activity both in vitro and in multiple xenograft models. Mechanistically, transcriptional profiles reveal that the optimized CAR-T cells delay differentiation and resist exhaustion. Collectively, our study supports CD97 as a promising target for CAR-T therapy against AML.

Advances in T Cell-Based Cancer Immunotherapy: From Fundamental Mechanisms to Clinical Prospects

T cells and their T cell receptors (TCRs) play crucial roles in the adaptive immune system's response against pathogens and tumors. However, immunosenescence, characterized by declining T cell function and quantity with age, significantly impairs antitumor immunity. Recent years have witnessed remarkable progress in T cell-based cancer treatments, driven by a deeper understanding of T cell biology and innovative screening technologies. This review comprehensively examines T cell maturation mechanisms, T cell-mediated antitumor responses, and the implications of thymic involution on T cell diversity and cancer prognosis. We discuss recent advances in adoptive T cell therapies, including tumor-infiltrating lymphocyte (TIL) therapy, engineered T cell receptor (TCR-T) therapy, and chimeric antigen receptor T cell (CAR-T) therapy. Notably, we highlight emerging DNA-encoded library technologies in mammalian cells for high-throughput screening of TCR-antigen interactions, which are revolutionizing the discovery of novel tumor antigens and optimization of TCR affinity. The review also explores strategies to overcome challenges in the solid tumor microenvironment and emerging approaches to enhance the efficacy of T cell therapy. As our understanding of T cell biology deepens and screening technologies advances, T cell-based immunotherapies show increasing promise for delivering durable clinical benefits to a broader patient population.

Progress, Applications and Prospects of CRISPR-Based Genome Editing Technology in Gene Therapy for Cancer and Sickle Cell Disease

The advent of genome-editing technologies, particularly the RNA-guided the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated system (Cas) 9, which originates from prokaryotic CRISPR/Cas adaptive immune mechanisms, has revolutionized molecular biology. Renowned for its simplicity, cost-effectiveness, and capacity for multiplexed gene editing, CRISPR/Cas9 has emerged as the most versatile and widely adopted genome-editing platform. Its applications span fundamental research, biotechnology, medicine, and therapeutics. This review highlights recent advancements in CRISPR-based technologies, focusing on CRISPR/Cas9, CRISPR/Cas12a, and CRISPR/Cas12f. It emphasizes precision editing methods like base editing and prime editing, which enable targeted nucleotide changes without double-strand breaks. The specificity of these tools, including on-target accuracy and off-target risks, is critically evaluated. Additionally, recent preclinical and clinical efforts to treat diseases such as cancer and sickle cell disease using CRISPR are summarized. Finally, the challenges and future directions of CRISPR-mediated gene therapy are discussed, emphasizing its potential to integrate with other molecular approaches to address unmet medical needs.

Gene regulation technologies for gene and cell therapy

Gene therapy stands at the forefront of medical innovation, offering unique potential to treat the underlying causes of genetic disorders and broadly enable regenerative medicine. However, unregulated production of therapeutic genes can lead to decreased clinical utility due to various complications. Thus, many technologies for controlled gene expression are under development, including regulated transgenes, modulation of endogenous genes to leverage native biological regulation, mapping and repurposing of transcriptional regulatory networks, and engineered systems that dynamically react to cell state changes. Transformative therapies enabled by advances in tissue-specific promoters, inducible systems, and targeted delivery have already entered clinical testing and demonstrated significantly improved specificity and efficacy. This review highlights next-generation technologies under development to expand the reach of gene therapies by enabling precise modulation of gene expression. These technologies, including epigenome editing, antisense oligonucleotides, RNA editing, transcription factor-mediated reprogramming, and synthetic genetic circuits, have the potential to provide powerful control over cellular functions. Despite these remarkable achievements, challenges remain in optimizing delivery, minimizing off-target effects, and addressing regulatory hurdles. However, the ongoing integration of biological insights with engineering innovations promises to expand the potential for gene therapy, offering hope for treating not only rare genetic disorders but also complex multifactorial diseases.

Optimizing viral transduction in immune cell therapy manufacturing: key process design considerations

Immune cell therapies have revolutionized the treatment of cancers, autoimmune disorders, and infectious diseases. A critical step in their manufacturing is viral transduction, which enables the delivery of therapeutic genes into immune cells. However, the complexity of this process presents significant challenges for optimization and scalability. This review provides a comprehensive analysis of viral transduction process in immune cell therapy manufacturing, highlighting key design considerations to support the development of safe, effective, and scalable production methods. Additionally, it examines current technological challenges in immune cell transduction and explores future innovations poised to advance the field.

Addressing graft-versus-host disease in allogeneic cell-based immunotherapy for cancer

Allogeneic cell-based immunotherapies, particularly CAR-T cell therapy, represent a significant advancement in cancer treatment, offering scalable and consistent alternatives to autologous therapies. However, their widespread use is limited by the risk of graft-versus-host disease (GvHD). This review provides a comprehensive overview of GvHD in the context of allogeneic cell-based cancer immunotherapy and evaluates current strategies to mitigate its effects. Key strategies include genetic engineering approaches such as T cell receptor (TCR) knockout (KO) and T cell receptor alpha constant (TRAC) CAR knock-in. Alternative immune cell types like natural killer (NK) cells and natural killer T (NKT) cells offer potential solutions due to their lower alloreactivity. Additionally, stem cell technology, utilizing induced pluripotent stem cells (iPSCs), enables standardized and scalable production of engineered CAR-T cells. Clinical trials evaluating these strategies, such as UCART19 and CTX110, demonstrate promising results in preventing GvHD while maintaining anti-tumor efficacy. The review also addresses manufacturing considerations for allogeneic cell products and the challenges in translating preclinical findings into clinical success. By addressing these challenges, allogeneic cell-based immunotherapy continues to advance, paving the way for more accessible, scalable, and effective cancer treatments.

Generating allogeneic CAR-NKT cells for off-the-shelf cancer immunotherapy with genetically engineered HSP cells and feeder-free differentiation culture

The clinical potential of current chimeric antigen receptor-engineered T (CAR-T) cell therapy is hampered by its autologous nature that poses considerable challenges in manufacturing, costs and patient selection. This spurs demand for off-the-shelf therapies. Here we introduce an ex vivo feeder-free culture method to differentiate gene-engineered hematopoietic stem and progenitor (HSP) cells into allogeneic invariant natural killer T (AlloNKT) cells and their CAR-armed derivatives (AlloCAR-NKT cells). We include detailed information on lentivirus generation and titration, as well as the five stages of ex vivo culture required to generate AlloCAR-NKT cells, including HSP cell engineering, HSP cell expansion, NKT cell differentiation, NKT cell deep differentiation and NKT cell expansion. In addition, we describe procedures for evaluating the pharmacology, antitumor efficacy and mechanism of action of AlloCAR-NKT cells. It takes ~2 weeks to generate and titrate lentiviruses and ~6 weeks to generate mature AlloCAR-NKT cells. Competence with human stem cell and T cell culture, gene engineering and flow cytometry is required for optimal results.

Unravelling the modified T cell receptor through Gen-Next CAR T cell therapy in Glioblastoma: Current status and future challenges

PURPOSE

Despite current technological advancements in the treatment of glioma, immediate alleviation of symptoms can be catered by therapeutic modalities, including surgery, chemotherapy, and combinatorial radiotherapy that exploit aberrations of glioma. Additionally, a small number of target antigens, their heterogeneity, and immune evasion are the potential reasons for developing targeted therapies. This oncologic milestone has catalyzed interest in developing immunotherapies against Glioblastoma to improve overall survival and cure patients with high-grade glioma. The next-gen CAR-T Cell therapy is one of the effective immunotherapeutic strategies in which autologous T cells have been modified to express receptors against GBM and it modulates cytotoxicity.

METHODS

In this review article, we examine preclinical and clinical outcomes, and limitations as well as present cutting-edge techniques to improve the function of CAR-T cell therapy and explore the possibility of combination therapy.

FINDINGS

To date, several CAR T-cell therapies are being evaluated in clinical trials for GBM and other brain malignancies and multiple preclinical studies have demonstrated encouraging outcomes.

IMPLICATIONS

CAR-T cell therapy represents a promising therapeutic paradigm in the treatment of solid tumors but a few limitations include, the blood-brain barrier (BBB), antigen escape, tumor microenvironment (TME), tumor heterogeneity, and its plasticity that suppresses immune responses weakens the ability of this therapy. Additional investigation is required that can accurately identify the targets and reflect the similar architecture of glioblastoma, thus optimizing the efficiency of CAR-T cell therapy; allowing for the selection of patients most likely to benefit from immuno-based treatments.

Novel strategies to manage CAR-T cell toxicity

The immune-related adverse events associated with chimeric antigen receptor (CAR)-T cell therapy result in substantial morbidity as well as considerable cost to the health-care system, and can limit the use of these treatments. Current therapeutic strategies to manage immune-related adverse events include interleukin-6 receptor (IL-6R) blockade and corticosteroids. However, because these interventions do not always address the side effects, nor prevent progression to higher grades of adverse events, new approaches are needed. A deeper understanding of the cell types involved, and their associated signalling pathways, cellular metabolism and differentiation states, should provide the basis for alternative strategies. To preserve treatment efficacy, cytokine-mediated toxicity needs to be uncoupled from CAR-T cell function, expansion, long-term persistence and memory formation. This may be achieved by targeting CAR or independent cytokine signalling axes transiently, and through novel T cell engineering strategies, such as low-affinity CAR-T cells, reversible on-off switches and versatile adaptor systems. We summarize the current management of cytokine release syndrome and immune effector cell-associated neurotoxicity syndrome, and review T cell- and myeloid cell-intrinsic druggable targets and cellular engineering strategies to develop safer CAR-T cells.

CAR-T Cell Therapy: Managing Side Effects and Overcoming Challenges

Chimeric antigen receptor T (CAR-T) cell therapy is an innovative and promising approach to treat cancer. Clinical trials have demonstrated remarkable results, providing hope for patients who have exhausted more traditional therapies. However, this new therapy is not without challenges, as significant side effects have been associated with it. Cytokine release syndrome (CRS) is a widely recognized and consequential side effect of CAR-T cell therapy. Neurological toxicity is another potential side effect that can cause confusion and seizures in some patients. Hematologic toxicities, such as anemia and thrombocytopenia, can increase the risk of bleeding or infection. B-cell aplasia can also occur, leading to increased vulnerability to infections. Strategies to reduce the incidence and severity of toxicities include suicide, endogenous, and exogenous switches to modulate the activity of the immune system toward cancer while minimizing toxicity. Despite the obstacles faced by CAR-T cell therapy, continuous research and development in this area offer considerable potential for improving this treatment as a more reliable and efficient method for treating cancer.

Tailoring CAR surface density and dynamics to improve CAR-T cell therapy

Chimeric antigen receptor (CAR)-T cell therapy has revolutionized the treatment landscape for relapsed and/or refractory B-cell neoplasms, garnering Food and Drug Administration/European Medicines Agency approval for six commercial products. Despite this success, challenges persist, including a relapse rate of 30-50% in hematologic tumors, limited clinical efficacy in solid tumors, and severe side effects. This review addresses the critical need for therapeutic enhancement by focusing on the often-overlooked strategy of modulating CAR protein density on the cell membrane. We delve into the key factors influencing CAR surface expression, such as CAR downmodulation following antigen encounter and antigen-related factors. The dynamics of CAR downmodulation remain underexplored; however, recent data point to its modification as a useful tool for improving functionality. Notably, transcriptional control of CAR expression and the incorporation of specific elements into the CAR design have emerged as interesting strategies to tailor CAR expression profiles. Therefore, controlling CAR dynamic density may represent an attractive strategy for achieving optimal therapeutic outcomes.

Cellular immunotherapy targeting CLL-1 for juvenile myelomonocytic leukemia

Juvenile myelomonocytic leukemia (JMML) is a myeloproliferative disorder that predominantly affects infants and young children. Hematopoietic stem cell transplantation (HSCT) is standard of care, but post-HSCT relapse is common, highlighting the need for innovative therapies. While adoptive immunotherapy with chimeric antigen receptor (CAR) T cells has improved outcomes for patients with advanced lymphoid malignancies, it has not been comprehensively evaluated in JMML. In the present study, we use bulk and single-cell RNA sequencing, mass spectrometry, and flow cytometry to identify overexpression of CLL-1 (encoded by CLEC12A) on the cell surface of cells from patients with JMML. We develop immunotherapy with CLL-1 CAR T cells (CLL1CART) for preclinical testing and report in vitro and in vivo anti-leukemia activity. Notably, CLL1CART reduce the number of leukemic stem cells and serial transplantability in vivo. These preclinical data support the development and clinical investigation of CLL-1-targeting immunotherapy in children with relapsed/refractory JMML.

CAR T-cells for acute leukemias in children: current status, challenges, and future directions

CAR T-cells therapy is seen as one of the most promising immunotherapies for leukemias, since targeting CD19 has revolutionized the treatment of relapsed/refractory B-cell acute lymphoblastic leukemia (B-ALL) in children, adolescents, and young adults. Early phase clinical trials have shown a very high initial response rate confirmed by follow up and real-world studies. However, almost half of patients relapse with the available commercial product currently suggesting the need of a consolidative treatment after CAR T-cell infusion in well-defined cases, according to several pre- and post-CAR clinical and biological factors. This finding highlights that numerous challenges exist before the extension of CAR T-cell indications (first relapse and high-risk first line) in the field of B-ALL: to enhance persistence of CAR T-cells to avoid CD19-positive relapse and to avoid CD19-negative relapse by reducing tumor burden pre-CAR-T infusion and/or by multitargeting. Promising approaches with exciting early clinical data are emerging in the field of T-cell ALL. The use of CAR T-cells for acute myeloid leukemias remains challenging due to the lack of leukemia-specific antigens and to the immunosuppressive microenvironment.

CAR-T therapy in solid tumors

While chimeric antigen receptor (CAR) T cell therapy has shown great success in hematologic malignancies, the effectiveness in solid tumors has been limited by several factors, including antigenic heterogeneity and the immunosuppressive nature of the tumor microenvironment (TME). In this review, we discuss the advancements made in clinical studies and challenges faced by CAR-T therapy for solid tumors. To enhance CAR-T cell efficacy in solid tumors, we explore strategies such as enhancing T cell persistence and cytotoxicity, targeting multiple antigens, and utilizing innovative allogeneic CAR-T cell manufacturing. Additionally, we highlight the potential benefits of combining CAR-T therapies with immune checkpoint inhibitors and other treatment modalities to overcome TME limitations. We remain optimistic about the future of CAR-T cell therapy in solid tumors, emphasizing the need for continued research to refine therapeutic approaches and address the clinical needs of patients with cancer.

The road ahead for chimeric antigen receptor T cells

Chimeric antigen receptor T (CART) cell therapy is an innovative form of immunotherapy that has shown remarkable and long-term responses in patients with B-cell malignancies. Over the years, the field has made significant progress in our understanding of the successes and challenges associated with CART cell therapy. In this review, we provide an overview of the current state of CART cell therapy in the clinic. We detail current challenges including patient access, CART-associated toxicity, tumor heterogeneity, CART cell trafficking, the tumor microenvironment, and different CART cell fates. With each challenge, we review lessons learned, potential solutions and outline areas for future development. Finally, we discuss how the field of engineered cell therapy is moving into the treatment of solid tumors and other diseases beyond cancer.

CAR-NK cell therapy: promise and challenges in solid tumors

Over the past few years, cellular immunotherapy has emerged as a promising treatment for certain hematologic cancers, with various CAR-T therapies now widely used in clinical settings. However, challenges related to the production of autologous cell products and the management of CAR-T cell toxicity highlight the need for new cell therapy options that are universal, safe, and effective. Natural killer (NK) cells, which are part of the innate immune system, offer unique advantages, including the potential for off-the-shelf therapy. A recent first-in-human trial of CD19-CAR-NK infusion in patients with relapsed/refractory lymphoid malignancies demonstrated safety and promising clinical activity. Building on these positive clinical outcomes, current research focuses on enhancing CAR-NK cell potency by increasing their in vivo persistence and addressing functional exhaustion. There is also growing interest in applying the successes seen in hematologic malignancies to solid tumors. This review discusses current trends and emerging concepts in the engineering of next-generation CAR- NK therapies. It will cover the process of constructing CAR-NK cells, potential targets for their manufacturing, and their role in various solid tumors. Additionally, it will examine the mechanisms of action and the research status of CAR-NK therapies in the treatment of solid tumors, along with their advantages, limitations, and future challenges. The insights provided may guide future investigations aimed at optimizing CAR-NK therapy for a broader range of malignancies.

Development and validation of optimized lentivirus-like particles for gene editing tool delivery with Gag-Only strategy

BACKGROUND

The development of gene editing tools such as CRISPR-Cas9 and base editors (BE) is critical for genetic diseases and cancer. Lentivirus-like particles (LVLPs) grows into an auspicious platform for delivering mRNA or ribonucleic proteins (RNPs) due to it integrates the advantage of viral and non-viral vectors. Current LVLP systems predominantly utilize HIV-Gag and Pol proteins. However, the reverse transcriptase and integrase of Pol, pose risks of genomic integration and potential tumorigenesis. Enhancing the safety of VLP system is essential. This study focuses on improving the LVLP to minimize these risks.

METHODS

We implemented a Gag-Only strategy, constructing LVLPs with HIV-Gag protein, thereby eliminating the integration risks linked to Pol. By leveraging the interactions between MS2-MCP (MS2 coat protein), PP7 and PP7 BP (PP7 binding protein), and the psi (HIV packaging signal) with HIV-Gag, we encapsulated PAMless andesine base editor (CE-8e-SpRY) mRNA and sgRNA targeting the PD1 start codon (ATG) into the LVLP. Using recombinant lentiviral vector technology, we developed a stable PD1-expressing 293T cell line (PD1-293T) to assess the editing efficiency of LVLP.

RESULTS

The psi-LVLP demonstrated effective packaging capabilities, achieving 15% base editing efficiency in 293T cells. By optimizing plasmid ratios, we observed increased CE-8e-SpRY mRNA copy numbers, with 30% base editing efficiency. Additionally, the integration of HDVrz (hepatitis delta virus ribozyme) and psi into sgRNA (HDVrz-psi-LVLP) substantially enhanced sgRNA copy numbers, resulting in approximately 50% base editing efficiency in 293T cells and 20% base editing efficiency in Jurkat cells. Mendelian randomization analyses revealed significant genetic correlations between PD1, B2M, CIITA, and TIGIT genes with various cancer risks. Furthermore, HDVrz-psi-LVLPs targeting the start codons of B2M, CIITA, and TIGIT exhibited high base editing activity in both Jurkat and 293T cells.

CONCLUSION

In conclusion, this optimized platform effectively encapsulates CE-8e-SpRY mRNA and sgRNA, achieving high editing efficiencies across multiple genes and cell types. We introduce a safer and more efficient gene editing tool delivery system by constructing LVLPs based on the Gag-Only strategy. Our study presents a promising implication for cancer immunotherapy.

Turning "trashed" genomic loci into treasurable sites for integrating chimeric antigen receptors in T and NK cells

Chimeric antigen receptor (CAR)-based immune cell therapy involves genetically engineering immune cells, such as T cells and natural killer (NK) cells, to express CARs that can specifically recognize target antigens. This modification enables T/NK cells to selectively eliminate tumor cells following adoptive transfer. One common approach to stably integrate CARs into the genome of T/NK cells is through retroviral or lentiviral vectors. However, these vectors mediate semi-random gene integration, posing risks such as oncogenic mutations, gene silencing, and variable CAR expression levels. Targeted integration of CAR genes into the specific genomic locus could overcome these limitations, but identifying the optimal integration sites to maximize the safety and efficacy of CAR-T/NK cell products remains a critical question. Improper integration sites may disturb the endogenous genes surrounding the integration sites, raising safety concerns. Additionally, regulatory elements at the integration sites, such as promoters, can influence the expression level of CAR genes, thus affecting the efficacy of CAR-T/NK cells. In this review, we summarized current strategies for selecting integration sites and promoters in the engineering of CAR-T/NK cells to achieve potent anti-tumor efficacy in preclinical studies.

TOPO-seq reveals DNA topology-induced off-target activity by Cas9 and base editors

With the increasing use of CRISPR-Cas9, detecting off-target events is essential for safety. Current methods primarily focus on guide RNA (gRNA) sequence mismatches, often overlooking the impact of DNA topology in regulating off-target activity. Here we present TOPO-seq, a high-throughput and sensitive method that identifies genome-wide off-target effects of Cas9 and base editors while accounting for DNA topology. TOPO-seq revealed that topology-induced off-target sites frequently harbor higher mismatches than the relaxed DNA sequence, with over 50% of off-target sites containing six mismatches, which are usually overlooked using previous methods. Applying TOPO-seq to three therapeutic gRNAs in hematopoietic stem cells identified 47 bona fide off-target loci, six of which are specifically induced by DNA topology. These findings highlight DNA topology as a regulator of off-target editing rates, establish TOPO-seq as a robust method for capturing DNA topology-induced off-target events and underscore its importance in off-target detection for developing safe genome-editing therapies.

HIV immune evasin Nef enhances allogeneic CAR T cell potency

Autologous chimeric antigen receptor (CAR) T cells are a genetically engineered therapy that is highly effective against B cell malignancies and multiple myeloma1. However, the length and cost of personalized manufacturing limits access and leaves patients vulnerable to disease progression. Allogeneic cell therapies have the potential to increase patient access and improve treatment outcomes but are limited by immune rejection2,3. To devise a strategy to protect allogeneic CAR T cells from host immune cells, we turned to lymphotropic viruses that have evolved integrated mechanisms for immune escape of virus-infected lymphocytes4. We find that viral evasins that partially reduce human leukocyte antigen class I expression can shelter CAR T cells from mismatched CD8+ T cells without triggering 'missing-self' rejection by natural killer cells. However, this protection alone is insufficient to sustain effective allogeneic CAR T cell therapy. HIV-1 Nef uniquely also acts through the serine/threonine kinase Pak2 to abate activation-induced cell death and promote survival of CAR T cells in vivo. Thus, virus-like immune escape can harness several mechanisms that act in concert to enhance the therapeutic efficacy of allogeneic CAR T cells.

DHODH inhibition alters T cell metabolism limiting acute graft-versus-host disease while retaining graft-versus-leukemia response

Acute graft-versus-host disease (GVHD) is a donor T cell driven complication and the leading cause of non-relapse mortality in patients receiving an allogeneic hematopoietic cell transplantation (allo-HCT). Allogeneic donor T cells eradicate residual leukemia and prevent relapse via the graft-versus-leukemia (GVL) effect and are critical for responding against opportunistic infections post-transplant. Current regimens successful in preventing GVHD are broadly immunosuppressive and come at the cost of increased risk of relapse and/or infection. Therefore, there is an urgent need for new approaches that limit GVHD while retaining GVL responses. During GVHD, alloreactive T cells boost their energy production through oxidative phosphorylation (OXPHOS) and glycolysis, supporting heightened proliferation and pathogenicity against healthy host tissues. The enzyme dihydroorate dehydrogenase (DHODH), is essential for de novo pyrimidine biosynthesis and for maintaining mitochondrial membrane potential during OXPHOS. Having shown upregulation of DHODH messenger RNA and protein expression in activated human T cells, we evaluated DHODH inhibition, via a small molecule inhibitor HOSU-53, as a therapeutic approach for GVHD. Inhibiting DHODH significantly reduced oxidative metabolism in T cells both during and after activation, while selectively suppressing inflammatory cytokine production in de novo activated, but not previously activated, T cells. In a xenogeneic model, HOSU-53 treatment limited GVHD severity, decreased pathogenic Th1 and Th17 response, and preserved beneficial GVL effects. Altogether, we identify DHODH inhibition as an innovative treatment strategy in allo-HCT recipients to reduce GVHD severity and retain effective GVL response.

Natural killer cells: a new promising source for developing chimeric antigen receptor anti-cancer cells in hematological malignancies

In recent times, the application of CAR-T cell treatment has significantly progressed, showing auspicious treatment outcomes in hematologic malignancies. However, along with these advances, certain limitations and challenges hurdle the widespread utilization of this technology. Recently, CAR-NK cells have gained attention in cancer treatment, as this approach has an important advantage over CART therapy (i.e. no need for HLA matching) for targeting foreign cells. This review aims to explore the benefits of CAR NK cell therapy, and generation strategies, as well as the challenges and limitations hindering the application of CAR NK cells in experimental studies and trials on hematologic malignancies.

Clinical development of allogeneic chimeric antigen receptor αβ-T cells

Ready-made banks of allogeneic chimeric antigen receptor (CAR) T cells, produced to be available at the time of need, offer the prospect of accessible and cost-effective cellular therapies. Various strategies have been developed to overcome allogeneic barriers, drawing on cell engineering platforms including RNA interference, protein-based restriction, and genome editing, including RNA-guided CRISPR-Cas and base editing tools. Alloreactivity and the risk of graft-versus-host disease from non-matched donor cells have been mitigated by disruption of αβ-T cell receptor expression on the surface of T cells and stringent removal of any residual αβ-T cell populations. In addition, host-mediated rejection has been tackled through a combination of augmented lymphodepletion and cell engineering strategies that have allowed infused cells to evade immune recognition or conferred resistance to lymphodepleting agents to promote persistence and expansion of effector populations. Early-phase studies using off-the-shelf universal donor CAR T cells have been undertaken mainly in the context of blood malignancies, where emerging data of clinical responses have supported wider adoption and further applications. These developments offer the prospect of alternatives to current autologous approaches through the emerging application of genome engineering solutions to improve safety, persistence, and function of universal donor products.

The role of B2M in cancer immunotherapy resistance: function, resistance mechanism, and reversal strategies

Immunotherapy has emerged as a preeminent force in the domain of cancer therapeutics and achieved remarkable breakthroughs. Nevertheless, the high resistance has become the most substantial impediment restricting its clinical efficacy. Beta-2 microglobulin (B2M), the light chain of major histocompatibility complex (MHC) class I, plays an indispensable part by presenting tumor antigens to cytotoxic T lymphocytes (CTLs) for exerting anti-tumor effects. Accumulating evidence indicates that B2M mutation/defect is one of the key mechanisms underlying tumor immunotherapy resistance. Therefore, elucidating the role played by B2M and devising effective strategies to battle against resistance are pressing issues. This review will systematically expound upon them, aiming to provide insight into the potential of B2M as a promising target in anticancer immune response.

T cell receptor precision editing of regulatory T cells for celiac disease

Celiac disease, a gluten-sensitive enteropathy, demonstrates a strong human leukocyte antigen (HLA) association, with more than 90% of patients carrying the HLA-DQ2.5 allotype. No therapy is available for the condition except for a lifelong gluten-free diet. To address this gap, we explored the therapeutic potential of regulatory T cells (Tregs). By orthotopic replacement of T cell receptors (TCRs) through homology-directed repair, we generated gluten-reactive HLA-DQ2.5-restricted CD4+ engineered (e) T effector cells (Teffs) and eTregs and performed in vivo experiments in HLA-DQ2.5 transgenic mice. Of five validated TCRs, TCRs specific for two immunodominant and deamidated gluten epitopes (DQ2.5-glia-α1a and DQ2.5-glia-α2) were selected for further evaluation. CD4+ eTeffs exposed to deamidated gluten through oral gavage colocalized with dendritic and B cells in the Peyer's patches and gut-draining lymph nodes and specifically migrated to the intestine. The suppressive function of human eTregs correlated with high TCR functional activity. eTregs specific for one epitope suppressed the proliferation and gut migration of CD4+ eTeffs specific for the same and the other gluten epitope, demonstrating bystander suppression. The suppression requires an antigen-specific activation of eTregs given that polyclonal Tregs failed to suppress CD4+ eTeffs. These findings highlight the potential of gluten-reactive eTregs as a therapeutic for celiac disease.

Efficient nonviral integration of large transgenes into human T cells using Cas9-CLIPT

CRISPR-Cas9 ribonucleoproteins (RNPs) combined with a nucleic acid template encoding a chimeric antigen receptor (CAR) transgene can edit human cells to produce CAR T cells with precise CAR insertion at a single locus. However, many human cells have adverse innate immune responses to foreign nucleic acids, particularly circular double-stranded DNA (dsDNA). Here, we introduce Cleaved, LInearized with Protein Template (Cas9-CLIPT), a circular plasmid containing a single target sequence for the Cas9 RNP, such that during manufacturing, Cas9-RNP binds and cleaves the plasmid to linearize the dsDNA in vitro. Cas9-RNP remains bound to the linearized template and is delivered to cells to promote precise knock-in via homology-directed repair with Cas9-CLIPT. Cas9-CLIPT Nanoplasmids generate up to 1.7-fold higher rates of precise knock-in relative to linearized dsDNA, reaching efficiencies up to 60% with non-homologous end joining inhibition. Cas9-CLIPT-manufactured GD2 TRAC-CAR T cells are potent against GD2+ neuroblastoma cells and exhibit an enriched stem cell memory phenotype. On several electroporation instruments and approaching clinically relevant yields, we successfully manufactured TRAC-CAR T cells using Cas9-CLIPT plasmids containing large (2-6 kb) transgenes. Cas9-CLIPT strategies have the potential to simplify donor template production and integrate large transgenes, allowing for more efficient nonviral manufacturing of multifunctional, genome-edited immune cell therapies.

Advanced delivery systems for gene editing: A comprehensive review from the GenE-HumDi COST Action Working Group

In the past decade, precise targeting through genome editing has emerged as a promising alternative to traditional therapeutic approaches. Genome editing can be performed using various platforms, where programmable DNA nucleases create permanent genetic changes at specific genomic locations due to their ability to recognize precise DNA sequences. Clinical application of this technology requires the delivery of the editing reagents to transplantable cells ex vivo or to tissues and organs for in vivo approaches, often representing a barrier to achieving the desired editing efficiency and safety. In this review, authored by members of the GenE-HumDi European Cooperation in Science and Technology (COST) Action, we described the plethora of delivery systems available for genome-editing components, including viral and non-viral systems, highlighting their advantages, limitations, and potential application in a clinical setting.

TCR-T cell therapy for solid tumors: challenges and emerging solutions

With the use of T cell receptor T cells (TCR-T cells) and chimeric antigen receptor T cells (CAR-T cells), T-cell immunotherapy for cancer has advanced significantly in recent years. CAR-T cell therapy has demonstrated extraordinary success when used to treat hematologic malignancies. Nevertheless, there are several barriers that prevent this achievement from being applied to solid tumors, such as challenges with tumor targeting and inadequate transit and adaption of genetically modified T-cells, especially in unfavorable tumor microenvironments The deficiencies of CAR-T cell therapy in the treatment of solid tumors are compensated for by TCR-T cells, which have a stronger homing ability to initiate intracellular commands, 90% of the proteins can be used as developmental targets, and they can recognize target antigens more broadly. As a result, TCR-T cells may be more effective in treating solid tumors. In this review, we discussed the structure of TCR-T and have outlined the drawbacks of TCR-T in cancer therapy, and suggested potential remedies. This review is crucial in understanding the current state and future potential of TCR-T cell therapy. We emphasize how important it is to use combinatorial approaches, combining new combinations of various emerging strategies with over-the-counter therapies designed for TCR-T, to increase the anti-tumor efficacy of TCR-T inside the TME and maximize treatment safety, especially when it comes to solid tumor immunotherapies.

Gene editing of CD3 epsilon to redirect regulatory T cells for adoptive T cell transfer

Adoptive transfer of antigen-specific regulatory T cells (Tregs) is a promising strategy to combat immunopathologies in transplantation and autoimmune diseases. However, their low frequency in peripheral blood poses challenges for both manufacturing and clinical application. Chimeric antigen receptors have been used to redirect the specificity of Tregs, using retroviral vectors. However, retroviral gene transfer is costly, time consuming, and raises safety issues. Here, we explored non-viral CRISPR-Cas12a gene editing to redirect Tregs, using human leukocyte antigen (HLA)-A2-specific constructs for proof-of-concept studies in transplantation models. Knock-in of an antigen-binding domain into the N terminus of CD3 epsilon (CD3ε) gene generates Tregs expressing a chimeric CD3ε-T cell receptor fusion construct (TRuC) protein that integrates into the endogenous TCR/CD3 complex. These CD3ε-TRuC Tregs exhibit potent antigen-dependent activation while maintaining responsiveness to TCR/CD3 stimulation. This enables preferential enrichment of TRuC-redirected Tregs over CD3ε knockout Tregs via repetitive CD3/CD28 stimulation in a good manufacturing practice-compatible expansion system. CD3ε-TRuC Tregs retained their phenotypic, epigenetic, and functional identity. In a humanized mouse model, HLA-A2-specific CD3ε-TRuC Tregs demonstrate superior protection of allogeneic HLA-A2+ skin grafts from rejection compared with polyclonal Tregs. This approach provides a pathway for developing clinical-grade CD3ε-TRuC-based Treg cell products for transplantation immunotherapy and other immunopathologies.

Peptide-enabled ribonucleoprotein delivery for CRISPR engineering (PERC) in primary human immune cells and hematopoietic stem cells

Peptide-enabled ribonucleoprotein delivery for CRISPR engineering (PERC) is a new approach for ex vivo genome editing of primary human cells. PERC uses a single amphiphilic peptide reagent to mediate intracellular delivery of the same pre-formed CRISPR ribonucleoprotein enzymes that are broadly used in research and therapeutics, resulting in high-efficiency editing of stimulated immune cells and cultured hematopoietic stem and progenitor cells (HSPCs). PERC facilitates nuclease-mediated gene knockout, precise transgene knock-in and base editing. The protocol involves mixing the CRISPR ribonucleoprotein enzyme with peptide and then incubating with cultured cells. For efficient transgene knock-in, adeno-associated virus (AAV) homology-directed repair template (HDRT) DNA may be included. In contrast to electroporation, PERC is appealing because it needs no dedicated hardware and has less impact on cell phenotype and viability. Because of the gentle nature of PERC, delivery can be performed multiple times without substantial impact to cell health or phenotype. Editing efficiencies can surpass 90% when using either Cas9 or Cas12a in primary T cells or HSPCs. After 3 h dedicated to reagent preparation, the PERC delivery step can be completed in 1 h, with the associated cell culture steps taking 3-7 d total. Because the protocol calls for only three readily available reagents (protein, RNA and peptide) and does not require dedicated hardware for any step, PERC demands no special expertise and is exceptionally straightforward to adopt. The inherent compatibility of PERC with established cell engineering pipelines makes the protocol appealing for rapid deployment in research and clinical settings.

Intelligent Design of Lipid Nanoparticles for Enhanced Gene Therapeutics

Lipid nanoparticles (LNPs) are an effective delivery system for gene therapeutics. By optimizing their formulation, the physiochemical properties of LNPs can be tailored to improve tissue penetration, cellular uptake, and precise targeting. The application of these targeted delivery strategies within the LNP framework ensures efficient delivery of therapeutic agents to specific organs or cell types, thereby maximizing therapeutic efficacy. In the realm of genome editing, LNPs have emerged as a potent vehicle for delivering CRISPR/Cas components, offering significant advantages such as high in vivo efficacy. The incorporation of machine learning into the optimization of LNP platforms for gene therapeutics represents a significant advancement, harnessing its predictive capabilities to substantially accelerate the research and development process. This review highlights the dynamic evolution of LNP technology, which is expected to drive transformative progress in the field of gene therapy.

Blood cancer therapy with synthetic receptors and CRISPR technology

Chimeric antigen receptor (CAR)-T and -NK cells showed great success in treating hematological malignancies, including leukemia, lymphoma, and myeloma. CRISPR technology and other synthetic receptors (GPCR and synNotch) have helped to address some of the limitations and challenges associated with CAR-based therapies. Herein, this review aims to discuss how CAR can be integrated with other synthetic receptors and various CRISPR/Cas tools for blood cancer therapy. CAR-expressing cells equipped with other synthetic receptors can conditionally execute tumoricidal functions, prevent tumor escape from immune surveillance, and minimize non-tumor off-target toxicity. We also discussed how various CRISPR-Cas tools can be harnessed to enhance CAR cells functionality and persistence. The advances, pitfalls, and future perspectives for these synthetic receptors and CRISPR technology in blood cancer therapy are comprehensively discussed.

From TCR fundamental research to innovative chimeric antigen receptor design

Engineered T cells that express chimeric antigen receptors (CARs) have transformed the treatment of haematological cancers. CARs combine the tumour-antigen-binding function of antibodies with the signalling functions of the T cell receptor (TCR) ζ chain and co-stimulatory receptors. The resulting constructs aim to mimic the TCR-based and co-receptor-based activation of T cells. Although these have been successful for some types of cancer, new CAR formats are needed, to limit side effects and broaden their use to solid cancers. Insights into the mechanisms of TCR signalling, including the identification of signalling motifs that are not present in the TCR ζ chain and mechanistic insights in TCR activation, have enabled the development of CAR formats that outcompete the current CARs in preclinical mouse models and clinical trials. In this Perspective, we explore the mechanistic rationale behind new CAR designs.

Is there a place for engineered immune cell therapies in autoimmune diseases?

The ability to engineer immune cells yielded a transformative era in oncology. Early clinical trials demonstrated the efficacy of chimeric antigen receptor (CAR) T cells in resetting the immune system, motivating the expansion of this treatment beyond cancer, including autoimmune conditions. In this review, we discuss the current state of CAR T cell research in autoimmune diseases, examining the main challenges that limit widespread adoption of this therapy, such as complex isolation protocols, stringent immunosuppression, risk of secondary malignancies, and variable efficacy. We also review the studies addressing these limitations by development of off-the-shelf allogeneic CAR T cells, tunable safety systems, and antigen-specific therapies, which hold the potential to improve safety and accessibility of this treatment in clinical practice.

Expanding the horizon of CAR T cell therapy: from cancer treatment to autoimmune diseases and beyond

Chimeric antigen receptor (CAR)-T-cell therapy has garnered significant attention for its transformative impact on the treatment of hematologic malignancies such as leukemia and lymphoma. Despite its remarkable success, challenges such as resistance, limited efficacy in solid tumors, and adverse side effects remain prominent. This review consolidates recent advancements in CAR-T-cell therapy and explores innovative engineering techniques and strategies to overcome the immunosuppressive tumor microenvironment (TME). We also discuss emerging applications beyond cancer, including autoimmune diseases and chronic infections. Future perspectives highlight the development of more potent CAR-T cells with increased specificity and persistence and reduced toxicity, providing a roadmap for next-generation immunotherapies.

From Origin to the Present: Establishment, Mechanism, Evolutions and Biomedical Applications of the CRISPR/Cas-Based Macromolecular System in Brief

Advancements in biological and medical science are intricately linked to the biological central dogma. In recent years, gene editing techniques, especially CRISPR/Cas systems, have emerged as powerful tools for modifying genetic information, supplementing the central dogma and holding significant promise for disease diagnosis and treatment. Extensive research has been conducted on the continuously evolving CRISPR/Cas systems, particularly in relation to challenging diseases, such as cancer and HIV infection. Consequently, the integration of CRISPR/Cas-based techniques with contemporary medical approaches and therapies is anticipated to greatly enhance healthcare outcomes for humans. This review begins with a brief overview of the discovery of the CRISPR/Cas system. Subsequently, using CRISPR/Cas9 as an example, a clear description of the classical molecular mechanism underlying the CRISPR/Cas system was given. Additionally, the development of the CRISPR/Cas system and its applications in gene therapy and high-sensitivity disease diagnosis were discussed. Furthermore, we address the prospects for clinical applications of CRISPR/Cas-based gene therapy, highlighting the ethical considerations associated with altering genetic information. This brief review aims to enhance understanding of the CRISPR/Cas macromolecular system and provide insight into the potential of genetic macromolecular drugs for therapeutic purposes.

Scalable intracellular delivery via microfluidic vortex shedding enhances the function of chimeric antigen receptor T-cells

Adoptive chimeric antigen receptor T-cell (CAR-T) therapy is transformative and approved for hematologic malignancies. It is also being developed for the treatment of solid tumors, autoimmune disorders, heart disease, and aging. Despite unprecedented clinical outcomes, CAR-T and other engineered cell therapies face a variety of manufacturing and safety challenges. Traditional methods, such as lentivirus transduction and electroporation, result in random integration or cause significant cellular damage, which can limit the safety and efficacy of engineered cell therapies. We present hydroporation as a gentle and effective alternative for intracellular delivery. Hydroporation resulted in 1.7- to 2-fold higher CAR-T yields compared to electroporation with superior cell viability and recovery. Hydroporated cells exhibited rapid proliferation, robust target cell lysis, and increased pro-inflammatory and regulatory cytokine secretion in addition to improved CAR-T yield by day 5 post-transfection. We demonstrate that scaled-up hydroporation can process 5 × 108 cells in less than 10 s, showcasing the platform as a viable solution for high-yield CAR-T manufacturing with the potential for improved therapeutic outcomes.

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.

Targeting HLA-E-overexpressing cancers with a NKG2A/C switch receptor

BACKGROUND

Human leukocyte antigen (HLA)-E is overexpressed by a large proportion of solid tumors, including malignant glioblastoma, and acts as a major checkpoint for NKG2A+ CD8+ T cells and natural killer (NK) cells in the tumor microenvironment and circulation. This axis operates alongside PD-L1 to inhibit effector responses by T and NK cells.

METHODS

We engineered a chimeric A/C switch receptor, combining the high HLA-E binding affinity of the NKG2A receptor ectodomain with the activating signaling of the NKG2C receptor endodomain. The cytotoxic function of A/C switch-transduced NK and T cells was evaluated against tumor cells with varying levels of HLA-E expression. In vivo efficacy was assessed using a xenograft model of glioblastoma.

FINDINGS

A/C switch-transduced NK and T cells exhibited superior and specific cytotoxicity against tumor cells with medium to high HLA-E expression. A/C switch-expressing human T cells demonstrated enhanced anti-tumor function in a glioblastoma xenograft model. The activity of the modified T cells was governed by an equilibrium between A/C switch levels and HLA-E expression, creating a therapeutic window to minimize on-target, off-tumor toxicities. Normal cells remained insensitive to A/C switch T cells, even after interferon (IFN)-γ pretreatment to induce HLA-E expression.

CONCLUSIONS

The A/C switch receptor effectively targets tumor cells expressing high levels of HLA-E, either alone or in combination with other engineered specificities, to overcome the suppressive NKG2A/HLA-E checkpoint. This approach offers a promising therapeutic strategy with a favorable safety profile for targeting HLA-E-overexpressing tumors.

FUNDING

This work was funded by The Research Council of Norway, the Norwegian Cancer Society, and the National Cancer Institute.

Tumor-Infiltrating Lymphocytes, CAR-, and T-Cell Receptor-Modified T Cells in Solid Cancer Oncology

BACKGROUND

Adoptive cellular therapy (ACT) is a promising treatment approach aiming at enhancing T-cell antitumor immune response. ACT includes tumor-infiltrating lymphocytes, chimeric antigen receptor (CAR) and T-cell receptor gene-modified T cells. Despite a milestone achievement with CAR-T cells in hematopoietic malignancies, ACT has shown modest clinical responses in refractory solid cancers and durable responses remain limited to a minor fraction of patients.

SUMMARY

In this review, we highlight major advances, limitations and current developments of T-cell therapies for solid cancers. We discuss emerging promising strategies as next-generation ACT, exploring local delivery routes to maximize efficacy and improve safety, integrating predictive biomarkers to optimize selection of patients who most likely would benefit from ACT, using combination therapy to overcome the immunosuppressive tumor microenvironment, targeting multiple tumor antigen to avoid tumor antigen escape, selection of the most potent T-cell product to overcome T-cell dysfunction, and incorporating cutting-edge new technologies, such as gene-editing to further improve antitumor T-cell functions and reduce therapy-related toxicity.

KEY MESSAGES

Advances made in ACT trials have move the field of immunotherapy for refractory solid cancers to a new stage, by constantly incorporating new strategies to develop next-generation therapies designed to enhance efficacy and improve safety and to allow a broaden access to a large numbers of patients.

DNA-dependent protein kinase inhibitors PI-103 and samotolisib augment CRISPR/Cas9 knock-in efficiency in human T cells

The adoptive transfer of autologous peripheral blood T cells gene-modified to express preselected, tumor antigen-specific T-cell receptors (TCRs) is a promising treatment for solid cancers. While gene-transfer by viral transduction is highly efficient, the insertional site is not targeted and persistence of the T cells is oftentimes limited. In contrast, site-specific integration of the TCR into the TCR α chain (TRAC) locus by CRISPR/Cas9 has been shown to enable more consistent and physiologic levels of exogenous TCR expression coupled with superior persistence and tumor control in preclinical studies. Here, we sought to improve the efficiency of CRISPR/Cas9 mediated TCR knock-in (KI) into the TRAC locus of primary human T cells. In addition to the previously reported DNA-dependent protein kinase (DNA-PK) inhibitor M3814, we demonstrated that PI-103 and samotolisib markedly increase KI efficiency in a process that is good manufacturing process (GMP)-compatible. Importantly, samotolisib enabled the generation of a potent T-cell product, having no negative impact on T-cell viability, phenotype, expansion, effector function, and tumor control. Overall, we conclude that our GMP-compatible CRISPR/Cas9 protocol comprising samotolisib to augment TCR KI efficiency is suitable for the generation of genetically modified T cells for clinical use.

Chimeric antigen receptor T-cell therapy in patients with malignant glioma-From neuroimmunology to clinical trial design considerations

Clinical trials evaluating chimeric antigen receptor (CAR) T-cell therapy in patients with malignant gliomas have shown some early promise in pediatric and adult patients. However, the long-term benefits and safety for patients remain to be established. The ultimate success of CAR T-cell therapy for malignant glioma will require the integration of an in-depth understanding of the immunology of the central nervous system (CNS) parenchyma with strategies to overcome the paucity and heterogeneous expression of glioma-specific antigens. We also need to address the cold (immunosuppressive) microenvironment, exhaustion of the CAR T-cells, as well as local and systemic immunosuppression. Here, we discuss the basics and scientific considerations for CAR T-cell therapies and highlight recent clinical trials. To help identify optimal CAR T-cell administration routes, we summarize our current understanding of CNS immunology and T-cell homing to the CNS. We also discuss challenges and opportunities related to clinical trial design and patient safety/monitoring. Finally, we provide our perspective on future prospects in CAR T-cell therapy for malignant gliomas by discussing combinations and novel engineering strategies to overcome immuno-regulatory mechanisms. We hope this review will serve as a basis for advancing the field in a multiple discipline-based and collaborative manner.

SEED-Selection enables high-efficiency enrichment of primary T cells edited at multiple loci

Engineering T cell specificity and function at multiple loci can generate more effective cellular therapies, but current manufacturing methods produce heterogenous mixtures of partially engineered cells. Here we develop a one-step process to enrich unlabeled cells containing knock-ins at multiple target loci using a family of repair templates named synthetic exon expression disruptors (SEEDs). SEEDs associate transgene integration with the disruption of a paired target endogenous surface protein while preserving target expression in nonmodified and partially edited cells to enable their removal (SEED-Selection). We design SEEDs to modify three critical loci encoding T cell specificity, coreceptor expression and major histocompatibility complex expression. The results demonstrate up to 98% purity after selection for individual modifications and up to 90% purity for six simultaneous edits (three knock-ins and three knockouts). This method is compatible with existing clinical manufacturing workflows and can be readily adapted to other loci to facilitate production of complex gene-edited cell therapies.