Low-dose decitabine priming endows CAR T cells with enhanced and persistent antitumour potential via epigenetic reprogramming

Next-generation immunotherapeutic approaches for blood cancers: Exploring the efficacy of CAR-T and cancer vaccines

Recent advancements in immunotherapy, particularly Chimeric antigen receptor (CAR)-T cell therapy and cancer vaccines, have significantly transformed the treatment landscape for leukemia. CAR-T cell therapy, initially promising in hematologic cancers, faces notable obstacles in solid tumors due to the complex and immunosuppressive tumor microenvironment. Challenges include the heterogeneous immune profiles of tumors, variability in antigen expression, difficulties in therapeutic delivery, T cell exhaustion, and reduced cytotoxic activity at the tumor site. Additionally, the physical barriers within tumors and the immunological camouflage used by cancer cells further complicate treatment efficacy. To overcome these hurdles, ongoing research explores the synergistic potential of combining CAR-T cell therapy with cancer vaccines and other therapeutic strategies such as checkpoint inhibitors and cytokine therapy. This review describes the various immunotherapeutic approaches targeting leukemia, emphasizing the roles and interplay of cancer vaccines and CAR-T cell therapy. In addition, by discussing how these therapies individually and collectively contribute to tumor regression, this article aims to highlight innovative treatment paradigms that could enhance clinical outcomes for leukemia patients. This integrative approach promises to pave the way for more effective and durable treatment strategies in the oncology field. These combined immunotherapeutic strategies hold great promise for achieving more complete and lasting remissions in leukemia patients. Future research should prioritize optimizing treatment sequencing, personalizing therapeutic combinations based on individual patient and tumor characteristics, and developing novel strategies to enhance T cell persistence and function within the tumor microenvironment. Ultimately, these efforts will advance the development of more effective and less toxic immunotherapeutic interventions, offering new hope for patients battling this challenging disease.

Hypermethylation of DNA impairs megakaryogenesis in delayed platelet recovery after allogeneic hematopoietic stem cell transplantation

Delayed platelet recovery (DPR) is a common and complex complication of hematopoietic stem cell transplantation (HSCT) with unclear mechanisms and poor patient outcomes. Emerging evidence suggests that impaired megakaryogenesis plays a critical role in the development of DPR. In this study, we report remarkable hypermethylation within CG islands of HSCs and megakaryocyte progenitor cells (MKPs) in patients with DPR. Treatment with the hypomethylating agent decitabine reduced methylated CG levels in MKPs and enhanced megakaryocyte production in mice. In addition, we found that DNMT3A negatively regulated megakaryogenesis in megakaryocyte lineages derived from primary HSCs. Transplantation with HSC-overexpressed DNMT3A impeded platelet engraftment following HSCT in mice. We further demonstrated that DNMT3A was directly bound to and methylated ETS1 and RUNX1 during megakaryogenesis. These findings highlight abnormal DNA methylation in DPR and indicate that hypomethylating agents may improve megakaryocyte proliferation and differentiation by targeting DNMT3A-mediated methylation.

New insights on potency assays from recent advances and discoveries in CAR T-cell therapy

This review explores recent advances in the characteristics and manufacturing of CAR T-cell products. Traditional potency assays have been designed based on well-established CAR T-cell functionalities. However, the advent of innovative tools and methodologies has revealed a broader spectrum of important CAR T-cell characteristics that correlate with function. Furthermore, as manufacturing strategies continue to evolve, conventional potency assays may no longer fully capture the complexity of these products. Therefore, it is essential to examine these emerging characteristics and manufacturing approaches and consider the development of tailored potency assays to ensure products are fully characterized.

DNA methylation in melanoma immunotherapy: mechanisms and therapeutic opportunities

Abnormal DNA methylation is a hallmark of cancer and a nearly universal feature of melanoma. DNA methylation plays well-appreciated melanoma cell-intrinsic roles, including silencing tumor-suppressor genes, regulating genomic stability, deregulating expression of oncogenes to potentiate proliferative signaling and tumor migration. With the recent success of immunological therapies for melanoma, important roles for DNA methylation are also emerging at the interface between melanoma and immune cells with the potential to regulate the anti-tumor immune response. These newly recognized roles for DNA methylation in controlling melanoma cell immunogenicity, expression of MHC and immune checkpoint molecules as well as T cell phenotypes in the tumor microenvironment raise the possibility of using DNA methylation to develop improved therapies and methylation-based biomarkers. In addition to reviewing the "immune dimension" of DNA methylation, we summarize recent developments with potential clinical applications in melanoma, such as targeted DNA methylation editing, single-cell methylation approaches, and measurement of circulating methylated DNA. An improved understanding of the immune roles of DNA methylation presents an exciting opportunity for continued improvement of care and outcomes for patients with melanoma.

Epigenetic modification and tumor immunity: Unraveling the interplay with the tumor microenvironment and its therapeutic vulnerability and implications

In the ever-evolving arena of molecular biology, epigenetic modifications stand out as crucial determinants in the orchestration of cellular identity, function, and fate. This review analyzes the close relationship between epigenetics and tumor immunity, emphasizing the intricate interplay with the tumor microenvironment (TME). Rooted in the knowledge that the incidence of cancer correlates strongly with the biological and genetic age, we highlight DNA methylation as a cornerstone of the "epigenetic aging" process with close ties to tumorigenesis. The TME, with its diverse cellular and acellular constituents, is an active participant in tumor biology, further complicated by epigenetic alterations. These modifications, from DNA methylation to histone changes, not only shape the TME but are reciprocally influenced by it, reinforcing a cycle that propels malignancy. Through this exploration, we underline the importance of understanding this mutual relationship, as it holds significant implications for tumor growth, heterogeneity, and therapeutic resistance. Ultimately, this review illuminates the potential of harnessing epigenetic insights for innovative cancer therapeutic strategies, pointing towards a promising avenue for future cancer management.

Strategies to overcome tumour relapse caused by antigen escape after CAR T therapy

Chimeric antigen receptor (CAR) T cell therapy has revolutionized the treatment of B cell and plasma cell malignancies, and numerous promising targets against solid tumours are being explored. Despite their initial therapeutic success in hematological cancers, relapse occurs in a significant fraction of patients, highlighting the need for further innovations in advancing CAR T cell therapy. Tumour antigen heterogeneity and acquired tumour resistance leading to antigen escape (antigen loss/downregulation) have emerged as a crucial factor contributing to immune escape and CAR T cell resistance, particularly in the case of solid tumours with only limited success achieved to date. In this review, we discuss mechanisms of tumour relapse in CAR T cell therapy and the promising strategies that are under development to overcome multiple resistance mechanisms, thereby reducing outgrowth of antigen escape variants. Specifically, we emphasize the importance of designing clinical translational strategies to enhance CAR T cell crosstalk with host immune cells, eliciting endogenous antitumour immune responses through antigen/epitope spreading, which offers a genuine solution to the limitations of targeting tumour antigen heterogeneity in solid tumours with monospecific T cell therapies.

Cellular immunotherapy targeting CLL-1 for juvenile myelomonocytic leukemia

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

Epigenetic landscapes drive CAR-T cell kinetics and fate decisions: Bridging persistence and resistance

Chimeric antigen receptor-T (CAR-T) cell therapy has revolutionized the treatment paradigm for B-cell malignancies and holds promise for solid tumor immunotherapy. However, CAR-T-cell therapy still faces many challenges, especially primary and secondary resistance. Some mechanisms of resistance, including CAR-T-cell dysfunction, an inhibitory tumor microenvironment, and tumor-intrinsic resistance, have been identified in previous studies. As insights into CAR-T-cell biology have increased, the role of epigenetic reprogramming in influencing the clinical effectiveness of CAR-T cells has become increasingly recognized. An increasing number of direct and indirect epigenetic targeting methods are being developed in combination with CAR-T-cell therapy. In this review, we emphasize the broad pharmacological links between epigenetic therapies and CAR-T-cell therapy, not only within CAR-T cells but also involving tumors and the tumor microenvironment. To elucidate the mechanisms through which epigenetic therapies promote CAR-T-cell therapy, we provide a comprehensive overview of the epigenetic basis of CAR-T-cell kinetics and differentiation, tumor-intrinsic factors and the microenvironment. We also describe some epigenetic strategies that have implications for CAR-T-cell therapy in the present and future. Because targeting epigenetics can have pleiotropic effects, developing more selective and less toxic targeting strategies and determining the optimal administration strategy in clinical trials are the focus of the next phase of research. In summary, we highlight the possible mechanisms and clinical potential of epigenetic regulation in CAR-T-cell therapy.

Advances in strategies to improve the immunotherapeutic efficacy of chimeric antigen receptor-T cell therapy for lymphoma

Chimeric antigen receptor-T (CAR-T) cell therapy is a precise immunotherapy for lymphoma. However, its long-term efficacy faces many challenges related to tumor cell heterogeneity, interference from immunosuppressive microenvironments, CAR-T cell exhaustion, and unmanageable adverse events. Diverse modifications have been introduced into conventional CAR-T cells to overcome these obstacles; examples include addition of recognition sites to prevent immune escape, coupling of cytokine domains to enhance killing ability, blocking of immune checkpoint signals to resist tumor microenvironments, and inclusion of suicide systems or safety switches to improve safety and flexibility. With increasing understanding of the importance of metabolism and epigenetics in cancer and cytotherapy, glycolysis, methylation, and acetylation have become crucial CAR-T cell therapeutic targets. Universal and in situ CAR-T cells are also expected to be used in clinical applications, thus providing hope to patients with relapsed/refractory lymphomas.

CAR-T therapy in solid tumors

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

Presetting CAR-T cells during ex vivo biomanufacturing

Chimeric antigen receptor (CAR)-T cell therapy has revolutionized the treatment of hematologic malignancies. However, it continues to encounter significant obstacles, including treatment relapse and limited efficacy in solid tumors. While effector T cells exhibit robust cytotoxicity, central memory T cells and stem cell-like T cells are essential for in vivo expansion, long-term survival, and persistence. Strategies such as genetic engineering to enhance CAR-T cell efficacy and durability are often accompanied by increased safety risks, which not only raise regulatory approval thresholds but also escalate CAR-T production costs. In contrast, optimizing ex vivo manufacturing conditions represents a more straightforward and practical approach, offering the potential for rapid application to commercially approved CAR-T products and enhancement of their clinical outcomes. This review examines several factors that have been shown to improve T cell memory phenotype and in vivo cytotoxic activity, including cytokines, electrolytes, signaling pathway inhibitors, metabolic modulators, and epigenetic agents. The insights provided will guide the optimization of CAR-T cell industrial production. Furthermore, considerations for selecting appropriate conditions are discussed, balancing effectiveness, cost-efficiency, safety, and regulatory compliance while addressing current challenges in the field.

The epigenetic landscape of fate decisions in T cells

Specialized T cell subsets mediate adaptive immunity in response to cytokine signaling and specific transcription factor activity. The epigenetic landscape of T cells has an important role in facilitating and establishing T cell fate decisions. Here, we review the interplay between transcription factors, histone modifications, DNA methylation and three-dimensional chromatin organization to define key elements of the epigenetic landscape in T cells. We introduce key technologies in the areas of sequencing, microscopy and proteomics that have enabled the multi-scale profiling of the epigenetic landscape. We highlight the dramatic changes of the epigenetic landscape as multipotent progenitor cells commit to the T cell lineage during development and discuss the epigenetic changes that favor the emergence of CD4+ and CD8+ T cells. Finally, we discuss the inheritance of epigenetic marks and its potential effects on immune responses as well as therapeutic strategies with potential for epigenetic regulation.

Two chemotherapeutic agents expand stem-like CD62L+CD8+ T cells in antitumor immune responses

Introduction

Recent findings reveal that the precursors of exhausted CD8+ T (CD8+ Tpex) cells possess stem-like signatures in tumor immunity, which originate from tumor draining lymph node (TdLN)-derived tumor-specific memory (CD8+ TTSM) cells. Both of these T subsets can be collectively referred to as stem-like CD8+ T cells, which demonstrate robust self-renewal ability and can proliferate and differentiate into transitory effector-like exhausted T cells (Texint). There are reports that chemotherapeutic drugs can promote the antitumor immune responses of patients by increasing the number of CD8+ T cells; however, whether chemotherapeutic drugs increase these two stem-like CD8+ T cells remain further exploration.

Methods

Tpex cell-associated subpopulations in human colorectal tumors were analyzed by using single-cell sequencing data. CT26 and B16 tumor models of wild type and Eomes conditional knockout mice were constructed, and the changes of TTSM, Tpex and Tex subsets in mice were dissected by flow cytometry after treatment with decitabine (DAC), doxorubicin (DOX) and 5-Fluorouracil (5-FU).

Results

In this study, we demonstrated that DAC and 5-FU expanded CD8+ TTSM cells in TdLNs. At the same time, we validated that DAC and 5-FU substantially promoted the expansion of CD62L+CD8+ Tpex cells and subsequently increased effector function of CX3CR1+ CD8+ Texint cells. In addition, the conditional knockout of transcription factor Eomes in CD8+ T cells partially eliminated DAC-amplified CD62L+ CD8+ Tpex cells, but had no effect on such CD8+ T subset expanded by 5-FU.

Conclusion

The present study demonstrated that both DAC and 5-FU promoted the differentiation of stem-like CD8+ TTSM cells in TdLNs and significantly enhanced the differentiation and expansion of stem-like CD62L+ CD8+ Tpex and CX3CR1+ Texint cells in tumor microenvironment. The knockout of Eomes partially influenced the role of DAC in promoting the differentiation and expansion of stem-like CD8+ T cells.

T cell-based cancer immunotherapy: opportunities and challenges

T cells play a central role in the cancer immunity cycle. The therapeutic outcomes of T cell-based intervention strategies are determined by multiple factors at various stages of the cycle. Here, we summarize and discuss recent advances in T cell immunotherapy and potential barriers to it within the framework of the cancer immunity cycle, including T-cell recognition of tumor antigens for activation, T cell trafficking and infiltration into tumors, and killing of target cells. Moreover, we discuss the key factors influencing T cell differentiation and functionality, including TCR stimulation, costimulatory signals, cytokines, metabolic reprogramming, and mechanistic forces. We also highlight the key transcription factors dictating T cell differentiation and discuss how metabolic circuits and specific metabolites shape the epigenetic program of tumor-infiltrating T cells. We conclude that a better understanding of T cell fate decision will help design novel strategies to overcome the barriers to effective cancer immunity.

DNMT1 inhibition reprograms T cells to NK-like cells with potent antitumor activity

Inactivation of the transcription factor BCL11B reprograms T cells into induced-T-to-NK cells (ITNKs). However, it remains unclear how BCL11B suppresses natural killer (NK) cell transcriptional programs. Here, we identified that the DNA methyltransferase DNMT1 physically interacts with BCL11B, increasing BCL11B stability and the fidelity of DNA methylation maintenance for NK cell-related genes, thereby repressing their expression. Moreover, DNMT1 maintains the epigenetic silencing of a distinct subset of NK cell-related genes independent of BCL11B. DNMT1 inhibition or depletion reprograms T cells and chimeric antigen receptor (CAR)-T cells into NK-like cells that exhibit more robust antitumor effects than BCL11B-deficient ITNKs and parental CAR-T cells. Moreover, H3K27me3 (trimethylation of histone 3 lysine 27) synergizes with DNA methylation to repress NK cell-related pathways, and combined EZH2 (enhancer of zeste homolog 2) and DNMT1 inhibition potentiates both the reprogramming and cytotoxicity of NK-like cells. Our findings uncover the molecular mechanisms that safeguard T cell identity and provide a rationale for deriving NK-like cells with epigenetic inhibitors for cancer immunotherapy.

The epigenetic hallmarks of immune cells in cancer

Targeting the dysregulation of epigenetic mechanisms in cancer has emerged as a promising therapeutic strategy. Although the significant rationale progress of epigenetic therapies in blocking cancer cells, how epigenetic regulation shapes tumor microenvironment (TME) and establishes antitumor immunity remains less understood. Recent study focus has been put on the epigenetic-mediated changes in the fate of immune cells, including the differentiation, expansion, recruitment, functionalization, and exhaustion of T cells, natural killer (NK) cells, tumor-associated macrophages (TAMs), dendritic cells (DCs), myeloid-derived suppressor cells (MDSCs), and B cells within the TME. Here, we review the latest molecular and clinical insights into how DNA modifications, histone modification, and epitranscriptome-related regulations shape immune cells of various cancers. We also discuss opportunities for leveraging epigenetic therapies to improve cancer immunotherapies. This review provides the epigenetic foundations of cancer immunity and proposes the future direction of combination therapies.

Aberrant DNA methylation as a key modulator of cell death pathways: insights into cancer progression and other diseases

Cell death plays a significant role in the physiology of all living organisms, and its disruption is the underlying cause of various diseases. Previously, it was assumed that apoptosis and necrosis were the only means of cell death. Recent discoveries of alternative cell death pathways highlighted a complicated interplay between cell death regulation and its role in numerous human pathologies. DNA methylation is a universal epigenetic mechanism characterized by the covalent addition of a methyl group to cytosine in CpG dinucleotides. Alterations in DNA methylation patterns lead to the dysregulation of multiple cell death pathways. DNA methylome studies on cell death pathways have improved our understanding of the mechanism of various types of cell death, such as apoptosis, pyroptosis, necroptosis, ferroptosis, anoikis, autophagy, and cuproptosis. The irregular DNA methylation patterns of genes encoding proteins linked to multiple cell death pathways could underlie resistance to cell death. Dysregulation of cell death is linked to ailments in humans, such as cancer. However, unlike genetic alterations, DNA methylation is reversible, making it extremely interesting for therapeutics considering the potential use of DNA methyltransferase inhibitors. Furthermore, tumor microenvironment and genetic heterogeneity of cancers may influence the methylation-dependent regulation of cell death, contributing to tumor progression and therapeutic resistance. Understanding how DNA methylation influences cell death pathways may illuminate the underlying causes of cancer. This review explores the significance of the DNA methylation patterns of key genes involved in cell death pathways, emphasizing their connections and identifying potential gaps that could be exploited for developing epigenetic therapies targeting cancer.

Mechanisms of antigen-dependent resistance to chimeric antigen receptor (CAR)-T cell therapies

Cancer immunotherapy has reshaped the landscape of cancer treatment over the past decades. Genetic manipulation of T cells to express synthetic receptors, known as chimeric antigen receptors (CAR), has led to the creation of tremendous commercial and therapeutic success for the treatment of certain hematologic malignancies. However, since the engagement of CAR-T cells with their respective antigens is solely what triggers their cytotoxic reactions against target cells, the slightest changes to the availability and/or structure of the target antigen often result in the incapacitation of CAR-T cells to enforce tumoricidal responses. This results in the resistance of tumor cells to a particular CAR-T cell therapy that requires meticulous heeding to sustain remissions in cancer patients. In this review, we highlight the antigen-dependent resistance mechanisms by which tumor cells dodge being recognized and targeted by CAR-T cells. Moreover, since substituting the target antigen is the most potent strategy for overcoming antigen-dependent disease relapse, we tend to highlight the current status of some target antigens that might be considered suitable alternatives to the currently available antigens in various cancers. We also propose target antigens whose targeting might reduce the off-tumor adverse events of CAR-T cells in certain malignancies.

Targeting regulated cell death: Apoptosis, necroptosis, pyroptosis, ferroptosis, and cuproptosis in anticancer immunity

In the evolving landscape of cancer treatment, the strategic manipulation of regulated cell death (RCD) pathways has emerged as a crucial component of effective anti-tumor immunity. Evidence suggests that tumor cells undergoing RCD can modify the immunogenicity of the tumor microenvironment (TME), potentially enhancing its ability to suppress cancer progression and metastasis. In this review, we first explore the mechanisms of apoptosis, necroptosis, pyroptosis, ferroptosis, and cuproptosis, along with the crosstalk between these cell death modalities. We then discuss how these processes activate antigen-presenting cells, facilitate the cross-priming of CD8+ T cells, and trigger anti-tumor immune responses, highlighting the complex effects of novel forms of tumor cell death on TME and tumor biology. Furthermore, we summarize potential drugs and nanoparticles that can induce or inhibit these emerging RCD pathways and their therapeutic roles in cancer treatment. Finally, we put forward existing challenges and future prospects for targeting RCD in anti-cancer immunity. Overall, this review enhances our understanding of the molecular mechanisms and biological impacts of RCD-based therapies, providing new perspectives and strategies for cancer treatment.

Upregulation of CD19 by low-dose chidamide promotes CAR T cells functionality in B-cell non-Hodgkin lymphoma

B-cell non-Hodgkin lymphoma (B-NHL) is a highly heterogeneous group of lymphopoietic malignancies that account for 85% to 90% of all non-Hodgkin lymphomas. In recent years, CD19 Chimeric antigen receptor T (CAR T) cell immunotherapy has significantly improved the cure rate of B-NHL patients, but there are still some patients who cannot achieve remission after treatment, or relapse after remission. Therefore, it is of great importance to overcome the drug resistance of CD19 CAR T cells after B-NHL treatment and reduce the recurrence rate of CD19 CAR T cells after B-NHL treatment. We found that low concentrations of chidamide did not enhance the ability of CD19 CAR T cells to kill B-NHL cells during and after preparation. B-NHL cells pretreated with chidamide were more likely to be killed by CD19 CAR T cells. CD19 CAR T cells secreted more cytokines (IL-2, TNF-α, and IFN-γ) after co-culture with B-NHL cells pretreated with chidamide. At the same time, the expression of CD19 on B-NHL cell surface was increased by chidamide. In vivo experiments showed that infusion of CD19 CAR T cells after chidamide bridging intervention can enhance the therapeutic effect of B-NHL and prolong the overall survival of mice. This study provides a new direction and theoretical foundation for CD19 CAR T cell therapy in B-NHL.

Effect of epigenetic changes in hypoxia induced factor (HIF) gene across cancer types

Cancer hypoxia, a crucial characteristic of malignancy, ranging from practically non-hypoxic to severe, impacts gene expression, metabolism and mechanisms associated with tumor formation serves as a key obstacle in cancer therapy. It triggers a complex network of cell signaling pathways, such as the NF-κB, PI3K, mTOR/AKT,MAPK, HIF and their associated genes regulating the effects of the same. The onset and advancement of cancer are attributed to genetic and epigenetic modifications which are intrinsically related. Off late, it has been observed that in disease progression, the epigenetic modifications lead to gene mutations that in turn alter the epigenome, presenting a major hurdle in fabricating treatment strategies. However, theprogress in science and technology has led to the emergence of various surfacing omics and multi-view clustering algorithms, which offer unparalleled prospects for further subtyping cancers, enhancing the prognosis and treatment results of these subtypes, and comprehending crucial pathophysiological mechanisms across diverse molecular strata. Multi-omics has allowed scientists to gain a more comprehensive understanding of the various ways that cellular malfunction can lead to cancer. So, it becomes of utmost importance to firstly understand the epigenetic changes taking place in tumor hypoxia at gene level. This review sheds light on the role of HIF gene in hypoxic milieu and its relationship with mechanisms of cancer epigenetics. It further glances as to how omics approach can be used to study the oncogenic cellular changes and how bioinformatic tools aid in identification of complex gene networks involved in disease progression. Lastly, it glimpses through the benefits and shortcomings of the existing epi drug therapy and how it can be used in developing novel treatment options.

Optimal chemokine receptors for enhancing immune cell trafficking in adoptive cell therapy

Recently, a strategy involving the engineering of chemokine receptors on immune cells was developed to optimize adoptive cell therapy (ACT) for solid tumors. Given the variability in chemokine secretion among different tumor types, identifying and modulating the appropriate chemokine receptors is crucial. In this study, we utilized extensive RNA sequencing data from both tumor tissues from The Cancer Genome Atlas and normal tissues from Genotype-Tissue Expression to investigate the expression profiles of chemokines. Through analysis, we identified eight chemokine receptors associated with increased chemokine levels in tumor tissues compared to normal tissues, making them promising candidates for enhancing ACT. Subsequent examination of tumor-infiltrating lymphocytes and chimeric antigen receptor-T cells revealed that five out of the eight candidate chemokine receptors did not exhibit elevated expression in T cells. Among five candidates, we demonstrated that CXCR5 is a particularly promising candidate for enhancing cell migration without compromising cell viability or cytotoxicity. In conclusion, our study underscores the potential of five chemokine receptors (CCR6, CCR9, CXCR1, CXCR5, and XCR1) as valuable targets for modulating ACT to enhance cell trafficking and potentially improve cancer therapy outcomes.

Inhalable nanovesicles loaded with a STING agonist enhance CAR-T cell activity against solid tumors in the lung

Suppression of chimeric antigen receptor-modified T (CAR-T) cells by the immunosuppressive tumor microenvironment remains a major barrier to their efficacy against solid tumors. To address this, we develop an anti-PD-L1-expressing nanovesicle loaded with the STING agonist cGAMP (aPD-L1 NVs@cGAMP) to remodel the tumor microenvironment and thereby enhance CAR-T cell activity. Following pulmonary delivery, the nanovesicles rapidly accumulate in the lung and selectively deliver STING agonists to PD-L1-overexpressing cells via the PD-1/PD-L1 interaction. This targeted delivery effectively avoids the systemic inflammation and poor cellular uptake that plague free STING agonists. Internalized STING agonists trigger STING signaling and induce interferon responses, which diminish immunosuppressive cell populations such as myeloid-derived suppressor cells in the tumor microenvironment and promote CAR-T cell infiltration. Importantly, the anti-PD-L1 single chain variable fragment on the nanovesicle surface blocks PD-L1 upregulation induced by STING agonists and prevents CAR-T cell exhaustion. In both orthotopic lung cancer and lung metastasis model, combined therapy with CAR-T cells and aPD-L1 NVs@cGAMP potently inhibits tumor growth and prevents recurrence. Therefore, aPD-L1 NVs@cGAMP is expected to serve as an effective CAR-T cell enhancer to improve the efficacy of CAR-T cells against solid tumors.

5-Aza-2'-deoxycytidin (Decitabine) increases cancer-testis antigen expression in head and neck squamous cell carcinoma and modifies immune checkpoint expression, especially in CD39-positive CD8 and CD4 T cells

Failure of immunotherapy in head and neck squamous cell carcinoma (HNSCC) patients represents an unmet need to augment leverage of adaptive immunity. Immunogenic cancer-testis antigen (CTA) expression as well as lymphocyte differentiation and function are regulated by DNA methylation. Therefore, epigenetic therapy via inhibition of DNA-Methyltransferases by 5-Aza-2'-deoxycytidine (DAC) serves a promising adjuvant in immunotherapy. We investigated the effects of DAC on CTA expression and proliferative capacity in HNSCC cell lines and on the expression of 12 immune checkpoint molecules (ICM) on lymphocytes of oropharyngeal squamous cell carcinoma (OPSCC) patients and healthy donors. In all cell lines CTA were upregulated accompanied by decreased proliferation. In lymphocytes pronounced alterations of the ICM repertoire were observed, influenced by donor type and subpopulation. On CD39+ CD4 and CD8 T cells, the expression of co-stimulatory ICM GITR and OX40 increased dose dependently, whereas expression decreased on CD39- CD4 T cells. PD1 expression increased primarily on CD39+ CD8 T cells and decreased on CD39- CD4 T cells. CD27 expression decreased primarily in CD8 T cells, but increased in CD39- CD4 T cells, whereas ICOS expression was lowered in both CD39+ and CD39- subsets of CD4 as well as CD8 T cells. DAC treatment increased immunogenicity and decreased proliferation in HNSCC cells while enhancing expression of co-stimulatory ICM GITR and OX40. We propose low dose DAC treatment as a adjuvant to immunotherapy.

Therapeutic advantage of combinatorial chimeric antigen receptor T cell and chemotherapies

Chimeric antigen receptor (CAR) T cell therapies have transformed outcomes for many patients with hematological malignancies. However, some patients do not respond to CAR T cell treatment, and adapting CAR T cells for treatment of solid and brain tumors has been met with many challenges, including a hostile tumor microenvironment and poor CAR T cell persistence. Thus, it is unlikely that CAR T cell therapy alone will be sufficient for consistent, complete tumor clearance across patients with cancer. Combinatorial therapies of CAR T cells and chemotherapeutics are a promising approach for overcoming this because chemotherapeutics could augment CAR T cells for improved antitumor activity or work in tandem with CAR T cells to clear tumors. Herein, we review efforts toward achieving successful CAR T cell and chemical drug combination therapies. We focus on combination therapies with approved chemotherapeutics because these will be more easily translated to the clinic but also review nonapproved chemotherapeutics and drug screens designed to reveal promising new CAR T cell and chemical drug combinations. Overall, this review highlights the promise of CAR T cell and chemotherapy combinations with a specific focus on how combinatorial therapy overcomes challenges faced by either monotherapy and supports the potential of this therapeutic strategy to improve outcomes for patients with cancer. SIGNIFICANCE STATEMENT: Improving currently available CAR T cell products via combinatorial therapy with chemotherapeutics has the potential to drastically expand the types of cancers and number of patients that could benefit from these therapies when neither alone has been sufficient to achieve tumor clearance. Herein, we provide a thorough review of the current efforts toward studying CAR T and chemotherapy combinatorial therapies and offer perspectives on optimal ways to identify new and effective combinations moving forward.

Optimizing CAR-T cell function in solid tumor microenvironment: insights from culture media additives

Cancer remains one of the most pressing health challenges worldwide. Recently, chimeric antigen receptor (CAR)-T cell therapy has emerged as a promising approach for treating hematological cancers. However, the translation of CAR-T cell therapy to solid tumors faces formidable obstacles, notably the immunosuppressive tumor microenvironment. Within solid tumors, CAR-T cells encounter a hostile milieu that promotes exhaustion and diminishes their long-term effectiveness against cancer cells. Optimizing the manufacturing process is paramount to ensuring the efficacy of CAR-T cell therapy in solid tumors. A critical aspect of this optimization lies in refining the composition of cell culture media. By supplementing basic culture media with specific additives, researchers aim to improve the behavior and functionality of CAR-T cells, thereby enhancing their therapeutic potential. This review delves into the culture media additives that have been investigated or show promise in modulating CAR-T cell phenotypes and enhancing their anti-tumor efficacy. We explore various types of additives and their mechanisms of action to mitigate exhaustion and augment persistence within the challenging solid tumor microenvironment. By shedding light on the latest advancements in culture media optimization for CAR-T cell therapy, this review aims to provide insights into novel strategies for overcoming the hurdles posed by solid tumors. Ultimately, these insights hold the potential to enhance the effectiveness of CAR-T cell therapy and improve outcomes for cancer patients.

Cullin-5 deficiency promotes chimeric antigen receptor T cell effector functions potentially via the modulation of JAK/STAT signaling pathway

Chimeric antigen receptor (CAR) T cell is a promising therapy for cancer, but factors that enhance the efficacy of CAR T cell remain elusive. Here we perform a genome-wide CRISPR screening to probe genes that regulate the proliferation and survival of CAR T cells following repetitive antigen stimulations. We find that genetic ablation of CUL5, encoding a core element of the multi-protein E3 ubiquitin-protein ligase complex, cullin-RING ligase 5, enhances human CD19 CAR T cell expansion potential and effector functions, potentially via the Janus kinase/signal transducers and activators of transcription (JAK/STAT) pathway. In this regard, CUL5 knockout CD19 CAR T cells show sustained STAT3 and STAT5 phosphorylation, as well as delayed phosphorylation and degradation of JAK1 and JAK3. In vivo, shRNA-mediated knockdown of CUL5 enhances CD19 CAR T treatment outcomes in tumor-bearing mice. Our findings thus imply that targeting CUL5 in the ubiquitin system may enhance CAR T cell effector functions to enhance immunotherapy efficacy.

Advancing Chimeric Antigen Receptor T-Cell Therapy for Acute Myeloid Leukemia: Current Limitations and Emerging Strategies

Chimeric antigen receptor (CAR) T-cell therapy represents one of the most impressive advances in anticancer therapy of the last decade. While CAR T-cells are gaining ground in various B cell malignancies, their use in acute myeloid leukemia (AML) remains limited, and no CAR-T product has yet received approval for AML. The main limitation of CAR-T therapy in AML is the lack of specific antigens that are expressed in leukemic cells but not in their healthy counterparts, such as hematopoietic stem cells (HSCs), as their targeting would result in an on-target/off-tumor toxicity. Moreover, the heterogeneity of AML and the tendency of blasts to modify surface antigens' expression in the course of the disease make identification of suitable targets even more challenging. Lastly, AML's immunosuppressive microenvironment dampens CAR-T therapeutic activities. In this review, we focus on the actual pitfalls of CAR T-cell therapy in AML, and we discuss promising approaches to overcome them.

Long-term exposure and response to azacitidine for post-hematopoietic stem cell transplantation relapse of early T-cell precursor acute lymphoblastic leukemia: a case report and review of the literature

Adult T-cell acute lymphoblastic leukemia has a poor outcome after relapse. Because the subtype of early T-cell precursor displays characteristics close of those of acute myeloid leukemia, such as epigenetic dysregulation, hypomethylating agents might prove of interest. We describe the case of a patient relapsing 3 months only after allogeneic stem cell transplantation who achieved complete remission on azacitidine, and is still on therapy 9 years later. We discuss the biological background of this very long-term response, underlining the immunological effects of hypomethylating agents, and the perspectives opened by combination of hypomethylating agents with other drugs such as venetoclax.

Advancements in adoptive CAR immune cell immunotherapy synergistically combined with multimodal approaches for tumor treatment

Adoptive immunotherapy, notably involving chimeric antigen receptor (CAR)-T cells, has obtained Food and Drug Administration (FDA) approval as a treatment for various hematological malignancies, demonstrating promising preclinical efficacy against cancers. However, the intricate and resource-intensive autologous cell processing, encompassing collection, expansion, engineering, isolation, and administration, hamper the efficacy of this therapeutic modality. Furthermore, conventional CAR T therapy is presently confined to addressing solid tumors due to impediments posed by physical barriers, the potential for cytokine release syndrome, and cellular exhaustion induced by the immunosuppressive and heterogeneous tumor microenvironment. Consequently, a strategic integration of adoptive immunotherapy with synergistic multimodal treatments, such as chemotherapy, radiotherapy, and vaccine therapy etc., emerges as a pivotal approach to surmount these inherent challenges. This collaborative strategy holds the key to addressing the limitations delineated above, thereby facilitating the realization of more precise personalized therapies characterized by heightened therapeutic efficacy. Such synergistic strategy not only serves to mitigate the constraints associated with adoptive immunotherapy but also fosters enhanced clinical applicability, thereby advancing the frontiers of therapeutic precision and effectiveness.

CD28 co-stimulation: novel insights and applications in cancer immunotherapy

Substantial progress in understanding T cell signalling, particularly with respect to T cell co-receptors such as the co-stimulatory receptor CD28, has been made in recent years. This knowledge has been instrumental in the development of innovative immunotherapies for patients with cancer, including immune checkpoint blockade antibodies, adoptive cell therapies, tumour-targeted immunostimulatory antibodies, and immunostimulatory small-molecule drugs that regulate T cell activation. Following the failed clinical trial of a CD28 superagonist antibody in 2006, targeted CD28 agonism has re-emerged as a technologically viable and clinically promising strategy for cancer immunotherapy. In this Review, we explore recent insights into the molecular functions and regulation of CD28. We describe how CD28 is central to the success of current cancer immunotherapies and examine how new questions arising from studies of CD28 as a clinical target have enhanced our understanding of its biological role and may guide the development of future therapeutic strategies in oncology.

Advances in ligand-based surface engineering strategies for fine-tuning T cell mechanotransduction toward efficient immunotherapy

T cell-based immunotherapy has recently emerged as a promising strategy to treat cancer, requiring the activation of antigen-directed cytotoxicity to eliminate cancer cells. Mechanical signaling, although often overshadowed by its biochemical counterpart, plays a crucial role in T cell anticancer responses, from activation to cytolytic killing. Rapid advancements in the fields of chemistry, biomaterials, and micro/nanoengineering offer an interdisciplinary approach to incorporating mechano- and immunomodulatory ligands, including but not limited to synthetic peptides, small molecules, cytokines, and artificial antigens, onto the biomaterial-based platforms to modulate mechanotransducive processes in T cells. The surface engineering of these immunomodulatory ligands with optimization of ligand density, geometrical arrangement, and mobility has been proven to better mimic the natural ligation between immunoreceptors and ligands to directly enhance or inhibit mechanotransduction pathways in T cells, through triggering upstream mechanosensitive channels, adhesion molecules, cytoskeletal components, or downstream mechanoimmunological regulators. Despite its tremendous potential, current research on this new biomaterial surface engineering approach for mechanomodulatory T cell activation and effector functions remains in a nascent stage. This review highlights the recent progress in this new direction, focusing on achievements in mechanomodulatory ligand-based surface engineering strategies and underlying principles, and outlooks the further research in the rapidly evolving field of T cell mechanotransduction engineering for efficient immunotherapy.

Afatinib boosts CAR-T cell antitumor therapeutic efficacy via metabolism and fate reprogramming

BACKGROUND

Chimeric antigen receptor T (CAR-T) cell therapy has been shown remarkable efficacy in the treatment of hematological malignancies in recent years. However, a considerable proportion of patients would experience tumor recurrence and deterioration. Insufficient CAR-T cell persistence is the major reason for relapse. Multiple strategies to enhance the long-term antitumor effects of CAR-T cells have been explored and developed. In this study, we focused on tyrosine kinase inhibitors (TKIs), which have emerged immunomodulatory potential besides direct tumoricidal effects.

METHODS

Here, we screened 50 approved TKIs drugs and identified that afatinib (AFA) markedly enhanced the expressing of CD62L and inhibited reactive oxygen species level in T cells. And the underlying mechanisms of AFA medicating T cells were explored by detecting signal transduction, and metabolism pattern. Furthermore, we co-cultured AFA with CAR-T cells during the preparation stage and multianalyses of differentiation characteristics, metabolic profiling, and RNA sequencing revealed that AFA induce comprehensive metabolism remodeling and fate reprogramming. Based on it, we finally identified the antitumor efficacy of AFA-pretreatment CAR-T compared with negative-control CAR-T.

RESULTS

We identified that AFA blocked the T-cell receptor (TCR) and phosphoinositide 3-kinase-protein kinase B-mechanistic target of rapamycin signaling pathways, induced metabolic reprogramming and modulated T-cell differentiation. When combined with CAR-T cells, AFA inhibited the exhaustion and enhanced the persistence and cytotoxicity. Our results revealed that the pretreatment of AFA enables to boost CAR-T cells with strong antitumor cytotoxicity in leukemia mouse model.

CONCLUSIONS

Our study systematically demonstrated that AFA pretreatment effectively enhanced CAR-T cells antitumor performance, which presents a novel optimization strategy for potent and durable CAR-T cell therapy.

Significant Advancements and Evolutions in Chimeric Antigen Receptor Design

Recent times have witnessed remarkable progress in cancer immunotherapy, drastically changing the cancer treatment landscape. Among the various immunotherapeutic approaches, adoptive cell therapy (ACT), particularly chimeric antigen receptor (CAR) T cell therapy, has emerged as a promising strategy to tackle cancer. CAR-T cells are genetically engineered T cells with synthetic receptors capable of recognising and targeting tumour-specific or tumour-associated antigens. By leveraging the intrinsic cytotoxicity of T cells and enhancing their tumour-targeting specificity, CAR-T cell therapy holds immense potential in achieving long-term remission for cancer patients. However, challenges such as antigen escape and cytokine release syndrome underscore the need for the continued optimisation and refinement of CAR-T cell therapy. Here, we report on the challenges of CAR-T cell therapies and on the efforts focused on innovative CAR design, on diverse therapeutic strategies, and on future directions for this emerging and fast-growing field. The review highlights the significant advances and changes in CAR-T cell therapy, focusing on the design and function of CAR constructs, systematically categorising the different CARs based on their structures and concepts to guide researchers interested in ACT through an ever-changing and complex scenario. UNIVERSAL CARs, engineered to recognise multiple tumour antigens simultaneously, DUAL CARs, and SUPRA CARs are some of the most advanced instances. Non-molecular variant categories including CARs capable of secreting enzymes, such as catalase to reduce oxidative stress in situ, and heparanase to promote infiltration by degrading the extracellular matrix, are also explained. Additionally, we report on CARs influenced or activated by external stimuli like light, heat, oxygen, or nanomaterials. Those strategies and improved CAR constructs in combination with further genetic engineering through CRISPR/Cas9- and TALEN-based approaches for genome editing will pave the way for successful clinical applications that today are just starting to scratch the surface. The frontier lies in bringing those approaches into clinical assessment, aiming for more regulated, safer, and effective CAR-T therapies for cancer patients.

Targeting METTL3 as a checkpoint to enhance T cells for tumour immunotherapy

BACKGROUND

Immunotherapy has emerged as a crucial treatment modality for solid tumours, yet tumours often evade immune surveillance. There is an imperative to uncover novel immune regulators that can boost tumour immunogenicity and increase the efficacy of immune checkpoint blockade (ICB) therapy. Epigenetic regulators play critical roles in tumour microenvironment remodelling, and N6-methyladenosine (m6A) is known to be involved in tumourigenesis. However, the role of m6A in regulating T-cell function and enhancing anti-tumour immunity remains unexplored.

METHODS

Several cancer cell lines were treated with STM2457, an enzymatic inhibitor of RNA m6A methyltransferase METTL3, and explored the transcriptome changes with RNA sequencing (RNA-seq). We then utilised mouse melanoma (B16) and mouse colorectal adenocarcinoma (MC38) models to investigate the effects of METTL3 inhibition on immunotherapy, and analysed the dynamics of the tumour microenvironment via single-cell RNA-seq (scRNA-seq). Furthermore, in vitro and in vivo T-cell cytotoxicity killing assay and CRISPR Cas9-mediated m6A reader YTHDF1-3 knockout in B16 were performed to assess the role and the molecular mechanism of RNA m6A in tumour killing. Finally, the efficacy of METTL3 inhibition was also tested on human melanoma model (A375) and human T cells.

RESULTS

We demonstrate that inhibiting METTL3 augments tumour immunogenicity and sustains T-cell function, thereby enhancing responsiveness to ICB therapy. Mechanistically, METTL3 inhibition triggers an interferon response within tumour cells, amplifying the anti-tumour immune response, along with deletion of the m6A reader protein YTHDF2 in tumours inhibiting major histocompatibility complex (MHC)-I degradation. Remarkably, these anti-tumour effects are reliant on the immune system. Specifically, METTL3 inhibition enhances interferon-gamma (IFNγ) and granzyme B (GzmB) expression, thereby strengthening T-cell killing ability, and concurrently dampening the expression of exhaustion-related genes.

CONCLUSION

Targeting METTL3 enhances anti-tumour immunity by boosting T-cell cytotoxicity and reversing T-cell exhaustion. Our study positions METTL3 as an epigenetic checkpoint, highlighting the potential of targeting METTL3 to invigorate intrinsic anti-tumour defenses and overcome immune resistance.

KEY POINTS

Targeting METTL3 augments tumour cell immunogenicity and sustains T-cell function. T cell with METTL3 inhibition can reverse T-cell exhaustion, and promote expression of IFNγ and GzmB, thereby enhancing cytotoxicity in anti-PD-1 therapy. YTHDF2 deletion in tumours prolong the lifespan of MHC-I mRNAs.

BRD4 inhibitor reduces exhaustion and blocks terminal differentiation in CAR-T cells by modulating BATF and EGR1

BACKGROUND

Exhaustion is a key factor that influences the efficacy of chimeric antigen receptor T (CAR-T) cells. Our previous study demonstrated that a bromodomain protein 4 (BRD4) inhibitor can revise the phenotype and function of exhausted T cells from leukemia patients. This study aims to elucidate the mechanism by which a BRD4 inhibitor reduces CAR-T cell exhaustion using single-cell RNA sequencing (scRNA-Seq).

METHODS

Exhausted CD123-specific CAR-T cells were prepared by co-culture with CD123 antigen-positive MV411 cells. After elimination of MV411 cells and upregulation of inhibitory receptors on the surface, exhausted CAR-T cells were treated with a BRD4 inhibitor (JQ1) for 72 h. The CAR-T cells were subsequently isolated, and scRNA-Seq was conducted to characterize phenotypic and functional changes in JQ1-treated cells.

RESULTS

Both the proportion of exhausted CD8+ CAR-T cells and the exhausted score of CAR-T cells decreased in JQ1-treated compared with control-treated cells. Moreover, JQ1 treatment led to a higher proportion of naïve, memory, and progenitor exhausted CD8+ CAR-T cells as opposed to terminal exhausted CD8+ CAR-T cells accompanied by enhanced proliferation, differentiation, and activation capacities. Additionally, with JQ1 treatment, BATF activity and expression in naïve, memory, and progenitor exhausted CD8+ CAR-T cells decreased, whereas EGR1 activity and expression increased. Interestingly, AML patients with higher EGR1 and EGR1 target gene ssGSEA scores, coupled with lower BATF and BATF target gene ssGSEA scores, had the best prognosis.

CONCLUSIONS

Our study reveals that a BRD4 inhibitor can reduce CAR-T cell exhaustion and block exhausted T cell terminal differentiation by downregulating BATF activity and expression together with upregulating EGR1 activity and expression, presenting an approach for improving the effectiveness of CAR-T cell therapy.

[The mechanisms and salvage treatment strategies underlying positive relapse following CD19 CAR-T cell therapy in B-acute lymphoblastic leukemia]

Approximately 50% of patients suffering from relapsed/refractory B-acute lymphoblastic leukemia (R/R B-ALL), experience relapse within one year, with around 60% of these relapses being antigen-positive, despite the transformative impact of chimeric antigen receptor (CAR) T cell therapy. The mechanisms underlying relapse are primarily associated with tumor heterogeneity, CAR-T cell dysfunction, subopimal in vivo expansion and persistence, and an inhibitory immune microenvironment. This review aims to investigate salvage strategies designed to enhance outcomes for patients undergoing relapse or disease progression following the CAR-T cell therapy. These strategies include a second CAR-T cell infusion that targets either the same antigen or an alternative target, the administration of immune checkpoint inhibitors, and the utilization of novel targeted therapies including monoclonal antibodies, antibody-conjugated drugs and small molecule compounds aimed at mitigating CD19-positive relapse or overcoming CAR-T cell resistance. Nevertheless, achieving improved long-term survival for these patients continues be challenging.

T cell exhaustion methylation signature drives differential immune responses in glioblastoma

BACKGROUND

Methylation-related signatures play crucial roles in tumorigenesis and progression. However, their roles in the immune response in primary glioblastoma (GBM) remains unclear.

METHODS

We analyzed the differential expression of specific members of T cell exhaustion-related pathways in GBM from the perspective of T cell exhaustion. We further screened for significantly negatively correlated methylation sites as candidate methylation markers for T cell exhaustion. Using consensus clustering, we divided the samples into two categories with significant differences in overall survival (OS). We then performed univariate and multivariate Cox regression analyses to construct the T Cell Exhaustion Methylation (TEXM) signature. Finally, we confirmed that this signature served as an independent prognostic factor, and further characterized it in terms of drug resistance and immunotherapy.

RESULTS

We identified 95 significantly differentially expressed T cell exhaustion-related genes and 51 methylation markers associated with T cell exhaustion. The cancer samples were classified according to methylation site markers, thus indicating two subtypes with significant differences in OS: subtype A and subtype B. Tumor scores, stromal scores, tumor purity, and ESTIMATE scores all showed significant differences between subtypes (P < 0.05). Univariate Cox regression analysis identified five methylation sites significantly associated with OS, and multivariate Cox regression analysis was used to construct the TEXM signature model by using these five methylation sites. Significant differences in OS were found between the groups with high and low TEXM signature scores, on the basis of calculation of the TEXM signature scores of tumor samples and using the median score to divide them into high and low score groups. Survival analysis revealed that the high score group had poorer OS and DFS than the low score group in the validation set. Notably, we observed a significant difference in drug sensitivity between the high and low TEXM signature score groups, with the high score group showing higher drug resistance and poorer prognosis. The tumor immune state, as predicted with Tracking Tumor Immunophenotype (TIP), revealed significant differences in antitumor immune scores between the high and low TEXM signature score groups. Finally, we identified 43 significantly differentially regulated metabolism-associated biological processes.

CONCLUSION

The epigenetic methylation-related TEXM signature plays a key role in driving differential immune responses in GBM.

Decitabine consolidation after CD19/CD22 CAR-T therapy as a novel maintenance treatment significantly improves survival outcomes in relapsed/refractory B-ALL patients

OBJECTIVE

We aimed to evaluate the efficacy of decitabine consolidation after treatment with CD19/CD22 chimeric antigen receptor T-cell (CAR-T) for patients with relapsed/refractory B-cell acute lymphoblastic leukaemia (r/r B-ALL).

METHODS

We retrospectively analysed 48 patients with r/r B-ALL who received CD19/CD22 CAR-T therapy between September 2017 and May 2021. Sixteen patients received decitabine consolidation (20 mg/m2/day for 5 days at 3-month intervals) after CAR-T therapy (DAC group), while 32 patients did not receive decitabine consolidation (CON group). Overall survival (OS), leukaemia-free survival (LFS), and cumulative incidence of relapse (CIR) were evaluated in both groups. Time-to-event analysis was performed using the Kaplan-Meier method.

RESULTS

The median follow-up periods in the DAC and CON groups were 41.2 months and 28.6 months, respectively. The 4-year OS and 4-year LFS rates in both groups were 93.3 % and 64.3 % (P=0.029) and 87.5 % and 55.9 % (P=0.059), respectively. The 1-year CIR was 6.25 % and 28.6 %, respectively. Univariate and multivariate Cox regression analyses showed that decitabine consolidation after CAR-T therapy was significantly associated with superior OS (hazard ratio [HR]: 0.121, 95 % confidence interval [CI]: 0.015-0.947, P=0.044), and bridging to haematopoietic stem cell transplantation after CAR-T therapy was significantly associated with superior LFS (HR: 0.279, 95 %CI: 0.093-0.840, P=0.023).

CONCLUSIONS

Our study recommends decitabine consolidation after CD19/CD22 CAR-T therapy as a novel maintenance strategy to improve the survival outcomes of patients with r/r B-ALL.

Generating advanced CAR-based therapy for hematological malignancies in clinical practice: targets to cell sources to combinational strategies

Chimeric antigen receptor T (CAR-T) cell therapy has been a milestone breakthrough in the treatment of hematological malignancies, offering an effective therapeutic option for multi-line therapy-refractory patients. So far, abundant CAR-T products have been approved by the United States Food and Drug Administration or China National Medical Products Administration to treat relapsed or refractory hematological malignancies and exhibited unprecedented clinical efficiency. However, there were still several significant unmet needs to be progressed, such as the life-threatening toxicities, the high cost, the labor-intensive manufacturing process and the poor long-term therapeutic efficacy. According to the demands, many researches, relating to notable technical progress and the replenishment of alternative targets or cells, have been performed with promising results. In this review, we will summarize the current research progress in CAR-T eras from the "targets" to "alternative cells", to "combinational drugs" in preclinical studies and clinical trials.

T cell exhaustion in human cancers

T cell exhaustion refers to a progressive state in which T cells become functionally impaired due to sustained antigenic stimulation, which is characterized by increased expression of immune inhibitory receptors, but weakened effector functions, reduced self-renewal capacity, altered epigenetics, transcriptional programme and metabolism. T cell exhaustion is one of the major causes leading to immune escape of cancer, creating an environment that supports tumor development and metastatic spread. In addition, T cell exhaustion plays a pivotal role to the efficacy of current immunotherapies for cancer. This review aims to provide a comprehensive view of roles of T cell exhaustion in cancer development and progression. We summerized the regulatory mechanisms that involved in T cell exhaustion, including transcription factors, epigenetic and metabolic reprogramming events, and various microenvironmental factors such as cytokines, microorganisms, and tumor autocrine substances. The paper also discussed the challenges posed by T cell exhaustion to cancer immunotherapies, including immune checkpoint blockade (ICB) therapies and chimeric antigen receptor T cell (CAR-T) therapy, highlightsing the obstacles encountered in ICB therapies and CAR-T therapies due to T cell exhaustion. Finally, the article provides an overview of current therapeutic options aimed to reversing or alleviating T cell exhaustion in ICB and CAR-T therapies. These therapeutic approaches seek to overcome T cell exhaustion and enhance the effectiveness of immunotherapies in treating tumors.

Emerging applications of hypomethylating agents in the treatment of glioblastoma (Review)

DNA hypomethylating agents (HMAs) such as decitabine and 5-azacytidine have established roles in the treatment paradigms for myelodysplastic syndrome and acute myelogenous leukemia, where they are considered to exert their anticancer effects by restoring the expression of tumor suppressor genes. Due to their relatively favorable adverse effect profile and known ability to pass through the blood-brain barrier, applications in the treatment of glioblastoma (GBM) and other central nervous system malignancies are under active investigation. The present review examines the types of HMAs currently available, their known and less-understood antineoplastic mechanisms, and the evidence to date of their preclinical and clinical efficacy in glioblastoma and other solid malignancies. The present review discusses the potential synergies HMAs may have with established and emerging GBM treatments, including temozolomide, immune checkpoint inhibitors and cancer vaccines. Recent successes and setbacks in clinical trials for newly diagnosed and recurrent GBM are summarized in order to highlight opportunities for HMAs to improve therapeutic responses. Challenges for future clinical trials are also assessed.

Exploring epigenetic drugs as potential inhibitors of SARS-CoV-2 main protease: a docking and MD simulation study

The COVID-19 pandemic has caused havoc around the globe since 2019 and is considered the largest global epidemic of the twentieth century. Although the first antiviral drug, Remdesivir, was initially introduced against COVID‑19, virtually no tangible therapeutic drugs exist to treat SARS-CoV-2 infection. FDA-approved Paxlovid (Nirmatrelvir supplemented by Ritonavir) was recently announced as a promising drug against the SARS-CoV-2 major protease (Mpro). Here we report for the first time the remarkable inhibitory potentials of lead epigenetic-targeting drugs (epi-drugs) against SARS-CoV-2 Mpro. Epi-drugs are promising compounds to be used in combination with cancer chemotherapeutics to regulate gene expression. The search for all known epi-drugs for the specific inhibition of SARS-CoV-2 Mpro was performed for the first time by consensus (three high-order program) molecular docking studies and end-state free energy calculations. Several epi-drugs were identified with highly comparable binding affinity to SARS-CoV-2 Mpro compared to Nirmatrelvir. In particular, potent histone methyltransferase inhibitor EPZ005687 and DNA methyltransferase inhibitor Guadecitabine were prominent as the most promising epi-drug inhibitors for SARS-CoV-2 Mpro. Long Molecular dynamics (MD) simulations (200 ns each) and corresponding MM-GBSA calculations confirmed the stability of the EPZ005687-Mpro complex with MM-GBSA binding free energy (ΔGbind) -48.2 kcal/mol (EPZ005687) compared to Nirmatrelvir (-44.7 kcal/mol). Taken together, the antiviral activities of the highlighted epi-drugs are reported beyond widespread use in combination with anti-cancer agents. The current findings therefore highlight as yet unexplored antiviral potential of epi-drugs suitable for use in patients struggling with chronic immunosuppressive disorders.Communicated by Ramaswamy H. Sarma.

Overcoming the challenges of primary resistance and relapse after CAR-T cell therapy

INTRODUCTION

While CAR T-cell therapy has led to remarkable responses in relapsed B-cell hematologic malignancies, only 50% of patients ultimately have a complete, sustained response. Understanding the mechanisms of resistance and relapse after CAR T-cell therapy is crucial to future development and improving outcomes.

AREAS COVERED

We review reasons for both primary resistance and relapse after CAR T-cell therapies. Reasons for primary failure include CAR T-cell manufacturing problems, suboptimal fitness of autologous T-cells themselves, and intrinsic features of the underlying cancer and tumor microenvironment. Relapse after initial response to CAR T-cell therapy may be antigen-positive, due to CAR T-cell exhaustion or limited persistence, or antigen-negative, due to antigen-modulation on the target cells. Finally, we discuss ongoing efforts to overcome resistance to CAR T-cell therapy with enhanced CAR constructs, manufacturing methods, alternate cell types, combinatorial strategies, and optimization of both pre-infusion conditioning regimens and post-infusion consolidative strategies.

EXPERT OPINION

There is a continued need for novel approaches to CAR T-cell therapy for both hematologic and solid malignancies to obtain sustained remissions. Opportunities for improvement include development of new targets, optimally combining existing CAR T-cell therapies, and defining the role for adjunctive immune modulators and stem cell transplant in enhancing long-term survival.

Current Strategies to Improve Chimeric Antigen Receptor T (CAR-T) Cell Persistence

Chimeric antigen receptor T (CAR-T) cell therapy has transformed the field of immunology by redirecting T lymphocytes toward tumor antigens. Despite successes in attaining high remission rates as high as 90%, the performance of CAR therapy is limited by the survival of T cells. T cell persistence is crucial as it sustains immune response against malignancies, playing a critical role in cancer treatment outcomes. This review explores various approaches to improve CAR-T cell persistence, focusing on the choice between autologous and allogeneic cell sources, optimization of culture conditions for T cell subsets, metabolite adjustments to modify T cell metabolism, the use of oncolytic viruses (OVs), and advancements in CAR design. Autologous CAR-T cells generally exhibit longer persistence but are less accessible and cost-effective than their allogeneic counterparts. Optimizing culture conditions by promoting TSCM and TCM cell differentiation has also demonstrated increased persistence, as seen with the use of cytokine combinations like IL-7 and IL-15. Metabolic adjustments, such as using 2-deoxy-D-glucose (2-DG) and L-arginine, have enhanced the formation of memory T cells, leading to improved antitumor activity. OVs, when combined with CAR-T therapy, can amplify CAR-T cell penetration and persistence in solid tumors, although further clinical validation is needed. Advances in CAR design from second to fifth generations have progressively improved T cell activation and survival, with fifth-generation CARs demonstrating strong cytokine-mediated signaling and long-lasting persistence. Understanding the underlying mechanisms behind these strategies is essential for maximizing the potential of CAR-T therapy in treating cancer. Further research is needed to improve safety and efficacy and seamlessly integrate the discussed strategies into the manufacturing process.

Pan-cancer analysis of T-cell proliferation regulatory genes as potential immunotherapeutic targets

T cells are the key to killing tumor cells. However, the exact mechanism of their role in cancer is not fully understood. Therefore, a comprehensive understanding of the role of T-cell proliferation regulatory genes in tumors is needed. In our study, we investigated the expression levels of genes controlling T-cell proliferation, their impact on prognosis, and their genetic variations. Additionally, we explored their associations with TMB, MSI, ESTIMATEScore, ImmuneScore, StromalScore, and immune cell infiltration. We examined the role of these genes in cancer-related pathways using GSEA. Furthermore, we calculated their activity levels across various types of cancer. Drug analysis was also conducted targeting these genes. Single-cell analysis, LASSO Cox model construction, and prognosis analysis were performed. We observed distinct expression patterns of T-cell proliferation regulatory genes across different malignant tumors. Their abnormal expression may be caused by CNA and DNA methylation. In certain cancers, they also showed complex associations with TMB and MSI. Moreover, in many tumors, they exhibited significant positive correlations with ESTIMATEScores, ImmuneScore, and StromalScore. Additionally, in most tumors, their GSVA scores were significantly positively correlated with various T-cell subtypes. GSEA analysis revealed their involvement in multiple immune pathways. Furthermore, we found that model scores were associated with patient prognosis and related to tumor malignancy progression. T-cell proliferation regulatory genes are closely associated with the tumor immune microenvironment (TIM), especially T cells. Targeting them may be an essential approach for cancer immunotherapy.

CAR-T therapy and targeted treatments: Emerging combination strategies in solid tumors

CAR-T cell therapies hold great potential in achieving long-term remission in patients suffering from malignancies. However, their efficacy in treating solid tumors is impeded by challenges such as limited infiltration, compromised cancer recognition, decreased cytotoxicity, heightened exhaustion, absence of memory phenotypes, and inevitable toxicity. To surmount these obstacles, researchers are exploring innovative strategies, including the integration of CAR-T cells with targeted inhibitors. The combination of CAR-T therapies with specific targeted drugs has shown promise in enhancing CAR-T cell infiltration into tumor sites, boosting their tumor recognition capabilities, strengthening their cytotoxicity, alleviating exhaustion, promoting the development of a memory phenotype, and reducing toxicity. By harnessing the synergistic potential, a wider range of patients with solid tumors may potentially experience favorable outcomes. To summarize the current combined strategies of CAR-T therapies and targeted therapies, outline the potential mechanisms, and provide insights for future studies, we conducted this review by collecting existing experimental and clinical evidence.

Therapeutic targeting of DNA methylation alterations in cancer

DNA methylation is a critical component of gene regulation and plays an important role in the development of cancer. Hypermethylation of tumor suppressor genes and silencing of DNA repair pathways facilitate uncontrolled cell growth and synergize with oncogenic mutations to perpetuate cancer phenotypes. Additionally, aberrant DNA methylation hinders immune responses crucial for antitumor immunity. Thus, inhibiting dysregulated DNA methylation is a promising cancer therapy. Pharmacologic inhibition of DNA methylation reactivates silenced tumor suppressors and bolster immune responses through induction of viral mimicry. Now, with the advent of immunotherapies and discovery of the immune-modulatory effects of DNA methylation inhibitors, there is great interest in understanding how targeting DNA methylation in combination with other therapies can enhance antitumor immunity. Here, we describe the role of aberrant DNA methylation in cancer and mechanisms by which it promotes tumorigenesis and modulates immune responses. Finally, we review the initial discoveries and ongoing efforts to target DNA methylation as a cancer therapeutic.

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

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