TanCAR: A Novel Bispecific Chimeric Antigen Receptor for Cancer Immunotherapy

Therapeutic targets of armored chimeric antigen receptor T cells navigating the tumor microenvironment

Chimeric antigen receptor (CAR) T cell therapy, which targets tumors with high specificity through the recognition of particular antigens, has emerged as one of the most rapidly advancing modalities in immunotherapy, demonstrating substantial success against hematological malignancies. However, previous generations of CAR-T cell therapy encountered numerous challenges in treating solid tumors, such as the lack of suitable targets, high immunosuppression, suboptimal persistence, and insufficient infiltration owing to the complexities of the tumor microenvironment, all of which limited their efficacy. In this review, we focus on the current therapeutic targets of fourth-generation CAR-T cells, also known as armored CAR-T cells, and explore the mechanisms by which these engineered cells navigate the tumor microenvironment by targeting its various components. Enhancing CAR-T cells with these therapeutic targets holds promise for improving their effectiveness against solid tumors, thus achieving substantial clinical value and advancing the field of CAR-T cell therapy. Additionally, we discuss potential strategies to overcome existing challenges and highlight novel targets that could further enhance the efficacy of CAR-T cell therapy in treating solid tumors.

Current Insights into CAR T-Cell-Based Therapies for Myelodysplastic Syndrome

Myelodysplastic syndromes (MDS) are due to defective hematopoiesis in bone marrow characterized by cytopenia and dysplasia of blood cells, with a varying degree of risk of acute myeloid leukemia (AML). Currently, the only potentially curative strategy is hematopoietic stem cell transplantation (HSCT). Many patients are ineligible for HSCT, due to late diagnosis, presence of co-morbidities, old age and complications likely due to graft-versus-host disease (GvHD). As a consequence, patients with MDS are often treated conservatively with blood transfusions, chemotherapy, immunotherapy etc. based on the grade and manifestations of MDS. The development of chimeric antigen receptor (CAR)-T cell therapy has revolutionized immunotherapy for hematological malignancies, as evidenced by a large body of literature. However, resistance and toxicity associated with it are also a challenge. Hence, there is an urgent need to develop new strategies for immunological and hematopoetic management of MDS. Herein, we discuss current limitations of CAR T-cell therapy and summarize novel approaches to mitigate this. Further, we discuss the in vivo activation of tumor-specific T cells, immune check inhibitors (ICI) and other approaches to normalize the bone marrow milieu for the management of MDS.

Bispecific CAR-T cells targeting CD19/20 in patients with relapsed or refractory B cell non-Hodgkin lymphoma: a phase I/II trial

Non-Hodgkin lymphoma (NHL) is a common malignancy in the hematologic system, and traditional therapy has limited efficacy for people with recurrent/refractory NHL (R/R NHL), especially for patients with diffuse large B cell lymphoma (DLBCL). Chimeric antigen receptor (CAR) T-cell therapy is a novel and effective immunotherapy strategy for R/R hematopoietic malignancies, but relapses can occur due to the loss of CAR-T cells in vivo or the loss of antigen. One strategy to avoid antigen loss after CAR-T cell therapy is to target one more antigen simultaneously. Tandem CAR targeting CD19 and CD22 has demonstrated the reliability of tandem CAR-T cell therapy for R/R B-ALL. This study explores the therapeutic potential of tandem CD19/20 CAR-T in the treatment of R/R B cell NHL. The efficacy and safety of autologous CD19/20 CAR-T cells in eleven R/R B cell NHL adult patients were evaluated in an open-label, single-arm trial. Most patients achieved complete response, exhibiting the efficacy and safety of tandem CD19/20 CAR-T cells. The TCR repertoire diversity of CAR-T cells decreased after infusion. The expanded TCR clones in vivo were mainly derived from TCR clones that had increased expression of genes associated with immune-related signaling pathways from the infusion product (IP). The kinetics of CAR-T cells in vivo were linked to an increase in the expression of genes related to immune response and cytolysis/cytotoxicity.

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.

Fully equipped CARs to address tumor heterogeneity, enhance safety, and improve the functionality of cellular immunotherapies

Although adoptive transfer of chimeric antigen receptor (CAR)-engineered T cells has achieved unprecedented response rates in patients with certain hematological malignancies, this therapeutic modality is still far from fulfilling its remarkable potential, especially in the context of solid cancers. Antigen escape variants, off-tumor destruction of healthy tissues expressing tumor-associated antigens (TAAs), poor CAR-T cell persistence, and the occurrence of functional exhaustion represent some of the most prominent hurdles that limit CAR-T cell ability to induce long-lasting remissions with a tolerable adverse effect profile. In this review, we summarize the main approaches that have been developed to face such bottlenecks, including the adapter CAR (AdCAR) system, Boolean-logic gating, epitope editing, the modulation of cell-intrinsic signaling pathways, and the incorporation of safety switches to precisely control CAR-T cell activation. We also discuss the most pressing issues pertaining to the selection of co-stimulatory domains, with a focus on strategies aimed at promoting CAR-T cell persistence and optimal antitumor functionality.

CAR-T cell therapy: a game-changer in cancer treatment and beyond

In recent years, cancer has become one of the primary causes of mortality, approximately 10 million deaths worldwide each year. The most advanced, chimeric antigen receptor (CAR) T cell immunotherapy has turned out as a promising treatment for cancer. CAR-T cell therapy involves the genetic modification of T cells obtained from the patient's blood, and infusion back to the patients. CAR-T cell immunotherapy has led to a significant improvement in the remission rates of hematological cancers. CAR-T cell therapy presently limited to hematological cancers, there are ongoing efforts to develop additional CAR constructs such as bispecific CAR, tandem CAR, inhibitory CAR, combined antigens, CRISPR gene-editing, and nanoparticle delivery. With these advancements, CAR-T cell therapy holds promise concerning potential to improve upon traditional cancer treatments such as chemotherapy and radiation while reducing associated toxicities. This review covers recent advances and advantages of CAR-T cell immunotherapy.

CAR-T Cells in Acute Myeloid Leukemia: Where Do We Stand?

Despite recent advances, the prognosis of acute myeloid leukemia (AML) remains unsatisfactory due to disease recurrence and the development of resistance to both conventional and novel therapies. Engineered T cells expressing chimeric antigen receptors (CARs) on their cellular surface represent one of the most promising anticancer agents. CAR-T cells are increasingly used in patients with B cell malignancies, with remarkable clinical results despite some immune-related toxicities. However, at present, the role of CAR-T cells in myeloid neoplasms, including AML, is extremely limited, as specific molecular targets for immune cells are generally lacking on AML blasts. Besides the paucity of dispensable targets, as myeloid antigens are often co-expressed on normal hematopoietic stem and progenitor cells with potentially intolerable myeloablation, the AML microenvironment is hostile to T cell proliferation due to inhibitory soluble factors. In addition, the rapidly progressive nature of the disease further complicates the use of CAR-T in AML. This review discusses the current state of CAR-T cell therapy in AML, including the still scanty clinical evidence and the potential approaches to overcome its limitations, including genetic modifications and combinatorial strategies, to make CAR-T cell therapy an effective option for AML patients.

Synthetic biology approaches for improving the specificity and efficacy of cancer immunotherapy

Immunotherapy has shown robust efficacy in treating a broad spectrum of hematological and solid cancers. Despite the transformative impact of immunotherapy on cancer treatment, several outstanding challenges remain. These challenges include on-target off-tumor toxicity, systemic toxicity, and the complexity of achieving potent and sustainable therapeutic efficacy. Synthetic biology has emerged as a promising approach to overcome these obstacles, offering innovative tools for engineering living cells with customized functions. This review provides an overview of the current landscape and future prospects of cancer immunotherapy, particularly emphasizing the role of synthetic biology in augmenting its specificity, controllability, and efficacy. We delineate and discuss two principal synthetic biology strategies: those targeting tumor surface antigens with engineered immune cells and those detecting intratumoral disease signatures with engineered gene circuits. This review concludes with a forward-looking perspective on the enduring challenges in cancer immunotherapy and the potential breakthroughs that synthetic biology may contribute to the field.

CAR-based immunotherapy for breast cancer: peculiarities, ongoing investigations, and future strategies

Surgery, chemotherapy, and endocrine therapy have improved the overall survival and postoperative recurrence rates of Luminal A, Luminal B, and HER2-positive breast cancers but treatment modalities for triple-negative breast cancer (TNBC) with poor prognosis remain limited. The effective application of the rapidly developing chimeric antigen receptor (CAR)-T cell therapy in hematological tumors provides new ideas for the treatment of breast cancer. Choosing suitable and specific targets is crucial for applying CAR-T therapy for breast cancer treatment. In this paper, we summarize CAR-T therapy's effective targets and potential targets in different subtypes based on the existing research progress, especially for TNBC. CAR-based immunotherapy has resulted in advancements in the treatment of breast cancer. CAR-macrophages, CAR-NK cells, and CAR-mesenchymal stem cells (MSCs) may be more effective and safer for treating solid tumors, such as breast cancer. However, the tumor microenvironment (TME) of breast tumors and the side effects of CAR-T therapy pose challenges to CAR-based immunotherapy. CAR-T cells and CAR-NK cells-derived exosomes are advantageous in tumor therapy. Exosomes carrying CAR for breast cancer immunotherapy are of immense research value and may provide a treatment modality with good treatment effects. In this review, we provide an overview of the development and challenges of CAR-based immunotherapy in treating different subtypes of breast cancer and discuss the progress of CAR-expressing exosomes for breast cancer treatment. We elaborate on the development of CAR-T cells in TNBC therapy and the prospects of using CAR-macrophages, CAR-NK cells, and CAR-MSCs for treating breast cancer.

Car T Cells in Solid Tumors: Overcoming Obstacles

Chimeric antigen receptor T cell (CAR T cell) therapy has emerged as a prominent adoptive cell therapy and a therapeutic approach of great interest in the fight against cancer. This approach has shown notorious efficacy in refractory hematological neoplasm, which has bolstered its exploration in the field of solid cancers. However, successfully managing solid tumors presents considerable intrinsic challenges, which include the necessity of guiding the modified cells toward the tumoral region, assuring their penetration and survival in adverse microenvironments, and addressing the complexity of identifying the specific antigens for each type of cancer. This review focuses on outlining the challenges faced by CAR T cell therapy when used in the treatment of solid tumors, as well as presenting optimizations and emergent approaches directed at improving its efficacy in this particular context. From precise localization to the modulation of the tumoral microenvironment and the adaptation of antigen recognition strategies, diverse pathways will be examined to overcome the current limitations and buttress the therapeutic potential of CAR T cells in the fight against solid tumors.

Adoptive cell therapy for solid tumors beyond CAR-T: Current challenges and emerging therapeutic advances

Adoptive cellular immunotherapy using immune cells expressing chimeric antigen receptors (CARs) is a highly specific anti-tumor immunotherapy that has shown promise in the treatment of hematological malignancies. However, there has been a slow progress toward the treatment of solid tumors owing to the complex tumor microenvironment that affects the localization and killing ability of the CAR cells. Solid tumors with a strong immunosuppressive microenvironment and complex vascular system are unaffected by CAR cell infiltration and attack. To improve their efficacy toward solid tumors, CAR cells have been modified and upgraded by "decorating" and "pruning". This review focuses on the structure and function of CARs, the immune cells that can be engineered by CARs and the transformation strategies to overcome solid tumors, with a view to broadening ideas for the better application of CAR cell therapy for the treatment of solid tumors.

Targeting solid tumor antigens with chimeric receptors: cancer biology meets synthetic immunology

Chimeric antigen receptor (CAR) T cell therapy is a medical breakthrough in the treatment of B cell malignancies. There is intensive focus on developing solid tumor-targeted CAR-T cell therapies. Although clinically approved CAR-T cell therapies target B cell lineage antigens, solid tumor targets include neoantigens and tumor-associated antigens (TAAs) with diverse roles in tumor biology. Multiple early-stage clinical trials now report encouraging signs of efficacy for CAR-T cell therapies that target solid tumors. We review the landscape of solid tumor target antigens from the perspective of cancer biology and gene regulation, together with emerging clinical data for CAR-T cells targeting these antigens. We then discuss emerging synthetic biology strategies and their application in the clinical development of novel cellular immunotherapies.

Overall review of curative impact and barriers of CAR-T cells in osteosarcoma

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.

Chimeric Antigen Receptor T Cell Therapy for Hepatocellular Carcinoma: Where Do We Stand?

Hepatocellular carcinoma (HCC) remains a global health challenge that urgently calls for innovative therapeutic strategies. Chimeric antigen receptor T cell (CAR T) therapy has emerged as a promising avenue for HCC treatment. However, the therapeutic efficacy of CAR T immunotherapy in HCC patients is significantly compromised by some major issues including the immunosuppressive environment within the tumor, antigen heterogeneity, CAR T cell exhaustion, and the advanced risk for on-target/off-tumor toxicity. To overcome these challenges, many ongoing preclinical and clinical trials are underway focusing on the identification of optimal target antigens and the decryption of the immunosuppressive milieu of HCC. Moreover, limited tumor infiltration constitutes a significant obstacle of CAR T cell therapy that should be addressed. The continuous effort to design molecular targets for CAR cells highlights the importance for a more practical approach for CAR-modified cell manufacturing. This review critically examines the current landscape of CAR T cell therapy for HCC, shedding light on the changes in innate and adaptive immune responses in the context of HCC, identifying potential CAR T cell targets, and exploring approaches to overcome inherent challenges. Ongoing advancements in scientific research and convergence of diverse treatment modalities offer the potential to greatly enhance HCC patients' care in the future.

Peptide-scFv antigen recognition domains effectively confer CAR T cell multiantigen specificity

The emergence of immune escape is a significant roadblock to developing effective chimeric antigen receptor (CAR) T cell therapies against hematological malignancies, including acute myeloid leukemia (AML). Here, we demonstrate feasibility of targeting two antigens simultaneously by combining a GRP78-specific peptide antigen recognition domain with a CD123-specific scFv to generate a peptide-scFv bispecific antigen recognition domain (78.123). To achieve this, we test linkers with varying length and flexibility and perform immunophenotypic and functional characterization. We demonstrate that bispecific CAR T cells successfully recognize and kill tumor cells that express GRP78, CD123, or both antigens and have improved antitumor activity compared to their monospecific counterparts when both antigens are expressed. Protein structure prediction suggests that linker length and compactness influence the functionality of the generated bispecific CARs. Thus, we present a bispecific CAR design strategy to prevent immune escape in AML that can be extended to other peptide-scFv combinations.

Programmable synthetic receptors: the next-generation of cell and gene therapies

Cell and gene therapies hold tremendous promise for treating a range of difficult-to-treat diseases. However, concerns over the safety and efficacy require to be further addressed in order to realize their full potential. Synthetic receptors, a synthetic biology tool that can precisely control the function of therapeutic cells and genetic modules, have been rapidly developed and applied as a powerful solution. Delicately designed and engineered, they can be applied to finetune the therapeutic activities, i.e., to regulate production of dosed, bioactive payloads by sensing and processing user-defined signals or biomarkers. This review provides an overview of diverse synthetic receptor systems being used to reprogram therapeutic cells and their wide applications in biomedical research. With a special focus on four synthetic receptor systems at the forefront, including chimeric antigen receptors (CARs) and synthetic Notch (synNotch) receptors, we address the generalized strategies to design, construct and improve synthetic receptors. Meanwhile, we also highlight the expanding landscape of therapeutic applications of the synthetic receptor systems as well as current challenges in their clinical translation.

Tandem bispecific CD123/CLL-1 CAR-T cells exhibit specific cytolytic effector functions against human acute myeloid leukaemia

OBJECTIVES

The treatment of refractory and recurrent acute myeloid leukaemia (AML) is still a challenge with poor response rates and short survival times. In an attempt to solve this problem, we constructed a tandem bispecific chimeric antigen receptor (CAR) targeting CD123 and C-type lectin-like molecule 1 (CLL-1), two different AML antigens, and verified its cytotoxic effects in vitro.

METHODS

We established and cultured K562 cell lines expressing both CD123 and CLL1 antigens. Single-target CAR-T cells specific to CD123 and CLL1 were engineered, alongside tandem CD123/CLL1 bispecific CAR-T cells. Flow cytometry was used to determine cell phenotypes, transfection efficiencies, cytokine release, and CAR-T-cell proliferation, and an lactate dehydrogenase assay was used to detect the cytotoxicity of CD123/CLL-1 bispecific tandem CAR-T cells in vitro.

RESULTS

Two types of tandem CAR-T cells exhibited significant killing effects on CLL-1 + CD123+ leukaemia cell lines and primary AML tumour cells. The killing efficiency of tandem CAR-T cells in the case of single antigen expression is comparable to that of single target CAR-T cells. When faced with dual target tumour cells, dual target CAR-T cells significantly surpass single target CAR-T cells. CD123/CLL-1 CAR-T cells in tandem targeted and killed CD123- and CLL-1-positive leukaemia cell lines and released a large number of cytokines.

CONCLUSIONS

CD123/CLL-1 CAR-T cells in tandem can simultaneously target CD123 and CLL-1 on AML cells, demonstrating a significant ability to kill single antigens and multi-target tumour cells. This suggests that CD123/CLL-1 CAR-T cells exhibit significant advantages in the expression of multiple antigens in a wide range of target cells, which may help overcome the challenges posed by tumour heterogeneity and evasion mechanisms.

The research status and prospects of MUC1 in immunology

In immune processes, molecular - molecular interactions are complex. As MUC1 often appears to be an important molecule in inflammation and tumor immunity, it is necessary to summarize the leading countries, authors, journals, and the cooperation among these entities and, most importantly, to determine the main research directions related to MUC1 in this field and the associated research frontiers. A total of 3,397 related studies published from 2012-2021 were retrieved from the Web of Science core database. The search strategy is TS= (MUC1 OR Mucin-1) refined by WEB OF SCIENCE CATEGORY (IMMUNOLOGY) AND [excluding] PUBLICATION YEARS: (2022) AND DOCUMENT TYPES: (ARTICLE OR REVIEW) AND LANGUAGES: (ENGLISH) AND WEB OF SCIENCE INDEX: (Web of Science Core Collection. SCI), with a timespan of 2012 to 2021. Documented bibliometric visual analysis was performed by CiteSpace and VOSviewer. The number of studies has increased every year. There are 1,982 articles and 1,415 reviews from 89 countries and regions, 3,722 organizations, 1,042 journals, and 17,948 authors. The United States, China, and Germany are the major countries producing publications on this issue. The most published author is Finn OJ and the most influential author is June CH. The key words "chimeric antigen receptor" and "T-cell" highlight the current hot spots and future trends in this field. Research on MUC1 in the field of immunology is still evolving. Through the bibliometric analysis of the existing publications, the current research hotspots and future development trends in this field can be obtained.

Recruiting In Vitro Transcribed mRNA against Cancer Immunotherapy: A Contemporary Appraisal of the Current Landscape

Over 100 innovative in vitro transcribed (IVT)-mRNAs are presently undergoing clinical trials, with a projected substantial impact on the pharmaceutical market in the near future. Τhe idea behind this is that after the successful cellular internalization of IVT-mRNAs, they are subsequently translated into proteins with therapeutic or prophylactic relevance. Simultaneously, cancer immunotherapy employs diverse strategies to mobilize the immune system in the battle against cancer. Therefore, in this review, the fundamental principles of IVT-mRNA to its recruitment in cancer immunotherapy, are discussed and analyzed. More specifically, this review paper focuses on the development of mRNA vaccines, the exploitation of neoantigens, as well as Chimeric Antigen Receptor (CAR) T-Cells, showcasing their clinical applications and the ongoing trials for the development of next-generation immunotherapeutics. Furthermore, this study investigates the synergistic potential of combining the CAR immunotherapy and the IVT-mRNAs by introducing our research group novel, patented delivery method that utilizes the Protein Transduction Domain (PTD) technology to transduce the IVT-mRNAs encoding the CAR of interest into the Natural Killer (NK)-92 cells, highlighting the potential for enhancing the CAR NK cell potency, efficiency, and bioenergetics. While IVT-mRNA technology brings exciting progress to cancer immunotherapy, several challenges and limitations must be acknowledged, such as safety, toxicity, and delivery issues. This comprehensive exploration of IVT-mRNA technology, in line with its applications in cancer therapeutics, offers valuable insights into the opportunities and challenges in the evolving landscape of cancer immunotherapy, setting the stage for future advancements in the field.

Mechanisms and strategies for safe chimeric antigen receptor T-cell activity control

The clinical application of chimeric antigen receptor (CAR) T-cell therapy has rapidly changed the treatment options for terminally ill patients with defined blood-borne cancer types. However, CAR T-cell therapy can lead to severe therapy-associated toxicities including CAR-related hematotoxicity, ON-target OFF-tumor toxicity, cytokine release syndrome (CRS) or immune effector cell-associated neurotoxicity syndrome (ICANS). Just as CAR T-cell therapy has evolved regarding receptor design, gene transfer systems and production protocols, the management of side effects has also improved. However, because of measures taken to abrogate adverse events, CAR T-cell viability and persistence might be impaired before complete remission can be achieved. This has fueled efforts for the development of extrinsic and intrinsic strategies for better control of CAR T-cell activity. These approaches can mediate a reversible resting state or irreversible T-cell elimination, depending on the route chosen. Control can be passive or active. By combination of CAR T-cells with T-cell inhibiting compounds, pharmacologic control, mostly independent of the CAR construct design used, can be achieved. Other strategies involve the genetic modification of T-cells or further development of the CAR construct by integration of molecular ON/OFF switches such as suicide genes. Alternatively, CAR T-cell activity can be regulated intracellularly through a self-regulation function or extracellularly through titration of a CAR adaptor or of a priming small molecule. In this work, we review the current strategies and mechanisms to control activity of CAR T-cells reversibly or irreversibly for preventing and for managing therapy-associated toxicities.

CAR-T Cell Therapy: From the Shop to Cancer Therapy

Cancer is a worldwide health problem. Nevertheless, new technologies in the immunotherapy field have emerged. Chimeric antigen receptor (CAR) technology is a novel biological form to treat cancer; CAR-T cell genetic engineering has positively revolutionized cancer immunotherapy. In this paper, we review the latest developments in CAR-T in cancer treatment. We present the structure of the different generations and variants of CAR-T cells including TRUCK (T cells redirected for universal cytokine killing. We explain the approaches of the CAR-T cells manufactured ex vivo and in vivo. Moreover, we describe the limitations and areas of opportunity for this immunotherapy and the current challenges of treating hematological and solid cancer using CAR-T technology as well as its constraints and engineering approaches. We summarize other immune cells that have been using CAR technology, such as natural killer (NK), macrophages (M), and dendritic cells (DC). We conclude that CAR-T cells have the potential to treat not only cancer but other chronic diseases.

Unlocking the potential of Tregs: innovations in CAR technology

Regulatory T cells (Tregs) adoptive immunotherapy is emerging as a viable treatment option for both autoimmune and alloimmune diseases. However, numerous challenges remain, including limitations related to cell number, availability of target-specific cells, stability, purity, homing ability, and safety concerns. To address these challenges, cell engineering strategies have emerged as promising solutions. Indeed, it has become feasible to increase Treg numbers or enhance their stability through Foxp3 overexpression, post-translational modifications, or demethylation of the Treg-specific demethylated region (TSDR). Specificity can be engineered by the addition of chimeric antigen receptors (CARs), with new techniques designed to fine-tune specificity (tandem chimeric antigen receptors, universal chimeric antigen receptors, synNotch chimeric antigen receptors). The introduction of B-cell targeting antibody receptor (BAR) Tregs has paved the way for effective regulation of B cells and plasma cells. In addition, other constructs have emerged to enhance Tregs activation and function, such as optimized chimeric antigen receptors constructs and the use of armour proteins. Chimeric antigen receptor expression can also be better regulated to limit tonic signaling. Furthermore, various opportunities exist for enhancing the homing capabilities of CAR-Tregs to improve therapy outcomes. Many of these genetic modifications have already been explored for conventional CAR-T therapy but need to be further considered for CAR-Tregs therapies. This review highlights innovative CAR-engineering strategies that have the potential to precisely and efficiently manage immune responses in autoimmune diseases and improve transplant outcomes. As these strategies are further explored and optimized, CAR-Treg therapies may emerge as powerful tools for immune intervention.

CD22 is a potential target of CAR-NK cell therapy for esophageal squamous cell carcinoma

BACKGROUND

Chimeric antigen receptor NK (CAR-NK) cell therapy is one of the most promising immunotherapies. Although it has shown a significant therapeutic effect in hematologic malignancies, few successes have been obtained in solid tumors including esophageal squamous cell carcinoma (ESCC). The major reasons are lack of specific cell surface antigens and complex tumor microenvironment. Here we identify CD22, a well-known tumor surface marker in hematologic malignancies, is expressed in ESCC, possibly serving as a potential target of CAR-NK cell therapy.

METHODS

The expression of 13 tumor cell surface antigens used clinically was analyzed in patients from The Cancer Genome Atlas (TCGA) database. Also, mRNA expression were detected in 2 ESCC cell lines and 2 patients samples by qCPR. Then according to Venn diagram, CD22 was selected for further investigation. Following this, the expression of CD22 by immunofluorescence (IF) in ESCC cell lines and by immunohistochemistry (IHC) in 87 cases of human ESCC samples was detected respectively. On the basis of H-score results, the correlation between CD22 expression and clinical parameters was analyzed. As a proof, the efficacy of CD22-targeted CAR-NK cells against ESCC cell lines was performed by a real-time cell analyzer (RTCA) platform.

RESULTS

KYSE-140 and KYSE-150 cell lines displayed surface expression of CD22. IHC showed an 80.46% (70/87) positive rate in ESCC patient samples. Among these, cell membranous expression of CD22 was observed in 27.59% (24/87) patient samples. Through chi-square test, expression of CD22 in ESCC was associated with lymph node metastasis while it was no related to the depth of tumor invasion and clinical stage. Engineered CD22-targeted CAR-NK cells exhibited inhibitory growth capability against ESCC cell lines (p < 0.0001).

CONCLUSIONS

CD22 is a potential tumor surface antigen capable of being targeted by CAR-NK cells in ESCC. And potential therapeutics for ESCC may be developed based on immune cells expressing anti-CD22 CAR. The study also indicates that CD22 CAR-NK cells could be used in other cancers and more in vivo experiments are needed.

Exploring CAR-T Cell Therapy Side Effects: Mechanisms and Management Strategies

Chimeric antigen receptor (CAR) T cell therapy has revolutionized the treatment of malignancies, especially hematological tumors, but toxicities have tempered its success. The main impediments to the development of CAR-T cell therapies are the following: cytokine release syndrome (CRS), immune-effector-cell-associated neurotoxicity syndrome (ICANS), tumor lysis syndrome (TLS), and on-target/off-tumor toxicity (OTOT). This review summarizes these side effects' underlying mechanisms and manifestations over time. It provides potential prevention and treatment according to the consensus grading, stressing the significance of establishing strategies that anticipate, reduce, and navigate the beginning of these side effects. It is essential to fully comprehend the mechanisms underlying these toxicities to create efficient treatment and preventive approaches.

Targeted cellular therapy for treatment of relapsed or refractory leukemia

While the mainstay of treatment for high-risk or relapsed, refractory leukemia has historically revolved around allogeneic hematopoietic stem cell transplant (allo-HSCT), targeted immunotherapies have emerged as a promising therapeutic option, especially given the poor prognosis of patients who relapse after allo-HSCT. Novel cellular immunotherapies that harness the cytotoxic abilities of the immune system in a targeted manner (often called "adoptive" cell therapy), have changed the way we treat r/r hematologic malignancies and continue to change the treatment landscape given the rapid evolution of these powerful, yet sophisticated precision therapies that often offer a less toxic alternative to conventional salvage therapies. Importantly, adoptive cell therapy can be allo-HSCT-enabling or a therapeutic option for patients in whom transplantation has failed or is contraindicated. A solid understanding of the core concepts of adoptive cell therapy is necessary for stem cell transplant physicians, nurses and ancillary staff given its proximity to the transplant field as well as its inherent complexities that require specific expertise in compliant manufacturing, clinical application, and risk mitigation. Here we will review use of targeted cellular therapy for the treatment of r/r leukemia, focusing on chimeric antigen receptor T-cells (CAR T-cells) given the remarkable sustained clinical responses leading to commercial approval for several hematologic indications including leukemia, with brief discussion of other promising investigational cellular immunotherapies and special considerations for sustainability and scalability.

Engineering enhanced chimeric antigen receptor-T cell therapy for solid tumors

The early clinical success and subsequent US Food and Drug Administration approval of chimeric antigen receptor (CAR)-T cell therapy for leukemia and lymphoma affirm that engineered T cells can be a powerful treatment for hematologic malignancies. Yet this success has not been replicated in solid tumors. Numerous challenges emerged from clinical experience and well-controlled preclinical animal models must be met to enable safe and efficacious CAR-T cell therapy in solid tumors. Here, we review recent advances in bioengineering strategies developed to enhance CAR-T cell therapy in solid tumors, focusing on targeted single-gene perturbation, genetic circuits design, cytokine engineering, and interactive biomaterials. These bioengineering approaches present a unique set of tools that synergize with CAR-T cells to overcome obstacles in solid tumors and achieve robust and long-lasting therapeutic efficacy.

CAR-T cells targeting CD38 and LMP1 exhibit robust antitumour activity against NK/T cell lymphoma

BACKGROUND

Natural killer/T cell lymphoma (NKTCL) is an aggressive lymphoma with a poor prognosis. Chimeric antigen receptor-transduced T (CAR-T) cell therapy has become a promising immunotherapeutic strategy against haematologic malignancies.

METHODS

In this study, four CAR-T cell lines (CD38-CAR, LMP1-CAR, CD38-LMP1 tandem CAR 1 and CD38-LMP1 tandem CAR 2) were generated. The effect of CAR-T cells against NKTCL cells was evaluated both in vitro and in vivo. Expression of T cell activation markers and cytokines produced by CAR-T cells were detected by flow cytometry.

RESULTS

The four CAR-T cell lines could effectively eliminate malignant NKTCL cells. They could be activated and produce inflammatory cytokines in a target-dependent manner. In vivo tests showed that the CAR-T cells exhibited significant antitumour effects in a xenotransplanted NKTCL mouse model.

CONCLUSIONS

In summary, four CAR-T cell lines exhibited significant cytotoxicity against NKTCL cells both in vitro and in vivo. These results indicated the effective therapeutic promise of CD38 and LMP1 CAR-T cells in NKTCL.

CAR-T cells dual-target CD123 and NKG2DLs to eradicate AML cells and selectively target immunosuppressive cells

Chimeric antigen receptor (CAR)-T cells have not made significant progress in the treatment of acute myeloid leukemia (AML) in earlyclinical studies. This lack of progress could be attributed in part to the immunosuppressive microenvironment of AML, such as monocyte-like myeloid-derived suppressor cells (M-MDSCs) and alternatively activated macrophages (M2 cells), which can inhibit the antitumor activity of CAR-T cells. Furthermore, AML cells are usually heterogeneous, and single-target CAR-T cells may not be able to eliminate all AML cells, leading to disease relapse. CD123 and NKG2D ligands (NKG2DLs) are commonly used targets for CAR-T therapy of AML, and M-MDSCs and M2 cells express both antigens. We developed dual-targeted CAR-T (123NL CAR-T) cells targeting CD123 and NKG2DL by various structural optimization screens. Our study reveals that 123NL CAR-T cells eradicate AML cells and selectively target immunosuppressive cells. A highly compact marker/suicide gene, RQR8, which binds targeting epitopes of CD34 and CD20 antigens, was also incorporated in front of the CAR structure. The binding of Rituximab to RQR8 leads to the elimination of 123NL CAR-T cells and cessation of their cytotoxicity. In conclusion, we successfully developed dual effects of 123NL CAR-T cells against tumor cells and immunosuppressive cells, which can avoid target escape and resist the effects of immunosuppressive microenvironment.

Challenges and new technologies in adoptive cell therapy

Adoptive cell therapies (ACTs) have existed for decades. From the initial infusion of tumor-infiltrating lymphocytes to the subsequent specific enhanced T cell receptor (TCR)-T and chimeric antigen receptor (CAR)-T cell therapies, many novel strategies for cancer treatment have been developed. Owing to its promising outcomes, CAR-T cell therapy has revolutionized the field of ACTs, particularly for hematologic malignancies. Despite these advances, CAR-T cell therapy still has limitations in both autologous and allogeneic settings, including practicality and toxicity issues. To overcome these challenges, researchers have focused on the application of CAR engineering technology to other types of immune cell engineering. Consequently, several new cell therapies based on CAR technology have been developed, including CAR-NK, CAR-macrophage, CAR-γδT, and CAR-NKT. In this review, we describe the development, advantages, and possible challenges of the aforementioned ACTs and discuss current strategies aimed at maximizing the therapeutic potential of ACTs. We also provide an overview of the various gene transduction strategies employed in immunotherapy given their importance in immune cell engineering. Furthermore, we discuss the possibility that strategies capable of creating a positive feedback immune circuit, as healthy immune systems do, could address the flaw of a single type of ACT, and thus serve as key players in future cancer immunotherapy.

Chimeric antigen receptor T cell and regulatory T cell therapy in non-oncology diseases: A narrative review of studies from 2017 to 2023

Recently, the remarkable success of chimeric antigen receptor T cell (CAR-T) therapy in treating certain tumors has led to numerous studies exploring its potential application to treat non-oncology diseases. This review discusses the progress and evolution of CAR-T cell therapies for treating non-oncology diseases over the past 5 years. Additionally, we summarize the advantages and disadvantages of CAR-T cell therapy in treating non-oncological diseases and identify any difficulties that should be overcome. After conducting an in-depth analysis of the most recent studies on CAR-T technology, we discuss the key elements of CAR-T therapy, such as developing an effective CAR design for non-oncological diseases, controlling the rate and duration of response, and implementing safety measures to reduce toxicity. These studies provide new insights into different delivery strategies, the discovery of new target molecules, and improvements in the safety of CAR-T therapy for non-oncological diseases.

Strategies for Reducing Toxicity and Enhancing Efficacy of Chimeric Antigen Receptor T Cell Therapy in Hematological Malignancies

Chimeric antigen receptor T cell (CAR-T) therapy in hematologic malignancies has made great progress, but there are still some problems. First, T cells from tumor patients show an exhaustion phenotype; thus, the persistence and function of the CAR-Ts are poor, and achieving a satisfactory curative effect is difficult. Second, some patients initially respond well but quickly develop antigen-negative tumor recurrence. Thirdly, CAR-T treatment is not effective in some patients and is accompanied by severe side effects, such as cytokine release syndrome (CRS) and neurotoxicity. The solution to these problems is to reduce the toxicity and enhance the efficacy of CAR-T therapy. In this paper, we describe various strategies for reducing the toxicity and enhancing the efficacy of CAR-T therapy in hematological malignancies. In the first section, strategies for modifying CAR-Ts using gene-editing technologies or combining them with other anti-tumor drugs to enhance the efficacy of CAR-T therapy are introduced. The second section describes some methods in which the design and construction of CAR-Ts differ from the conventional process. The aim of these methods is to enhance the anti-tumor activity of CAR-Ts and prevent tumor recurrence. The third section describes modifying the CAR structure or installing safety switches to radically reduce CAR-T toxicity or regulating inflammatory cytokines to control the symptoms of CAR-T-associated toxicity. Together, the knowledge summarized herein will aid in designing better-suited and safer CAR-T treatment strategies.

The Interplay between T Cells and Cancer: The Basis of Immunotherapy

Over the past decade, immunotherapy has emerged as one of the most promising approaches to cancer treatment. The use of immune checkpoint inhibitors has resulted in impressive and durable clinical responses in the treatment of various cancers. Additionally, immunotherapy utilizing chimeric antigen receptor (CAR)-engineered T cells has produced robust responses in blood cancers, and T cell receptor (TCR)-engineered T cells are showing promising results in the treatment of solid cancers. Despite these noteworthy advancements in cancer immunotherapy, numerous challenges remain. Some patient populations are unresponsive to immune checkpoint inhibitor therapy, and CAR T cell therapy has yet to show efficacy against solid cancers. In this review, we first discuss the significant role that T cells play in the body's defense against cancer. We then delve into the mechanisms behind the current challenges facing immunotherapy, starting with T cell exhaustion due to immune checkpoint upregulation and changes in the transcriptional and epigenetic landscapes of dysfunctional T cells. We then discuss cancer-cell-intrinsic characteristics, including molecular alterations in cancer cells and the immunosuppressive nature of the tumor microenvironment (TME), which collectively facilitate tumor cell proliferation, survival, metastasis, and immune evasion. Finally, we examine recent advancements in cancer immunotherapy, with a specific emphasis on T-cell-based treatments.

Targeting FLT3-specific chimeric antigen receptor T cells for acute lymphoblastic leukemia with KMT2A rearrangement

CD19-specific chimeric antigen receptor T (CAR T) immunotherapy is used to treat B-cell malignancies. However, antigen-escape mediated relapse following CAR T therapy has emerged as a major concern. In some relapsed cases, especially KMT2A rearrangement-positive B-acute lymphoblastic leukemia (KMT2A-r B-ALL), most of the B-cell antigens are lost via lineage conversion to the myeloid phenotype, rendering multi-B-cell-antigen-targeted CAR T cell therapy ineffective. Fms-related tyrosine kinase-3 (FLT3) is highly expressed in KMT2A-r B-ALL; therefore, in this study, we aimed to evaluate the antitumor efficacy of CAR T cells targeting both CD19 and FLT3 in KMT2A-r B-ALL cells. We developed piggyBac transposon-mediated CAR T cells targeting CD19, FLT3, or both (dual) and generated CD19-negative KMT2A-r B-ALL models through CRISPR-induced CD19 gene-knockout (KO). FLT3 CAR T cells showed antitumor efficacy against CD19-KO KMT2A-r B-ALL cells both in vitro and in vivo; dual-targeted CAR T cells showed cytotoxicity against wild-type (WT) and CD19-KO KMT2A-r B-ALL cells, whereas CD19 CAR T cells demonstrated cytotoxicity only against WT KMT2A-r B-ALL cells in vitro. Therefore, targeting FLT3-specific CAR T cells would be a promising strategy for KMT2A-r B-ALL cells even with CD19-negative relapsed cases.

Tuning CARs: recent advances in modulating chimeric antigen receptor (CAR) T cell activity for improved safety, efficacy, and flexibility

Cancer immunotherapies utilizing genetically engineered T cells have emerged as powerful personalized therapeutic agents showing dramatic preclinical and clinical results, particularly in hematological malignancies. Ectopically expressed chimeric antigen receptors (CARs) reprogram immune cells to target and eliminate cancer. However, CAR T cell therapy's success depends on the balance between effective anti-tumor activity and minimizing harmful side effects. To improve CAR T cell therapy outcomes and mitigate associated toxicities, scientists from different fields are cooperating in developing next-generation products using the latest molecular cell biology and synthetic biology tools and technologies. The immunotherapy field is rapidly evolving, with new approaches and strategies being reported at a fast pace. This comprehensive literature review aims to provide an up-to-date overview of the latest developments in controlling CAR T cell activity for improved safety, efficacy, and flexibility.

Chimeric antigen receptor T cells therapy in solid tumors

Chimeric antigen receptor T cells therapy (CAR-T therapy) is a class of ACT therapy. Chimeric antigen receptor (CAR) is an engineered synthetic receptor of CAR-T, which give T cells the ability to recognize tumor antigens in a human leukocyte antigen-independent (HLA-independent) manner and enables them to recognize more extensive target antigens than natural T cell surface receptor (TCR), resulting in tumor destruction. CAR-T is composed of an extracellular single-chain variable fragment (scFv) of antibody, which serves as the targeting moiety, hinge region, transmembrane spacer, and intracellular signaling domain(s). CAR-T has been developing in many generations, which differ according to costimulatory domains. CAR-T therapy has several limitations that reduce its wide availability in immunotherapy which we can summarize in antigen escape that shows either partial or complete loss of target antigen expression, so multiplexing CAR-T cells are promoted to enhance targeting of tumor profiles. In addition, the large diversity in the tumor microenvironment also plays a major role in limiting this kind of treatment. Therefore, engineered CAR-T cells can evoke immunostimulatory signals that rebalance the tumor microenvironment. Using CAR-T therapy in treating the solid tumor is mainly restricted by the difficulty of CAR-T cells infiltrating the tumor site, so local administration was developed to improve the quality of treatment. The most severe toxicity after CAR-T therapy is on-target/on-tumor toxicity, such as cytokine release syndrome (CRS). Another type of toxicity is on-target/off-tumor toxicity which originates from the binding of CAR-T cells to target antigen that has shared expression on normal cells leading to damage in healthy cells and organs. Toxicity management should become a focus of implementation to permit management beyond specialized centers.

Role of tumor microenvironment in cancer progression and therapeutic strategy

Cancer is now considered a tumor microenvironment (TME) disease, although it was originally thought to be a cell and gene expression disorder. Over the past 20 years, significant advances have been made in understanding the complexity of the TME and its impact on responses to various anticancer therapies, including immunotherapies. Cancer immunotherapy can recognize and kill cancer cells by regulating the body's immune system. It has achieved good therapeutic effects in various solid tumors and hematological malignancies. Recently, blocking of programmed death-1 (PD-1), programmed death-1 ligand-1 (PD-L1), and programmed death Ligand-2 (PD-L2), the construction of antigen chimeric T cells (CAR-T) and tumor vaccines have become popular immunotherapies Tumorigenesis, progression, and metastasis are closely related to TME. Therefore, we review the characteristics of various cells and molecules in the TME, the interaction between PD-1 and TME, and promising cancer immunotherapy therapeutics.

Immunotherapies against HER2-Positive Breast Cancer

Breast cancer is the leading cause of cancer-related deaths among women worldwide. HER2-positive breast cancer, which represents 15-20% of all cases, is characterized by the overexpression of the HER2 receptor. Despite the variety of treatments available for HER2-positive breast cancer, both targeted and untargeted, many patients do not respond to therapy and relapse and eventually metastasize, with a poor prognosis. Immunotherapeutic approaches aim to enhance the antitumor immune response to prevent tumor relapse and metastasis. Several immunotherapies have been approved for solid tumors, but their utility for HER2-positive breast cancer has yet to be confirmed. In this review, we examine the different immunotherapeutic strategies being tested in HER2-positive breast cancer, from long-studied cancer vaccines to immune checkpoint blockade, which targets immune checkpoints in both T cells and tumor cells, as well as the promising adoptive cell therapy in various forms. We discuss how some of these new approaches may contribute to the prevention of tumor progression and be used after standard-of-care therapies for resistant HER2-positive breast tumors, highlighting the benefits and drawbacks of each. We conclude that immunotherapy holds great promise for the treatment of HER2-positive tumors, with the potential to completely eradicate tumor cells and prevent the progression of the disease.

Multispecific CAR T Cells Deprive Lymphomas of Escape via Antigen Loss

Chimeric antigen receptor (CAR) modified T cell therapy has transformed the management of relapsed/refractory B cell malignancies. Despite high overall response rates, relapse post CAR T treatment remains a clinical challenge. Loss of target antigen, specifically CD19, is one well-defined mechanism of disease relapse. The mechanism of CD19 loss and which patients are at higher risk of CD19 loss remain poorly understood. To overcome CD19 loss, CARs targeting multiple antigens are being tested in clinical trials. CD19/20 and CD19/22 bispecific CARs demonstrate cytotoxicity against CD19-negative cells in preclinical studies. These CARs have also shown efficacy, safety, and a relatively low rate of CD19-negative relapse in phase I trials. These small studies suggest that multispecific CAR T cells can deprive lymphomas of escape via antigen loss. However, the selection of an ideal target, the right CAR construct, and whether these multispecific CARs can induce long-term remissions are still under investigation.

The current landscape of CAR T-cell therapy for solid tumors: Mechanisms, research progress, challenges, and counterstrategies

The successful outcomes of chimeric antigen receptor (CAR) T-cell therapy in treating hematologic cancers have increased the previously unprecedented excitement to use this innovative approach in treating various forms of human cancers. Although researchers have put a lot of work into maximizing the effectiveness of these cells in the context of solid tumors, few studies have discussed challenges and potential strategies to overcome them. Restricted trafficking and infiltration into the tumor site, hypoxic and immunosuppressive tumor microenvironment (TME), antigen escape and heterogeneity, CAR T-cell exhaustion, and severe life-threatening toxicities are a few of the major obstacles facing CAR T-cells. CAR designs will need to go beyond the traditional architectures in order to get over these limitations and broaden their applicability to a larger range of malignancies. To enhance the safety, effectiveness, and applicability of this treatment modality, researchers are addressing the present challenges with a wide variety of engineering strategies as well as integrating several therapeutic tactics. In this study, we reviewed the antigens that CAR T-cells have been clinically trained to recognize, as well as counterstrategies to overcome the limitations of CAR T-cell therapy, such as recent advances in CAR T-cell engineering and the use of several therapies in combination to optimize their clinical efficacy in solid tumors.

Tandem chimeric antigen receptor (CAR) T cells targeting EGFRvIII and IL-13Rα2 are effective against heterogeneous glioblastoma

Background

Chimeric antigen receptor (CAR) T cells have achieved remarkable responses in patients with hematological malignancies; however, the potential of this therapeutic platform for solid tumors like glioblastoma (GBM) has been limited, due in large part to the targeting of single antigens in a heterogeneous disease. Strategies that allow CAR T cells to engage multiple antigens concomitantly may broaden therapeutic responses and mitigate the effects of immune escape.

Methods

Here we have developed a novel, dual-specific, tandem CAR T (TanCART) cell with the ability to simultaneously target both EGFRvIII and IL-13Rα2, two well-characterized tumor antigens that are frequently found on the surface of GBM cells but completely absent from normal brain tissues. We employed both standard immunological assays and multiple orthotopic preclinical models including patient-derived xenograft to demonstrate efficacy of this approach against heterogeneous tumors.

Results

Tandem CAR T cells displayed enhanced cytotoxicity in vitro against heterogeneous GBM populations, including patient-derived brain tumor cultures (P < .05). Compared to CAR T cells targeting single antigens, dual antigen engagement through the tandem construct was necessary to achieve long-term, complete, and durable responses in orthotopic murine models of heterogeneous GBM, including patient-derived xenografts (P < .05).

Conclusions

We demonstrate that TanCART is effective against heterogeneous tumors in the brain. These data lend further credence to the development of multi-specific CAR T cells in the treatment of GBM and other cancers.

Engineering chimeric antigen receptor T cells for solid tumour therapy

Cell-based immunotherapy, for example, chimeric antigen receptor T (CAR-T) cell immunotherapy, has revolutionized cancer treatment, particularly for blood cancers. However, factors such as insufficient T cell tracking, tumour heterogeneity, inhibitory tumour microenvironment (TME) and T cell exhaustion limit the broad application of CAR-based immunotherapy for solid tumours. In particular, the TME is a complex and evolving entity, which is composed of cells of different types (e.g., cancer cells, immune cells and stromal cells), vasculature, soluble factors and extracellular matrix (ECM), with each component playing a critical role in CAR-T immunotherapy. Thus, developing approaches to mitigate the inhibitory TME factors is critical for future success in applying CAR-T cells for solid tumour treatment. Accordingly, understanding the bilateral interaction of CAR-T cells with the TME is in pressing need to pave the way for more efficient therapeutics. In the following review, we will discuss TME-associated aspects with an emphasis on T cell trafficking, ECM barriers, abnormal vasculature, solid tumour heterogenicity and immune suppressive microenvironment. We will then summarize current engineering strategies to overcome the challenges posed by the TME-associated factors. Lastly, the future directions for engineering efficient CAR-T cells for solid tumour therapy will be discussed.

In silico analysis of a novel protein in CAR T- cell therapy for the treatment of hematologic cancer through molecular modelling, docking, and dynamics approach

Cellular therapy has emerged as a key tool in the treatment of hematological malignancies. An advanced cell therapy known as chimeric antigen receptor T cell therapy (CAR T-cell therapy) has been approved by the United States Food and Drug Administration (FDA) as KYMRIAH by Novartis and YESCARTA by Gilead/Kite pharma in the year 2017. A chimeric receptor is composed of an extracellular antigen recognition site along with some co-stimulating and signalling domains. On the whole, it turns out to be one of the most potent receptors on T cells targeting a specific type of cancer cell based on its antigenic marker. CD19 CAR T-cell therapy is the first clinically approved therapy for lymphoma with remarkable results in complete remission of B cell lymphoblastic leukemia up to 90%. The high rate of effectiveness of the CAR T-cell therapy against B-ALL justifies the investigation and application of this therapy for fatal diseases like all types of hematological malignancies. The most critical aspect of chimeric receptor therapy is designing and building an artificial receptor that is specific to a given type of cancer. For this reason, the in silico technique is an appropriate model to investigate the integrity and effectiveness of the engineered chimeric receptor prior to commencing in vitro experiments followed by clinical trials. This computerized experimental study aids in predicting the molecular mechanism of chimeric protein and how it interacts with both ligands. We have anticipated various features of the chimeric protein in terms of qualitative analysis (structure, protein modelling, physiological properties) and functional analysis (antigenicity, allergenicity, its receptor-ligand binding ability, involving signalling pathways). Furthermore, the reliability and validation of the binding mode of the chimeric protein against receptors were performed through a complex molecular dynamics simulation for a 100 ns timeframe in an aqueous environment. The obtained simulation study showed that CD30 was a better approachable marker as compared to CD20 due to its better binding energy score and also binding conformations stability.

Overcoming resistance to anti-CD19 CAR T-cell therapy in B-cell malignancies

Anti-CD19 chimeric antigen receptor (CAR) T-cell therapy has rapidly changed current treatment pattern, providing a better option for individuals with primary refractory or relapsed B-cell non-Hodgkin lymphoma (r/r B-NHL) and B-cell acute lymphoblastic leukemia (r/r B-ALL). However, despite the outstanding efficacy, a high relapse rate is still found in some B-cell malignancies after anti-CD19 CAR T-cell therapy, which emerges as a main barrier for improving the overall response and long-term outcomes. Understanding the resistance mechanism is crucial to improve current CAR T products, better incorporate them into the current therapy system and develop novel CAR approaches. Herein, we discuss the latest advances in understanding the mechanisms limiting efficacy of CAR T-cell therapy, resulting in CD19 negative (CD19^- ) and CD19 positive (CD19⁺ ) relapses. We also provide a whole scenario of current potential strategies to overcome these barriers.

Current updates on generations, approvals, and clinical trials of CAR T-cell therapy

Chimeric antigen receptor (CAR) T-cell therapy is a novel, customized immunotherapy that is considered a 'living' and self-replicating drug to treat cancer, sometimes resulting in a complete cure. CAR T-cells are manufactured through genetic engineering of T-cells by equipping them with CARs to detect and target antigen-expressing cancer cells. CAR is designed to have an ectodomain extracellularly, a transmembrane domain spanning the cell membrane, and an endodomain intracellularly. Since its first discovery, the CAR structure has evolved greatly, from the first generation to the fifth generation, to offer new therapeutic alternatives for cancer patients. This treatment has achieved long-term and curative therapeutic efficacy in multiple blood malignancies that nowadays profoundly change the treatment landscape of lymphoma, leukemia, and multiple myeloma. But CART-cell therapy is associated with several hurdles, such as limited therapeutic efficacy, little effect on solid tumors, adverse effects, expensive cost, and feasibility issues, hindering its broader implications.

Learning from TCR Signaling and Immunological Synapse Assembly to Build New Chimeric Antigen Receptors (CARs)

Chimeric antigen receptor (CAR) T cell immunotherapy is a revolutionary pillar in cancer treatment. Clinical experience has shown remarkable successes in the treatment of certain hematological malignancies but only limited efficacy against B cell chronic lymphocytic leukemia (CLL) and other cancer types, especially solid tumors. A wide range of engineering strategies have been employed to overcome the limitations of CAR T cell therapy. However, it has become increasingly clear that CARs have unique, unexpected features; hence, a deep understanding of how CARs signal and trigger the formation of a non-conventional immunological synapse (IS), the signaling platform required for T cell activation and execution of effector functions, would lead a shift from empirical testing to the rational design of new CAR constructs. Here, we review current knowledge of CARs, focusing on their structure, signaling and role in CAR T cell IS assembly. We, moreover, discuss the molecular features accounting for poor responses in CLL patients treated with anti-CD19 CAR T cells and propose CLL as a paradigm for diseases connected to IS dysfunctions that could significantly benefit from the development of novel CARs to generate a productive anti-tumor response.

Recent progress of gene circuit designs in immune cell therapies

The success of chimeric antigen receptor (CAR) T cell therapy against hematological cancers has convincingly demonstrated the potential of using genetically engineered cells as therapeutic agents. Although much progress has been achieved in cell therapy, more beneficial capabilities have yet to be fully explored. One of the unique advantages afforded by cell therapies is the possibility to implement genetic control circuits, which enables diverse signal sensing and logical processing for optimal response in the complex tumor microenvironment. In this perspective, we will first outline design considerations for cell therapy control circuits that address clinical demands. We will compare and contrast key design features in some of the latest control circuits developments and conclude by discussing potential future directions.

Current and Future Perspectives for Chimeric Antigen Receptor T Cells Development in Poland

Chimeric antigen receptor T (CAR-T) cells are genetically modified autologous T cells that have revolutionized the treatment of relapsing and refractory haematological malignancies. In this review we present molecular pathways involved in the activation of CAR-T cells, describe in details the structures of receptors and the biological activity of CAR-T cells currently approved for clinical practice in the European Union, and explain the functional differences between them. Finally, we present the potential for the development of CAR-T cells in Poland, as well as indicate the possible directions of future research in this area, including novel modifications and applications of CAR-T cells and CAR-natural killer (NK) cells.

Clinical utility of CAR T cell therapy in brain tumors: Lessons learned from the past, current evidence and the future stakes

The unprecedented clinical success of Chimeric Antigen Receptor (CAR) T cell therapy in hematological malignancies has led researchers to study its role in solid tumors. Although, its utility in solid tumors especially in neuroblastoma has begun to emerge, preclinical studies of its efficacy in other solid tumors like osteosarcomas or gliomas has caught the attention of oncologist to be tried in clinical trials. Malignant high-grade brain tumors like glioblastomas or midline gliomas in children represent some of the most difficult malignancies to be managed with conventionally available therapeutics, while relapsed gliomas continue to have the most dismal prognosis due to limited therapeutic options. Innovative therapies such as CAR T cells could give an additional leverage to the treating oncologists by potentially improving outcomes and ameliorating the toxicity of the currently available therapies. Moreover, CAR T cell therapy has the potential to be integrated into the therapeutic paradigm for aggressive gliomas in the near future. In this review we discuss the challenges in using CAR T cell therapy in brain tumors, enumerate the completed and ongoing clinical trials of different types of CAR T cell therapy for different brain tumors with special emphasis on glioblastoma and also discuss the future role of CAR T cells in Brain tumors.

Recent advances in the production, reprogramming, and application of CAR-T cells for treating hematological malignancies

As genetically engineered cells, chimeric antigen receptor (CAR)-T cells express specific receptors on their surface to target and eliminate malignant cells. CAR proteins are equipped with elements that enhance the activity and survival of T cells. Once injected, CAR-T cells act as a "living drug" against tumor cells in the body. Up to now, CAR-T cell therapy has been demonstrated as a robust adoptive cell transfer (ACT) immunotherapeutic modality for eliminating tumor cells in refractory hematological malignancies. CAR-T cell therapy modality involves several steps, including the collecting of the blood from patients, the isolation of peripheral blood mononuclear cells (PBMCs), the enrichment of CD4⁺/CD8⁺ T cell, the genetic reprogramming, the expansion of modified T cells, and the injection of genetically engineered T cells. The production of CAR-T cells is a multi-step procedure, which needs precise and safety management systems, including good manufacturing practice (GMP), and in-line quality control and assurance. The current study describes the structure of CARs and concentrates on the next generations of CARs that are engaged in enhancing the anti-tumor responses and safety of the engineered T cells. This paper also highlights the important concerns in quality control and nonclinical research of CAR-T cells, as well as general insights into the manufacture, reprogramming, and application of CAR-T cells based on new and enhanced techniques for treating hematological malignancies. Besides, the application of the CRISPR-Cas9 genome editing technology and nanocarrier-based delivery systems containing CAR coding sequences to overcome the limitations of CAR-T cell therapy has also been explained.

CAR-T cell potency: from structural elements to vector backbone components

Chimeric antigen receptor (CAR) T cell therapy, in which a patient’s own T lymphocytes are engineered to recognize and kill cancer cells, has achieved remarkable success in some hematological malignancies in preclinical and clinical trials, resulting in six FDA-approved CAR-T products currently available in the market. Once equipped with a CAR construct, T cells act as living drugs and recognize and eliminate the target tumor cells in an MHC-independent manner. In this review, we first described all structural modular of CAR in detail, focusing on more recent findings. We then pointed out behind-the-scene elements contributing to CAR expression and reviewed how CAR expression can be drastically affected by the elements embedded in the viral vector backbone.