Enhanced safety and efficacy of protease-regulated CAR-T cell receptors

The development and potent antitumor efficacy of CD44/CD133 dual-targeting IL7Rα-armored CAR-T cells against glioblastoma

Tumor heterogeneity and an immunosuppressive microenvironment pose significant challenges for immunotherapy against solid tumors, particularly glioblastoma multiforme (GBM). Recent studies have highlighted the crucial role of glioma stem cells (GSCs) in tumor recurrence and therapeutic resistance. In this context, we developed a tandem chimeric antigen receptor (CAR)-T cell targeting CD44 and CD133 (PROM1), containing a truncated IL-7 receptor alpha intracellular domain (Δ7R) between the CD28 costimulatory receptor and the CD3ζ signaling chain (Tanζ-T28-Δ7R). Our target identification and validation were carried out using GSCs, samples from GBM patients, and the corresponding sequencing data. The antitumor efficacy of CAR-T cells was evaluated in patient-derived GSCs, intracranial xenograft models, patient-derived xenograft models, and glioblastoma organoids (GBOs). Single-cell RNA sequencing and mass cytometry were used to determine the immune phenotypes of CAR-T cells. We showed that locoregionally administered Tanζ-T28-Δ7R CAR-T cells induced long-term tumor regression with the desired safety outcomes. Patient-derived autologous Tanζ-T28-Δ7R CAR-T cells showed robust antitumor activity against GBOs. Our pre-clinical data has demonstrated the translational potential of Tanζ-T28-Δ7R CAR-T cell against GBM.

Engineering Gene and Protein Switches for Regulation of Lineage-Specifying Transcription Factors

Human pluripotent stem cells (hPSCs) can be differentiated in vitro to an increasing number of mature cell types, presenting significant promise for addressing a wide range of diseases and studying human development. One approach to further enhance stem cell differentiation methods would be to coordinate multiple inducible gene or protein switches to operate simultaneously within the same cell, with minimal cross-interference, to precisely regulate a network of lineage-specifying transcription factors (TFs) to guide cell fate decisions. Therefore, in this study, we designed and tested various mammalian gene and protein switches responsive to clinically safe small-molecule inhibitors of viral proteases. First, we leveraged hepatitis C virus and human rhinovirus proteases to control the activity of chimeric transcription factors, enabling gene expression activation exclusively in the presence of protease inhibitors and achieving high fold-inductions in hPSC lines. Second, we built single-chain protein switches regulating the activity of three differentiation-related pancreatic TFs, MafA, Pdx1, and Ngn3, each engineered with a protease cleavage site within its structure and having the corresponding protease fused at one terminus. While variants lacking the protease retained most of the unmodified TF activity, the attachment of the protease significantly decreased the activity, which could be rescued upon addition of the corresponding protease inhibitor. We confirmed the functionality of these protein switches for simultaneously controlling the activity of three TFs with a common input molecule, as well as the orthogonality of each protease-based system to independently regulate two TFs. Finally, we validated these very compact systems for precisely controlling TF activity in hPSCs. Our results suggest that they will be valuable tools for research in both developmental biology and regenerative medicine.

Construction and validation of a reliable disulfidptosis-related lncRNAs signature of the subtype, prognostic, and immune landscape in bladder cancer

BACKGROUND

Bladder cancer (BLCA) is one of the most frequently-diagnosed tumors globally. Disulfidptosis represents a critical framework for cell death mechanism in cancer therapy. Our study constructed a predictive model utilizing disulfidptosis-related lncRNAs (DRLs) to provide value in evaluating diagnosis, drug sensibility, and prognosis of BLCA patients.

METHODS

The study data of BLCA patients retrieved from TCGA-BLCA database. Cox and LASSO regression analysis were used to identify DRLs. Kaplan-Meier survival analysis, ROC curve, and nomograms were constructed to assess and forecast survival events. GSEA were performed to illustrate relevant enrichments results. Tumor mutation burden (TMB), immune status, and drug sensitivity were assessed. Muscle invasive bladder cancer (MIBC) tumor and tumor-adjacent normal tissues samples were collected in our department to validate the DRLs expression levels by RT-PCR.

RESULTS

Overall, nine DRLs (AL590428.1, LSAMP-AS1, LINC01184, LINC-PINT, AC023825.2, AC010331.1, AC009716.1, AC104785.1, AC008764.6) were identified. These DRLs were used to calculate risk scores and create a prognostic model. ROC revealed higher diagnostic efficiency of the model than other clinical characteristics. Nomogram was constructed using the risk scores, age, and tumor stage, which showed excellent predictive power and was verified by calibration graph. BLCA patients were further classified into high-risk group and low-risk group using median risk score as the cut-off value. The high-risk group showed lesser TMB levels and developed worse prognosis. GSEA of the high-risk group identified pathways associated with BLCA progression such as WNT signaling pathway. Immune cells including CD4+ and CD8+ T cells, and immune-related function like T cell co-stimulation also showed remarkable differences between two risk groups. Furthermore, IC50 values of twelve drugs such as Sorafenib, Nilotinib, and Navitoclax were significantly higher in the high-risk group. RT-PCR results revealed that 9 DRLs expression levels were statistically significant between tumor tissues samples and tumor-adjacent normal tissues samples. The expression trends of these DRLs in clinical tissues samples were the same as the findings in TCGA dataset.

CONCLUSION

Based on this study, it would be advisable to identify the key DRLs with potential prognostic value in BLCA to enhance the evaluation of clinical outcomes in this context.

Engineered T cells and macrophages: two arms to seize solid tumors

Following the breakthroughs of CAR T cells in the treatment of several hematological malignancies, clinical trials based on genetically modified immune cells are exponentially increasing. Redirecting T cell cytotoxicity against solid tumors via CARs, however, encountered several barriers that require the engineering of additional functions to improve safety, migration, efficacy, and persistence in solid tumors. Complementary strategies tried to harness macrophage properties such as cancer cell phagocytosis, cytokine release, and antigen presentation to induce broader antitumorigenic immune response. While providing a comprehensive overview on the latest technologies in the cell-based immunotherapy realm, we propose that engineering synthetic interplay between immune cells will be the next breakthrough to drive safer and more effective living therapeutics.

Cellular Kinetics and Biodistribution of Adoptive T Cell Therapies: from Biological Principles to Effects on Patient Outcomes

Cell-based immunotherapy has revolutionized cancer treatment in recent years and is rapidly expanding as one of the major therapeutic options in immuno-oncology. So far ten adoptive T cell therapies (TCTs) have been approved by the health authorities for cancer treatment, and they have shown remarkable anti-tumor efficacy with potent and durable responses. While adoptive T cell therapies have shown success in treating hematological malignancies, they are lagging behind in establishing promising efficacy in treating solid tumors, partially due to our incomplete understanding of the cellular kinetics (CK) and biodistribution (including tumoral penetration) of cell therapy products. Indeed, recent clinical studies have provided ample evidence that CK of TCTs can influence clinical outcomes in both hematological malignancies and solid tumors. In this review, we will discuss the current knowledge on the CK and biodistribution of anti-tumor TCTs. We will first describe the typical CK and biodistribution characteristics of these "living" drugs, and the biological factors that influence these characteristics. We will then review the relationships between CK and pharmacological responses of TCT, and potential strategies in enhancing the persistence and tumoral penetration of TCTs in the clinic. Finally, we will also summarize bioanalytical methods, preclinical in vitro and in vivo tools, and in silico modeling approaches used to assess the CK and biodistribution of TCTs.

Phase I Study of ROR1-Specific CAR-T Cells in Advanced Hematopoietic and Epithelial Malignancies

PURPOSE

The receptor tyrosine kinase-like orphan receptor 1 (ROR1) is expressed in hematopoietic and epithelial cancers but has limited expression on normal adult tissues. This phase I study evaluated the safety of targeting ROR1 with autologous T lymphocytes engineered to express a ROR1 chimeric antigen receptor (CAR). Secondary objectives evaluated the persistence, trafficking, and antitumor activity of CAR-T cells.

PATIENTS AND METHODS

Twenty-one patients with ROR1+ tumors received CAR-T cells at one of four dose levels: 3.3 × 105, 1 × 106, 3.3 × 106, and 1 × 107 cells/kg body weight, administered after lymphodepletion with cyclophosphamide/fludarabine or oxaliplatin/cyclophosphamide. Cohort A included patients with chronic lymphocytic leukemia (CLL, n = 3); cohort B included patients with triple-negative breast cancer (TNBC, n = 10) or non-small cell lung cancer (NSCLC, n = 8). A second infusion was administered to one patient in cohort A with residual CLL in the marrow and three patients in cohort B with stable disease after first infusion.

RESULTS

Treatment was well tolerated, apart from one dose-limiting toxicity at dose level 4 in a patient with advanced NSCLC. Two of the three (67%) patients with CLL showed robust CAR-T-cell expansion and a rapid antitumor response. In patients with NSCLC and TNBC, CAR-T cells expanded to variable levels and infiltrated tumors poorly and 1 of 18 patients (5.5%) achieved partial response by RECIST 1.1.

CONCLUSIONS

ROR1 CAR-T cells were well tolerated in most patients. Antitumor activity was observed in CLL but was limited in TNBC and NSCLC. Immunogenicity of the CAR and lack of sustained tumor infiltration were identified as limitations. See related commentary by Kobold, p. 437.

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.

DrugMAP 2.0: molecular atlas and pharma-information of all drugs

The escalating costs and high failure rates have decelerated the pace of drug development, which amplifies the research interests in developing combinatorial/repurposed drugs and understanding off-target adverse drug reaction (ADR). In other words, it is demanded to delineate the molecular atlas and pharma-information for the combinatorial/repurposed drugs and off-target interactions. However, such invaluable data were inadequately covered by existing databases. In this study, a major update was thus conducted to the DrugMAP, which accumulated (a) 20831 combinatorial drugs and their interacting atlas involving 1583 pharmacologically important molecules; (b) 842 repurposed drugs and their interacting atlas with 795 molecules; (c) 3260 off-targets relevant to the ADRs of 2731 drugs and (d) various types of pharmaceutical information, including diverse ADMET properties, versatile diseases, and various ADRs/off-targets. With the growing demands for discovering combinatorial/repurposed therapies and the rapidly emerging interest in AI-based drug discovery, DrugMAP was highly expected to act as an indispensable supplement to existing databases facilitating drug discovery, which was accessible at: https://idrblab.org/drugmap/.

Advances in CAR T cell therapy: antigen selection, modifications, and current trials for solid tumors

Chimeric antigen receptor (CAR) T cell therapy has revolutionized the treatment of hematologic malignancies, achieving remarkable clinical success with FDA-approved therapies targeting CD19 and BCMA. However, the extension of these successes to solid tumors remains limited due to several intrinsic challenges, including antigen heterogeneity and immunosuppressive tumor microenvironments. In this review, we provide a comprehensive overview of recent advances in CAR T cell therapy aimed at overcoming these obstacles. We discuss the importance of antigen identification by emphasizing the identification of tumor-specific and tumor-associated antigens and the development of CAR T therapies targeting these antigens. Furthermore, we highlight key structural innovations, including cytokine-armored CARs, protease-regulated CARs, and CARs engineered with chemokine receptors, to enhance tumor infiltration and activity within the immunosuppressive microenvironment. Additionally, novel manufacturing approaches, such as the Sleeping Beauty transposon system, mRNA-based CAR transfection, and in vivo CAR T cell production, are discussed as scalable solution to improve the accessibility of CAR T cell therapies. Finally, we address critical therapeutic limitations, including cytokine release syndrome (CRS), immune effector cell-associated neurotoxicity syndrome (ICANS), and suboptimal persistence of CAR T cells. An examination of emerging strategies for countering these limitations reveals that CRISPR-Cas9-mediated genetic modifications and combination therapies utilizing checkpoint inhibitors can improve CAR T cell functionality and durability. By integrating insights from preclinical models, clinical trials, and innovative engineering approaches, this review addresses advances in CAR T cell therapies and their performance in solid tumors.

Bioengineered therapeutic systems for improving antitumor immunity

Immunotherapy, a monumental advancement in antitumor therapy, still yields limited clinical benefits owing to its unguaranteed efficacy and safety. Therapeutic systems derived from cellular, bacterial and viral sources possess inherent properties that are conducive to antitumor immunotherapy. However, crude biomimetic systems have restricted functionality and may produce undesired toxicity. With advances in biotechnology, various toolkits are available to add or subtract certain properties of living organisms to create flexible therapeutic platforms. This review elaborates on the creation of bioengineered systems, via gene editing, synthetic biology and surface engineering, to enhance immunotherapy. The modifying strategies of the systems are discussed, including equipment for navigation and recognition systems to improve therapeutic precision, the introduction of controllable components to control the duration and intensity of treatment, the addition of immunomodulatory components to amplify immune activation, and the removal of toxicity factors to ensure biosafety. Finally, we summarize the advantages of bioengineered immunotherapeutic systems and possible directions for their clinical translation.

Stem Loop Mediated Transgene Modulation in Human T Cells

Controlling gene expression is useful for many applications, but current methods often require external user inputs, such as the addition of a drug. We present an alternative approach using cell-autonomous triggers based on RNA stem loop structures in the 3' untranslated regions (UTRs) of mRNA. These stem loops are targeted by the RNA binding proteins Regnase-1 and Roquin-1, allowing us to program stimulation-induced transgene regulation in primary human T cells. By incorporating engineered stem loops into the 3' UTRs of transgenes, we achieved transgene repression through Regnase-1 and Roquin-1 activity, dynamic upregulation upon stimulation, and orthogonal tunability. To demonstrate the utility of this system, we employed it to modulate payloads in CAR-T cells. Our findings highlight the potential of leveraging endogenous regulatory machinery in T cells for transgene regulation and suggest RNA structure as a valuable layer for regulatory modulation.

Engineering a controllable and reversible switch for CAR-based cellular immunotherapies via a genetic code expansion system

BACKGROUND

As one of the most promising adoptive cell therapies, CAR-T cell therapy has achieved notable clinical effects in patients with hematological tumors. However, several treatment-related obstacles remain in CAR-T therapy, such as cytokine release syndrome, neurotoxicity, and high-frequency recurrence, which severely limit the long-term effects and can potentially be fatal. Therefore, strategies to increase the controllability and safety of CAR-T therapy are urgently needed.

METHODS

In this study, we engineered a genetic code expansion-based therapeutic system to achieve rapid CAR protein expression and regulation in response to cognate unnatural amino acids at the translational level. When the unnatural amino acid N-ε-((tert-butoxy) carbonyl)-l-lysine (BOCK) is absent, the CAR protein cannot be completely translated, and CAR-T is "closed". When BOCK is present, complete translation of the CAR protein is induced, and CAR-T is "open". Therefore, we investigated whether the BOCK-induced device can control CAR protein expression and regulate CAR-T cell function using a series of in vitro and in vivo experiments.

RESULTS

First, we verified that the BOCK-induced genetic code expansion system enables the regulation of protein expression as a controllable switch. We subsequently demonstrated that when the system was combined with CAR-T cells, BOCK could effectively and precisely control CAR protein expression and induce CAR signaling activation. When incubated with tumor cells, BOCK regulated CAR-T cells cytotoxicity in a dose-dependent manner. Our results revealed that the presence of BOCK enables the activation of CAR-T cells with strong anti-tumor cytotoxicity in a NOG mouse model. Furthermore, we verified that the BOCK-induced CAR device provided NK cells with controllable anti-tumor activity, which confirmed the universality of this device.

CONCLUSIONS

Our study systematically demonstrated that the BOCK-induced genetic code expansion system effectively and precisely regulates CAR protein expression and controls CAR-T cell anti-tumor effects in vitro and in vivo. We conclude that this controllable and reversible switch has the potential for more effective, secure, and clinically available CAR-based cellular immunotherapies.

Photothermal-Triggered Extracellular Matrix Clearance and Dendritic Cell Maturation for Enhanced Osteosarcoma Immunotherapy

Osteosarcoma, a predominant malignant tumor among adolescents, exhibits high mortality and suboptimal immunotherapy efficacy due to a collagen-dense extracellular matrix (ECM) that hinders cytotoxic T lymphocyte (CTL) infiltration. Herein, we developed mesoporous polydopamine (MPDA) nanoparticles encapsulating bromelain and the immune adjuvant R848 (M@B/R), aimed at enhancing photothermal immunotherapy. These nanoparticles efficiently accumulate at the tumor site following injection. Upon near-infrared (NIR) light irradiation, photothermal therapy (PTT) induces immunogenic cell death in tumor cells and, with the aid of R848, efficiently promotes dendritic cell maturation, activating antitumor immunity and leading to CTL infiltration into the tumor. Concurrently, NIR-induced heating activates bromelain, resulting in ECM degradation and improved CTL penetration into the tumor. Our in vivo evaluations demonstrate potent antitumor effects in osteosarcoma-bearing mice. This integrated approach offers a promising strategy for overcoming physical barriers in ECM-rich tumors, marking a significant advancement in the treatment of osteosarcoma.

Unlocking the potential: advancements and future horizons in ROR1-targeted cancer therapies

While receptor tyrosine kinase-like orphan receptor 1 (ROR1) is typically expressed at low levels or absent in normal tissues, its expression is notably elevated in various malignant tumors and conditions, including chronic lymphocytic leukemia (CLL), breast cancer, ovarian cancer, melanoma, and lung adenocarcinoma. This distinctive feature positions ROR1 as an attractive target for tumor-specific treatments. Currently, several targeted drugs directed at ROR1 are undergoing clinical development, including monoclonal antibodies, antibody-drug conjugates (ADCs), and chimeric antigen receptor T-cell therapy (CAR-T). Additionally, there are four small molecule inhibitors designed to bind to ROR1, presenting promising avenues for the development of PROTAC degraders targeting ROR1. This review offers updated insights into ROR1's structural and functional characteristics, embryonic development implications, cell survival signaling pathways, and evolutionary targeting strategies, all of which have the potential to advance the treatment of malignant tumors.

Efficient combinatorial adaptor-mediated targeting of acute myeloid leukemia with CAR T-cells

CAR T-cell products targeting lineage-specific cell-of-origin antigens, thereby eliminating both tumor and healthy counterpart cells, are currently clinically approved therapeutics in B- and plasma-cell malignancies. While they represent a major clinical improvement, they are still limited in terms of efficacy by e.g. single, sometimes low-expressed antigen targeting, and in terms of safety by e.g., lack of on-off activity. Successful cell-of-origin non-discriminative targeting of heterogeneous hematopoietic stem and progenitor cell malignancies, such as acute myeloid leukemia (AML), will require antigen-versatile targeting and off-switching of effectors in order to then allow rescue by hematopoietic stem cell transplantation (HSCT), preventing permanent myeloablation. To address this, we developed adaptor-CAR (AdFITC-CAR) T-cells targeting fluoresceinated AML antigen-binding diabody adaptors. This platform enables the use of adaptors matching the AML-antigen-expression profile and conditional activity modulation. Combining adaptors significantly improved lysis of AML cells in vitro. In therapeutic xenogeneic mouse models, AdFITC-CAR T-cells co-administered with single diabody adaptors were as efficient as direct CAR T-cells, and combinatorial use of adaptors further enhanced therapeutic efficacy against both, cell lines and primary AML. Collectively, this study provides proof-of-concept that AdFITC-CAR T-cells and combinations of adaptors can efficiently enhance immune-targeting of AML.

Perspectives on Synthetic Protein Circuits in Mammalian Cells

Mammalian synthetic biology aims to engineer cellular behaviors for therapeutic applications, such as enhancing immune cell efficacy against cancers or improving cell transplantation outcomes. Programming complex biological functions necessitates an understanding of molecular mechanisms governing cellular responses to stimuli. Traditionally, synthetic biology has focused on transcriptional circuits, but recent advances have led to the development of synthetic protein circuits, leveraging programmable binding, proteolysis, or phosphorylation to modulate protein interactions and cellular functions. These circuits offer advantages including robust performance, rapid functionality, and compact design, making them suitable for cellular engineering or gene therapies. This review outlines the post-translational toolkit, emphasizing synthetic protein components utilizing proteolysis or phosphorylation to program mammalian cell behaviors. Finally, we focus on key differences between rewiring native signaling pathways and creating orthogonal behaviors, alongside a proposed framework for translating synthetic protein circuits from tool development to pre-clinical applications in biomedicine.

The redox sensor KEAP1 facilitates adaptation of T cells to chronic antigen stimulation by preventing hyperactivation

During persistent antigen stimulation, exhausted CD8+ T cells are continuously replenished by self-renewing stem-like T cells. However, how CD8+ T cells adapt to chronic stimulation remains unclear. Here, we show that persistent antigen stimulation primes chromatin for regulation by the redox-sensing KEAP1-NRF2 pathway. Loss of KEAP1 in T cells impaired control of chronic viral infection. T cell-intrinsic KEAP1 suppressed NRF2 to promote expansion and persistence of virus-specific CD8+ T cells, drive a stem-like T cell response, down-regulate immune checkpoint molecules, and limit T cell receptor (TCR) hyperactivation and apoptosis. NRF2 epigenetically derepressed BACH2 targets and opposed a stem-like program driven by BACH2. In exhausted T cells induced by tonic GD2 chimeric antigen receptor (CAR) signaling, the effects of KEAP1 deficiency were rescued by inhibiting proximal TCR signaling. Enhancing mitochondrial oxidation improved the expansion and survival of KEAP1-deficient CD8+ GD2 CAR T cells and up-regulated markers associated with stem-like cells. Thus, the KEAP1-NRF2 axis regulates stem-like CD8+ T cells and long-term T cell immunity during chronic antigen exposure.

Improved safety of chimeric antigen receptor T cells indirectly targeting antigens via switchable adapters

Chimeric antigen receptor T (CAR-T) cells show remarkable efficacy for some hematological malignancies. However, CAR targets that are expressed at high level and selective to tumors are scarce. Several strategies have been proposed to tackle the on-target off-tumor toxicity of CAR-T cells that arise from suboptimal selectivity, but these are complicated, with many involving dual gene expression for specificity. In this study, we show that switchable CAR-T cells with a tumor targeting adaptor can mitigate on-target off-tumor toxicity against a low selectivity tumor antigen that cannot be targeted by conventional CAR-T cells, such as CD40. Our system is composed of anti-cotinine murine CAR-T cells and cotinine-labeled anti-CD40 single chain variable fragments (scFv), with which we show selective tumor killing while sparing CD40-expressing normal cells including macrophages in a mouse model of lymphoma. Simple replacement of the tumor-targeting adaptor with a suicidal drug-conjugated tag may further enhance safety by enabling permanent in vivo depletion of the switchable CAR-T cells when necessary. In summary, our switchable CAR system can control CAR-T cell toxicity while maintaining therapeutic efficacy, thereby expanding the range of CAR targets.

Evolving strategies to overcome barriers in CAR-T cell therapy for acute myeloid leukemia

INTRODUCTION

Acute myeloid leukemia (AML) is a complex and heterogeneous disease characterized by an aggressive clinical course and limited efficacious treatment options in the relapsed/refractory (R/R) setting. Chimeric antigen receptor (CAR)-modified T (CAR-T) cell immunotherapy is an investigational treatment strategy for R/R AML that has shown some promise. However, obstacles to successful CAR-T cell immunotherapy for AML remain.

AREAS COVERED

In analyses of clinical trials of CAR-T cell therapy for R/R AML, complete responses without measurable residual disease have been reported, but the durability of those responses remains unclear. Significant barriers to successful CAR-T cell therapy in AML include the scarcity of suitable tumor-target antigens (TTA), inherent T cell functional deficits, and the immunoinhibitory and hostile tumor microenvironment (TME). This review will focus on these barriers to successful CAR-T cell therapy in AML, and discuss scientific advancements and evolving strategies to overcome them.

EXPERT OPINION

Achieving durable remissions in R/R AML will likely require a multifaceted approach that integrates advancements in TTA selection, enhancement of the intrinsic quality of CAR-T cells, and development of strategies to overcome inhibitory mechanisms in the AML TME.

Dual ON/OFF-switch chimeric antigen receptor controlled by two clinically approved drugs

The ability to remotely control the activity of chimeric antigen receptors (CARs) with small molecules can improve the safety and efficacy of gene-modified T cells. Split ON- or OFF-switch CARs involve the dissociation of tumor-antigen binding from T cell activation (i.e., CD3ζ) on the receptor (R-) and signaling (S-) chains, respectively, that either associate or are disrupted in the presence of a small molecule. Here, we have developed an inducible (i)ON-CAR comprising the anti-apoptotic B cell lymphoma protein 2 protein in the ectodomain of both chains which associate in the presence of venetoclax. We showed that inducible ON (iON)-CAR T cells respond to target tumors cells in the presence of venetoclax or the BH3 mimetic navitoclax in a dose-dependent manner, while there is no impact of the drugs on equivalent second generation-CAR T cells. Within 48 h of venetoclax withdrawal, iON-CAR T cells lose the ability to respond to target tumor cells in vitro as evaluated by Interferon-gamma (IFNγ) production, and they are reliant upon the presence of venetoclax for in vivo activity. Finally, by fusing a degron sequence to the endodomain of the iON-CAR S-chain we generated an all-in-one ON/OFF-switch CAR, the iONØ-CAR, down-regulated by lenalidomide within 4 to 6 for functionally inactive T cells (no IFNγ production) within 24 h. We propose that our remote-control CAR designs can reduce toxicity in the clinic. Moreover, the periodic rest of iON and iONØ-CAR T cells may alleviate exhaustion and hence augment persistence and long-term tumor control in patients.

CAR-T and CAR-NK as cellular cancer immunotherapy for solid tumors

In the past decade, chimeric antigen receptor (CAR)-T cell therapy has emerged as a promising immunotherapeutic approach for combating cancers, demonstrating remarkable efficacy in relapsed/refractory hematological malignancies in both pediatric and adult patients. CAR-natural killer (CAR-NK) cell complements CAR-T cell therapy by offering several distinct advantages. CAR-NK cells do not require HLA compatibility and exhibit low safety concerns. Moreover, CAR-NK cells are conducive to "off-the-shelf" therapeutics, providing significant logistic advantages over CAR-T cells. Both CAR-T and CAR-NK cells have shown consistent and promising results in hematological malignancies. However, their efficacy against solid tumors remains limited due to various obstacles including limited tumor trafficking and infiltration, as well as an immuno-suppressive tumor microenvironment. In this review, we discuss the recent advances and current challenges of CAR-T and CAR-NK cell immunotherapies, with a specific focus on the obstacles to their application in solid tumors. We also analyze in depth the advantages and drawbacks of CAR-NK cells compared to CAR-T cells and highlight CAR-NK CAR optimization. Finally, we explore future perspectives of these adoptive immunotherapies, highlighting the increasing contribution of cutting-edge biotechnological tools in shaping the next generation of cellular immunotherapy.

DeltaRex-G, tumor targeted retrovector encoding a CCNG1 inhibitor, for CAR-T cell therapy induced cytokine release syndrome

Cytokine release syndrome is a serious complication of chimeric antigen receptor-T cell therapy and is triggered by excessive secretion of inflammatory cytokines by chimeric T cells which could be fatal. Following an inquiry into the molecular mechanisms orchestrating cytokine release syndrome, we hypothesize that DeltaRex-G, a tumor targeted retrovector encoding a cytocidal CCNG1 inhibitor gene, may be a viable treatment option for corticosteroid-resistant cytokine release syndrome. DeltaRex-G received United States Food and Drug Administration Emergency Use Authorization to treat Covid-19-induced acute respiratory distress syndrome, which is due to hyperactivated immune cells. A brief administration of DeltaRex-G would inhibit a certain proportion of hyperactive chimeric T cells, consequently reducing cytokine release while retaining chimeric T cell efficacy.

T cell-redirecting therapies in hematological malignancies: Current developments and novel strategies for improved targeting

T cell-redirecting therapies (TCRTs), such as chimeric antigen receptor (CAR) or T cell receptor (TCR) T cells and T cell engagers, have emerged as a highly effective treatment modality, particularly in the B and plasma cell-malignancy setting. However, many patients fail to achieve deep and durable responses; while the lack of truly unique tumor antigens, and concurrent on-target/off-tumor toxicities, have hindered the development of TCRTs for many other cancers. In this review, we discuss the recent developments in TCRT targets for hematological malignancies, as well as novel targeting strategies that aim to address these, and other, challenges.

CAR-T therapy pulmonary adverse event profile: a pharmacovigilance study based on FAERS database (2017-2023)

Background

Chimeric antigen receptor T-cell (CAR-T) therapy, a rapidly emerging treatment for cancer that has gained momentum since its approval by the FDA in 2017, involves the genetic engineering of patients' T cells to target tumors. Although significant therapeutic benefits have been observed, life-threatening adverse pulmonary events have been reported.

Methods

Using SAS 9.4 with MedDRA 26.1, we retrospectively analyzed data from the Food and Drug Administration's Adverse Event Reporting System (FAERS) database, covering the period from 2017 to 2023. The analysis included the Reporting Odds Ratio Proportional Reporting Ratio Information Component and Empirical Bayes Geometric Mean to assess the association between CAR-T cell therapy and adverse pulmonary events (PAEs).

Results

The FAERS database recorded 9,400 adverse events (AEs) pertaining to CAR-T therapies, of which 940 (10%) were PAEs. Among these CAR-T cell-related AEs, hypoxia was the most frequently reported (344 cases), followed by respiratory failure (127 cases). Notably, different CAR-T cell treatments demonstrated varying degrees of association with PAEs. Specifically, Tisa-cel was associated with severe events including respiratory failure and hypoxia, whereas Axi-cel was strongly correlated with both hypoxia and tachypnea. Additionally, other CAR-T therapies, namely, Brexu-cel, Liso-cel, Ide-cel, and Cilta-cel, have also been linked to distinct PAEs. Notably, the majority of these PAEs occurred within the first 30 days post-treatment. The fatality rates varied among the different CAR-T therapies, with Tisa-cel exhibiting the highest fatality rate (43.6%), followed by Ide-cel (18.8%).

Conclusion

This study comprehensively analyzed the PAEs reported in the FAERS database among recipients of CAR-T cell therapy, revealing conditions such as hypoxia, respiratory failure, pleural effusion, and atelectasis. These CAR-T cell therapy-associated events are clinically significant and merit the attention of clinicians and researchers.

The cytokine Meteorin-like inhibits anti-tumor CD8+ T cell responses by disrupting mitochondrial function

Tumor-infiltrating lymphocyte (TIL) hypofunction contributes to the progression of advanced cancers and is a frequent target of immunotherapy. Emerging evidence indicates that metabolic insufficiency drives T cell hypofunction during tonic stimulation, but the signals that initiate metabolic reprogramming in this context are largely unknown. Here, we found that Meteorin-like (METRNL), a metabolically active cytokine secreted by immune cells in the tumor microenvironment (TME), induced bioenergetic failure of CD8+ T cells. METRNL was secreted by CD8+ T cells during repeated stimulation and acted via both autocrine and paracrine signaling. Mechanistically, METRNL increased E2F-peroxisome proliferator-activated receptor delta (PPARδ) activity, causing mitochondrial depolarization and decreased oxidative phosphorylation, which triggered a compensatory bioenergetic shift to glycolysis. Metrnl ablation or downregulation improved the metabolic fitness of CD8+ T cells and enhanced tumor control in several tumor models, demonstrating the translational potential of targeting the METRNL-E2F-PPARδ pathway to support bioenergetic fitness of CD8+ TILs.

Preclinical efficacy of a HER2 synNotch/CEA-CAR combinatorial immunotherapy against colorectal cancer with HER2 amplification

HER2 amplification occurs in approximately 5% of colorectal cancer (CRC) cases and is associated only partially with clinical response to combined human epidermal growth factor receptor 2 (HER2)/epidermal growth factor receptor (EGFR)-targeted treatment. An alternative approach based on adoptive cell therapy using T cells engineered with anti-HER2 chimeric antigen receptor (CAR) proved to be toxic due to on-target/off-tumor activity. Here we describe a combinatorial strategy to safely target HER2 amplification and carcinoembryonic antigen (CEA) expression in CRC using a synNotch-CAR-based artificial regulatory network. The natural killer (NK) cell line NK-92 was engineered with an anti-HER2 synNotch receptor driving the expression of a CAR against CEA only when engaged. After being transduced and sorted for HER2-driven CAR expression, cells were cloned. The clone with optimal performances in terms of specificity and amplitude of CAR induction demonstrated significant activity in vitro and in vivo specifically against HER2-amplified (HER2amp)/CEA+ CRC models, with no effects on cells with physiological HER2 levels. The HER2-synNotch/CEA-CAR-NK system provides an innovative, scalable, and safe off-the-shelf cell therapy approach with potential against HER2amp CRC resistant or partially responsive to HER2/EGFR blockade.

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

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

Finding Your CAR: The Road Ahead for Engineered T Cells

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

Efficient expansion and CRISPR-Cas9-mediated gene correction of patient-derived hepatocytes for treatment of inherited liver diseases

Cell-based ex vivo gene therapy in solid organs, especially the liver, has proven technically challenging. Here, we report a feasible strategy for the clinical application of hepatocyte therapy. We first generated high-quality autologous hepatocytes through the large-scale expansion of patient-derived hepatocytes. Moreover, the proliferating patient-derived hepatocytes, together with the AAV2.7m8 variant identified through screening, enabled CRISPR-Cas9-mediated targeted integration efficiently, achieving functional correction of pathogenic mutations in FAH or OTC. Importantly, these edited hepatocytes repopulated the injured mouse liver at high repopulation levels and underwent maturation, successfully treating mice with tyrosinemia following transplantation. Our study combines ex vivo large-scale cell expansion and gene editing in patient-derived transplantable hepatocytes, which holds potential for treating human liver diseases.

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

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

Advanced strategies in improving the immunotherapeutic effect of CAR-T cell therapy

Chimeric antigen receptor (CAR-T) cell therapy is a newly developed immunotherapy strategy and has achieved satisfactory outcomes in the treatment of hematological malignancies. However, some adverse effects related to CAR-T cell therapy have to be resolved before it is widely used in clinics as a cancer treatment. Furthermore, the application of CAR-T cell therapy in the treatment of solid tumors has been hampered by numerous limitations. Therefore, it is essential to explore novel strategies to improve the therapeutic effect of CAR-T cell therapy. In this review, we summarized the recently developed strategies aimed at optimizing the generation of CAR-T cells and improving the anti-tumor efficiency of CAR-T cell therapy. Furthermore, the discovery of new targets for CAR-T cell therapy and the combined treatment strategies of CAR-T cell therapy with chemotherapy, radiotherapy, cancer vaccines and nanomaterials are highlighted.

Leveraging oncovirus-derived antigen against the viral malignancies in adoptive cell therapies

Adoptive cell therapies (ACTs) have revolutionized cancer immunotherapy, prompting exploration into their application against oncoviruses. Oncoviruses such as human papillomavirus (HPV), hepatitis B virus (HBV), hepatitis C virus (HCV), and Epstein-Barr virus (EBV) contribute significantly (12-25%) to human malignancies through direct or indirect oncogenic mechanisms. These viruses persistently or latently infect cells, disrupt cellular homeostasis and pathways, challenging current antiviral treatment paradigms. Moreover, viral infections pose additional risks in the setting of long-term cancer therapy and lead to morbidity and mortality. Virally encoded oncoproteins, which are tumor-restricted, immunologically foreign, and even uniformly expressed, represent promising targets for patient-tailored ACTs. This review elucidates the rationale for leveraging viral antigen-specific ACTs in combating viral-associated malignancies. On this basis, ongoing preclinical studies consolidate our understanding of harnessing ACTs against viral malignancies, underscoring their potential to eradicate viruses implicated in cancer progression. Furthermore, we scrutinize the current landscape of clinical trials focusing on virus-specific ACTs and discuss their implications for therapeutic advancement.

Immunotherapies for locally aggressive cancers

Improving surgical resection outcomes for locally aggressive tumors is key to inducing durable locoregional disease control and preventing progression to metastatic disease. Macroscopically complete resection of the tumor is the standard of care for many cancers, including breast, ovarian, lung, sarcoma, and mesothelioma. Advancements in cancer diagnostics are increasing the number of surgically eligible cases through early detection. Thus, a unique opportunity arises to improve patient outcomes with decreased recurrence rates via intraoperative delivery treatments using local drug delivery strategies after the tumor has been resected. Of the current systemic treatments (e.g., chemotherapy, targeted therapies, and immunotherapies), immunotherapies are the latest approach to offer significant benefits. Intraoperative strategies benefit from direct access to the tumor microenvironment which improves drug uptake to the tumor and simultaneously minimizes the risk of drug entering healthy tissues thereby resulting in fewer or less toxic adverse events. We review the current state of immunotherapy development and discuss the opportunities that intraoperative treatment provides. We conclude by summarizing progress in current research, identifying areas for exploration, and discussing future prospects in sustained remission.

The potential therapeutic targets of glutamine metabolism in head and neck squamous cell carcinoma

Targeting metabolic reprogramming may be an effective strategy to enhance cancer treatment efficacy. Glutamine serves as a vital nutrient for cancer cells. Inhibiting glutamine metabolism has shown promise in preventing tumor growth both in vivo and in vitro through various mechanisms. Therefore, this review collates recent scientific literature concerning the correlation between glutamine metabolism and cancer treatment. Novel treatment modalities based on amino acid transporters, metabolites, and glutaminase are discussed. Moreover, we demonstrate the relationship between glutamine metabolism and tumor proliferation, drug resistance, and the tumor immune microenvironment, offering new perspectives for the clinical treatment of head and neck squamous cell carcinoma, particularly for combined therapies. Identifying innovative approaches for enhancing the efficacy of glutamine-based metabolic therapy is crucial to improving HNSCC treatment.

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.

Engineered CD47 protects T cells for enhanced antitumour immunity

Adoptively transferred T cells and agents designed to block the CD47-SIRPα axis are promising cancer therapeutics that activate distinct arms of the immune system1,2. Here we administered anti-CD47 antibodies in combination with adoptively transferred T cells with the goal of enhancing antitumour efficacy but observed abrogated therapeutic benefit due to rapid macrophage-mediated clearance of T cells expressing chimeric antigen receptors (CARs) or engineered T cell receptors. Anti-CD47-antibody-mediated CAR T cell clearance was potent and rapid enough to serve as an effective safety switch. To overcome this challenge, we engineered the CD47 variant CD47(Q31P) (47E), which engages SIRPα and provides a 'don't eat me' signal that is not blocked by anti-CD47 antibodies. TCR or CAR T cells expressing 47E are resistant to clearance by macrophages after treatment with anti-CD47 antibodies, and mediate substantial, sustained macrophage recruitment to the tumour microenvironment. Although many of the recruited macrophages manifested an M2-like profile3, the combined therapy synergistically enhanced antitumour efficacy. Our study identifies macrophages as major regulators of T cell persistence and illustrates the fundamental challenge of combining T-cell-directed therapeutics with those designed to activate macrophages. It delivers a therapeutic approach that is capable of simultaneously harnessing the antitumour effects of T cells and macrophages, offering enhanced potency against solid tumours.

A new era of cancer immunotherapy: combining revolutionary technologies for enhanced CAR-M therapy

Significant advancements have been made in the application of chimeric antigen receptor (CAR)-T treatment for blood cancers during the previous ten years. However, its effectiveness in treating solid tumors is still lacking, necessitating the exploration of alternative immunotherapies that can overcome the significant challenges faced by current CAR-T cells. CAR-based immunotherapy against solid tumors shows promise with the emergence of macrophages, which possess robust phagocytic abilities, antigen-presenting functions, and the ability to modify the tumor microenvironment and stimulate adaptive responses. This paper presents a thorough examination of the latest progress in CAR-M therapy, covering both basic scientific studies and clinical trials. This study examines the primary obstacles hindering the realization of the complete potential of CAR-M therapy, as well as the potential strategies that can be employed to overcome these hurdles. With the emergence of revolutionary technologies like in situ genetic modification, synthetic biology techniques, and biomaterial-supported gene transfer, which provide a wider array of resources for manipulating tumor-associated macrophages, we suggest that combining these advanced methods will result in the creation of a new era of CAR-M therapy that demonstrates improved efficacy, safety, and availability.

Small molecule-regulated switches to provide functional control of CAR T cells within the patient

INTRODUCTION

CAR T cells have generated great excitement due to their remarkable clinical response rates in selected hematologic malignancies. However, these engineered immune cells are living drugs which are hard to control after administration.

AREAS COVERED

We discuss small molecule-regulated switch systems which can potentially be used to control CAR T cell function within the patient, as well as the most important obstacles in the CAR T cell field, which might be overcome with those switch systems.

EXPERT OPINION

There is an urgent need to develop advanced switch systems. Once available, we expect that they will open up new avenues for future CAR T cell generations.

The dilemmas and possible solutions for CAR-T cell therapy application in solid tumors

Chimeric antigen receptor T (CAR-T) cell therapy, as an adoptive immunotherapy, is playing an increasingly important role in the treatment of malignant tumors. CAR-T cells are referred to as "living drugs" as they not only target tumor cells directly, but also induce long-term immune memory that has the potential to provide long-lasting protection. CD19.CAR-T cells have achieved complete response rates of over 90 % for acute lymphoblastic leukemia and over 60 % for non-Hodgkin's lymphoma. However, the response rate of CAR-T cells in the treatment of solid tumors remains extremely low and the side effects potentially severe. In this review, we discuss the limitations that the solid tumor microenvironment poses for CAR-T application and the solutions that are being developed to address these limitations, in the hope that in the near future, CAR-T cell therapy for solid tumors can attain the same success rates as are now being seen clinically for hematological malignancies.

Charting the Course: Sequencing Immunotherapy for Multiple Myeloma

Multiple chimeric antigen receptor (CAR) T-cell and bispecific antibody (bsAb) therapies have been approved, demonstrating impressive clinical efficacy in relapsed/refractory multiple myeloma (MM). Currently, these treatment share overlapping approval indications in the relapsed/refractory space, highlighting the importance of optimal selection and sequencing to maximize clinical efficacy. For patients previously unexposed to T-cell-directed therapies, several factors should be weighed when both options are available. These factors include access and logistical challenges associated with CAR T-cell therapy, disease-specific factors such as tempo of disease relapse, in addition to patient-specific factors such as frailty, and distinct toxicity profiles across these agents. Sequential therapy, whether it involves CAR T-cell therapy followed by bsAb or vice versa, has demonstrated clinical efficacy. When sequencing these agents, it is crucial to consider various factors that contribute to treatment resistance with careful selection of treatments for subsequent therapy in order to achieve favorable long-term patient outcomes.

Receptor tyrosine kinase-like orphan receptor 1: A novel antitumor target in gastrointestinal cancers

Receptor tyrosine kinase-like orphan receptor 1 (ROR1) is a member of the type I receptor tyrosine kinase family. ROR1 is pivotal in embryonic development and cancer, and serves as a biomarker and therapeutic target. It has soluble and membrane-bound subtypes, with the latter highly expressed in tumors. ROR1 is conserved throughout evolution and may play a role in the development of gastrointestinal cancer through multiple signaling pathways and molecular mechanisms. Studies suggest that overexpression of ROR1 may increase tumor invasiveness and metastasis. Additionally, ROR1 may regulate the cell cycle, stem cell characteristics, and interact with other signaling pathways to affect cancer progression. This review explores the structure, expression and role of ROR1 in the development of gastrointestinal cancers. It discusses current antitumor strategies, outlining challenges and prospects for treatment.

Chimeric antigen receptors: "CARs" in the fast lane for rheumatology

PURPOSE OF REVIEW

Recent advances in hematology-oncology have pioneered cell-mediated elimination of pathologic B-cell populations employing chimeric antigen receptor (CAR) T cells. In this review, we discuss recent adoption of CAR-T treatment for severe refractory autoimmune disease. We highlight unique aspects of the autoimmune model and review current clinical data regarding treatment of rheumatologic disease.

RECENT FINDINGS

To date, several CAR-Ts are FDA approved for Multiple Myeloma and B-cell malignancies and have demonstrated extraordinary clinical responses in refractory disease. Realizing the central role of B-cells in certain autoimmune diseases, CAR-T is now being explored for achieving drug-free remission induction, and potentially cure, of several rheumatologic diseases. The largest experience to date in the field of autoimmunity, building off the University Hospital Erlangen groups' earlier success treating a single patient with CD19-CAR in severe refractory SLE, Mackensen et al. enrolled five patients in a compassionate use program. Following autologous CD19-CAR T infusion, they demonstrated drug-free clinical and laboratory remission for at least 12 months in all five patients, with reconstitution of B cells expressing a naïve phenotype.

SUMMARY

CAR-T treatment has shown striking drug-free responses in severe lupus and other autoimmune diseases, creating a need for further exploration and development.

Advances in molecular targeted drugs in combination with CAR-T cell therapy for hematologic malignancies

Molecular targeted drugs and chimeric antigen receptor (CAR) T cell therapy represent specific biological treatments that have significantly improved the efficacy of treating hematologic malignancies. However, they face challenges such as drug resistance and recurrence after treatment. Combining molecular targeted drugs and CAR-T cells could regulate immunity, improve tumor microenvironment (TME), promote cell apoptosis, and enhance sensitivity to tumor cell killing. This approach might provide a dual coordinated attack on cancer cells, effectively eliminating minimal residual disease and overcoming therapy resistance. Moreover, molecular targeted drugs can directly or indirectly enhance the anti-tumor effect of CAR-T cells by inducing tumor target antigen expression, reversing CAR-T cell exhaustion, and reducing CAR-T cell associated toxic side effects. Therefore, combining molecular targeted drugs with CAR-T cells is a promising and novel tactic for treating hematologic malignancies. In this review article, we focus on analyzing the mechanism of therapy resistance and its reversal of CAR-T cell therapy resistance, as well as the synergistic mechanism, safety, and future challenges in CAR-T cell therapy in combination with molecular targeted drugs. We aim to explore the benefits of this combination therapy for patients with hematologic malignancies and provide a rationale for subsequent clinical studies.

[Closed-loop synthetic gene circuits for cell-based therapies]

Recent advances in synthetic biology have paved the way for new cellular therapies, using cells capable of autonomously treating chronic diseases. These cells integrate a set of genes functioning in a closed-loop synthetic circuit, delivering a therapeutic effector in response to a specific pathological signal. While promising in mice, these therapies face clinical challenges related to safety and feasibility of in vivo implementation. The latest generations of synthetic circuits aim to address these issues through advanced bioengineering strategies outlined in this article.

Enhancing antitumor response by efficiently generating large-scale TCR-T cells targeting a single epitope across multiple cancer antigens

The need to contrive interventions to curb the rise in cancer incidence and mortality is critical for improving patients' prognoses. Adoptive cell therapy is challenged with quality large-scale production, heightening its production cost. Several cancer types have been associated with the expression of highly-immunogenic CTAG1 and CTAG2 antigens, which share common epitopes. Targeting two antigens on the same cancer could improve the antitumor response of TCR-T cells. In this study, we exploited an efficient way to generate large-fold quality TCR-T cells and also demonstrated that the common epitopes of CTAG1 and CTAG2 antigens provide an avenue for improved cancer-killing via dual-antigen-epitope targeting. Our study revealed that xeno/sera-free medium could expand TCR-T cells to over 500-fold, posing as a better replacement for FBS-supplemented media. Human AB serum was also shown to be a good alternative in the absence of xeno/sera-free media. Furthermore, TCR-T cells stimulated with beads-coated T-activator showed a better effector function than soluble T-activator stimulated TCR-T cells. Additionally, TCR-T cells that target multiple antigens in the same cancer yield better anticancer activity than those targeting a single antigen. This showed that targeting multiple antigens with a common epitope may enhance the antitumor response efficacy of T cell therapies.

Control of the antitumour activity and specificity of CAR T cells via organic adapters covalently tethering the CAR to tumour cells

On-target off-tumour toxicity limits the anticancer applicability of chimaeric antigen receptor (CAR) T cells. Here we show that the tumour-targeting specificity and activity of T cells with a CAR consisting of an antibody with a lysine residue that catalytically forms a reversible covalent bond with a 1,3-diketone hapten can be regulated by the concentration of a small-molecule adapter. This adapter selectively binds to the hapten and to a chosen tumour antigen via a small-molecule binder identified via a DNA-encoded library. The adapter therefore controls the formation of a covalent bond between the catalytic antibody and the hapten, as well as the tethering of the CAR T cells to the tumour cells, and hence the cytotoxicity and specificity of the cytotoxic T cells, as we show in vitro and in mice with prostate cancer xenografts. Such small-molecule switches of T-cell cytotoxicity and specificity via an antigen-independent 'universal' CAR may enhance the control and safety profile of CAR-based cellular immunotherapies.

Acoustothermal transfection for cell therapy

Transfected stem cells and T cells are promising in personalized cell therapy and immunotherapy against various diseases. However, existing transfection techniques face a fundamental trade-off between transfection efficiency and cell viability; achieving both simultaneously remains a substantial challenge. This study presents an acoustothermal transfection method that leverages acoustic and thermal effects on cells to enhance the permeability of both the cell membrane and nuclear envelope to achieve safe, efficient, and high-throughput transfection of primary T cells and stem cells. With this method, two types of plasmids were simultaneously delivered into the nuclei of mesenchymal stem cells (MSCs) with efficiencies of 89.6 ± 1.2%. CXCR4-transfected MSCs could efficiently target cerebral ischemia sites in vivo and reduce the infarct volume in mice. Our acoustothermal transfection method addresses a key bottleneck in balancing the transfection efficiency and cell viability, which can become a powerful tool in the future for cellular and gene therapies.

Synthetic transcription factor engineering for cell and gene therapy

Synthetic transcription factors (synTFs) that control beneficial transgene expression are an important method to increase the safety and efficacy of cell and gene therapy. Reliance on synTF components from non-human sources has slowed progress in the field because of concerns about immunogenicity and inducer drug properties. Recent advances in human-derived DNA-binding domains (DBDs) and transcriptional activation domains (TADs) paired with novel control modules responsive to clinically approved small molecules have poised the synTF field to overcome these hurdles. Advances include controllers inducible by autonomous signaling inputs and more complex, multi-input synTF circuits. Demonstrations of advanced control strategies with human-derived transcription factor components in clinically relevant vectors and in vivo models will facilitate progression into the clinic.