Cellular immunotherapy for acute myeloid leukemia: How specific should it be?

Double-negative T cells utilize a TNFα-JAK1-ICAM-1 cytotoxic axis against acute myeloid leukemia

ABSTRACT

Allogeneic double-negative T cells (DNTs) are a rare T-cell subset that effectively target acute myeloid leukemia (AML) without inducing graft-versus-host disease in an allogeneic setting. A phase 1 clinical trial demonstrated the feasibility, safety, and potential efficacy of allogeneic DNT therapy among patients with relapsed AML. However, the molecular mechanisms of DNT-mediated cytotoxicity against AML remain elusive. Thus, we used a flow cytometry-based high throughput screening to compare the surface molecule expression profile on DNTs during their interaction with DNT-susceptible or -resistant AML cells and identified a tumor necrosis factor α (TNFα)-dependent cytotoxic pathway in DNT-AML interaction. TNFα secreted by DNTs, upon encountering susceptible AML targets, sensitized AML cells to DNT-mediated killing, including those otherwise resistant to DNTs. Mechanistically, TNFα upregulated ICAM-1 on AML cells through a noncanonical JAK1-dependent pathway. DNTs then engaged with AML cells more effectively through an ICAM-1 receptor, lymphocyte function-associated antigen 1, leading to enhanced killing. These results reveal a TNFα-JAK1-ICAM-1 axis in DNT-mediated cytotoxicity against AML to improve therapeutic efficacy.

Immune Specific and Tumor-Dependent mRNA Vaccines for Cancer Immunotherapy: Reprogramming Clinical Translation into Tumor Editing Therapy

Extensive research into mRNA vaccines for cancer therapy in preclinical and clinical trials has prepared the ground for the quick development of immune-specific mRNA vaccines during the COVID-19 pandemic. Therapeutic cancer vaccines based on mRNA are well tolerated, and are an attractive choice for future cancer immunotherapy. Ideal personalized tumor-dependent mRNA vaccines could stimulate both humoral and cellular immunity by overcoming cancer-induced immune suppression and tumor relapse. The stability, structure, and distribution strategies of mRNA-based vaccines have been improved by technological innovations, and patients with diverse tumor types are now being enrolled in numerous clinical trials investigating mRNA vaccine therapy. Despite the fact that therapeutic mRNA-based cancer vaccines have not yet received clinical approval, early clinical trials with mRNA vaccines as monotherapy and in conjunction with checkpoint inhibitors have shown promising results. In this review, we analyze the most recent clinical developments in mRNA-based cancer vaccines and discuss the optimal platforms for the creation of mRNA vaccines. We also discuss the development of the cancer vaccines' clinical research, paying particular attention to their clinical use and therapeutic efficacy, which could facilitate the design of mRNA-based vaccines in the near future.

Identification of a venetoclax-resistance prognostic signature base on 6-senescence genes and its clinical significance for acute myeloid leukemia

Background

Satisfactory responses can be obtained for acute myeloid leukemia (AML) treated by Venetoclax (VEN)-based therapy. However, there are still quite a few AML patients (AMLs) resistant to VEN, and it is critical to understand whether VEN-resistance is regulated by senescence.

Methods

Here, we established and validated a signature for predicting AML prognosis based on VEN resistance-related senescence genes (VRSGs). In this study, 51 senescence genes were identified with VEN-resistance in AML. Using LASSO algorithms and multiple AML cohorts, a VEN-resistance senescence prognostic model (VRSP-M) was developed and validated based on 6-senescence genes.

Results

According to the median score of the signature, AMLs were classified into two subtypes. A worse prognosis and more adverse features occurred in the high-risk subtype, including older patients, non-de novo AML, poor cytogenetics, adverse risk of European LeukemiaNet (ELN) 2017 recommendation, and TP53 mutation. Patients in the high-risk subtype were mainly involved in monocyte differentiation, senescence, NADPH oxidases, and PD1 signaling pathway. The model's risk score was significantly associated with VEN-resistance, immune features, and immunotherapy response in AML. In vitro, the IC50 values of ABT-199 (VEN) rose progressively with increasing expression of G6PD and BAG3 in AML cell lines.

Conclusions

The 6-senescence genes prognostic model has significant meaning for the prediction of VEN-resistance, guiding personalized molecularly targeted therapies, and improving AML prognosis.

CAR-T cells for pediatric malignancies: Past, present, future and nursing implications

The treatment landscape for pediatric cancers over the last 11 years has undergone a dramatic change, especially with relapsed and refractory B-cell acute lymphoblastic leukemia (ALL), due to the introduction of chimeric antigen receptor-T (CAR-T) cell therapy. Because of the success of CAR-T cell therapy in patients with relapsed and refractory B-cell ALL, this promising therapy is undergoing trials in multiple other pediatric malignancies. This article will focus on the introduction of CAR-T cell therapy in pediatric B-cell ALL and discuss past and current trials. We will also discuss trials for CAR-T cell therapy in other pediatric malignancies. This information was gathered through a comprehensive literature review along with using first hand institutional experience. Due to the potential severe toxicities related to CAR-T cell therapy, safe practices and monitoring are key. These authors demonstrate that nurses have a profound responsibility in preparing and caring for patients and families, monitoring and managing side effects in these patients, ensuring that study guidelines are followed, and providing continuity for patients, families, and referring providers. Education of nurses is crucial for improved patient outcomes.

Blasts in context: the impact of the immune environment on acute myeloid leukemia prognosis and treatment

Acute myeloid leukemia (AML) is a cancer that originates from the bone marrow (BM). Under physiological conditions, the bone marrow supports the homeostasis of immune cells and hosts memory lymphoid cells. In this review, we summarize our present understanding of the role of the immune microenvironment on healthy bone marrow and on the development of AML, with a focus on T cells and other lymphoid cells. The types and function of different immune cells involved in the AML microenvironment as well as their putative role in the onset of disease and response to treatment are presented. We also describe how the immune context predicts the response to immunotherapy in AML and how these therapies modulate the immune status of the bone marrow. Finally, we focus on allogeneic stem cell transplantation and summarize the current understanding of the immune environment in the post-transplant bone marrow, the factors associated with immune escape and relevant strategies to prevent and treat relapse.

In Pursuit of Genetic Prognostic Factors and Treatment Approaches in Secondary Acute Myeloid Leukemia—A Narrative Review of Current Knowledge

Secondary acute myeloid leukemia can be divided into two categories: AML evolving from the antecedent hematological condition (AHD-AML) and therapy related AML (t-AML). AHD-AML can evolve from hematological conditions such as myelodysplastic syndromes, myeloproliferative neoplasms, MDS/MPN overlap syndromes, Fanconi anemia, and aplastic anemia. Leukemic transformation occurs as a consequence of the clonal evolution—a process of the acquisition of mutations in clones, while previous mutations are also passed on, leading to somatic mutations accumulation. Compared de novo AML, secondary AML is generally associated with poorer response to chemotherapy and poorer prognosis. The therapeutic options for patients with s-AML have been confirmed to be limited, as s-AML has often been analyzed either both with de novo AML or completely excluded from clinical trials. The treatment of s-AML was not in any way different than de novo AML, until, that is, the introduction of CPX-351—liposomal daunorubicin and cytarabine. CPX-351 significantly improved the overall survival and progression free survival in elderly patients with s-AML. The only definitive treatment in s-AML at this time is allogeneic hematopoietic cell transplantation. A better understanding of the genetics and epigenetics of s-AML would allow us to determine precise biologic drivers leading to leukogenesis and thus help to apply a targeted treatment, improving prognosis.

Allogeneic double-negative CAR-T cells inhibit tumor growth without off-tumor toxicities

The development of autologous chimeric antigen receptor T (CAR-T) cell therapies has revolutionized cancer treatment. Nevertheless, the delivery of CAR-T cell therapy faces challenges, including high costs, lengthy production times, and manufacturing failures. To overcome this, attempts have been made to develop allogeneic CAR-T cells using donor-derived conventional CD4⁺ or CD8⁺ T cells (T_convs), but severe graft-versus-host disease (GvHD) and host immune rejection have made this challenging. CD3⁺CD4^-CD8^- double-negative T cells (DNTs) are a rare subset of mature T cells shown to fulfill the requirements of an off-the-shelf cellular therapy, including scalability, cryopreservability, donor-independent anticancer function, resistance to rejection, and no observed off-tumor toxicity including GvHD. To overcome the challenges faced with CAR-T_convs, we evaluated the feasibility, safety, and efficacy of using healthy donor-derived allogeneic DNTs as a CAR-T cell therapy platform. We successfully transduced DNTs with a second-generation anti-CD19-CAR (CAR19) without hampering their endogenous characteristics or off-the-shelf properties. CAR19-DNTs induced antigen-specific cytotoxicity against B cell acute lymphoblastic leukemia (B-ALL). In addition, CAR19-DNTs showed effective infiltration and tumor control against lung cancer genetically modified to express CD19 in xenograft models. CAR19-DNT efficacy was comparable with that of CAR19-T_convs. However, unlike CAR19-T_convs, CAR19-DNTs did not cause alloreactivity or xenogeneic GvHD-related mortality in xenograft models. These studies demonstrate the potential of using allogeneic DNTs as a platform for CAR technology to provide a safe, effective, and patient-accessible CAR-T cell treatment option.

Combinatorial antigen targeting strategies for acute leukemia: application in myeloid malignancy

BACKGROUND AIMS

Efforts to safely and effectively treat acute myeloid leukemia (AML) by targeting a single leukemia-associated antigen with chimeric antigen receptor (CAR) T cells have met with limited success, due in part to heterogeneous expression of myeloid antigens. The authors hypothesized that T cells expressing CARs directed toward two different AML-associated antigens would eradicate tumors and prevent relapse.

METHODS

For co-transduction with the authors' previously optimized CLL-1 CAR currently in clinical study (NCT04219163), the authors generated two CARs targeting either CD123 or CD33. The authors then tested the anti-tumor activity of T cells expressing each of the three CARs either alone or after co-transduction. The authors analyzed CAR T-cell phenotype, expansion and transduction efficacy and assessed function by in vitro and in vivo activity against AML cell lines expressing high (MOLM-13: CD123 high, CD33 high, CLL-1 intermediate), intermediate (HL-60: CD123 low, CD33 intermediate, CLL-1 intermediate/high) or low (KG-1a: CD123 low, CD33 low, CLL-1 low) levels of the target antigens.

RESULTS

The in vitro benefit of dual expression was most evident when the target cell line expressed low antigen levels (KG-1a). Mechanistically, dual expression was associated with higher pCD3z levels in T cells compared with single CAR T cells on exposure to KG-1a (P < 0.0001). In vivo, combinatorial targeting with CD123 or CD33 and CLL-1 CAR T cells improved tumor control and animal survival for all lines (KG-1a, MOLM-13 and HL-60); no antigen escape was detected in residual tumors.

CONCLUSIONS

Overall, these findings demonstrate that combinatorial targeting of CD33 or CD123 and CLL-1 with CAR T cells can control growth of heterogeneous AML tumors.

Enhancing Therapeutic Efficacy of Double Negative T Cells against Acute Myeloid Leukemia Using Idelalisib

Simple Summary

Persistence of infused cells is an important factor that dictates the outcome of adoptive cellular therapy (ACT). DNT therapy is a novel form of ACT with promising result in treating relapsed or refractory AML in preclinical and early clinical studies. However, in vivo kinetics of human DNTs in cancer-bearing host have not been previously investigated. This study was the first to investigate the persistence of DNTs and ways to improve it in patient-derived xenograft models. DNTs persistence was observed up to 50 days in various organs of leukemia-bearing hosts. However, the detected DNT level was low while significant level of persisting AMLs was observed. To improve the in vivo persistence and therapeutic efficacy of DNTs, we expanded DNTs in the presence of an PI3Kδ inhibitor, idelalisib (Ide). Ide treatment of healthy donor-derived DNTs promoted early memory subsets and improved overall fitness, reducing exhaustion while improving viability. These Ide-induced attributes led to prolonged persistence of DNTs, resulting in superior anti-leukemic activity in vivo. Further, Ide-treated DNTs improved the durability of the treatment response. Collectively, our study highlights the importance of DNT persistence and Ide-mediated improvements in the overall fitness of DNTs, which promote longer persistence in vivo and better treatment outcome.

Abstract

The double negative T cell (DNT) is a unique subset of T cells with potent anti-leukemic potential. Previously, DNT therapy has been shown to effectively target AML cells in patient-derived xenograft (PDX) models. Further, a recently completed phase I/IIa clinical study demonstrated the safety, feasibility, and potential efficacy in AML patients that relapsed after allogeneic hematopoietic stem cell transplantation. However, the persistence and durability of DNT-mediated anti-leukemic response is less well understood. In this study, we characterized the in vivo persistence of DNTs in PDX models. Further, we improved the efficacy and durability of DNT-mediated activity with phosphoinositide 3-kinase delta (PI3Kδ) inhibition. Mechanistically, DNTs treated with the PI3Kδ inhibitor, Idelalisib (Ide), exhibited early memory phenotype with superior viability and proliferative capacity but less cell exhaustion. Collectively, the findings from this study support the use of Ide-treated DNTs to improve its therapeutic outcome.

Venetoclax enhances T cell-mediated antileukemic activity by increasing ROS production

Venetoclax, a Bcl-2 inhibitor, in combination with the hypomethylating agent azacytidine, achieves complete remission with or without count recovery in ∼70% of treatment-naive elderly patients unfit for conventional intensive chemotherapy. However, the mechanism of action of this drug combination is not fully understood. We discovered that venetoclax directly activated T cells to increase their cytotoxicity against acute myeloid leukemia (AML) in vitro and in vivo. Venetoclax enhanced T-cell effector function by increasing reactive oxygen species generation through inhibition of respiratory chain supercomplexes formation. In addition, azacytidine induced a viral mimicry response in AML cells by activating the STING/cGAS pathway, thereby rendering the AML cells more susceptible to T cell-mediated cytotoxicity. Similar findings were seen in patients treated with venetoclax, as this treatment increased reactive oxygen species generation and activated T cells. Collectively, this study presents a new immune-mediated mechanism of action for venetoclax and azacytidine in the treatment of AML and highlights a potential combination of venetoclax and adoptive cell therapy for patients with AML.

Profiling pharmacokinetics of double-negative T cells and cytokines via a single intravenous administration in NSG mice

This study was intended to delineate the profile of double-negative T cells (DNTs) in NOD.Cg-Prkdcscid Il2rgtm1wj /SzJ mice and cytokines released from DNTs in vivo and in vitro. Total 4 × 107 cells of RC1012 injection per mice were intravenously infused. IFN-γ, TNF-α, IL-1β, IL-2, IL-4, IL-6, IL-10 were measured in vivo and in vitro. A quantitative polymerase chain reaction (PCR) was employed to determine the gene copies of Notch2-NLA per DNT cell from collected organs. Cytokines were significantly increased in vitro (4 h) and in vivo (3 h). DNT cells were distributed into the lung, liver, heart, and kidney earlier, and redistributed to lymphocyte homing spleen and bone marrow, which seemed to frame a two-compartment pharmacokinetics (PK) model but more data are needed to confirm this, and the clearance of DNT cells fell into first-order kinetics.

State-of-Art of Cellular Therapy for Acute Leukemia

With recent clinical breakthroughs, immunotherapy has become the fourth pillar of cancer treatment. Particularly, immune cell-based therapies have been envisioned as a promising treatment option with curative potential for leukemia patients. Hence, an increasing number of preclinical and clinical studies focus on various approaches of immune cell-based therapy for treatment of acute leukemia (AL). However, the use of different immune cell lineages and subsets against different types of leukemia and patient disease statuses challenge the interpretation of the clinical applicability and outcome of immune cell-based therapies. This review aims to provide an overview on recent approaches using various immune cell-based therapies against acute B-, T-, and myeloid leukemias. Further, the apparent limitations observed and potential approaches to overcome these limitations are discussed.

Profiling of immune-cancer interactions at the single-cell level using a microfluidic well array

Cancer immunotherapy has achieved great success in hematological cancers. However, immune cells are a highly heterogeneous population and can vary highly in clonal expansion, migration and function status, making it difficult to evaluate and predict patient response to immune therapy. Conventional technologies only yield information on the average population information of the treatment, masking the heterogeneity of the individual T cell activation status, the formation of immune synapse, as well as the efficacy of tumor cell killing at the single-cell level. To fully interrogate these single-cell events in detail, herein, we present a microfluidic microwell array device that enables the massive parallel analysis of the immunocyte's heterogeneity upon its interaction pairs with tumor cells at the single-cell level. By precisely controlling the number and ratio of tumor cells and T cells, our technique can interrogate the dynamics of the CD8+ T cell and leukemia cell interaction inside 6400 microfluidic wells simultaneously. We have demonstrated that by investigating the interactions of T cell and tumor cell pairs at the single-cell level using our microfluidic chip, details hidden in bulk investigations, such as heterogeneity in T cell killing capacity, time-dependent killing dynamics, as well as drug treatment-induced dynamic shifts, can be revealed. This method opens up avenues to investigate the efficacy of cancer immunotherapy and resistance at the single-cell level and can explore our understanding of fundamental cancer immunity as well as determine cancer immunotherapy efficacy for personalized therapy.

Pathogenic and therapeutic roles of cytokines in acute myeloid leukemia

Acute myeloid leukemia (AML) is a heterogeneous disease with high mortality that accounts for the most common acute leukemia in adults. Despite all progress in the therapeutic strategies and increased rate of complete remission, many patients will eventually relapse and die from the disease. Cytokines as molecular messengers play a pivotal role in the immune system. The imbalance release of cytokine has been shown to exert a significant influence on the progression of hematopoietic malignancies including acute myeloid leukemia. This article aimed to summarize current knowledge about cytokines and their critical roles in the pathogenesis, treatment, and survival of AML patients.

Acute Myeloid Leukemia: From Biology to Clinical Practices Through Development and Pre-Clinical Therapeutics

Recent studies have provided several insights into acute myeloid leukemia. Studies based on molecular biology have identified eight functional mutations involved in leukemogenesis, including driver and passenger mutations. Insight into Leukemia stem cells (LSCs) and assessment of cell surface markers have enabled characterization of LSCs from hematopoietic stem and progenitor cells. Clonal evolution has been described as having an effect similar to that of microenvironment alterations. Such biological findings have enabled the development of new targeted drugs, including drug inhibitors and monoclonal antibodies with blockage functions. Some recently approved targeted drugs have resulted in new therapeutic strategies that enhance standard intensive chemotherapy regimens as well as supportive care regimens. Besides the progress made in adoptive immunotherapy, since allogenic hematopoietic stem cell transplantation enabled the development of new T-cell transfer therapies, such as chimeric antigen receptor T-cell and transgenic TCR T-cell engineering, new promising strategies that are investigated.

Combination of Detoxified Pneumolysin Derivative ΔA146Ply and Berbamine as a Treatment Approach for Breast Cancer

Increasing evidence demonstrates that microorganisms and their products can modulate host responses to cancer therapies and contribute to tumor shrinkage via various mechanisms, including intracellular signaling pathways modulation and immunomodulation. Detoxified pneumolysin derivative ΔA146Ply is a pneumolysin mutant lacking hemolytic activity. To determine the antitumor activity of ΔA146Ply, the combination of ΔA146Ply and berbamine, a well-established antitumor agent, was used for breast cancer therapy, especially for triple-negative breast cancer. The efficacy of the combination therapy was evaluated in vitro using four breast cancer cell lines and in vivo using a synergistic mouse tumor model. We demonstrated that in vitro, the combination therapy significantly inhibited cancer cell proliferation, promoted cancer cell apoptosis, caused cancer cell-cycle arrest, and suppressed cancer cell migration and invasion. In vivo, the combination therapy significantly suppressed tumor growth and prolonged the median survival time of tumor-bearing mice partially through inhibiting tumor cell proliferation, promoting tumor cell apoptosis, and activating systemic antitumor immune responses. The safety analysis demonstrated that the combination therapy showed no obvious liver and kidney toxicity to tumor-bearing mice. Our study provides a new treatment option for breast cancer and lays the experimental basis for the development of ΔA146Ply as an antitumor agent.

Successful Anti-CLL1 CAR T-Cell Therapy in Secondary Acute Myeloid Leukemia

Secondary acute myeloid leukemia (sAML) is a high-risk AML evolving from heterogenous prior hematological disorders. Compared to de novo AML, sAML has even worse responses to current therapy and thus is associated with lower remission rates, inferior overall survival (OS) and higher relapse rates. Many efforts have been devoted to improving the overall but with limited success, and novel strategy is thus highly needed. Recent research has identified that CLL1 is highly expressed on AML leukemia stem cells and blasts cells but not on normal hematopoietic stem cells. In this case report, we treated a secondary AML patient with anti -CLL1 CAR-T therapy and achieved morphological, immunophenotypic and molecular complete remission for over 10 months. Although only one successful case is presented here, the anti-CLL1 CAR T-cells should be considered as another treatment option for secondary AML in the future.

Alterations of T-cell-mediated immunity in acute myeloid leukemia

Acute myeloid leukemia (AML) is a systemic, heterogeneous hematologic malignancy with poor overall survival. While some malignancies have seen improvements in clinical outcomes with immunotherapy, success of these agents in AML remains elusive. Despite limited progress, stem cell transplantation and donor lymphocyte infusions show that modulation of the immune system can improve overall survival of AML patients. Understanding the causes of immune evasion and disease progression will identify potential immune-mediated targets in AML. This review explores immunosuppressive mechanisms that alter T-cell-mediated immunity in AML.

Characterization of Immune Dysfunction and Identification of Prognostic Immune-Related Risk Factors in Acute Myeloid Leukemia

PURPOSE

This study aims to provide comprehensive insights into longitudinal immune landscape in acute myeloid leukemia (AML) development and treatment, which may contribute to predict prognosis and guide clinical decisions.

EXPERIMENTAL DESIGN

Periphery blood samples from 79 patients with AML (at diagnosis or/and after chemotherapy or at relapse) and 24 healthy controls were prospectively collected. We performed phenotypic and functional analysis of various lymphocytes through multiparametric flow cytometry and investigated prognostic immune-related risk factors.

RESULTS

Immune defects in AML were reflected in T and natural killer (NK) cells, whereas B-cell function remained unaffected. Both CD8⁺ T and CD4⁺ T cells exhibited features of senescence and exhaustion at diagnosis. NK dysfunction was supported by excessive maturation and downregulation of NKG2D and NKP30. Diseased γδ T cells demonstrated a highly activated or even exhausted state through PD-1 upregulation and NKG2D downregulation. Effective therapeutic response following chemotherapy correlated with T and NK function restoration. Refractory and relapsed patients demonstrated even worse immune impairments, and selective immune signatures apparently correlated clinical outcomes and survival. PD-1 expression in CD8⁺ T cells was independently predictive of poor overall survival and event-free survival.

CONCLUSIONS

T-cell senescence and exhaustion, together with impaired NK and γδ T-cell function, are dominant aspects involved in immune dysfunction in AML. Noninvasive immune testing of blood samples could be applied to predict therapeutic reactivity, high risk for relapse, and unfavorable prognosis.