CRISPR-engineered T cells in patients with refractory 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.

Global research trends in CAR-T cell therapy for solid tumors: A comprehensive visualization and bibliometric study (2012-2023)

CAR-T cell therapy has emerged as a significant approach for the management of hematological malignancies. Over the past few years, the utilization of CAR-T cells in the investigation and treatment of solid tumors has gained momentum, thereby establishing itself as a prominent area of research. This descriptive study involved the retrieval of articles about CAR-T cell therapy for solid tumors from the Web of Science Core Collection (WoSCC) database. Subsequently, bibliometric analysis and knowledge map analysis were conducted on these articles. The field under consideration is currently experiencing a period of swift advancement, as evidenced by the escalating number of publications in this domain each year. The United States holds an indisputable position as the foremost leader in this particular field, with the University of Pennsylvania emerging as the most active institution. The authors with the highest citation frequency and co-citation frequency are Carl H. June and Shannon L. Maude, respectively. The research hotspots in this field mainly focus on five aspects. Additionally, 10 emerging themes were identified. This study undertakes a comprehensive, systematic, and objective analysis and exploration of the field of CAR-T cell treatment for solid tumors, utilizing bibliometric methods. The findings of this study are expected to serve as a valuable reference and enlightenment for future research endeavors in this particular domain.

Gene therapy in preeclampsia: the dawn of a new era

Preeclampsia is a severe complication of pregnancy, affecting an estimated 4 million women annually. It is one of the leading causes of maternal and fetal mortality worldwide, and it has life-long consequences. The maternal multisystemic symptoms are driven by poor placentation, which causes syncytiotrophoblastic stress and the release of factors into the maternal bloodstream. Amongst them, the soluble fms-like tyrosine kinase-1 (sFLT-1) triggers extensive endothelial dysfunction by acting as a decoy receptor for the vascular endothelial growth factor (VEGF) and the placental growth factor (PGF). Current interventions aim to mitigate hypertension and seizures, but the only definite treatment remains induced delivery. Thus, there is a pressing need for novel therapies to remedy this situation. Notably, CBP-4888, a siRNA drug delivered subcutaneously to knock down sFLT1 expression in the placenta, has recently obtained Fast Track approval from the Food and Drug Administration (FDA) and is undergoing a phase 1 clinical trial. Such advance highlights a growing interest and significant potential in gene therapy to manage preeclampsia. This review summarizes the advances and prospects of gene therapy in treating placental dysfunction and illustrates crucial challenges and considerations for these emerging treatments.

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, as well being developed for 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, like lentivirus transduction and electroporation, result in random integration or cause significant cellular damage, which can limit the safety and efficacy of engineered cell therapies, such as CAR-T. We present hydroporation as a gentle and effective alternative for intracellular delivery. Hydroporation resulted in 1.7 to 2x 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 demonstrated scaled-up hydroporation can process 5 x 10 8 cells in less than 10 seconds, showcasing the platform as a viable solution for high-yield, precise CAR-T cell manufacturing with the potential for improved therapeutic outcomes.

HLA reduction of human T cells facilitates generation of immunologically multicompatible cellular products

ABSTRACT

Adoptive cellular therapies have shown enormous potential but are complicated by personalization. Because of HLA mismatch, rejection of transferred T cells frequently occurs, compromising the T-cell graft's functionality. This obstacle has led to the development of HLA knock-out (KO) T cells as universal donor cells. Whether such editing directly affects T-cell functionality remains poorly understood. In addition, HLA KO T cells are susceptible to missing self-recognition through natural killer (NK) cells and lack of canonical HLA class I expression may represent a safety hazard. Engineering of noncanonical HLA molecules could counteract NK-cell recognition, but further complicates the generation of cell products. Here, we show that HLA KO does not alter T-cell functionality in vitro and in vivo. Although HLA KO abrogates allogeneic T-cell responses, it elicits NK-cell recognition. To circumvent this problem, we demonstrate that selective editing of individual HLA class I molecules in primary human T cells is possible. Such HLA reduction not only inhibits T-cell alloreactivity and NK-cell recognition simultaneously, but also preserves the T-cell graft's canonical HLA class I expression. In the presence of allogeneic T cells and NK cells, T cells with remaining expression of a single, matched HLA class I allele show improved functionality in vivo in comparison with conventional allogeneic T cells. Since reduction to only a few, most frequent HLA haplotypes would already be compatible with large shares of patient populations, this approach significantly extends the toolbox to generate broadly applicable cellular products.

Allogeneic CD19-targeted CAR-T therapy in patients with severe myositis and systemic sclerosis

Allogeneic chimeric antigen receptor (CAR)-T cells hold great promise for expanding the accessibility of CAR-T therapy, whereas the risks of allograft rejection have hampered its application. Here, we genetically engineered healthy-donor-derived, CD19-targeting CAR-T cells using CRISPR-Cas9 to address the issue of immune rejection and treated one patient with refractory immune-mediated necrotizing myopathy and two patients with diffuse cutaneous systemic sclerosis with these cells. This study was registered at ClinicalTrials.gov (NCT05859997). The infused cells persisted for over 3 months, achieving complete B cell depletion within 2 weeks of treatment. During the 6-month follow-up, we observed deep remission without cytokine release syndrome or other serious adverse events in all three patients, primarily shown by the significant improvement in the clinical response index scores for the two diseases, respectively, and supported by the observations of reversal of inflammation and fibrosis. Our results demonstrate the high safety and promising immune modulatory effect of the off-the-shelf CAR-T cells in treating severe refractory autoimmune diseases.

Cancer organoids 2.0: modelling the complexity of the tumour immune microenvironment

The development of neoplasia involves a complex and continuous interplay between malignantly transformed cells and the tumour microenvironment (TME). Cancer immunotherapies targeting the immune TME have been increasingly validated in clinical trials but response rates vary substantially between tumour histologies and are often transient, idiosyncratic and confounded by resistance. Faithful experimental models of the patient-specific tumour immune microenvironment, capable of recapitulating tumour biology and immunotherapy effects, would greatly improve patient selection, target identification and definition of resistance mechanisms for immuno-oncology therapeutics. In this Review, we discuss currently available and rapidly evolving 3D tumour organoid models that capture important immune features of the TME. We highlight diverse opportunities for organoid-based investigations of tumour immunity, drug development and precision medicine.

Differential impact of genetic deletion of TIGIT or PD-1 on melanoma-specific T-lymphocytes

Immune checkpoint (IC) blockade and adoptive transfer of tumor-specific T-cells (ACT) are two major strategies to treat metastatic melanoma. Their combination can potentiate T-cell activation in the suppressive tumor microenvironment, but the autoimmune adverse effects associated with systemic injection of IC blockers persist with this strategy. ACT of tumor-reactive T-cells defective for IC expression would overcome this issue. For this purpose, PD-1 and TIGIT appear to be relevant candidates, because their co-expression on highly tumor-reactive lymphocytes limits their therapeutic efficacy within the tumor microenvironme,nt. Our study compares the consequences of PDCD1 or TIGIT genetic deletion on anti-tumor properties and T-cell fitness of melanoma-specific T lymphocytes. Transcriptomic analyses revealed down-regulation of cell cycle-related genes in PD-1KO T-cells, consistent with biological observations, whereas proliferative pathways were preserved in TIGITKO T-cells. Functional analyses showed that PD-1KO and TIGITKO T-cells displayed superior antitumor reactivity than their wild-type counterpart in vitro and in a preclinical melanoma model using immunodeficient mice. Interestingly, it appears that TIGITKO T-cells were more effective at inhibiting tumor cell proliferation in vivo, and persist longer within tumors than PD-1KO T-cells, consistent with the absence of impact of TIGIT deletion on T-cell fitness. Taken together, these results suggest that TIGIT deletion, over PD-1 deletion, in melanoma-specific T-cells is a compelling option for future immunotherapeutic strategies.

Genetic ablation of adhesion ligands mitigates rejection of allogeneic cellular immunotherapies

Allogeneic cellular immunotherapies hold promise for broad clinical implementation but face limitations due to potential rejection of donor cells by the host immune system. Silencing of beta-2 microglobulin (B2M) expression is commonly employed to evade T cell-mediated rejection by the host, although the absence of B2M is expected to trigger missing-self responses by host natural killer (NK) cells. Here, we demonstrate that genetic deletion of the adhesion ligands CD54 and CD58 in B2M-deficient chimeric antigen receptor (CAR) T cells and multi-edited induced pluripotent stem cell (iPSC)-derived CAR NK cells reduces their susceptibility to rejection by host NK cells in vitro and in vivo. The absence of adhesion ligands limits rejection in a unidirectional manner in B2M-deficient and B2M-sufficient settings without affecting the antitumor functionality of the engineered donor cells. Thus, these data suggest that genetic ablation of adhesion ligands effectively alleviates rejection by host immune cells, facilitating the implementation of universal immunotherapy.

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

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

Gene editing in allergic diseases: Identification of novel pathways and impact of deleting allergen genes

Gene editing technology has emerged as a powerful tool in all aspects of health research and continues to advance our understanding of critical and essential elements in disease pathophysiology. The clustered regularly interspaced short palindromic repeats (CRISPR) gene editing technology has been used with precision to generate gene knockouts, alter genes, and identify genes that cause disease. The full spectrum of allergic/atopic diseases, in part because of shared pathophysiology, is ripe for studies with this technology. In this way, novel culprit genes are being identified and allow for manipulation of triggering allergens to reduce allergenicity and disease. Notwithstanding current limitations on precision and potential off-target effects, newer approaches are rapidly being introduced to more fully understand specific gene functions as well as the consequences of genetic manipulation. In this review, we examine the impact of editing technologies of novel genes relevant to peanut allergy and asthma as well as how gene modification of common allergens may lead to the deletion of allergenic proteins.

Engineered CARD11-PIK3R3 T-cell therapies as weapons of cancer mass destruction

Garcia et al. discover a novel immunotherapy approach by engineering naturally occurring mutations in therapeutic T cells to strongly elevate anti-tumor activity. The authors identify a gene fusion, CARD11-PIK3R3, to increase activator protein 1 and nuclear factor-κB signaling, interleukin-2 production, and tumor death in vitro and in vivo .

Disruption of TGF-β signaling pathway is required to mediate effective killing of hepatocellular carcinoma by human iPSC-derived NK cells

Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer. Transforming growth factor beta (TGF-β) is highly expressed in the liver tumor microenvironment and is known to inhibit immune cell activity. Here, we used human induced pluripotent stem cells (iPSCs) to produce natural killer (NK) cells engineered to mediate improved anti-HCC activity. Specifically, we produced iPSC-NK cells with either knockout TGF-β receptor 2 (TGFBR2-KO) or expression of a dominant negative (DN) form of the TGF-β receptor 2 (TGFBR2-DN) combined with chimeric antigen receptors (CARs) that target either GPC3 or AFP. The TGFBR2-KO and TGFBR2-DN iPSC-NK cells are resistant to TGF-β inhibition and improved anti-HCC activity. However, expression of anti-HCC CARs on iPSC-NK cells did not lead to effective anti-HCC activity unless there was also inhibition of TGF-β activity. Our findings demonstrate that TGF-β signaling blockade is required for effective NK cell function against HCC and potentially other malignancies that express high levels of TGF-β.

An aptamer-mediated base editing platform for simultaneous knockin and multiple gene knockout for allogeneic CAR-T cells generation

Gene editing technologies hold promise for enabling the next generation of adoptive cellular therapies. In conventional gene editing platforms that rely on nuclease activity, such as clustered regularly interspaced short palindromic repeats CRISPR-associated protein 9 (CRISPR-Cas9), allow efficient introduction of genetic modifications; however, these modifications occur via the generation of DNA double-strand breaks (DSBs) and can lead to unwanted genomic alterations and genotoxicity. Here, we apply a novel modular RNA aptamer-mediated Pin-point base editing platform to simultaneously introduce multiple gene knockouts and site-specific integration of a transgene in human primary T cells. We demonstrate high editing efficiency and purity at all target sites and significantly reduced frequency of chromosomal translocations compared with the conventional CRISPR-Cas9 system. Site-specific knockin of a chimeric antigen receptor and multiplex gene knockout are achieved within a single intervention and without the requirement for additional sequence-targeting components. The ability to perform complex genome editing efficiently and precisely highlights the potential of the Pin-point platform for application in a range of advanced cell therapies.

Advances in CAR-T-cell therapy in T-cell malignancies

Significant advances have been made in chimeric antigen receptor T (CAR-T)-cell therapy for the treatment of recurrent or refractory B-cell hematologic malignancies. However, CAR-T-cell therapy has not yet achieved comparable success in the management of aggressive T-cell malignancies. This article reviews the challenges of CAR-T-cell therapy in treating T-cell malignancies and summarizes the progress of preclinical and clinical studies in this area. We present an analysis of clinical trials of CAR-T-cell therapies for the treatment of T-cell malignancies grouped by target antigen classification. Moreover, this review focuses on the major challenges encountered by CAR-T-cell therapies, including the nonspecific killing due to T-cell target antigen sharing and contamination with cell products during preparation. This review discusses strategies to overcome these challenges, presenting novel therapeutic approaches that could enhance the efficacy and applicability of CAR-T-cell therapy in the treatment of T-cell malignancies. These ideas and strategies provide important information for future studies to promote the further development and application of CAR-T-cell therapy in this field.

Deletion of CD38 enhances CD19 chimeric antigen receptor T cell function

Cell surface molecules transiently upregulated on activated T cells can play a counter-regulatory role by inhibiting T cell function. Deletion or blockade of such immune checkpoint receptors has been investigated to improve the function of engineered immune effector cells. CD38 is upregulated on activated T cells, and although there have been studies showing that CD38 can play an inhibitory role in T cells, how it does so has not fully been elucidated. In comparison with molecules such as PD1, CTLA4, LAG3, and TIM3, we found that CD38 displays more sustained and intense expression following acute activation. After deleting CD38 from human chimeric antigen receptor (CAR) T cells, we showed relative resistance to exhaustion in vitro and improved anti-tumor function in vivo. CD38 is a multifunctional ectoenzyme with hydrolase and cyclase activities. Reintroduction of CD38 mutants into T cells lacking CD38 provided further evidence supporting the understanding that CD38 plays a crucial role in producing the immunosuppressive metabolite adenosine and utilizing nicotinamide adenine dinucleotide (NAD) in human T cells. Taken together, these results highlight a role for CD38 as an immunometabolic checkpoint in T cells and lead us to propose CD38 deletion as an additional avenue for boosting CAR T cell function.

Optimizing 5'UTRs for mRNA-delivered gene editing using deep learning

mRNA therapeutics are revolutionizing the pharmaceutical industry, but methods to optimize the primary sequence for increased expression are still lacking. Here, we design 5'UTRs for efficient mRNA translation using deep learning. We perform polysome profiling of fully or partially randomized 5'UTR libraries in three cell types and find that UTR performance is highly correlated across cell types. We train models on our datasets and use them to guide the design of high-performing 5'UTRs using gradient descent and generative neural networks. We experimentally test designed 5'UTRs with mRNA encoding megaTALTM gene editing enzymes for two different gene targets and in two different cell lines. We find that the designed 5'UTRs support strong gene editing activity. Editing efficiency is correlated between cell types and gene targets, although the best performing UTR was specific to one cargo and cell type. Our results highlight the potential of model-based sequence design for mRNA therapeutics.

Nanomaterials-assisted gene editing and synthetic biology for optimizing the treatment of pulmonary diseases

The use of nanomaterials in gene editing and synthetic biology has emerged as a pivotal strategy in the pursuit of refined treatment methodologies for pulmonary disorders. This review discusses the utilization of nanomaterial-assisted gene editing tools and synthetic biology techniques to promote the development of more precise and efficient treatments for pulmonary diseases. First, we briefly outline the characterization of the respiratory system and succinctly describe the principal applications of diverse nanomaterials in lung ailment treatment. Second, we elaborate on gene-editing tools, their configurations, and assorted delivery methods, while delving into the present state of nanomaterial-facilitated gene-editing interventions for a spectrum of pulmonary diseases. Subsequently, we briefly expound on synthetic biology and its deployment in biomedicine, focusing on research advances in the diagnosis and treatment of pulmonary conditions against the backdrop of the coronavirus disease 2019 pandemic. Finally, we summarize the extant lacunae in current research and delineate prospects for advancement in this domain. This holistic approach augments the development of pioneering solutions in lung disease treatment, thereby endowing patients with more efficacious and personalized therapeutic alternatives.

Building a novel TRUCK by harnessing the endogenous IFN-gamma promoter for cytokine expression

Despite the remarkable success of chimeric antigen receptor (CAR) T therapy in hematological malignancies, its efficacy in solid tumors remains limited. Cytokine-engineered CAR T cells offer a promising avenue, yet their clinical translation is hindered by the risks associated with constitutive cytokine expression. In this proof-of-concept study, we leverage the endogenous interferon (IFN)-γ promoter for transgenic interleukin (IL)-15 expression. We demonstrate that IFN-γ expression is tightly regulated by T cell receptor signaling. By introducing an internal ribosome entry site IL15 into the 3' UTR of the IFN-γ gene via homology directed repair-mediated knock-in, we confirm that IL-15 expression can co-express with IFN-γ in an antigen stimulation-dependent manner. Importantly, the insertion of transgenes does not compromise endogenous IFN-γ expression. In vitro and in vivo data demonstrate that IL-15 driven by the IFN-γ promoter dramatically improves CAR T cells' antitumor activity, suggesting the effectiveness of IL-15 expression. Last, as a part of our efforts toward clinical translation, we have developed an innovative two-gene knock-in approach. This approach enables the simultaneous integration of CAR and IL-15 genes into TRAC and IFN-γ gene loci using a single AAV vector. CAR T cells engineered to express IL-15 using this approach demonstrate enhanced antitumor efficacy. Overall, our study underscores the feasibility of utilizing endogenous promoters for transgenic cytokines expression in CAR T cells.

CRISPR/Cas9 gene editing: a novel strategy for fighting drug resistance in respiratory disorders

Respiratory disorders are among the conditions that affect the respiratory system. The healthcare sector faces challenges due to the emergence of drug resistance to prescribed medications for these illnesses. However, there is a technology called CRISPR/Cas9, which uses RNA to guide DNA targeting. This technology has revolutionized our ability to manipulate and visualize the genome, leading to advancements in research and treatment development. It can effectively reverse epigenetic alterations that contribute to drug resistance. Some studies focused on health have shown that targeting genes using CRISPR/Cas9 can be challenging when it comes to reducing drug resistance in patients with respiratory disorders. Nevertheless, it is important to acknowledge the limitations of this technology, such as off-target effects, immune system reactions to Cas9, and challenges associated with delivery methods. Despite these limitations, this review aims to provide knowledge about CRISPR/Cas9 genome editing tools and explore how they can help overcome resistance in patients with respiratory disorders. Additionally, this study discusses concerns related to applications of CRISPR and provides an overview of successful clinical trial studies.

Base editing strategies to convert CAG to CAA diminish the disease-causing mutation in Huntington's disease

An expanded CAG repeat in the huntingtin gene (HTT) causes Huntington's disease (HD). Since the length of uninterrupted CAG repeat, not polyglutamine, determines the age-at-onset in HD, base editing strategies to convert CAG to CAA are anticipated to delay onset by shortening the uninterrupted CAG repeat. Here, we developed base editing strategies to convert CAG in the repeat to CAA and determined their molecular outcomes and effects on relevant disease phenotypes. Base editing strategies employing combinations of cytosine base editors and guide RNAs (gRNAs) efficiently converted CAG to CAA at various sites in the CAG repeat without generating significant indels, off-target edits, or transcriptome alterations, demonstrating their feasibility and specificity. Candidate BE strategies converted CAG to CAA on both expanded and non-expanded CAG repeats without altering HTT mRNA and protein levels. In addition, somatic CAG repeat expansion, which is the major disease driver in HD, was significantly decreased in the liver by a candidate BE strategy treatment in HD knock-in mice carrying canonical CAG repeats. Notably, CAG repeat expansion was abolished entirely in HD knock-in mice carrying CAA-interrupted repeats, supporting the therapeutic potential of CAG-to-CAA conversion strategies in HD and potentially other repeat expansion disorders.

Metabolic priming of GD2 TRAC-CAR T cells during manufacturing promotes memory phenotypes while enhancing persistence

Manufacturing chimeric antigen receptor (CAR) T cell therapies is complex, with limited understanding of how medium composition impacts T cell phenotypes. CRISPR-Cas9 ribonucleoproteins can precisely insert a CAR sequence while disrupting the endogenous T cell receptor alpha constant (TRAC) gene resulting in TRAC-CAR T cells with an enriched stem cell memory T cell population, a process that could be further optimized through modifications to the medium composition. In this study we generated anti-GD2 TRAC-CAR T cells using "metabolic priming" (MP), where the cells were activated in glucose/glutamine-low medium and then expanded in glucose/glutamine-high medium. T cell products were evaluated using spectral flow cytometry, metabolic assays, cytokine production, cytotoxicity assays in vitro, and potency against human GD2+ xenograft neuroblastoma models in vivo. Compared with standard TRAC-CAR T cells, MP TRAC-CAR T cells showed less glycolysis, higher CCR7/CD62L expression, more bound NAD(P)H activity, and reduced IFN-γ, IL-2, IP-10, IL-1β, IL-17, and TGF-β production at the end of manufacturing ex vivo, with increased central memory CAR T cells and better persistence observed in vivo. MP with medium during CAR T cell biomanufacturing can minimize glycolysis and enrich memory phenotypes ex vivo, which could lead to better responses against solid tumors in vivo.

Enhancing cell-based therapies with synthetic gene circuits responsive to molecular stimuli

Synthetic biology aims to contribute to the development of next-generation patient-specific cell-based therapies for chronic diseases especially through the construction of sophisticated synthetic gene switches to enhance the safety and spatiotemporal controllability of engineered cells. Indeed, switches that sense and process specific cues, which may be either externally administered triggers or endogenous disease-associated molecules, have emerged as powerful tools for programming and fine-tuning therapeutic outputs. Living engineered cells, often referred to as designer cells, incorporating such switches are delivered to patients either as encapsulated cell implants or by infusion, as in the case of the clinically approved CAR-T cell therapies. Here, we review recent developments in synthetic gene switches responsive to molecular stimuli, spanning regulatory mechanisms acting at the transcriptional, translational, and posttranslational levels. We also discuss current challenges facing clinical translation of cell-based therapies employing these devices.

Downregulation of Ripk1 and Nsf mediated by CRISPR-CasRx ameliorates stroke volume and neurological deficits after ischemia stroke in mice

Necroptosis is implicated in the pathogenesis of ischemic stroke. However, the mechanism underlying the sequential recruitment of receptor-interacting protein kinase 1 (RIPK1) and N-ethylmaleimide-sensitive fusion ATPase (NSF) in initiating necroptosis remains poorly understood, and the role of NSF in ischemic stroke is a subject of controversy. Here, we utilized a recently emerging RNA-targeting CRISPR system known as CasRx, delivered by AAVs, to knockdown Ripk1 mRNA and Nsf mRNA around the ischemic brain tissue. This approach resulted in a reduction in infarct and edema volume, as well as an improvement in neurological deficits assessed by Bederson score, RotaRod test, and Adhesive removal test, which were achieved by RIPK1/receptor-interacting protein kinase 3/mixed lineage kinase domain-like protein signaling pathway involved in neuronal necroptosis. In conclusion, the downregulation of Ripk1 mRNA and Nsf mRNA mediated by CRISPR-CasRx holds promise for future therapeutic applications aimed at ameliorating cerebral lesions and neurological deficits following the ischemic stroke.

Progress and pitfalls of gene editing technology in CAR-T cell therapy: a state-of-the-art review

CAR-T cell therapy has shown remarkable promise in treating B-cell malignancies, which has sparked optimism about its potential to treat other types of cancer as well. Nevertheless, the Expectations of CAR-T cell therapy in solid tumors and non-B cell hematologic malignancies have not been met. Furthermore, safety concerns regarding the use of viral vectors and the current personalized production process are other bottlenecks that limit its widespread use. In recent years the use of gene editing technology in CAR-T cell therapy has opened a new way to unleash the latent potentials of CAR-T cell therapy and lessen its associated challenges. Moreover, gene editing tools have paved the way to manufacturing CAR-T cells in a fully non-viral approach as well as providing a universal, off-the-shelf product. Despite all the advantages of gene editing strategies, the off-target activity of classical gene editing tools (ZFNs, TALENs, and CRISPR/Cas9) remains a major concern. Accordingly, several efforts have been made in recent years to reduce their off-target activity and genotoxicity, leading to the introduction of advanced gene editing tools with an improved safety profile. In this review, we begin by examining advanced gene editing tools, providing an overview of how these technologies are currently being applied in clinical trials of CAR-T cell therapies. Following this, we explore various gene editing strategies aimed at enhancing the safety and efficacy of CAR-T cell therapy.

Precision in Action: The Role of Clustered Regularly Interspaced Short Palindromic Repeats/Cas in Gene Therapies

Clustered Regularly Interspaced Short Palindromic Repeat (CRISPR)-associated enzyme-CAS holds great promise for treating many uncured human diseases and illnesses by precisely correcting harmful point mutations and disrupting disease-causing genes. The recent Food and Drug Association (FDA) approval of the first CRISPR-based gene therapy for sickle cell anemia marks the beginning of a new era in gene editing. However, delivering CRISPR specifically into diseased cells in vivo is a significant challenge and an area of intense research. The identification of new CRISPR/Cas variants, particularly ultra-compact CAS systems with robust gene editing activities, paves the way for the low-capacity delivery vectors to be used in gene therapies. CRISPR/Cas technology has evolved beyond editing DNA to cover a wide spectrum of functionalities, including RNA targeting, disease diagnosis, transcriptional/epigenetic regulation, chromatin imaging, high-throughput screening, and new disease modeling. CRISPR/Cas can be used to engineer B-cells to produce potent antibodies for more effective vaccines and enhance CAR T-cells for the more precise and efficient targeting of tumor cells. However, CRISPR/Cas technology has challenges, including off-target effects, toxicity, immune responses, and inadequate tissue-specific delivery. Overcoming these challenges necessitates the development of a more effective and specific CRISPR/Cas delivery system. This entails strategically utilizing specific gRNAs in conjunction with robust CRISPR/Cas variants to mitigate off-target effects. This review seeks to delve into the intricacies of the CRISPR/Cas mechanism, explore progress in gene therapies, evaluate gene delivery systems, highlight limitations, outline necessary precautions, and scrutinize the ethical considerations associated with its application.

Recent Updates of the CRISPR/Cas9 Genome Editing System: Novel Approaches to Regulate Its Spatiotemporal Control by Genetic and Physicochemical Strategies

The genome editing approach by clustered regularly interspaced short palindromic repeats (CRISPR)/associated protein 9 (CRISPR/Cas9) is a revolutionary advancement in genetic engineering. Owing to its simple design and powerful genome-editing capability, it offers a promising strategy for the treatment of different infectious, metabolic, and genetic diseases. The crystal structure of Streptococcus pyogenes Cas9 (SpCas9) in complex with sgRNA and its target DNA at 2.5 Å resolution reveals a groove accommodating sgRNA:DNA heteroduplex within a bilobate architecture with target recognition (REC) and nuclease (NUC) domains. The presence of a PAM is significantly required for target recognition, R-loop formation, and strand scission. Recently, the spatiotemporal control of CRISPR/Cas9 genome editing has been considerably improved by genetic, chemical, and physical regulatory strategies. The use of genetic modifiers anti-CRISPR proteins, cell-specific promoters, and histone acetyl transferases has uplifted the application of CRISPR/Cas9 as a future-generation genome editing tool. In addition, interventions by chemical control, small-molecule activators, oligonucleotide conjugates and bioresponsive delivery carriers have improved its application in other areas of biological fields. Furthermore, the intermediation of physical control by using heat-, light-, magnetism-, and ultrasound-responsive elements attached to this molecular tool has revolutionized genome editing further. These strategies significantly reduce CRISPR/Cas9's undesirable off-target effects. However, other undesirable effects still offer some challenges for comprehensive clinical translation using this genome-editing approach. In this review, we summarize recent advances in CRISPR/Cas9 structure, mechanistic action, and the role of small-molecule activators, inhibitors, promoters, and physical approaches. Finally, off-target measurement approaches, challenges, future prospects, and clinical applications are discussed.

OliTag-seq enhances in cellulo detection of CRISPR-Cas9 off-targets

The potential for off-target mutations is a critical concern for the therapeutic application of CRISPR-Cas9 gene editing. Current detection methodologies, such as GUIDE-seq, exhibit limitations in oligonucleotide integration efficiency and sensitivity, which could hinder their utility in clinical settings. To address these issues, we introduce OliTag-seq, an in-cellulo assay specifically engineered to enhance the detection of off-target events. OliTag-seq employs a stable oligonucleotide for precise break tagging and an innovative triple-priming amplification strategy, significantly improving the scope and accuracy of off-target site identification. This method surpasses traditional assays by providing comprehensive coverage across various sgRNAs and genomic targets. Our research particularly highlights the superior sensitivity of induced pluripotent stem cells (iPSCs) in detecting off-target mutations, advocating for using patient-derived iPSCs for refined off-target analysis in therapeutic gene editing. Furthermore, we provide evidence that prolonged Cas9 expression and transient HDAC inhibitor treatments enhance the assay's ability to uncover off-target events. OliTag-seq merges the high sensitivity typical of in vitro assays with the practical application of cellular contexts. This approach significantly improves the safety and efficacy profiles of CRISPR-Cas9 interventions in research and clinical environments, positioning it as an essential tool for the precise assessment and refinement of genome editing applications.

Electrotransfer for nucleic acid and protein delivery

Electrotransfer of nucleic acids and proteins has become crucial in biotechnology for gene augmentation and genome editing. This review explores the applications of electrotransfer in both ex vivo and in vivo scenarios, emphasizing biomedical uses. We provide insights into completed clinical trials and successful instances of nucleic acid and protein electrotransfer into therapeutically relevant cells such as immune cells and stem and progenitor cells. In addition, we delve into emerging areas of electrotransfer where nanotechnology and deep learning techniques overcome the limitations of traditional electroporation.

The BTLA-HVEM axis restricts CAR T cell efficacy in cancer

The efficacy of T cell-based immunotherapies is limited by immunosuppressive pressures in the tumor microenvironment. Here we show a predominant role for the interaction between BTLA on effector T cells and HVEM (TNFRSF14) on immunosuppressive tumor microenvironment cells, namely regulatory T cells. High BTLA expression in chimeric antigen receptor (CAR) T cells correlated with poor clinical response to treatment. Therefore, we deleted BTLA in CAR T cells and show improved tumor control and persistence in models of lymphoma and solid malignancies. Mechanistically, BTLA inhibits CAR T cells via recruitment of tyrosine phosphatases SHP-1 and SHP-2, upon trans engagement with HVEM. BTLA knockout thus promotes CAR signaling and subsequently enhances effector function. Overall, these data indicate that the BTLA-HVEM axis is a crucial immune checkpoint in CAR T cell immunotherapy and warrants the use of strategies to overcome this barrier.

CRISPR technologies for genome, epigenome and transcriptome editing

Our ability to edit genomes lags behind our capacity to sequence them, but the growing understanding of CRISPR biology and its application to genome, epigenome and transcriptome engineering is narrowing this gap. In this Review, we discuss recent developments of various CRISPR-based systems that can transiently or permanently modify the genome and the transcriptome. The discovery of further CRISPR enzymes and systems through functional metagenomics has meaningfully broadened the applicability of CRISPR-based editing. Engineered Cas variants offer diverse capabilities such as base editing, prime editing, gene insertion and gene regulation, thereby providing a panoply of tools for the scientific community. We highlight the strengths and weaknesses of current CRISPR tools, considering their efficiency, precision, specificity, reliance on cellular DNA repair mechanisms and their applications in both fundamental biology and therapeutics. Finally, we discuss ongoing clinical trials that illustrate the potential impact of CRISPR systems on human health.

Recent progress in chimeric antigen receptor therapy for acute myeloid leukemia

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

Highly Efficient Ex Vivo Correction of COL7A1 through Ribonucleoprotein-Based CRISPR/Cas9 and Homology-Directed Repair to Treat Recessive Dystrophic Epidermolysis Bullosa

Recessive dystrophic epidermolysis bullosa (RDEB) is a rare and severe genetic skin disease responsible for blistering of the skin and mucosa after minor trauma. RDEB is caused by a wide variety of variants in COL7A1 encoding type VII Collagen, the major component of anchoring fibrils that form key attachment structures for dermal-epidermal adherence. In this study, we achieved highly efficient COL7A1 editing in primary RDEB keratinocytes and fibroblasts from 2 patients homozygous for the c.6508C>T (p.Gln2170∗) variant through CRISPR/Cas9-mediated homology-directed repair. Three guide RNAs targeting the c.6508C>T variant or harboring sequences were delivered together with high-fidelity Cas9 as a ribonucleoprotein complex. Among them, one achieved 73% cleavage activity in primary RDEB keratinocytes and RDEB fibroblasts. Then, we treated RDEB keratinocytes and RDEB fibroblasts with this specific ribonucleoprotein complex and the corresponding donor template delivered as single-stranded oligodeoxynucleotide and achieved up to 58% of genetic correction as well as type VII Collagen rescue. Finally, grafting of corrected 3-dimensional skin onto nude mice induced re-expression and normal localization of type VII Collagen as well as anchoring fibril formation at the dermal-epidermal junction 5 and 10 weeks after grafting. With this promising nonviral approach, we achieved therapeutically relevant specific gene editing that could be applicable to all variants in exon 80 of COL7A1 in primary RDEB cells.

Non-viral expression of chimeric antigen receptors with multiplex gene editing in primary T cells

Efficient engineering of T cells to express exogenous tumor-targeting receptors such as chimeric antigen receptors (CARs) or T-cell receptors (TCRs) is a key requirement of effective adoptive cell therapy for cancer. Genome editing technologies, such as CRISPR/Cas9, can further alter the functional characteristics of therapeutic T cells through the knockout of genes of interest while knocking in synthetic receptors that can recognize cancer cells. Performing multiple rounds of gene transfer with precise genome editing, termed multiplexing, remains a key challenge, especially for non-viral delivery platforms. Here, we demonstrate the efficient production of primary human T cells incorporating the knockout of three clinically relevant genes (B2M, TRAC, and PD1) along with the non-viral transfection of a CAR targeting disialoganglioside GD2. Multiplexed knockout results in high on-target deletion for all three genes, with low off-target editing and chromosome alterations. Incorporating non-viral delivery to knock in a GD2-CAR resulted in a TRAC-B2M-PD1-deficient GD2 CAR T-cell product with a central memory cell phenotype and high cytotoxicity against GD2-expressing neuroblastoma target cells. Multiplexed gene-editing with non-viral delivery by CRISPR/Cas9 is feasible and safe, with a high potential for rapid and efficient manufacturing of highly potent allogeneic CAR T-cell products.

CRISPR in Targeted Therapy and Adoptive T Cell Immunotherapy for Hepatocellular Carcinoma

Despite recent therapeutic advancements, outcomes for advanced hepatocellular carcinoma (HCC) remain unsatisfactory, highlighting the need for novel treatments. The CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) gene-editing technology offers innovative treatment approaches, involving genetic manipulation of either cancer cells or adoptive T cells to combat HCC. This review comprehensively assesses the applications of CRISPR systems in HCC treatment, focusing on in vivo targeting of cancer cells and the development of chimeric antigen receptor (CAR) T cells and T cell receptor (TCR)-engineered T cells. We explore potential synergies between CRISPR-based cancer therapeutics and existing treatment options, discussing ongoing clinical trials and the role of CRISPR technology in improving HCC treatment outcomes with advanced safety measures. In summary, this review provides insights into the promising prospects and current challenges of using CRISPR technology in HCC treatment, with the ultimate goal of improving patient outcomes and revolutionizing the landscape of HCC therapeutics.

The recent advancement of TCR-T cell therapies for cancer treatment

Adoptive cell therapies involve infusing engineered immune cells into cancer patients to recognize and eliminate tumor cells. Adoptive cell therapy, as a form of living drug, has undergone explosive growth over the past decade. The recognition of tumor antigens by the T-cell receptor (TCR) is one of the natural mechanisms that the immune system used to eliminate tumor cells. TCR-T cell therapy, which involves introducing exogenous TCRs into patients' T cells, is a novel cell therapy strategy. TCR-T cell therapy can target the entire proteome of cancer cells. Engineering T cells with exogenous TCRs to help patients combat cancer has achieved success in clinical trials, particularly in treating solid tumors. In this review, we examine the progress of TCR-T cell therapy over the past five years. This includes the discovery of new tumor antigens, protein engineering techniques for TCR, reprogramming strategies for TCR-T cell therapy, clinical studies on TCR-T cell therapy, and the advancement of TCR-T cell therapy in China. We also propose several potential directions for the future development of TCR-T cell therapy.

Development of pharmacological immunoregulatory anti-cancer therapeutics: current mechanistic studies and clinical opportunities

Immunotherapy represented by anti-PD-(L)1 and anti-CTLA-4 inhibitors has revolutionized cancer treatment, but challenges related to resistance and toxicity still remain. Due to the advancement of immuno-oncology, an increasing number of novel immunoregulatory targets and mechanisms are being revealed, with relevant therapies promising to improve clinical immunotherapy in the foreseeable future. Therefore, comprehending the larger picture is important. In this review, we analyze and summarize the current landscape of preclinical and translational mechanistic research, drug development, and clinical trials that brought about next-generation pharmacological immunoregulatory anti-cancer agents and drug candidates beyond classical immune checkpoint inhibitors. Along with further clarification of cancer immunobiology and advances in antibody engineering, agents targeting additional inhibitory immune checkpoints, including LAG-3, TIM-3, TIGIT, CD47, and B7 family members are becoming an important part of cancer immunotherapy research and discovery, as are structurally and functionally optimized novel anti-PD-(L)1 and anti-CTLA-4 agents and agonists of co-stimulatory molecules of T cells. Exemplified by bispecific T cell engagers, newly emerging bi-specific and multi-specific antibodies targeting immunoregulatory molecules can provide considerable clinical benefits. Next-generation agents also include immune epigenetic drugs and cytokine-based therapeutics. Cell therapies, cancer vaccines, and oncolytic viruses are not covered in this review. This comprehensive review might aid in further development and the fastest possible clinical adoption of effective immuno-oncology modalities for the benefit of patients.

Immunogenicity Risk Assessment of Process-Related Impurities in An Engineered T Cell Receptor Cellular Product

Cell therapies such as genetically modified T cells have emerged as a promising and viable treatment for hematologic cancers and are being aggressively pursued for a wide range of diseases and conditions that were previously difficult to treat or had no cure. The process development requires genetic modifications to T cells to express a receptor (engineered T cell receptor (eTCR)) of specific binding qualities to the desired target. Protein reagents utilized during the cell therapy manufacturing process, to facilitate these genetic modifications, are often present as process-related impurities at residual levels in the final drug product and can represent a potential immunogenicity risk upon infusion. This manuscript presents a framework for the qualification of an assay for assessing the immunogenicity risk of AA6 and Cas9 residuals. The same framework applies for other residuals; however, AAV6 and Cas9 were selected as they were residuals from the manufacturing of an engineered T cell receptor cellular product in development. The manuscript: 1) elucidates theoretical risks, 2) summarizes analytical data collected during process development, 3) describes the qualification of an in vitro human PBMC cytokine release assay to assess immunogenicity risk from cellular product associated process residuals; 4) identifies a multiplexed inflammatory innate and adaptive cytokine panel with pre-defined criteria using relevant positive controls; and 5) discusses qualification challenges and potential solutions for establishing meaningful thresholds. The assessment is not only relevant to establishing safe exposure levels of these residuals but also in guiding risk assessment and CMC strategy during the conduct of clinical trials.

Regulatory mechanisms of PD-1/PD-L1 in cancers

Immune evasion contributes to cancer growth and progression. Cancer cells have the ability to activate different immune checkpoint pathways that harbor immunosuppressive functions. The programmed death protein 1 (PD-1) and programmed cell death ligands (PD-Ls) are considered to be the major immune checkpoint molecules. The interaction of PD-1 and PD-L1 negatively regulates adaptive immune response mainly by inhibiting the activity of effector T cells while enhancing the function of immunosuppressive regulatory T cells (Tregs), largely contributing to the maintenance of immune homeostasis that prevents dysregulated immunity and harmful immune responses. However, cancer cells exploit the PD-1/PD-L1 axis to cause immune escape in cancer development and progression. Blockade of PD-1/PD-L1 by neutralizing antibodies restores T cells activity and enhances anti-tumor immunity, achieving remarkable success in cancer therapy. Therefore, the regulatory mechanisms of PD-1/PD-L1 in cancers have attracted an increasing attention. This article aims to provide a comprehensive review of the roles of the PD-1/PD-L1 signaling in human autoimmune diseases and cancers. We summarize all aspects of regulatory mechanisms underlying the expression and activity of PD-1 and PD-L1 in cancers, including genetic, epigenetic, post-transcriptional and post-translational regulatory mechanisms. In addition, we further summarize the progress in clinical research on the antitumor effects of targeting PD-1/PD-L1 antibodies alone and in combination with other therapeutic approaches, providing new strategies for finding new tumor markers and developing combined therapeutic approaches.

Structure and genome editing of type I-B CRISPR-Cas

Type I CRISPR-Cas systems employ multi-subunit effector Cascade and helicase-nuclease Cas3 to target and degrade foreign nucleic acids, representing the most abundant RNA-guided adaptive immune systems in prokaryotes. Their ability to cause long fragment deletions have led to increasing interests in eukaryotic genome editing. While the Cascade structures of all other six type I systems have been determined, the structure of the most evolutionarily conserved type I-B Cascade is still missing. Here, we present two cryo-EM structures of the Synechocystis sp. PCC 6714 (Syn) type I-B Cascade, revealing the molecular mechanisms that underlie RNA-directed Cascade assembly, target DNA recognition, and local conformational changes of the effector complex upon R-loop formation. Remarkably, a loop of Cas5 directly intercalated into the major groove of the PAM and facilitated PAM recognition. We further characterized the genome editing profiles of this I-B Cascade-Cas3 in human CD3+ T cells using mRNA-mediated delivery, which led to unidirectional 4.5 kb deletion in TRAC locus and achieved an editing efficiency up to 41.2%. Our study provides the structural basis for understanding target DNA recognition by type I-B Cascade and lays foundation for harnessing this system for long range genome editing in human T cells.

Autoimmune CD8+ T cells in type 1 diabetes: from single-cell RNA sequencing to T-cell receptor redirection

Type 1 diabetes (T1D) is an organ-specific autoimmune disease caused by pancreatic β cell destruction and mediated primarily by autoreactive CD8+ T cells. It has been shown that only a small number of stem cell-like β cell-specific CD8+ T cells are needed to convert normal mice into T1D mice; thus, it is likely that T1D can be cured or significantly improved by modulating or altering self-reactive CD8+ T cells. However, stem cell-type, effector and exhausted CD8+ T cells play intricate and important roles in T1D. The highly diverse T-cell receptors (TCRs) also make precise and stable targeted therapy more difficult. Therefore, this review will investigate the mechanisms of autoimmune CD8+ T cells and TCRs in T1D, as well as the related single-cell RNA sequencing (ScRNA-Seq), CRISPR/Cas9, chimeric antigen receptor T-cell (CAR-T) and T-cell receptor-gene engineered T cells (TCR-T), for a detailed and clear overview. This review highlights that targeting CD8+ T cells and their TCRs may be a potential strategy for predicting or treating T1D.

mRNA-based therapeutic strategies for cancer treatment

In the rapidly evolving landscape of medical research, the emergence of RNA-based therapeutics is paradigm shifting. It is mainly driven by the molecular adaptability and capacity to provide precision in targeting. The coronavirus disease 2019 pandemic crisis underscored the effectiveness of the mRNA therapeutic development platform and brought it to the forefront of RNA-based interventions. These RNA-based therapeutic approaches can reshape gene expression, manipulate cellular functions, and correct the aberrant molecular processes underlying various diseases. The new technologies hold the potential to engineer and deliver tailored therapeutic agents to tackle genetic disorders, cancers, and infectious diseases in a highly personalized and precisely tuned manner. The review discusses the most recent advancements in the field of mRNA therapeutics for cancer treatment, with a focus on the features of the most utilized RNA-based therapeutic interventions, current pre-clinical and clinical developments, and the remaining challenges in delivery strategies, effectiveness, and safety considerations.

The potential and promise for clinical application of adoptive T cell therapy in cancer

Adoptive cell therapy has revolutionized cancer treatment, especially for hematologic malignancies. T cells are the most extensively utilized cells in adoptive cell therapy. Currently, tumor-infiltrating lymphocytes, T cell receptor-transgenic T cells and chimeric antigen receptor T cells are the three main adoptive T cell therapies. Tumor-infiltrating lymphocytes kill tumors by reinfusing enlarged lymphocytes that naturally target tumor-specific antigens into the patient. T cell receptor-transgenic T cells have the ability to specifically destroy tumor cells via the precise recognition of exogenous T cell receptors with major histocompatibility complex. Chimeric antigen receptor T cells transfer genes with specific antigen recognition structural domains and T cell activation signals into T cells, allowing T cells to attack tumors without the assistance of major histocompatibility complex. Many barriers have been demonstrated to affect the clinical efficacy of adoptive T cell therapy, such as tumor heterogeneity and antigen loss, hard trafficking and infiltration, immunosuppressive tumor microenvironment and T cell exhaustion. Several strategies to improve the efficacy of adoptive T cell therapy have been explored, including multispecific chimeric antigen receptor T cell therapy, combination with immune checkpoint blockade, targeting the immunosuppressive tumor microenvironment, etc. In this review, we will summarize the current status and clinical application, followed by major bottlenecks in adoptive T cell therapy. In addition, we will discuss the promising strategies to improve adoptive T cell therapy. Adoptive T cell therapy will result in even more incredible advancements in solid tumors if the aforementioned problems can be handled.

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

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

Expanding the horizon of transient CAR T therapeutics using virus-free technology

The extraordinary success that chimeric antigen receptor (CAR) T cell therapies have shown over the years on fighting hematological malignancies is evidenced by the six FDA-approved products present on the market. CAR T treatments have forever changed the way we understand cellular immunotherapies, as current research in the topic is expanding even outside the field of cancer with very promising results. Until now, virus-based strategies have been used for CAR T cell manufacturing. However, this methodology presents relevant limitations that need to be addressed prior to wide spreading this technology to other pathologies and in order to optimize current cancer treatments. Several approaches are being explored to overcome these challenges such as virus-free alternatives that additionally offer the possibility of developing transient CAR expression or in vivo T cell modification. In this review, we aim to spotlight a pivotal juncture in the history of medicine where a significant change in perspective is occurring. We review the current progress made on viral-based CAR T therapies as well as their limitations and we discuss the future outlook of virus-free CAR T strategies to overcome current challenges and achieve affordable immunotherapies for a wide variety of pathologies, including cancer.

ScRNA-seq reveals novel immune-suppressive T cells and investigates CMV-TCR-T cells cytotoxicity against GBM

BACKGROUND

Glioblastoma (GBM) is a fatal primary brain malignancy in adults. Previous studies have shown that cytomegalovirus (CMV) is a risk factor for tumorigenesis and aggressiveness for glioblastoma. However, little is known about how CMV infection affects immune cells in the tumor microenvironment of GBM. Furthermore, there has been almost no engineered T-cell receptor (TCR)-T targeting CMV for GBM research to date.

METHODS

We evaluated the CMV infection status of patients with GBM's tumor tissue by immune electron microscopy, immunofluorescence, and droplet digital PCR. We performed single-cell RNA sequencing for CMV-infected GBM to investigate the effects of CMV on the GBM immune microenvironment. CellChat was applied to analyze the interaction between cells in the GBM tumor microenvironment. Additionally, we conducted single-cell TCR/B cell receptor (BCR) sequencing and Grouping of Lymphocyte Interactions with Paratope Hotspots 2 algorithms to acquire specific CMV-TCR sequences. Genetic engineering was used to introduce CMV-TCR into primary T cells derived from patients with CMV-infected GBM. Flow cytometry was used to measure the proportion and cytotoxicity status of T cells in vitro.

RESULTS

We identified two novel immune cell subpopulations in CMV-infected GBM, which were bipositive CD68+SOX2+ tumor-associated macrophages and FXYD6+ T cells. We highlighted that the interaction between bipositive TAMs or cancer cells and T cells was predominantly focused on FXYD6+ T cells rather than regulatory T cells (Tregs), whereas, FXYD6+ T cells were further identified as a group of novel immunosuppressive T cells. CMV-TCR-T cells showed significant therapeutic effects on the human-derived orthotopic GBM mice model.

CONCLUSIONS

These findings provided an insight into the underlying mechanism of CMV infection promoting the GBM immunosuppression, and provided a novel potential immunotherapy strategy for patients with GBM.

CAR affinity modulates the sensitivity of CAR-T cells to PD-1/PD-L1-mediated inhibition

Chimeric antigen receptor (CAR)-T cell therapy for solid tumors faces significant hurdles, including T-cell inhibition mediated by the PD-1/PD-L1 axis. The effects of disrupting this pathway on T-cells are being actively explored and controversial outcomes have been reported. Here, we hypothesize that CAR-antigen affinity may be a key factor modulating T-cell susceptibility towards the PD-1/PD-L1 axis. We systematically interrogate CAR-T cells targeting HER2 with either low (LA) or high affinity (HA) in various preclinical models. Our results reveal an increased sensitivity of LA CAR-T cells to PD-L1-mediated inhibition when compared to their HA counterparts by using in vitro models of tumor cell lines and supported lipid bilayers modified to display varying PD-L1 densities. CRISPR/Cas9-mediated knockout (KO) of PD-1 enhances LA CAR-T cell cytokine secretion and polyfunctionality in vitro and antitumor effect in vivo and results in the downregulation of gene signatures related to T-cell exhaustion. By contrast, HA CAR-T cell features remain unaffected following PD-1 KO. This behavior holds true for CD28 and ICOS but not 4-1BB co-stimulated CAR-T cells, which are less sensitive to PD-L1 inhibition albeit targeting the antigen with LA. Our findings may inform CAR-T therapies involving disruption of PD-1/PD-L1 pathway tailored in particular for effective treatment of solid tumors.

Engineering CRISPR/Cas9 therapeutics for cancer precision medicine

The discovery of Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) and CRISPR-associated protein 9 (Cas9) technology has revolutionized field of cancer treatment. This review explores usage of CRISPR/Cas9 for editing and investigating genes involved in human carcinogenesis. It provides insights into the development of CRISPR as a genetic tool. Also, it explores recent developments and tools available in designing CRISPR/Cas9 systems for targeting oncogenic genes for cancer treatment. Further, we delve into an overview of cancer biology, highlighting key genetic alterations and signaling pathways whose deletion prevents malignancies. This fundamental knowledge enables a deeper understanding of how CRISPR/Cas9 can be tailored to address specific genetic aberrations and offer personalized therapeutic approaches. In this review, we showcase studies and preclinical trials that show the utility of CRISPR/Cas9 in disrupting oncogenic targets, modulating tumor microenvironment and increasing the efficiency of available anti treatments. It also provides insight into the use of CRISPR high throughput screens for cancer biomarker identifications and CRISPR based screening for drug discovery. In conclusion, this review offers an overview of exciting developments in engineering CRISPR/Cas9 therapeutics for cancer treatment and highlights the transformative potential of CRISPR for innovation and effective cancer treatments.

Rationale for immune checkpoint inhibitors plus targeted therapy for advanced renal cell carcinoma

Renal cell carcinoma (RCC) is a frequent urological malignancy characterized by a high rate of metastasis and lethality. The treatment strategy for advanced RCC has moved through multiple iterations over the past three decades. Initially, cytokine treatment was the only systemic treatment option for patients with RCC. With the development of medicine, antiangiogenic agents targeting vascular endothelial growth factor and mammalian target of rapamycin and immunotherapy, immune checkpoint inhibitors (ICIs) have emerged and received several achievements in the therapeutics of advanced RCC. However, ICIs have still not brought completely satisfactory results due to drug resistance and undesirable side effects. For the past years, the interests form researchers have been attracted by the combination of ICIs and targeted therapy for advanced RCC and the angiogenesis and immunogenic tumor microenvironmental variations in RCC. Therefore, we emphasize the potential principle and the clinical progress of ICIs combined with targeted treatment of advanced RCC, and summarize the future direction.

CRISPR-Cas9 applications in T cells and adoptive T cell therapies

T cell immunity is central to contemporary cancer and autoimmune therapies, encompassing immune checkpoint blockade and adoptive T cell therapies. Their diverse characteristics can be reprogrammed by different immune challenges dependent on antigen stimulation levels, metabolic conditions, and the degree of inflammation. T cell-based therapeutic strategies are gaining widespread adoption in oncology and treating inflammatory conditions. Emerging researches reveal that clustered regularly interspaced palindromic repeats-associated protein 9 (CRISPR-Cas9) genome editing has enabled T cells to be more adaptable to specific microenvironments, opening the door to advanced T cell therapies in preclinical and clinical trials. CRISPR-Cas9 can edit both primary T cells and engineered T cells, including CAR-T and TCR-T, in vivo and in vitro to regulate T cell differentiation and activation states. This review first provides a comprehensive summary of the role of CRISPR-Cas9 in T cells and its applications in preclinical and clinical studies for T cell-based therapies. We also explore the application of CRISPR screen high-throughput technology in editing T cells and anticipate the current limitations of CRISPR-Cas9, including off-target effects and delivery challenges, and envisioned improvements in related technologies for disease screening, diagnosis, and treatment.