Genetic engineering of T cells with chimeric antigen receptors for hematological malignancy immunotherapy

Human serum albumin promotes interactions between HSA-IL-2 fusion protein and CD122 for enhancing immunotherapy

Interleukin 2 (IL-2) is a multifunctional cytokine that is crucial for T-lymphocytes proliferation and differentiation. However, IL-2 binds to IL-2Rα (CD25) subunit preferentially and tends to stimulate regulatory T cells (Tregs), which express high-affinity trimeric receptors (IL-2Rαβγ), resulting in immunosuppressive effects. Therefore, development of methods that enhance IL-2/CD122 interactions and activate immune responses without affecting therapeutic efficacy of IL-2 may be desirable. In this work, we constructed a recombinant IL-2 fusion protein (HSA-IL-2), comprising human serum albumin (HSA) and IL-2, there was a new interaction interface between HSA domain and CD122 in HSA-IL-2 fusion protein predicted by AlphaFold2, and followed by determining binding affinity between HSA-IL-2 and CD122 through ForteBio's Bio-Layer Interferometry technology. Strikingly, HSA did promoted interactions between HSA-IL-2 fusion protein and CD122 compared with wild-type IL-2. In vivo experiments, HSA-IL-2 fusion protein had capacity to promote CD8+ T cells infiltration while reducing Treg cells infiltration for boosting immunotherapeutic efficacy. Furthermore, it facilitated synergistic therapeutic effect with α-PD-L1 to inhibit tumor growth. Overall, our research unveiled an enhanced binding affinity method underlying interactions between IL-2 and CD122 via fusing albumin, and propose a promising therapeutic strategy to facilitate IL-2 administration and broaden its clinical use.

Advances in the treatment of relapsed/refractory marginal zone lymphoma

Marginal zone lymphoma (MZL) is the second most common subtype of inert B-cell non-Hodgkin's lymphoma, accounting for 5-15% of non-Hodgkin's lymphoma cases. Patients with MZL have a long survival period, with a median survival of >10 years, and patients treated with a combination of anti-CD20 monoclonal antibody can achieve an overall effective rate of 81%. However, 20% of patients with MZL show relapse or experience disease progression within 2 years, with a median survival of only 3-5 years. Currently, the treatment options for patients with relapsed/refractory (R/R) MZL are limited, underscoring the pressing need for novel therapeutic drugs. The advent of novel anti-CD20 monoclonal antibodies, small molecule kinase inhibitors, immunomodulators, and other therapeutic strategies has ushered in a new era in the treatment of R/R MZL. Our objective is to summarize the existing treatment strategies, including immunotherapy and the emergent targeted therapies, and to evaluate their effectiveness and safety in the management of R/R MZL. By doing so, we aim to provide a clear understanding of the therapeutic landscape for R/R MZL, and to guide future research directions toward improving the prognosis and quality of life for patients afflicted with this challenging disease.

Advances in the treatment of graft-versus-host disease with immunomodulatory cells

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) has been widely used to treat hematological malignancies and genetic diseases. Graft-versus-host disease (GVHD) induced by donor immune system is the most common complication, contributing to severe morbidity and mortality after allo-HSCT. Currently, in terms of the prevention and treatment of GVHD, the major first-line therapeutic drugs are corticosteroids. However, most patients with systemic corticosteroid treatment are prone to steroid-refractory and poor prognosis. The use of several immune cells including Tregs, Bregs and mesenchymal stromal cells (MSCs) as an alternative on prevention or therapy of GVHD has been demonstrated to be beneficial. However, there are still many defects to a certain degree. Based on immune cells, it is promising to develop new and better approaches to improve GVHD. In this article, we will review the current advance of immune cells (Tregs, Bregs, MSCs) with negative regulation in the treatment of GVHD and present emerging strategies for the prevention and treatment of GVHD by other immune regulatory cells and chimeric antigen receptor (CAR) Tregs. In addition, these new therapeutic options need to be further evaluated in well-designed prospective multicenter trials to determine the optimal treatment for GVHD patients and improve their prognosis.

Chimeric Antigen Receptor (CAR) T Cell Therapy for Cancer. Challenges and Opportunities: An Overview

The use of immunotherapy as an alternative treatment for cancer patients has become of great interest in the scientific community as it is required to overcome many of the currently unsolved problems such as tumor escape, immunosuppression and unwanted unspecific toxicity. The use of chimeric antigen receptor T cells has been a very successful strategy in some hematologic malignancies. However, the application of CAR T cells has been limited to solid tumors, and this has aimed the development of new generation of CARs with enhanced effectivity and specificity. Here, we review the state of the art of CAR T cell therapy with special emphasis on the current challenges and opportunities.

Emerging role of metabolic reprogramming in tumor immune evasion and immunotherapy

Mounting evidence has revealed that the therapeutic efficacy of immunotherapies is restricted to a small portion of cancer patients. A deeper understanding of how metabolic reprogramming in the tumor microenvironment (TME) regulates immunity remains a major challenge to tumor eradication. It has been suggested that metabolic reprogramming in the TME may affect metabolism in immune cells and subsequently suppress immune function. Tumor cells compete with infiltrating immune cells for nutrients and metabolites. Notably, the immunosuppressive TME is characterized by catabolic and anabolic processes that are critical for immune cell function, and elevated inhibitory signals may favor cancer immune evasion. The major energy sources that supply different immune cell subtypes also undergo reprogramming. We herein summarize the metabolic remodeling in tumor cells and different immune cell subtypes and the latest advances underlying the use of metabolic checkpoints in antitumor immunotherapies. In this context, targeting both tumor and immune cell metabolic reprogramming may enhance therapeutic efficacy.

Adaptive T cell immunotherapy in cancer

Impaired tumor-specific effector T cells contribute to tumor progression and unfavorable clinical outcomes. As a compensatory T cell-dependent cancer immunoediting strategy, adoptive T cell therapy (ACT) has achieved encouraging therapeutic results, and this strategy is now on the center stage of cancer treatment and research. ACT involves the ex vivo stimulation and expansion of tumor-infiltrating lymphocytes (TILs) with inherent tumor reactivity or T cells that have been genetically modified to express the cognate chimeric antigen receptor or T cell receptor (CAR/TCR), followed by the passive transfer of these cells into a lymphodepleted host. Primed T cells must provide highly efficient and long-lasting immune defense against transformed cells during ACT. Anin-depth understanding of the basic mechanisms of these living drugs can help us improve upon current strategies and design better next-generation T cell-based immunotherapies. From this perspective, we provide an overview of current developments in different ACT strategies, with a focus on frontier clinical trials that offer a proof of principle. Meanwhile, insights into the determinants of ACT are discussed, which will lead to more rational, potent and widespread applications in the future.

Targeting Cancer Stem Cells by Genetically Engineered Chimeric Antigen Receptor T Cells

The term cancer stem cell (CSC) starts 25 years ago with the evidence that CSC is a subpopulation of tumor cells that have renewal ability and can differentiate into several distinct linages. Therefore, CSCs play crucial role in the initiation and the maintenance of cancer. Moreover, it has been proposed throughout several studies that CSCs are behind the failure of the conventional chemo-/radiotherapy as well as cancer recurrence due to their ability to resist the therapy and their ability to re-regenerate. Thus, the need for targeted therapy to eliminate CSCs is crucial; for that reason, chimeric antigen receptor (CAR) T cells has currently been in use with high rate of success in leukemia and, to some degree, in patients with solid tumors. This review outlines the most common CSC populations and their common markers, in particular CD133, CD90, EpCAM, CD44, ALDH, and EGFRVIII, the interaction between CSCs and the immune system, CAR T cell genetic engineering and signaling, CAR T cells in targeting CSCs, and the barriers in using CAR T cells as immunotherapy to treat solid cancers.

Chimeric antigen receptor T cells in solid tumors: a war against the tumor microenvironment

Chimeric antigen receptor (CAR) T cell is a novel approach, which utilizes anti-tumor immunity for cancer treatment. As compared to the traditional cell-mediated immunity, CAR-T possesses the improved specificity of tumor antigens and independent cytotoxicity from major histocompatibility complex molecules through a monoclonal antibody in addition to the T-cell receptor. CAR-T cell has proven its effectiveness, primarily in hematological malignancies, specifically where the CD 19 CAR-T cells were used to treat B-cell acute lymphoblastic leukemia and B-cell lymphomas. Nevertheless, there is little progress in the treatment of solid tumors despite the fact that many CAR agents have been created to target tumor antigens such as CEA, EGFR/EGFRvIII, GD2, HER2, MSLN, MUC1, and other antigens. The main obstruction against the progress of research in solid tumors is the tumor microenvironment, in which several elements, such as poor locating ability, immunosuppressive cells, cytokines, chemokines, immunosuppressive checkpoints, inhibitory metabolic factors, tumor antigen loss, and antigen heterogeneity, could affect the potency of CAR-T cells. To overcome these hurdles, researchers have reconstructed the CAR-T cells in various ways. The purpose of this review is to summarize the current research in this field, analyze the mechanisms of the major barriers mentioned above, outline the main solutions, and discuss the outlook of this novel immunotherapeutic modality.