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Hu8F4 is a T-cell receptor–like antibody with high affinity for the leukemia-associated antigen PR1/HLA-A2 epitope. Adapted into a chimeric antigen receptor (CAR) format, Hu8F4-CAR is composed of the Hu8F4 single-chain variable fragment, the human IgG1 CH2CH3 extracellular spacer domain, a human CD28 costimulatory domain and the human CD3ζ signaling domain. We have demonstrated high efficacy of Hu8F4-CAR-T cells against PR1/HLA-A2-expressing cell lines and leukemic blasts from patients with acute myeloid leukemia in vitro. Previous studies have shown that modification of the Fc domains of IgG4 CH2CH3 spacer regions can eliminate activation-induced cell death and off-target killing mediated by mouse Fc gamma receptor–expressing cells. We generated Hu8F4-CAR(PQ) with mutated Fc receptor binding sites on the CH2 domain of Hu8F4-CAR to prevent unwanted interactions with Fc gamma receptor–expressing cells in vivo. The primary human T cells transduced with Hu8F4-CAR(PQ) can specifically lyse HLA-A2+ PR1-expressing leukemia cell lines in vitro. Furthermore, both adult donor-derived and cord blood-derived Hu8F4-CAR(PQ)-T cells are active and can eliminate U937 leukemia cells in NSG mice. Herein, we demonstrate that modification of the IgG1-based spacer can eliminate Fc receptor binding–induced adverse effects and Hu8F4-CAR(PQ)-T cells can kill leukemia in vivo. [ABSTRACT FROM AUTHOR]

T cells engineered to express chimeric-antigen receptors (CAR-T cells) can effectively control relapsed and refractory haematological malignancies in the clinic. However, the successes of CAR-T cell therapy have not been recapitulated in solid tumours due to a range of barriers such as immunosuppression, poor infiltration, and tumour heterogeneity. Numerous strategies are being developed to overcome these barriers, which include improving culture conditions and manufacturing protocols, implementing novel CAR designs, and novel approaches to engineering the T cell phenotype. In this review, we describe the various emerging strategies to improve CAR T cell therapy for solid tumours. We specifically focus on new strategies to modulate cell function and fate that have precipitated from the growing knowledge of transcriptional circuits driving T cell differentiation, with the ultimate goal of driving more productive antitumour T cell immunity. Evidence shows that enrichment of particular phenotypic subsets of T cells in the initial cell product correlates to improved therapeutic responses and clinical outcomes. Furthermore, T cell exhaustion and poor persistence are major factors limiting therapeutic efficacy. The latest preclinical work shows that targeting specific master regulators and transcription factors can overcome these key barriers, resulting in superior T cell therapeutic products. This can be achieved by targeting key transcriptional circuits promoting memory-like phenotypes or sustaining key effector functions within the hostile tumour microenvironment. Additional discussion points include emerging considerations for the field such as (i) targeting permutations of transcription factors, (ii) transient expression systems, (iii) tissue specificity, and (iv) expanding this strategy beyond CAR-T cell therapy and cancer. [ABSTRACT FROM AUTHOR]

Acute myeloid leukemia (AML) is a hostile hematological malignancy under great danger of relapse and poor long-term survival rates, despite recent therapeutic advancements. To deal with this unfulfilled clinical necessity, innovative cell-based immunotherapies have surfaced as promising approaches to improve antitumor immunity and enhance patient outcomes. In this comprehensive review, we provide a detailed examination of the latest developments in cell-based immunotherapies for AML, including chimeric antigen receptor (CAR) T-cell therapy, T-cell receptor (TCR)-engineered T-cell therapy, and natural killer (NK) cell-based therapies. We critically evaluate the unique mechanisms of action, current challenges, and evolving strategies to improve the efficacy and safety of these modalities. The review emphasizes how promising these cutting-edge immune-based strategies are in overcoming the inherent complexities and heterogeneity of AML. We discuss the identification of optimal target antigens, the importance of mitigating on-target/off-tumor toxicity, and the need to enhance the persistence and functionality of engineered immune effector cells. All things considered, this review offers a thorough overview of the rapidly evolving field of cell-based immunotherapy for AML, underscoring the significant progress made and the ongoing efforts to translate these innovative approaches into more effective and durable treatments for this devastating disease. [ABSTRACT FROM AUTHOR]

Summary Immune effector cell‐associated hematotoxicity (ICAHT) is a common toxicity associated with an important morbidity after chimeric antigen receptor (CAR)‐T‐cell therapy. Multiple factors seem to be involved in the development of severe ICAHT, making its management difficult. Here, we report three cases of severe ICAHT after axicabtagene‐ciloleucel (axi‐cel) for diffuse large B‐cell lymphoma showing an expansion of large granular lymphocyte in the bone marrow with a CD3/CD57‐positive non‐CAR‐T immunophenotype. We show that it is possible to treat them with low‐dose steroids, obtaining a striking resolution of cytopenias with no deleterious impact on the underlying malignancy. [ABSTRACT FROM AUTHOR]

The potential of chimeric antigen receptor (CAR)-based immunotherapy as a promising therapeutic approach is often hindered by the presence of highly immunosuppressive tumor microenvironments (TME). Combination therapies with either co-administration or built-in expression of additional TME-modulating therapeutic molecules to potentiate the functions of CAR-T cells can cause systemic toxicities due to the lack of control over the delivery of biologics. Here, we present a proof-of-concept engineered platform in human Jurkat T cells that combines CAR with a therapeutic gene circuit capable of sensing β-galactosidase (a reported cancer-associated signal) and subsequently activate the production of customized therapeutic gene products. We have demonstrated the integration of the chemically induced proximity (CIP) and associated signal sensing technologies with CAR in this study. A β-galactosidase-activatable prodrug was designed by conjugating a galactose moiety with a CIP inducer abscisic acid (ABA). We showed that Jurkat T cells engineered with CAR and the ABA-inducible genetic circuits can respond to recombinant β-galactosidase to drive the production and secretion of various immunotherapeutics including an anti-cancer agent, an immunomodulatory cytokine, and immune checkpoint inhibitors. Our design is highly modular and could be adapted to sense different cancer-related signals to locally produce antitumor therapeutics that can potentially boost CAR-T efficacy and persistence. [ABSTRACT FROM AUTHOR]

Introduction: Almost one-quarter of immune checkpoint inhibitor (ICI) recipients experience sicca syndrome, while Sjögren's disease (SjD) is estimated at 0.3–2.5%, possibly underreported. Areas covered: This narrative review (Medline/Embase until January/31/2024) addresses the pathophysiology, incidence, demographic/clinical features, biomarkers, labial salivary gland biopsy (LSGB), fulfillment of the idiopathic SjD (iSjD) classificatory criteria, differential diagnosis, and management of sicca syndrome/SjD associated with ICIs. Expert opinion: SjD associated with ICIs is underdiagnosed, since studies that performed the mandatory SjD investigation identified that 40–60% of patients with sicca syndrome associated with ICIs meet the iSjD classificatory criteria. LSGB played a fundamental role in recognizing these cases, as most of them had negative anti-Ro/SS-A antibody. Despite the finding of focal lymphocytic sialoadenitis in LSGB samples mimicking iSjD, immunohistochemical analysis provided novel evidence of a distinct pattern for sicca syndrome/SjD associated with ICIs compared to iSjD. The former has scarcity of B lymphocytes, which are a hallmark of iSjD. Additionally, patients with sicca syndrome/SjD associated with ICIs have demographical/clinical/serological and treatment response dissimilarities compared to iSjD. Dryness symptoms are more acute in the former than in iSjD, with predominance of xerostomia over xerophthalmia, and partial/complete response to glucocorticoids. Dryness symptoms in ICI-treated patients warrant prompt SjD investigation. [ABSTRACT FROM AUTHOR]

Chimeric antigen receptor (CAR)‐T cell therapy has demonstrated poor efficacy for solid tumors. The low number and poor functional persistence of CAR‐T cells in tumors are the main limiting factors. Here a Chemokine‐based Injectable platform for enhancing adoptive T cells' Efficacy (CITE) is presented. CITE consists of peritumorally‐injected immunogel co‐loading chemotactic CXCL9 particles with PD‐1 antibody (aPD1) and intravenously‐infused tumor‐penetrating peptide iRGD. Immunogel formed drug depots and allowed sustained release of cargo peritumorally while iRGD facilitated tumor infiltration of gel‐released drugs, thus remarkably increasing the amount of CXCL9 and aPD1 in the tumor. CITE induced an effective chemotactic gradient to promote the tumor‐specific migration of CAR‐T cells and boosted the function of infiltrated T cells by blocking immunosuppression via a two‐in‐one approach. Consequently, CITE yielded a 218‐fold increase in the intratumoral number of transferred T cells and substantially improved the efficacies of transferred T cell receptor (TCR)‐T cells and CAR‐T cells in multiple syngeneic tumor models, including immunologically "cold" tumors, in immunocompetent mice. More importantly, CITE enhanced systemic antitumor immunity and elicited immune memory, enabling CITE to treat multimodal, metastatic, and recurrent tumors. CITE is broadly applicable to adoptive cell therapies involving CAR‐T or TCR‐T cells. [ABSTRACT FROM AUTHOR]

Chimeric antigen receptor (CAR) T-cell products are commonly generated using lentiviral vector (LV) transduction. Optimal final formulation buffer (FFB) supporting LV stability during cryostorage is crucial for cost-effective manufacturing. To identify the ideal LV FFB composition for ex vivo CAR-T production, primary human T cells were transduced with vesicular stomatitis virus G-protein (VSV-G) -pseudotyped LVs (encoding a reporter gene or an anti-CD19-CAR). The formulations included phosphate-buffered saline (PBS), HEPES, or X-VIVOTM 15, and stabilizing excipients. The functional and viral particle titers and vector copy number were measured after LV cryopreservation and up to 24 h post-thaw incubation. CAR-Ts were produced with LVs in selected FFBs, and the resulting cells were characterized. Post-cryopreservation, HEPES-based FFBs provided higher LV functional titers than PBS and X-VIVOTM 15, and 10% trehalose-20 mM MgCl 2 improved LV transduction efficiency in PBS and 50 mM HEPES. Thawed vectors remained stable at +4°C, while a ≤ 25% median decrease in the functional titer occurred during 24 h at room temperature. Tested excipients did not enhance LV post-thaw stability. CAR-Ts produced using LVs cryopreserved in 10% trehalose- or sucrose-20 mM MgCl 2 in 50 mM HEPES showed comparable transduction rates, cell yield, viability, phenotype, and in vitro functionality. A buffer consisting of 10% trehalose-20 mM MgCl 2 in 50 mM HEPES provided a feasible FFB to cryopreserve a VSV-G -pseudotyped LV for CAR-T-cell production. The LVs remained relatively stable for at least 24 h post-thaw, even at ambient temperatures. This study provides insights into process development, showing LV formulation data generated using the relevant target cell type for CAR-T-cell manufacturing. [ABSTRACT FROM AUTHOR]

The current CAR-T cell therapy products have been hampered in their druggability due to the personalized preparation required, unclear pharmacokinetic characteristics, and unpredictable adverse reactions. Enabling standardized manufacturing and having clear efficacy and pharmacokinetic characteristics are prerequisites for ensuring the effective practicality of CAR-T cell therapy drugs. This review provides a broad overview of the different approaches for controlling behaviors of CAR-T cells in vivo. The utilization of genetically modified vectors enables in vivo production of CAR-T cells, thereby abbreviating or skipping the lengthy in vitro expansion process. By equipping CAR-T cells with intricately designed control elements, using molecule switches or small-molecule inhibitors, the control of CAR-T cell activity can be achieved. Moreover, the on–off control of CAR-T cell activity would yield potential gains in phenotypic remodeling. These methods provide beneficial references for the future development of safe, controllable, convenient, and suitable for standardized production of CAR-T cell therapy products. [ABSTRACT FROM AUTHOR]

Anti-CD19 CAR-T cell therapy represents a breakthrough in the treatment of B-cell malignancies, and it is expected that this therapy modality will soon cover a range of solid tumors as well. Therefore, a universal cheap and sensitive method to detect CAR expression is of foremost importance. One possibility is the use of epitope tags such as c-Myc, HA or FLAG tags attached to the CAR extracellular domain, however, it is important to determine whether these tags can influence binding of the CAR with its target molecule. Here, we conducted in-silico structural modelling of an FMC63-based anti-CD19 single-chain variable fragment (scFv) with and without a c-Myc peptide tag added to the N-terminus portion and performed molecular dynamics simulation of the scFv with the CD19 target. We show that the c-Myc tag presence in the N-terminus portion does not affect the scFv’s structural equilibrium and grants more stability to the scFv. However, intermolecular interaction potential (IIP) analysis reveals that the tag can approximate the complementarity-determining regions (CDRs) present in the scFv and cause steric impediment, potentially disturbing interaction with the CD19 protein. We then tested this possibility with CAR-T cells generated from human donors in a Nalm-6 leukemia model, showing that CAR-T cells with the c-Myc tag have overall worse antitumor activity, which was also observed when the tag was added to the C-terminus position. Ultimately, our results suggest that tag addition is an important aspect of CAR design and can influence CAR-T cell function, therefore its use should be carefully considered.

Background: Chimeric antigen receptor T‐cell (CAR‐T) therapy has shown promise in treating hematologic malignancies, yet its potential cardiotoxic effects require thorough investigation. Objectives: We aim to conduct a systematic review and meta‐analysis to examine the cardiotoxic effects of CAR‐T therapy in adults with hematologic malignancies. Methods: We searched PubMed, Embase, and the Cochrane Central Register of Controlled Trials for studies reporting cardiovascular outcomes, such as arrhythmias, heart failure, and reduced left ventricle ejection fraction (LVEF). Results: Our analysis of 20 studies involving 4789 patients revealed a 19.68% incidence rate of cardiovascular events, with arrhythmias (7.70%), heart failure (5.73%), and reduced LVEF (3.86%) being the most prevalent. Troponin elevation was observed in 23.61% of patients, while NT‐Pro‐BNP elevation was observed in 9.4. Subgroup analysis showed higher risks in patients with pre‐existing conditions, such as atrial arrhythmia (OR 3.12; p <.001), hypertension (OR 1.85; p =.002), previous heart failure (OR 3.38; p =.003), and coronary artery disease (OR 2.80; p =.003). Conclusion: Vigilant cardiovascular monitoring is crucial for patients undergoing CAR‐T therapy to enhance safety and treatment efficacy.Novelty Statements. [ABSTRACT FROM AUTHOR]

Abstract Chimeric antigen receptor (CAR) serves as the foundational element of CAR-T cells. Exogenous CAR molecules can exert functional effects on allogeneic T cells, leading to their activation and subsequent functional alterations. Here we show a new method based on this biological principle: the transfer of CAR molecules from exogenous cells to the membrane of receptor T cells. This process facilitates receptor T cell to recognize target antigens and induces their activation. These patches imbued normal T cells with enhanced tumor targeting capabilities and activated their inherent killing functions. This method’s efficacy introduces an approach for constructing non-genetically manipulated CAR-T cells and holds potential for application to other immune cells. Graphical Abstract

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.

Abstract Chimeric antigen receptor (CAR)-T cell adoptive immunotherapy is a promising cancer treatment that uses genetically engineered T cells to attack tumors. However, this therapy can have some adverse effects. CAR-T cell-derived exosomes are a potential alternative to CAR-T cells that may overcome some limitations. Exosomes are small vesicles released by cells and can carry a variety of molecules, including proteins, RNA, and DNA. They play an important role in intercellular communication and can be used to deliver therapeutic agents to cancer cells. The application of CAR-T cell-derived exosomes could make CAR-T cell therapy more clinically controllable and effective. Exosomes are cell-free, which means that they are less likely to cause adverse reactions than CAR-T cells. The combination of CAR-T cells and exosomes may be a more effective way to treat cancer than either therapy alone. Exosomes can deliver therapeutic agents to cancer cells where CAR-T cells cannot reach. The appropriate application of both cellular and exosomal platforms could make CAR-T cell therapy a more practicable treatment for cancer. This combination therapy could offer a safe and effective way to treat a variety of cancers.

Chimeric antigen receptor (CAR) serves as the foundational element of CAR-T cells. Exogenous CAR molecules can exert functional effects on allogeneic T cells, leading to their activation and subsequent functional alterations. Here we show a new method based on this biological principle: the transfer of CAR molecules from exogenous cells to the membrane of receptor T cells. This process facilitates receptor T cell to recognize target antigens and induces their activation. These patches imbued normal T cells with enhanced tumor targeting capabilities and activated their inherent killing functions. This method's efficacy introduces an approach for constructing non-genetically manipulated CAR-T cells and holds potential for application to other immune cells. [ABSTRACT FROM AUTHOR]

Simple Summary: Lck is an important kinase that plays a key role in the physiological responses of T lymphocytes as well as in several other tissues such as the lung, intestine, brain, endometrium, and prostate. It can be found bound to the cell membrane, free in the cytosol, and even in the nucleus as it interacts with different proteins involved in various biological responses. Additionally, Lck is considered a proto-oncogene. Phosphatases and the Csk kinase control Lck activity: phosphatases can open and inactivate the structure, while Csk can only close it. The activation and modifications of Lck differ between normal and pathological conditions, such as cancer, allergy, autoimmunity, and graft vs. host disease. These differences may lead to new targets for pharmacological therapy. This overview briefly summarizes the characteristics and modulations of the enzyme. Lck, a member of the Src kinase family, is a non-receptor tyrosine kinase involved in immune cell activation, antigen recognition, tumor growth, and cytotoxic response. The enzyme has usually been linked to T lymphocyte activation upon antigen recognition. Lck activation is central to CD4, CD8, and NK activation. However, recently, it has become clearer that activating the enzyme in CD8 cells can be independent of antigen presentation and enhance the cytotoxic response. The role of Lck in NK cytotoxic function has been controversial in a similar fashion as the role of the enzyme in CAR T cells. Inhibiting tyrosine kinases has been a highly successful approach to treating hematologic malignancies. The inhibitors may be useful in treating other tumor types, and they may be useful to prevent cell exhaustion. New, more selective inhibitors have been documented, and they have shown interesting activities not only in tumor growth but in the treatment of autoimmune diseases, asthma, and graft vs. host disease. Drug repurposing and bioinformatics can aid in solving several unsolved issues about the role of Lck in cancer. In summary, the role of Lck in immune response and tumor growth is not a simple event and requires more research. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Currently available chimeric antigen receptor (CAR)-engineered T-cell therapies targeting B-cell maturation antigen (BCMA), namely, idecabtagene vicleucel and ciltacabtagene autoleucel, have shown marked efficacy against relapsed and refractory multiple myeloma. However, further improvement in CAR-T-cell function is warranted as most patients treated with these products eventually relapse due to various mechanisms such as antigen loss and T-cell dysfunction or disappearance. Strategies for improving CAR-T-cell function include targeting of dual antigens, enhancing cell longevity through genetic modification, and eliminating the immunosuppressive tumor microenvironment. Serious side effects can also occur after CAR-T-cell infusions. Although understanding of the molecular pathogenesis of cytokine release syndrome and immune effector cell-associated neurotoxicity syndrome is growing, the unique movement disorder caused by BCMA-targeted therapy is less understood, and its molecular mechanisms must be further elucidated to establish better management strategies. In this article, we will review the current status of BCMA-targeting CAR-T-cell therapy. We will also highlight progress in the development of CAR-T cells targeting other antigens, as well as universal allogeneic CAR-T cells and bispecific antibodies. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Chimeric antigen receptor (CAR)-T cell adoptive immunotherapy is a promising cancer treatment that uses genetically engineered T cells to attack tumors. However, this therapy can have some adverse effects. CAR-T cell-derived exosomes are a potential alternative to CAR-T cells that may overcome some limitations. Exosomes are small vesicles released by cells and can carry a variety of molecules, including proteins, RNA, and DNA. They play an important role in intercellular communication and can be used to deliver therapeutic agents to cancer cells. The application of CAR-T cell-derived exosomes could make CAR-T cell therapy more clinically controllable and effective. Exosomes are cell-free, which means that they are less likely to cause adverse reactions than CAR-T cells. The combination of CAR-T cells and exosomes may be a more effective way to treat cancer than either therapy alone. Exosomes can deliver therapeutic agents to cancer cells where CAR-T cells cannot reach. The appropriate application of both cellular and exosomal platforms could make CAR-T cell therapy a more practicable treatment for cancer. This combination therapy could offer a safe and effective way to treat a variety of cancers. [ABSTRACT FROM AUTHOR]

Chimeric antigen receptor (CAR) T cell therapy shows promise in treating malignant tumors. However, the use of human epidermal growth factor receptor-2 (HER2) CAR-T cells carries the risk of severe toxicity, including cytokine release syndrome, due to their "on-target off-tumor" recognition of HER2. Enhancing the quality and functionality of HER2 CARs could greatly improve the therapeutic potential of CAR-T cells. In this study, we developed a novel anti-HER2 monoclonal antibody, Ab8, which targets domain III of HER2, distinct from the domain IV recognition of trastuzumab. Although two anti-HER2 mAbs induced similar levels of antibody-dependent cellular cytotoxicity, trastuzumab-based CAR-T cells exhibited potent antitumor activity against HER2-positive cancer cells. In conclusion, our findings provide scientific evidence that antibody recognition of the membrane-proximal domain promotes the anti-tumor response of HER2-specific CAR-T cells. [ABSTRACT FROM AUTHOR]

Gene therapy represents a significant potential to revolutionize the field of hematology with applications in correcting genetic mutations, generating cell lines and animal models, and improving the feasibility and efficacy of cancer immunotherapy. Compared to different genetic engineering tools, clustered regularly interspaced short palindromic repeats (CRISPR) CRISPR-associated protein 9 (Cas9) emerged as an effective and versatile genetic editor with the ability to precisely modify the genome. The applications of genetic engineering in various hematological disorders have shown encouraging results. Monogenic hematological disorders can conceivably be corrected with single gene modification. Through the use of CRISPR-CAS9, restoration of functional red blood cells and hemostasis factors were successfully attained in sickle cell anemia, beta-thalassemia, and hemophilia disorders. Our understanding of hemato-oncology has been advanced via CRIPSR-CAS9 technology. CRISPR-CAS9 aided to build a platform of mutated genes responsible for cell survival and proliferation in leukemia. Therapeutic application of CRISPR-CAS9 when combined with chimeric antigen receptor (CAR) T cell therapy in multiple myeloma and acute lymphoblastic leukemia was feasible with attenuation of CAR T cell therapy pitfalls. Our review outlines the latest literature on the utilization of CRISPR-Cas9 in the treatment of beta-hemoglobinopathies and hemophilia disorders. We present the strategies that were employed and the findings of preclinical and clinical trials. Also, the review will discuss gene engineering in the field of hemato-oncology as a proper tool to facilitate and overcome the drawbacks of chimeric antigen receptor T cell therapy (CAR-T). [ABSTRACT FROM AUTHOR]

Acute myeloid leukemia (AML) is a hostile hematological malignancy under great danger of relapse and poor long-term survival rates, despite recent therapeutic advancements. To deal with this unfulfilled clinical necessity, innovative cell-based immunotherapies have surfaced as promising approaches to improve anti-tumor immunity and enhance patient outcomes. In this comprehensive review, we provide a detailed examination of the latest developments in cell-based immunotherapies for AML, including chimeric antigen receptor (CAR) T-cell therapy, T-cell receptor (TCR)-engineered T-cell therapy, and natural killer (NK) cell-based therapies. We critically evaluate the unique mechanisms of action, current challenges, and evolving strategies to improve the efficacy and safety of these modalities. The review emphasizes how promising these cutting-edge immune-based strategies are in overcoming the inherent complexities and heterogeneity of AML. We discuss the identification of optimal target antigens, the importance of mitigating on-target/off-tumor toxicity, and the need to enhance the persistence and functionality of engineered immune effector cells. All things considered, this review offers a thorough overview of the rapidly evolving field of cell-based immunotherapy for AML, underscoring the significant progress made and the ongoing efforts to translate these innovative approaches into more effective and durable treatments for this devastating disease.

T cells engineered to express chimeric-antigen receptors (CAR-T cells) can effectively control relapsed and refractory haematological malignancies in the clinic. However, the successes of CAR-T cell therapy have not been recapitulated in solid tumours due to a range of barriers such as immunosuppression, poor infiltration, and tumour heterogeneity. Numerous strategies are being developed to overcome these barriers, which include improving culture conditions and manufacturing protocols, implementing novel CAR designs, and novel approaches to engineering the T cell phenotype. In this review, we describe the various emerging strategies to improve CAR T cell therapy for solid tumours. We specifically focus on new strategies to modulate cell function and fate that have precipitated from the growing knowledge of transcriptional circuits driving T cell differentiation, with the ultimate goal of driving more productive anti-tumour T cell immunity. Evidence shows that enrichment of particular phenotypic subsets of T cells in the initial cell product correlates to improved therapeutic responses and clinical outcomes. Furthermore, T cell exhaustion and poor persistence are major factors limiting therapeutic efficacy. The latest preclinical work shows that targeting specific master regulators and transcription factors can overcome these key barriers, resulting in superior T cell therapeutic products. This can be achieved by targeting key transcriptional circuits promoting memory-like phenotypes or sustaining key effector functions within the hostile tumour microenvironment. Additional discussion points include emerging considerations for the field such as (i) targeting permutations of transcription factors, (ii) transient expression systems, (iii) tissue specificity, and (iv) expanding this strategy beyond CAR-T cell therapy and cancer.

Enormous patients with gastric cancer (GC) are insensitive to chemotherapy and targeted therapy without the chance of radical surgery, so immunotherapy may supply a novel choice for them. Chimeric antigen receptor (CAR)-T cell therapy has the advantages of higher specificity, stronger lethality, and longer-lasting efficacy, and it has the potential for GC in the future. However, its application still faces numerous obstacles in terms of accuracy, efficacy, and safety. Cytokines can mediate the migration, proliferation, and survival of immune cells, regulate the duration and strength of immune responses, and are involved in the occurrence of severe side effects in CAR-T cell therapy. The expression levels of specific cytokines are associated with the genesis, invasion, metastasis, and prognosis of GC. Applications of cytokines and their receptors in CAR-T cell therapy have emerged, and various cytokines and their receptors have contributed to improving CAR-T cell anti-tumor capabilities. Large amounts of central cytokines in this therapy include chemokines, interleukins (ILs), transforming growth factor-β (TGF-β), and colony-stimulating factors (CSFs). Meanwhile, researchers have explored the combination therapy in treating GC, and several approaches applied to other malignancies can also be considered as references. Therefore, our review comprehensively outlines the biological functions and clinical significance of cytokines and summarizes current advances and innovative strategies for harnessing cytokines to optimize CAR-T cell therapy for GC.

The introduction of chimeric antigen receptor (CAR) T-cell therapy has revolutionized the treatment of hematological diseases, particularly in combating blood cancer. The success of this cell therapy approach has led to the development of approximately seven commercial CAR-T based drugs. However, the application of CAR-T therapy for solid tumors has proven to be less effective due to challenges such as the varied antigens in solid tumors, an immunosuppressive tumor environment, limited immune cell infiltration, reduced CAR-T cell activity and toxicity issues. To solve these problems, scientists are making efforts to improve and improve the methods of treatment of solid tumors. Chemotherapy is the standard treatment for a large number of malignant neoplasms. It is also used before starting cell therapy for lymphodepletion and better engraftment of injected CAR-T cells. It has been shown that chemotherapy can reduce the immunosuppressive effect of the tumor microenvironment, destroy the stroma, and promote better infiltration of the tumor by CAR-T cells, improving their survival, persistence, cytotoxicity, and influencing the metabolism of immune cells inside the tumor. The effectiveness of combining chemotherapy and CAR-T cell therapy relies on various factors such as tumor type, dosage, treatment schedule, CAR-T cell composition, and individual biological traits. Similarly, radiation therapy can enhance tumor cell vulnerability to specific treatments while also supporting tumor cell survival.In this review, we discuss the use of CAR-T therapy to combat solid tumors, regarding the challenges of treating solid tumors, ways to overcome them, and also touch upon the possibility of using combination treatments to improve the effectiveness of cell therapy.

In the past decade, a lot of insight was gathered into the composition of the host and tumor factors that promote oncogenesis and treatment resistance. This in turn has led to the ingenious design of multiple new classes of drugs, which have now become the new standards of care in cancer therapy. These include novel antibody-drug conjugates, chimeric antigen receptor T cell therapies (CAR-T), and bispecific T cell engagers (BitTE). Certain host factors, such as the microbiome composition, are also emerging not only as biomarkers for the response and toxicity to anti-cancer therapies but also as potentially useful tools to modulate anti-tumor responses. The field is slowly moving away from one-size-fits-all treatment options to personalized treatments tailored to the host and tumor. This commentary aims to cover the basic concepts associated with these emerging therapies and the promises and challenges to fight cancer.

Osteosarcoma (OS) is a rare form of cancer and primary bone malignancy in children and adolescents. Current therapies include surgery, chemotherapy, and amputation. Therefore, a new therapeutic strategy is needed to dramatically change cancer treatment. Recently, chimeric antigen receptor T cells (CAR-T cells) have been of considerable interest as it has provided auspicious results and patients suffering from low side effects after injection that resolve with current therapy. However, there are reports that cytokine release storm (CRS) can be observed in some patients. In addition, as researchers have faced problems that limit and suppress T cells, further studies are required to resolve these problems. In addition, to maximize the therapeutic benefit of CAR-T cell therapy, researchers have suggested that combination therapy could be better used to treat cancer by overcoming any problems and reducing side effects as much as possible. This review summarizes these problems, barriers, and the results of some studies on the evaluation of CAR-T cells in patients with osteosarcoma.

Abstract One should identify appropriate cell surface targets to develop new CAR-T cells. Currently, lineage-specific antigens such as CD19 or B cell maturation antigen (BCMA) are being used as targets for CAR-T cells. However, in most cancers, lineage-specific antigens cannot be used as targets because targeting normal counterparts expressing them causes fatal toxicity. Cancer-specific transcripts have been extensively searched for using transcriptome analysis, but only a few candidates were reported. We have been working on identifying tumor-specific antigen structures, for example constitutively activated conformer of integrin b7 in multiple myeloma. Recently, several researchers have been working on a logic gate system that can react only when two antigens are expressed on the cell surface.

ABSTRACTT cell-based immunotherapies for solid tumors have not achieved the clinical success observed in hematological malignancies, partially due to the immunosuppressive effect promoted by the tumor microenvironment, where PD-L1 and TGF-β play a pivotal role. However, durable responses to immune checkpoint inhibitors remain limited to a minority of patients, while TGF-β inhibitors have not reached the market yet. Here, we describe a bispecific antibody for dual blockade of PD-L1 and TFG-β, termed AxF (scFv)2, under the premise that combination with T cell redirecting strategies would improve clinical benefit. The AxF (scFv)2 antibody was well expressed in mammalian and yeast cells, bound both targets and inhibited dose-dependently the corresponding signaling pathways in luminescence-based cellular reporter systems. Moreover, combined treatment with trispecific T-cell engagers (TriTE) or CAR-T cells significantly boosted T cell activation status and cytotoxic response in breast, lung and colorectal (CRC) cancer models. Importantly, the combination of an EpCAMxCD3×EGFR TriTE with the AxF (scFv)2 delayed CRC tumor growth in vivo and significantly enhanced survival compared to monotherapy with the trispecific antibody. In summary, we demonstrated the feasibility of concomitant blockade of PD-L1 and TGF-β by a single molecule, as well as its therapeutic potential in combination with different T cell redirecting agents to overcome tumor microenvironment-mediated immunosuppression.

Precise targeting of large transgenes to T cells using homology-directed repair has been transformative for adoptive cell therapies and T cell biology. Delivery of DNA templates via adeno-associated virus (AAV) has greatly improved knockin efficiencies, but the tropism of current AAV serotypes restricts their use to human T cells employed in immunodeficient mouse models. To enable targeted knockins in murine T cells, we evolved Ark313, a synthetic AAV that exhibits high transduction efficiency in murine T cells. We performed a genome-wide knockout screen and identified QA2 as an essential factor for Ark313 infection. We demonstrate that Ark313 can be used for nucleofection-free DNA delivery, CRISPR-Cas9-mediated knockouts, and targeted integration of large transgenes. Ark313 enables preclinical modeling of Trac-targeted CAR-T and transgenic TCR-T cells in immunocompetent models. Efficient gene targeting in murine T cells holds great potential for improved cell therapies and opens avenues in experimental T cell immunology.

Acute myeloid leukemia (AML) is an aggressive hematologic malignancy with a poor prognosis despite the advent of novel therapies. Consequently, a major need exists for new therapeutic options, particularly for patients with relapsed/refractory (R/R) AML. In recent years, it has been possible to individualize the treatment of a subgroup of patients, particularly with the emergence of multiple targeted therapies. Nonetheless, a considerable number of patients remain without therapeutic options, and overall prognosis remains poor because of a high rate of disease relapse. In this sense, cellular therapies, especially chimeric antigen receptor (CAR)-T cell therapy, have dramatically shifted the therapeutic options for other hematologic malignancies, such as diffuse large B cell lymphoma and acute lymphoblastic leukemia. In contrast, effectively treating AML with CAR-based immunotherapy poses major biological and clinical challenges, most of them derived from the unmet need to identify target antigens with expression restricted to the AML blast without compromising the viability of the normal hematopoietic stem cell counterpart. Although those limitations have hampered CAR-T cell therapy translation to the clinic, there are several clinical trials where target antigens, such as CD123, CLL-1 or CD33 are being used to treat AML patients showing promising results. Moreover, there are continuing efforts to enhance the specificity and efficacy of CAR-T cell therapy in AML. These endeavors encompass the exploration of novel avenues, including the development of dual CAR-T cells and next-generation CAR-T cells, as well as the utilization of gene editing tools to mitigate off-tumor toxicities. In this review, we will summarize the ongoing clinical studies and the early clinical results reported with CAR-T cells in AML, as well as highlight CAR-T cell limitations and the most recent approaches to overcome these barriers. We will also discuss how and when CAR-T cells should be used in the context of AML. [ABSTRACT FROM AUTHOR]

Over the past three decades, the treatment of lymphoproliferative disorders has undergone profound changes, notably due to the increasing availability of innovative therapies with the potential to redefine clinical management paradigms. A major impact is related to the development of monoclonal antibodies, checkpoint inhibitors, bispecific antibodies, and chimeric antigen receptor T (CAR-T) cell therapies. This review discusses the current landscape of clinical trials targeting various hematological malignancies, highlighting promising early-phase results and strategies to overcome resistance. Lymphoproliferative disorders encompass a range of conditions: while in Hodgkin lymphoma (HL) the goal is to reduce chemotherapy-related toxicity by integrating immunotherapy into the frontline setting, peripheral T cell lymphoma (PTCL) lacks effective targeted therapies. The review emphasizes a shifting therapeutic landscape towards precision medicine and treatment modalities that are less toxic yet more effective. [ABSTRACT FROM AUTHOR]

In the past decade, a lot of insight was gathered into the composition of the host and tumor factors that promote oncogenesis and treatment resistance. This in turn has led to the ingenious design of multiple new classes of drugs, which have now become the new standards of care in cancer therapy. These include novel antibody-drug conjugates, chimeric antigen receptor T cell therapies (CAR-T), and bispecific T cell engagers (BitTE). Certain host factors, such as the microbiome composition, are also emerging not only as biomarkers for the response and toxicity to anti-cancer therapies but also as potentially useful tools to modulate anti-tumor responses. The field is slowly moving away from one-size-fits-all treatment options to personalized treatments tailored to the host and tumor. This commentary aims to cover the basic concepts associated with these emerging therapies and the promises and challenges to fight cancer. [ABSTRACT FROM AUTHOR]

CAR-T cell therapy, a novel immunotherapy, has made significant breakthroughs in clinical practice, particularly in treating B-cell-associated leukemia and lymphoma. However, it still faces challenges such as poor persistence, limited proliferation capacity, high manufacturing costs, and suboptimal efficacy. CRISPR/Cas system, an efficient and simple method for precise gene editing, offers new possibilities for optimizing CAR-T cells. It can increase the function of CAR-T cells and reduce manufacturing costs. The combination of CRISPR/Cas9 technology and CAR-T cell therapy may promote the development of this therapy and provide more effective and personalized treatment for cancer patients. Meanwhile, the safety issues surrounding the application of this technology in CAR-T cells require further research and evaluation. Future research should focus on improving the accuracy and safety of CRISPR/Cas9 technology to facilitate the better development and application of CAR-T cell therapy. This review focuses on the application of CRISPR/Cas9 technology in CAR-T cell therapy, including eliminating the inhibitory effect of immune checkpoints, enhancing the ability of CAR-T cells to resist exhaustion, assisting in the construction of universal CAR-T cells, reducing the manufacturing costs of CAR-T cells, and the security problems faced. The objective is to show the revolutionary role of CRISPR/Cas9 technology in CAR-T cell therapy for researchers. [ABSTRACT FROM AUTHOR]

The past decade has seen the development of immunotherapy for the treatment of multiple myeloma (MM), beginning with monoclonal antibodies (mAbs) in the relapsed and refractory setting and culminating in the market approval of chimeric antigen receptor T cells (CAR-T) and bispecific antibodies (BsAbs). The medical community is evaluating the efficacy and safety of these targeted immunotherapies, most of which currently target B-cell maturation antigen (BCMA) on the surface of plasma cells. Two anti-BCMA CAR-T products are available for treating relapsed or refractory MM: idecabtagene vicleucel (ide-cel) and ciltacabtagene autoleucel (cilta-cel). Ide-cel and cilta-cel demonstrate the ability to induce deep responses in heavily pretreated diseases, including patients with triple-class-refractory and penta-refractory diseases. However, there are key similarities and differences regarding these agents, unknowns regarding their comparative efficacy and toxicity, and mechanisms underlying resistance to these new immunotherapies. This review discusses CAR-T cell therapy in relapsed refractory MM, with a focus on efficacy, toxicities, and the evolving trajectories of these therapies in the USA, as well as access in Turkey.

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.

Zhang H, Zhao H, He X, Xi F, Liu J. Cancer Manag Res. 2020;12:9813–9824. We, the Editor and Publisher of the journal Cancer Management and Research are retracting the published article. Following publication of the article, concerns were raised regarding the duplication of images from Figures 2, 4 and 5 with images from unrelated articles. Specifically, The images for Figure 2J, Mock, BB-z and δIL2RBB-z have been duplicated with the images for Figure 3G, UTD, 20min; EGFR-CAT T, 4h and EGFR-CAR T, 12h, respectively from Li H, Huang Y, Jiang DQ, et al. Antitumor activity of EGFR-specific CAR T cells against non-small-cell lung cancer cells in vitro and in mice. Cell Death Dis. 2018;9:177. https://doi.org/10.1038/s41419-017-0238-6. The images for Figure 4A, have been duplicated with the images for Figure 6E from Mohammed S, Sukumaran S, Bajgain P, et al. Improving Chimeric Antigen Receptor-Modified T Cell Function by Reversing the Immunosuppressive Tumor Microenvironment of Pancreatic Cancer. Molecular Therapy. 2017;25;(1):249–258. https://doi.org/10.1016/j.ymthe.2016.10.016. The images for Figure 5A, have been duplicated with the images for Figure 6E, PBS and Anti-control, ZO-1, from Zhou W, Fong MY, Min Y, et al. Cancer-Secreted miR-105 Destroys Vascular Endothelial Barriers to Promote Metastasis. Cancer Cell. 2014;25(4):501–515. https://doi.org/10.1016/j.ccr.2014.03.007. The corresponding author did not respond to our queries and was unable to provide a satisfactory explanation for how the images came to be duplicated or provide satisfactory original data for the study. As verifying the validity of published work is core to the integrity of the scholarly record, the Publisher and Editor requested to retract the article and the corresponding author was notified of this. We have been informed in our decision-making by our editorial policies and COPE guidelines. The retracted article will remain online to maintain the scholarly record, but it will be digitally watermarked on each page as “Retracted”.

Chimeric receptor antigen T cell (CAR‐T cell) therapy has demonstrated effectiveness and therapeutic potential in the immunotherapy of hematological malignancies, representing a promising breakthrough in cancer treatment. Despite the efficacy of CAR‐T cell therapy in B‐cell lymphoma, response variability, resistance, and side effects remain persistent challenges. The tumor microenvironment (TME) plays an intricate role in CAR‐T cell therapy of B‐cell lymphoma. The TME is a complex and dynamic environment that includes various cell types, cytokines, and extracellular matrix components, all of which can influence CAR‐T cell function and behavior. This review discusses the design principles of CAR‐T cells, TME in B‐cell lymphoma, and the mechanisms by which TME influences CAR‐T cell function. We discuss emerging strategies aimed at modulating the TME, targeting immunosuppressive cells, overcoming inhibitory signaling, and improving CAR‐T cell infiltration and persistence. Therefore, these processes enhance the efficacy of CAR‐T cell therapy and improve patient outcomes in B‐cell lymphoma. Further research will be needed to investigate the molecular and cellular events that occur post‐infusion, including changes in TME composition, immune cell interactions, cytokine signaling, and potential resistance mechanisms. Understanding these processes will contribute to the development of more effective CAR‐T cell therapies and strategies to mitigate treatment‐related toxicities. [ABSTRACT FROM AUTHOR]

CD19‐targeted chimeric antigen receptor T (CAR‐T) cell therapy has shown unprecedented results in patients with B cell relapsed/refractory acute lymphoblastic leukemia (R/R‐ALL) and B cell non‐Hodgkin lymphomas where no other curative options are available. In vivo monitoring of CAR‐T cell kinetics is fundamental to understand the correlation between CAR‐T cells expansion and persistence with treatment response and toxicity development. The aim of this study was to define a robust, sensitive, and universal method for CAR‐T cell detection using flow cytometry. We set up and compared with each other three assays for CD19 CAR‐T cell detection, all based on commercially available reagents. All methods used a recombinant human CD19 protein fragment recognized by the single‐chain variable fragment of the CAR construct. The two indirect staining assays (CD19his + APC‐conjugated antihistidine antibody and CD19bio + APC‐conjugated antibiotin antibody) showed better sensitivity and specificity compared with the direct staining with CD19‐FITC, and CD19his had a better cost‐effective profile. We validated CAR detection with CD19his with parallel quantitative real‐time polymerase chain reaction data and we could demonstrate a strong positive correlation. We also showed that CD19his staining can be easily included in a multicolor flow cytometry panel to achieve additional information about the cell phenotype of CAR‐T cell positive subpopulations. Finally, this method can be used for different anti‐CD19 CAR‐T cell products and for different sample sources. These data demonstrate that detection of CAR‐T cells by CD19his flow cytometry staining is a reliable, robust, and broadly applicable tool for in vivo monitoring of CAR‐T cells. [ABSTRACT FROM AUTHOR]

Introduction: Chimeric antigen receptor T (CAR-T) cell therapy is an effective bridging treatment for allogeneic hematopoietic stem cell transplantation (allo-HSCT) in relapsed or refractory acute lymphoblastic leukemia (ALL). However, repetitive CAR-T cell therapy and allo-HSCT can only be performed in a few patients because of technical difficulties and patients' physical, economic, and social conditions. Case Presentation: A 23-year-old female patient with second relapsed B-cell ALL (B-ALL) underwent human-murine chimeric CD19 CAR-T cell therapy twice, human-murine chimeric CD22 CAR-T cell therapy once, and humanized CD19 CAR-T cell therapy once. Moreover, she was sequentially bridged to her mother donor allo-HSCT once and cousin donor allo-HSCT once. Conclusion: Repetitive CAR-T cell therapy bridging to repetitive allo-HSCT is still a safe and active therapeutic strategy for patients with relapsed or refractory ALL. [ABSTRACT FROM AUTHOR]

The treatment of human immunodeficiency virus (HIV-1) has evolved since the establishment of combination antiretroviral therapy (ART) in the 1990s, providing HIV-infected individuals with approaches that suppress viral replication, prevent acquired immunodeficiency syndrome (AIDS) throughout their lifetime with continuous therapy, and halt HIV transmission. However, despite the success of these regimens, the global HIV epidemic persists, prompting a comprehensive exploration of potential strategies for an HIV cure. Here, we offer a consolidated overview of cell-based therapies for HIV-1, focusing on CAR-T cell approaches, gene editing, and immune modulation. Persistent challenges, including CAR-T cell susceptibility to HIV infection, stability, and viral reservoir control, underscore the need for continued research. This review synthesizes current knowledge, highlighting the potential of cellular therapies to address persistent challenges in the pursuit of an HIV cure. [ABSTRACT FROM AUTHOR]

Acute myeloid leukemia (AML) is an aggressive hematologic malignancy with a poor prognosis despite the advent of novel therapies. Consequently, a major need exists for new therapeutic options, particularly for patients with relapsed/refractory (R/R) AML. In recent years, it has been possible to individualize the treatment of a subgroup of patients, particularly with the emergence of multiple targeted therapies. Nonetheless, a considerable number of patients remain without therapeutic options, and overall prognosis remains poor because of a high rate of disease relapse. In this sense, cellular therapies, especially chimeric antigen receptor (CAR)-T cell therapy, have dramatically shifted the therapeutic options for other hematologic malignancies, such as diffuse large B cell lymphoma and acute lymphoblastic leukemia. In contrast, effectively treating AML with CAR-based immunotherapy poses major biological and clinical challenges, most of them derived from the unmet need to identify target antigens with expression restricted to the AML blast without compromising the viability of the normal hematopoietic stem cell counterpart. Although those limitations have hampered CAR-T cell therapy translation to the clinic, there are several clinical trials where target antigens, such as CD123, CLL-1 or CD33 are being used to treat AML patients showing promising results. Moreover, there are continuing efforts to enhance the specificity and efficacy of CAR-T cell therapy in AML. These endeavors encompass the exploration of novel avenues, including the development of dual CAR-T cells and next-generation CAR-T cells, as well as the utilization of gene editing tools to mitigate off-tumor toxicities. In this review, we will summarize the ongoing clinical studies and the early clinical results reported with CAR-T cells in AML, as well as highlight CAR-T cell limitations and the most recent approaches to overcome these barriers. We will also discuss how and when CAR-T cells should be used in the context of AML.

Chimeric antigen receptor (CAR) T cell therapy shows promise in treating malignant tumors. However, the use of human epidermal growth factor receptor-2 (HER2) CAR-T cells carries the risk of severe toxicity, including cytokine release syndrome, due to their “on-target off-tumor” recognition of HER2. Enhancing the quality and functionality of HER2 CARs could greatly improve the therapeutic potential of CAR-T cells. In this study, we developed a novel anti-HER2 monoclonal antibody, Ab8, which targets domain III of HER2, distinct from the domain IV recognition of trastuzumab. Although two anti-HER2 mAbs induced similar levels of antibody-dependent cellular cytotoxicity, trastuzumab-based CAR-T cells exhibited potent antitumor activity against HER2-positive cancer cells. In conclusion, our findings provide scientific evidence that antibody recognition of the membrane-proximal domain promotes the anti-tumor response of HER2-specific CAR-T cells.

Abstract Background Carcinoma-associated fibroblasts (CAFs) play a critical role in cancer progression and immune cell modulation. In this study, it was aimed to evaluate the roles of CAFs-derived IL-6 in doxorubicin (Dox) resistance and PD-L1-mediated chimeric antigenic receptor (CAR)-T cell resistance in breast cancer (BCA). Methods CAF conditioned-media (CM) were collected, and the IL-6 level was measured by ELISA. CAF-CM were treated in MDA-MB-231 and HCC70 TNBC cell lines and siIL-6 receptor (IL-6R) knocked down (KD) cells to determine the effect of CAF-derived IL-6 on Dox resistance by flow cytometry and on increased PD-L1 through STAT3, AKT and ERK1/2 pathways by Western blot analysis. After pre-treating with CM, the folate receptor alpha (FRα)-CAR T cell cytotoxicity was evaluated in 2D and 3D spheroid culture assays. Results The results showed a significant level of IL-6 in CAF-CM compared to that of normal fibroblasts (NFs). The CM with high IL-6 level significantly induced Dox resistance; and PD-L1 expression through STAT3 and AKT pathways in MDA-MB-231 and HCC70 cells. These induction effects were attenuated in siIL-6R KD cells. Moreover, the TNBC cell lines that were CM-treated with STAT3 and an AKT inhibitor had a reduced effect of IL-6 on PD-L1 expression. BCA cells with high IL-6 containing-CM treatment had resistance to cancer cell killing by FRα CAR-T cells compared to untreated cells. Conclusion These results highlight CAF-derived IL-6 in the resistance of chemotherapy and T cell therapy. Using inhibitors of IL6-STAT3/AKT-PD-L1 axis may provide a potential benefit of Dox and CAR-T cell therapies in BCA patients.