NKG2D gene polymorphisms are associated with disease control of chronic myeloid leukemia by dasatinib

NK cell subsets and dysfunction during viral infection: a new avenue for therapeutics?

In the setting of viral challenge, natural killer (NK) cells play an important role as an early immune responder against infection. During this response, significant changes in the NK cell population occur, particularly in terms of their frequency, location, and subtype prevalence. In this review, changes in the NK cell repertoire associated with several pathogenic viral infections are summarized, with a particular focus placed on changes that contribute to NK cell dysregulation in these settings. This dysregulation, in turn, can contribute to host pathology either by causing NK cells to be hyperresponsive or hyporesponsive. Hyperresponsive NK cells mediate significant host cell death and contribute to generating a hyperinflammatory environment. Hyporesponsive NK cell populations shift toward exhaustion and often fail to limit viral pathogenesis, possibly enabling viral persistence. Several emerging therapeutic approaches aimed at addressing NK cell dysregulation have arisen in the last three decades in the setting of cancer and may prove to hold promise in treating viral diseases. However, the application of such therapeutics to treat viral infections remains critically underexplored. This review briefly explores several therapeutic approaches, including the administration of TGF-β inhibitors, immune checkpoint inhibitors, adoptive NK cell therapies, CAR NK cells, and NK cell engagers among other therapeutics.

Intrinsic and extrinsic factors determining natural killer cell fate: Phenotype and function

Natural killer (NK) cells are derived from hematopoietic stem cells. They belong to the innate lymphoid cell family, which is an important part of innate immunity. This family plays a role in the body mainly through the release of perforin, granzyme, and various cytokines and is involved in cytotoxicity and cytokine-mediated immune regulation. NK cells involved in normal immune regulation and the tumor microenvironment (TME) can exhibit completely different states. Here, we discuss the growth, development, and function of NK cells in regard to intrinsic and extrinsic factors. Intrinsic factors are those that influence NK cells to promote cell maturation and exert their effector functions under the control of internal metabolism and self-related genes. Extrinsic factors include the metabolism of the TME and the influence of related proteins on the "fate" of NK cells. This review targets the potential of NK cell metabolism, cellular molecules, regulatory genes, and other mechanisms involved in immune regulation. We further discuss immune-mediated tumor therapy, which is the trend of current research.

NKG2A gene variant predicts outcome of immunotherapy in AML and modulates the repertoire and function of NK cells

BACKGROUND

The natural killer (NK) complex (NKC) harbors multiple genes such as KLRC1 (encoding NKG2A) and KLRK1 (encoding NKG2D) that are central to regulation of NK cell function. We aimed at determining to what extent NKC haplotypes impact on NK cell repertoire and function, and whether such gene variants impact on outcome of IL-2-based immunotherapy in acute myeloid leukemia (AML).

METHODS

Genotype status of NKG2D rs1049174 and NKG2A rs1983526 was determined using the TaqMan-Allelic discrimination approach. To dissect the impact of single nucloetide polymorphim (SNP) on NK cell function, we engineered the K562 cell line with CRISPR to be killed in a highly NKG2D-dependent fashion. NK cells were assayed for degranulation, intracellular cytokine production and cytotoxicity using flow cytometry.

RESULTS

In AML patients receiving immunotherapy, the NKG2A gene variant, rs1983526, was associated with superior leukemia-free survival and overall survival. We observed that superior NK degranulation from individuals with the high-cytotoxicity NKG2D variant was explained by presence of a larger, highly responsive NKG2A+ subset. Notably, NK cells from donors homozygous for a favorable allele encoding NKG2A mounted stronger cytokine responses when challenged with leukemic cells, and NK cells from AML patients with this genotype displayed higher accumulation of granzyme B during histamine dihydrochloride/IL-2 immunotherapy. Additionally, among AML patients, the NKG2A SNP defined a subset of patients with HLA-B-21 TT with a strikingly favorable outcome.

CONCLUSIONS

The study results imply that a dimorphism in the NKG2A gene is associated with enhanced NK cell effector function and improved outcome of IL-2-based immunotherapy in AML.

Immunomodulatory Activity of the Tyrosine Kinase Inhibitor Dasatinib to Elicit NK Cytotoxicity against Cancer, HIV Infection and Aging

Tyrosine kinase inhibitors (TKIs) have been extensively used as a treatment for chronic myeloid leukemia (CML). Dasatinib is a broad-spectrum TKI with off-target effects that give it an immunomodulatory capacity resulting in increased innate immune responses against cancerous cells and viral infected cells. Several studies reported that dasatinib expanded memory-like natural killer (NK) cells and γδ T cells that have been related with increased control of CML after treatment withdrawal. In the HIV infection setting, these innate cells are associated with virus control and protection, suggesting that dasatinib could have a potential role in improving both the CML and HIV outcomes. Moreover, dasatinib could also directly induce apoptosis of senescence cells, being a new potential senolytic drug. Here, we review in depth the current knowledge of virological and immunogenetic factors associated with the development of powerful cytotoxic responses associated with this drug. Besides, we will discuss the potential therapeutic role against CML, HIV infection and aging.

Fetal hemoglobin level predicts lower-risk myelodysplastic syndrome

The relationship between fetal hemoglobin (HbF) levels and disease prognosis in patients with myelodysplastic syndrome (MDS) is unclear. This study aimed to clarify the relationship between HbF level and the prognosis of MDS. To this end, data from 217 patients diagnosed with MDS between April 2006 and August 2020 at Ebina General Hospital were analyzed retrospectively. The primary endpoint was leukemia-free survival (LFS) for 5 years after diagnosis. HbF levels were significantly higher in patients with MDS than in control patients without MDS (n = 155), with a cut-off value of 0.4%. Higher-risk patients had a similar prognosis regardless of HbF level, but lower-risk patients had longer LFS at intermediate HbF levels. Although prognosis based on pre-treatment HbF levels did not differ significantly among azacitidine-treated patients, prognosis tended to be better in lower-risk patients with intermediate HbF levels. Multivariate analysis showed that the intermediate HbF category correlated with LFS, independently of MDS lower-risk prognostic scoring system (LR-PSS)-related factors. This study is the first to assess the association between HbF levels and the new World Health Organization 2016 criteria for MDS, demonstrating the significance of HbF levels in the prognosis of MDS.

Current Progress of CAR-NK Therapy in Cancer Treatment

Simple Summary

Chimeric antigen receptor (CAR)-T and -natural killer (NK) therapies are promising in cancer treatment. CAR-NK therapy gains great attention due to the lack of adverse effects observed in CAR-T therapies and to the NK cells’ unique mechanisms of recognizing target cells. Off-the-shelf products are in urgent need, not only for good yields, but also for lower cost and shorter preparation time. The current progress of CAR-NK therapy is discussed.

Abstract

CD8⁺ T cells and natural killer (NK) cells eliminate target cells through the release of lytic granules and Fas ligand (FasL)-induced target cell apoptosis. The introduction of chimeric antigen receptor (CAR) makes these two types of cells selective and effective in killing cancer cells. The success of CAR-T therapy in the treatment of acute lymphoblastic leukemia (ALL) and other types of blood cancers proved that the immunotherapy is an effective approach in fighting against cancers, yet adverse effects, such as graft versus host disease (GvHD) and cytokine release syndrome (CRS), cannot be ignored for the CAR-T therapy. CAR-NK therapy, then, has its advantage in lacking these adverse effects and works as effective as CAR-T in terms of killing. Despite these, NK cells are known to be hard to transduce, expand in vitro, and sustain shorter in vivo comparing to infiltrated T cells. Moreover, CAR-NK therapy faces challenges as CAR-T therapy does, e.g., the time, the cost, and the potential biohazard due to the use of animal-derived products. Thus, enormous efforts are needed to develop safe, effective, and large-scalable protocols for obtaining CAR-NK cells. Here, we reviewed current progress of CAR-NK therapy, including its biological properties, CAR compositions, preparation of CAR-NK cells, and clinical progresses. We also discussed safety issues raised from genetic engineering. We hope this review is instructive to the research community and a broad range of readers.

Natural Killer cell receptors and ligand variants modulate response to tyrosine kinase inhibitors in patients with chronic myeloid leukemia

Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm treated with tyrosine kinase inhibitors (TKIs). Although survival rates have improved, response to these treatments is highly heterogeneous. Variations in response rates may be due to different causes such as, treatment adherence, mutations in the BCR-ABL1 gene, clonal evolution and amplification of the BCR-ABL1 gene, but innate immune response is also considered to play a very important role and, specifically, NK cell activity through their receptors and ligands, could be determinant. The aim of this retrospective study was to explore the role of different activating and inhibiting KIR genes as well as the activating NKG2D receptor, present in NK cells, and also their respective ligands, HLA-A, -B, -C, -G, -F, MICA and MICB, in the progression of 190 patients with CML and treated at two hospitals from Barcelona between 2000 and 2019. Early molecular response (EMR), major molecular response (MMR) or MR3.0 and deep molecular response (DMR) or MR4.0 were correlated. As control samples, healthy donors from the Barcelona Blood Bank were analyzed. The presence of KIR2DL2/KIR2DS2 was associated with the achievement of EMR, MR3.0 and MR4.0. Carriers of the higher expression NKG2D variant and MICA*009:01 were also likely to achieve molecular response (MR). The most remarkable difference between CML patients and controls was a higher frequency of the lower expression NKG2D variant in CML patients. In summary, our results showed that activating NK receptor phenotypes might help to achieve MR and DMR in CML patients treated with TKIs although confirmatory studies are necessary. This article is protected by copyright. All rights reserved.

Treatment-Free Remission in Chronic Myeloid Leukemia and New Approaches by Targeting Leukemia Stem Cells

The therapeutic landscape for chronic myeloid leukemia (CML) has improved significantly with the approval of tyrosine kinase inhibitors (TKIs) for therapeutic use. Most patients with optimal responses to TKIs can have a normal life expectancy. Treatment-free remission (TFR) after discontinuing TKI has increasingly become a new goal for CML treatment. However, TKI only "control" CML, and relapse after discontinuation has become a key factor hindering patient access to attempt TFR. In this study, we reviewed studies on TKI discontinuation, including both first and second-generation TKI. We also reviewed predictors of relapse, new monitoring methods, and strategies targeting leukemic stem cells.

Carbon ion (12C6+) irradiation induces the expression of Klrk1 in lung cancer and optimizes the tumor microenvironment based on the NKG2D/NKG2D-Ls pathway

With the identification of "negative immune regulation" defects in the immune system and the continuous improvement of immunotherapy, natural killer cells (NK) have received more attention, especially as tools in combined immunotherapy. Carbon ions (12C6+) have become the ideal radiation for combined immunotherapy due to their significant radiobiological advantages and synergistic effects. The purpose of this study was to explore the NK cell-mediated cytotoxicity pathway and related mechanisms in lung cancer induced by carbon ion irradiation. KLRK1, which specifically encodes the NKG2D receptor, was significantly correlated with the prognosis, clinical stage, functional status of NK cells, and the immune microenvironment of lung cancer, as shown by bioinformatics analysis. Based on RNA-seq data of Lewis lung cancer in C57BL/6 mice, carbon ion irradiation was found to significantly induce Klrk1 gene expression and activate the NKG2D/NKG2D-Ls pathway. The Treg inhibition pathway combined with carbon ion radiotherapy could significantly increase the infiltration and function of NK cells in the tumor microenvironment of lung cancer and prolong the survival time of C57BL/6 mice. In conclusion, carbon ions have significant radiobiological advantages, especially under conditions of combined immunotherapy. Carbon ions combined with Treg inhibitors can significantly improve the infiltration and functional status of NK cells.

NK Cells in Myeloproliferative Neoplasms (MPN)

Simple Summary

NK cells are important innate immune effectors that contribute substantially to tumor control, however the role of NK cells in haematological cancers is not as well understood. The aim of this review is to highlight the importance of the role of NK cells in the management of Ph+ Myeloproliferative Neoplasms, and emphasize the need and possible benefits of a more in-depth investigation into their role in classical MPNs and show potential strategies to harness the anti-tumoral capacities of NK cells.

Abstract

Myeloproliferative neoplasms (MPNs) comprise a heterogenous group of hematologic neoplasms which are divided into Philadelphia positive (Ph+), and Philadelphia negative (Ph−) or classical MPNs. A variety of immunological factors including inflammatory, as well as immunomodulatory processes, closely interact with the disease phenotypes in MPNs. NK cells are important innate immune effectors and substantially contribute to tumor control. Changes to the absolute and proportionate numbers of NK cell, as well as phenotypical and functional alterations are seen in MPNs. In addition to the disease itself, a variety of therapeutic options in MPNs may modify NK cell characteristics. Reports of suppressive effects of MPN treatment strategies on NK cell activity have led to intensive investigations into the respective compounds, to elucidate the possible negative effects of MPN therapy on control of the leukemic clones. We hereby review the available literature on NK cells in Ph+ and Ph− MPNs and summarize today’s knowledge on disease-related alterations in this cell compartment with particular focus on known therapy-associated changes. Furthermore, we critically evaluate conflicting data with possible implications for future projects. We also aim to highlight the relevance of full NK cell functionality for disease control in MPNs and the importance of considering specific changes related to therapy in order to avoid suppressive effects on immune surveillance.

Unleashing the power of NK cells in anticancer immunotherapy

Due to their physiological role in removing damaged cells, natural killer (NK) cells represent ideal candidates for cellular immunotherapy in the treatment of cancer. Thereby, the cytotoxicity of NK cells is regulated by signals on both, the NK cells as well as the targeted tumor cells, and the interplay and balance of these signals determine the killing capacity of NK cells. One promising avenue in cancer treatment is therefore the combination of NK cell therapy with agents that either help to increase the killing capacity of NK cells or sensitize tumor cells to an NK cell-mediated attack. In this mini-review, we present different strategies that can be explored to unleash the potential of NK cell immunotherapy. In particular, we summarize how modulation of apoptosis signaling within tumor cells can be exploited to sensitize tumor cells to NK cell-mediated cytotoxicity.

NKG2D Natural Killer Cell Receptor-A Short Description and Potential Clinical Applications

Natural Killer (NK) cells are natural cytotoxic, effector cells of the innate immune system. They can recognize transformed or infected cells. NK cells are armed with a set of activating and inhibitory receptors which are able to bind to their ligands on target cells. The right balance between expression and activation of those receptors is fundamental for the proper functionality of NK cells. One of the best known activating receptors is NKG2D, a member of the CD94/NKG2 family. Due to a specific NKG2D binding with its eight different ligands, which are overexpressed in transformed, infected and stressed cells, NK cells are able to recognize and attack their targets. The NKG2D receptor has an enormous significance in various, autoimmune diseases, viral and bacterial infections as well as for transplantation outcomes and complications. This review focuses on the NKG2D receptor, the mechanism of its action, clinical relevance of its gene polymorphisms and a potential application in various clinical settings.

Role of Polymorphisms of NKG2D Receptor and Its Ligands in Acute Myeloid Leukemia and Human Stem Cell Transplantation

Natural killer cells possess key regulatory function in various malignant diseases, including acute myeloid leukemia. NK cell activity is driven by signals received through ligands binding activating or inhibitory receptors. Their activity towards elimination of transformed or virally infected cells can be mediated through MICA, MICB and ULBP ligands binding the activating receptor NKG2D. Given the efficiency of NK cells, potential target cells developed multiple protecting mechanisms to overcome NK cells killing on various levels of biogenesis of NKG2D ligands. Targeted cells can degrade ligand transcripts via microRNAs or modify them at protein level to prevent their presence at cell surface via shedding, with added benefit of shed ligands to desensitize NKG2D receptor and avert the threat of destruction via NK cells. NK cells and their activity are also indispensable during hematopoietic stem cell transplantation, crucial treatment option for patients with malignant disease, including acute myeloid leukemia. Function of both NKG2D and its ligands is strongly affected by polymorphisms and particular allelic variants, as different alleles can play variable roles in ligand-receptor interaction, influencing NK cell function and HSCT outcome differently. For example, role of amino acid exchange at position 129 in MICA or at position 98 in MICB, as well as the role of other polymorphisms leading to different shedding of ligands, was described. Finally, match or mismatch between patient and donor in NKG2D ligands affect HSCT outcome. Having the information beyond standard HLA typing prior HSCT could be instrumental to find the best donor for the patient and to optimize effects of treatment by more precise patient-donor match. Here, we review recent research on the NKG2D/NKG2D ligand biology, their regulation, description of their polymorphisms across the populations of patients with AML and the influence of particular polymorphisms on HSCT outcome.

Recent Advances in Molecular Mechanisms of the NKG2D Pathway in Hepatocellular Carcinoma

Hepatocellular carcinoma is a common malignant tumor with high mortality. Its malignant proliferation, invasion, and metastasis are closely related to the cellular immune function of the patients. NKG2D is a key activated and type II membrane protein molecule expressed on the surface of almost all NK cells. The human NKG2D gene is 270 kb long, located at 12p12.3-p13.1, and contains 10 exons and 9 introns. The three-dimensional structure of the NKG2D monomeric protein contains two alpha-helices, two beta-lamellae, and four disulfide bonds, and its' signal of activation is transmitted mainly by the adaptor protein (DAP). NKG2D ligands, including MICA, MICB, and ULBPs, can be widely expressed in hepatoma cells. After a combination of NKG2D and DAP10 in the form of homologous two polymers, the YxxM motif in the cytoplasm is phosphorylated and then signaling pathways are also gradually activated, such as PI3K, PLCγ2, JNK-cJunN, and others. Activated NK cells can enhance the sensitivity to hepatoma cells and specifically dissolve by releasing a variety of cytokines (TNF-α and IFN-γ), perforin, and high expression of FasL, CD16, and TRAIL. NK cells may specifically bind to the over-expressed MICA, MICB, and ULBPs of hepatocellular carcinoma cells through the surface activating receptor NKG2D, which can help to accurately identify hepatoma, play a critical role in anti-hepatoma via the pathway of cytotoxic effects, and obviously delay the poor progress of hepatocellular carcinoma.

Pharmacology of tyrosine kinase inhibitors in chronic myeloid leukemia; a clinician's perspective

OBJECTIVE

In this review, we have summarized the pharmacokinetics, pharmacodynamics and adverse effects of imatinib, dasatinib, nilotinib, bosutinib, ponatinib and radotinib with focus on pharmacogenomic studies with clinical end points. We have discussed the key phase 3 trials of tyrosine kinase inhibitors (TKI) comparing with each other, treatment free remission (TFR) and selection of TKI. Upcoming concepts and related trials in the management of chronic myeloid leukemia (CML) along with future directions have been touched upon.

EVIDENCE ACQUISITION

PubMed, Embase, Google, Cochrane library and Medline were searched to identify relevant literature for the review. Clinicaltrial.gov was searched for upcoming data and trials.

RESULTS

There are lot of gap in pharmacokinetics and pharmacodynamics of TKI. Imatinib appears to be the safest TKI. Newer TKI's achieve better achievement of therapeutic milestones, deeper molecular response and less chances of progression of CML compared to imatinib. Newer TKI appears to be better choice for achieving TFR. When the objective is survival, imatinib is still the TKI of choice. Primary prophylaxis with antiplatelet drugs for TKI having cardiovascular and thromboembolic side effects should be considered.

CONCLUSION

Pharmacogenetic data of TKI is still immature to guide in therapeutic decision making in clinical practice. There is need for further research in pharmacology and pharmacogenomics of newer TKI's. Randomized controlled trials are required to decide the optimum TKI for TFR. Safe and effective TKI for targeting T315I mutation, CML accelerated phase and blast crisis are an active area of research.

Role of cancer immunology in chronic myelogenous leukemia

Chronic myelogenous leukemia (CML) is caused by the BCR-ABL chimeric tyrosine kinase, which is derived from the reciprocal translocation, t(9;22)(q34;q11). BCR-ABL tyrosine kinase inhibitors (TKIs) can provide prolonged overall survival in CML patients, resulting in life expectancy nearly to general population, and now approximately half of patients who achieved deep molecular response (DMR) can sustain durable molecular remission after discontinuation TKIs. However, residual leukemic cells still detected in the patients who sustained in molecular remission after discontinuation TKIs with the sensitive BCL-ABL1 transcript detection method. Given the fact that residual leukemic cells can exist in these patients, host immune systems can protect the patients to develop CML progression derived from residual leukemic cells. The human immune system is generally composed by innate and adaptive immune systems, corresponding to their functional diversities. Natural killer (NK) cells are major components of the innate immune system, while T lymphocytes (T cells) are major components of the adaptive immune system, and both NK cell and T cell mediate immune responses have an important role in CML. Myeloid-derived suppressor cells (MDSCs) that promote expansion of regulatory T cells (Tregs), leading to host immune suppression, are also important. Although regulation mechanism of these immune system has not been fully elucidated, tumor antigen (e.g. Wilms tumor-1), and surface receptors (e.g. killer immunoglobulin-like receptor and natural killer group 2) on NK cells, are pivotal role in these immune system regulations. Hence, we reviewed the current the immunological analysis, especially T cell and NK cell immunity in CML.

Natural killer cells and other innate lymphoid cells in cancer

Immuno-oncology is an emerging field that has revolutionized cancer treatment. Most immunomodulatory strategies focus on enhancing T cell responses, but there has been a recent surge of interest in harnessing the relatively underexplored natural killer (NK) cell compartment for therapeutic interventions. NK cells show cytotoxic activity against diverse tumour cell types, and some of the clinical approaches originally developed to increase T cell cytotoxicity may also activate NK cells. Moreover, increasing numbers of studies have identified novel methods for increasing NK cell antitumour immunity and expanding NK cell populations ex vivo, thereby paving the way for a new generation of anticancer immunotherapies. The role of other innate lymphoid cells (group 1 innate lymphoid cell (ILC1), ILC2 and ILC3 subsets) in tumours is also being actively explored. This Review provides an overview of the field and summarizes current immunotherapeutic approaches for solid tumours and haematological malignancies.

NKG2D/NKG2-Ligand Pathway Offers New Opportunities in Cancer Treatment

The antitumor functions of NK cells are regulated by the integration of positive and negative signals triggered by numerous membrane receptors present on the NK cells themselves. Among the main activating receptors, NKG2D binds several stress-induced molecules on tumor targets. Engagement of NKG2D by its ligands (NKG2D-Ls) induces NK cell activation leading to production of cytokines and target cell lysis. These effects have therapeutic potential as NKG2D-Ls are widely expressed by solid tumors, whereas their expression in healthy cells is limited. Here, we describe the genetic and environmental factors regulating the NKG2D/NKG2D-L pathway in tumors. NKG2D-L expression is linked to cellular stress and cell proliferation, and has been associated with oncogenic mutations. Tumors have been found to alter their to NKG2D-L expression as they progress, which interferes with the antitumor function of the pathway. Nevertheless, this pathway could be advantageously exploited for cancer therapy. Various cancer treatments, including chemotherapy and targeted therapies, indirectly interfere with the cellular and soluble forms of NKG2D-Ls. In addition, NKG2D introduced into chimeric antigen receptors in T- and NK cells is a promising tumor immunotherapy approach.

Dasatinib promotes TRAIL-mediated apoptosis by upregulating CHOP-dependent death receptor 5 in gastric cancer

Dasatinib, a tyrosine kinase inhibitor, has been approved for first‐line treatment of leukemia and has also been evaluated for use in numerous other cancers. However, its role in gastric cancer (GC) remains unclear. Therefore, the aim of this study was to investigate how dasatinib suppresses the growth of GC cells and interacts with chemotherapeutic drugs. The results showed that, in the presence of dasatinib, proliferation of GC cells decreased and apoptosis increased, and that Fas‐associated death domain protein and caspase‐8 are essential to dasatinib‐induced cell apoptosis in GC. In addition, we found that dasatinib increased the expression of death receptor 5 (DR5) in GC cells. Dasatinib enhanced apoptosis induced by tumor necrosis factor‐related apoptosis‐inducing ligand (TRAIL) in GC cells. Moreover, increased DR5 expression facilitated dasatinib‐induced apoptosis; the dasatinib‐induced increase in DR5 expression was mediated by CCAAT/enhancer‐binding protein homologous protein (CHOP). Furthermore, dasatinib also synergized with TRAIL to induce apoptosis via DR5 in GC cells. Our results show that dasatinib promoted TRAIL‐mediated apoptosis via upregulation of CHOP‐dependent DR5 expression in GC, suggesting that DR5 induction can be used as an indicator of dasatinib sensitivity.