Pluripotent stem cell-derived NK cells with high-affinity noncleavable CD16a mediate improved antitumor activity

Employing hypoxia characterization to predict tumour immune microenvironment, treatment sensitivity and prognosis in hepatocellular carcinoma

The hypoxic microenvironment was recognized as a major driving force of the malignant phenotype in hepatocellular carcinoma (HCC), which contributes to tumour immune microenvironment (TIM) remodeling and tumor progression. Dysregulated hypoxia-related genes (HRGs) result in treatment resistance and poor prognosis by reshaping tumor cellular activities and metabolism. Approaches to identify the relationship between hypoxia and tumor progression provided new sight for improving tumor treatment and prognosis. But, few practical tools, forecasting relationship between hypoxia, TIM, treatment sensitivity and prognosis in HCC were reported. Here, we pooled mRNA transcriptome and clinical pathology data from the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA), and later developed a hypoxia risk model including four HRGs (DCN, DDIT4, PRKCA and NDRG1). The high-risk group displayed poor clinical characteristics, a malignant phenotype with carcinogenesis/proliferation pathways activation (MTORC1 and E2F) and immunosuppressive TIM (decreased immune cell infiltrations and upregulated immunosuppressive cytokines). Meanwhile, activated B cells, effector memory CD8 T cells and EZH2 deregulation were associated with patient’s survival, which might be the core changes of HCC hypoxia. Finally, we validated the ability of the hypoxia risk model to predict treatment sensitivity and found high hypoxia risk patients had poor responses to HCC treatment, including surgical resection, Sorafenib, Transarterial Chemoembolization (TACE) and immunotherapy. In conclusion, based on 4 HRGs, we developed and validated a hypoxia risk model to reflect pathological features, evaluate TIM landscape, predict treatment sensitivity and compounds specific to hypoxia signatures in HCC patients.

Natural killer cells: of-the-shelf cytotherapy for cancer immunosurveillance

Natural killer (NK) cells are advantaged innate cytotoxic lymphocytes with characteristics of tumor immunosurveillance and microorganism elimination. Distinguish from the adaptive T and B lymphocytes, the autologous or allogeneic NK cells efficaciously fulfil the function of combating transformed hematological malignancies and metastatic solid tumors via the proverbial mechanisms including direct cytolytic effect and antibody-dependent cell-mediated cytotoxicity (ADCC) as well as paracrine effects dispense with antigen presentation. Herein, we review the candidate sources (e.g., peripheral blood, umbilical cord blood, placental blood, cell lines and stem cells) for large-scale and clinical-grade NK cell manufacturing, ex vivo cultivation (feeder-, cytokine cocktail- or physicochemical irritation-dependent strategies) for NK cell persistence and activation. Furthermore, we also figure out the promising prospects as well as the accompanied challenges of NK cell- or chimeric antigen receptor-transduced NK (CAR-NK) cell-based adoptive immunotherapy in standardizations for industrialized preparation and clinical practices.

Chimeric antigen receptor (CAR) natural killer (NK)-cell therapy: leveraging the power of innate immunity

Chimeric antigen receptor (CAR) T cells are a rapidly emerging form of cancer treatment, and have resulted in remarkable responses in refractory lymphoid malignancies. However, their widespread clinical use is limited by toxicity related to cytokine release syndrome and neurotoxicity, the logistic complexity of their manufacturing, cost and time-to-treatment for autologous CAR-T cells, and the risk of graft-versus-host disease (GvHD) associated with allogeneic CAR-T cells. Natural killer (NK) cells have emerged as a promising source of cells for CAR-based therapies due to their ready availability and safety profile. NK cells are part of the innate immune system, providing the first line of defence against pathogens and cancer cells. They produce cytokines and mediate cytotoxicity without the need for prior sensitisation and have the ability to interact with, and activate other immune cells. NK cells for immunotherapy can be generated from multiple sources, such as expanded autologous or allogeneic peripheral blood, umbilical cord blood, haematopoietic stem cells, induced pluripotent stem cells, as well as cell lines. Genetic engineering of NK cells to express a CAR has shown impressive preclinical results and is currently being explored in multiple clinical trials. In the present review, we discuss both the preclinical and clinical trial progress made in the field of CAR NK-cell therapy, and the strategies to overcome the challenges encountered.

Is Adoptive Cellular Therapy With Non-T-Cell Immune Effectors the Future?

ABSTRACT

Success from checkpoint blockade and adoptive cell therapy has brought a new hope in cancer immunotherapy. Adoptive cell therapy involves the isolation of immune cells, ex vivo activation and/or expansion, and reinfusion into the patients, and their effect can be dramatically increased by the incorporation of chimeric antigen receptors specific to molecules expressed on tumor cells. Chimeric antigen receptor T cells have shown exciting results in the treatment of liquid malignancies; nevertheless, they suffer from limitations including severe adverse effects such as cytokine release syndrome and neurotoxicity seen in patients as well as a potential for causing graft-versus-host disease in an allogeneic setting. It is thus imperial to explore innate immune cells including natural killer cells, macrophages, natural killer T cells, and γδ T cells. Here, we provide a broad overview of the major innate immune cells and their potential for adoptive cell therapy and chimeric antigen receptor engineering.

Antibody Afucosylation Augments CD16-Mediated Serial Killing and IFNγ Secretion by Human Natural Killer Cells

One mechanism by which monoclonal antibodies (mAb) help treat cancer or autoimmune disease is through triggering antibody-dependent cellular cytotoxicity (ADCC) via CD16 on Natural Killer (NK) cells. Afucosylation is known to increase the affinity of mAbs for CD16 on NK cells and here, we set out to assess how mAb afucosylation affects the dynamics of NK cell interactions, receptor expression and effector functions. An IgG1 version of a clinically important anti-CD20 mAb was compared to its afucosylated counterpart (anti-CD20-AF). Opsonization of CD20-expressing target cells, 721.221 or Daudi, with anti-CD20-AF increased NK cell cytotoxicity and IFNγ secretion, compared to anti-CD20. The afucosylated mAb also caused a more rapid and greater loss of CD16 from NK cell surfaces. Loss of CD16 has recently been shown to be important for NK cell detachment and sequential engagement of multiple target cells. Here, live-cell time-lapse microscopy of individual cell-cell interactions in an aqueous environment and a three-dimensional matrix, revealed that anti-CD20-AF induced more rapid killing of opsonized target cells. In addition, NK cells detached more quickly from target cells opsonized with anti-CD20-AF compared to anti-CD20, which increased engagement of multiple targets and enabled a greater proportion of NK cells to perform serial killing. Inhibition of CD16 shedding with TAPI-0 led to reduced detachment and serial killing. Thus, disassembly of the immune synapse caused by loss of cell surface CD16 is a factor determining the efficiency of ADCC and antibody afucosylation alters the dynamics of intercellular interactions to boost serial killing.

Taking T-Cell Oncotherapy Off-the-Shelf

Banked allogeneic or 'off-the-shelf' (OTS) T cells from healthy human donors are being developed to address the limitations of autologous cell therapies. Potential challenges of OTS T cell therapies are associated with their allogeneic origin and the possibility of graft-versus-host disease (GvHD) and host-versus-graft immune reactions. While the risk of GvHD from OTS T cells has been proved to be manageable in clinical studies, approaches to prevent immune rejection of OTS cells are at an earlier stage of development. We provide an overview of strategies to generate OTS cell therapies and mitigate alloreactivity-associated adverse events, with a focus on recent advances for preventing immune rejection.

Engineering Anti-Tumor Monoclonal Antibodies and Fc Receptors to Enhance ADCC by Human NK Cells

Tumor-targeting monoclonal antibodies (mAbs) are the most widely used and characterized immunotherapy for hematologic and solid tumors. The significance of this therapy is their direct and indirect effects on tumor cells, facilitated by the antibody's antigen-binding fragment (Fab) and fragment crystallizable region (Fc region), respectively. The Fab can modulate the function of cell surface markers on tumor cells in an agonistic or antagonistic manner, whereas the Fc region can be recognized by an Fc receptor (FcR) on leukocytes through which various effector functions, including antibody-dependent cell-mediated cytotoxicity (ADCC), can be elicited. This process is a key cytolytic mechanism of natural killer (NK) cells. These innate lymphocytes in the human body recognize tumor-bound antibodies exclusively by the IgG Fc receptor CD16A (FcγRIIIA). Two allelic versions of CD16A bind IgG with either lower or higher affinity. Cancer patients homozygous for the higher affinity allele of CD16A have been reported to respond significantly better to mAb therapies for various malignancies. These studies revealed that mAb therapy efficacy positively correlates with higher affinity binding to CD16A. Approaches to enhance tumor antigen targeting by NK cells by modifying the Fc portion of antibodies or the FcR on NK cells are the focus of this review.

Fc γ receptor compositional heterogeneity: Considerations for immunotherapy development

The antibody-binding crystallizable fragment (Fc) γ receptors (FcγRs) are expressed by leukocytes and activate or suppress a cellular response once engaged with an antibody-coated target. Therapeutic mAbs that require FcγR binding for therapeutic efficacy are now frontline treatments for multiple diseases. However, substantially fewer development efforts are focused on the FcγRs, despite accounting for half of the antibody-receptor complex. The recent success of engineered cell-based immunotherapies now provides a mechanism to introduce modified FcγRs into the clinic. FcγRs are highly heterogeneous because of multiple functionally distinct alleles for many genes, the presence of membrane-tethered and soluble forms, and a high degree of post-translational modification, notably asparagine-linked glycans. One significant factor limiting FcγR improvement is the fundamental lack of knowledge regarding endogenous receptor forms present in the human body. This review describes the composition of FcγRs isolated from primary human leukocytes, summarizes recent efforts to engineer FcγRs, and concludes with a description of potential FcγR features to enrich for enhanced function. Further understanding FcγR biology could accelerate the development of new clinical therapies targeting immune-related disease.

Design and Implementation of NK Cell-Based Immunotherapy to Overcome the Solid Tumor Microenvironment

Natural killer (NK) cells are innate immune effectors capable of broad cytotoxicity via germline-encoded receptors and can have conferred cytotoxic potential via the addition of chimeric antigen receptors. Combined with their reduced risk of graft-versus-host disease (GvHD) and cytokine release syndrome (CRS), NK cells are an attractive therapeutic platform. While significant progress has been made in treating hematological malignancies, challenges remain in using NK cell-based therapy to combat solid tumors due to their immunosuppressive tumor microenvironments (TMEs). The development of novel strategies enabling NK cells to resist the deleterious effects of the TME is critical to their therapeutic success against solid tumors. In this review, we discuss strategies that apply various genetic and non-genetic engineering approaches to enhance receptor-mediated NK cell cytotoxicity, improve NK cell resistance to TME effects, and enhance persistence in the TME. The successful design and application of these strategies will ultimately lead to more efficacious NK cell therapies to treat patients with solid tumors. This review outlines the mechanisms by which TME components suppress the anti-tumor activity of endogenous and adoptively transferred NK cells while also describing various approaches whose implementation in NK cells may lead to a more robust therapeutic platform against solid tumors.

Fc γ receptor IIIa/CD16a processing correlates with the expression of glycan-related genes in human natural killer cells

Many therapeutic monoclonal antibodies require binding to Fc γ receptors (FcγRs) for full effect and increasing the binding affinity increases efficacy. Preeminent among the five activating human FcγRs is FcγRIIIa/CD16a expressed by natural killer (NK) cells. CD16a is heavily processed, and recent reports indicate that the composition of the five CD16a asparagine(N)-linked carbohydrates (glycans) impacts affinity. These observations indicate that specific manipulation of CD16a N-glycan composition in CD16a-expressing effector cells including NK cells may improve treatment efficacy. However, it is unclear if modifying the expression of select genes that encode processing enzymes in CD16a-expressing effector cells is sufficient to affect N-glycan composition. We identified substantial processing differences using a glycoproteomics approach by comparing CD16a isolated from two NK cell lines, NK92 and YTS, with CD16a expressed by HEK293F cells and previous reports of CD16a from primary NK cells. Gene expression profiling by RNA-Seq and qRT-PCR revealed expression levels for glycan-modifying genes that correlated with CD16a glycan composition. These results identified a high degree of variability between the processing of the same human protein by different human cell types. N-glycan processing correlated with the expression of glycan-modifying genes and thus explained the substantial differences in CD16a processing by NK cells of different origins.

Natural killer cell-based immunotherapy for acute myeloid leukemia

Despite considerable progress has been achieved in the treatment of acute myeloid leukemia over the past decades, relapse remains a major problem. Novel therapeutic options aimed at attaining minimal residual disease-negative complete remission are expected to reduce the incidence of relapse and prolong survival. Natural killer cell-based immunotherapy is put forward as an option to tackle the unmet clinical needs. There have been an increasing number of therapeutic dimensions ranging from adoptive NK cell transfer, chimeric antigen receptor-modified NK cells, antibodies, cytokines to immunomodulatory drugs. In this review, we will summarize different forms of NK cell-based immunotherapy for AML based on preclinical investigations and clinical trials.

Paths taken towards NK cell-mediated immunotherapy of human cancer-a personal reflection

The discovery that NK cells are able to specifically recognize cells lacking the expression of self‐MHC class I molecules provided the first insight into NK cell recognition of tumour cells. It started a flourishing field of NK cell research aimed at exploring the molecular nature of NK cell receptors involved in tumour cell recognition. While much of the important early work was conducted in murine experimental model systems, studies of human NK cells rapidly followed. Over the years, human NK cell research has swiftly progressed, aided by new detailed molecular information on human NK cell development, differentiation, molecular specificity, tissue heterogeneity and functional capacity. NK cells have also been studied in many different diseases aside from cancer, including viral diseases, autoimmunity, allergy and primary immunodeficiencies. These fields of research have all, indirectly or directly, provided further insights into NK cell‐mediated recognition of target cells and paved the way for the development of NK cell‐based immunotherapies for human cancer. Excitingly, NK cell‐based immunotherapy now opens up for novel strategies aimed towards treating malignant diseases, either alone or in combination with other drugs. Reviewed here are some personal reflections of select contributions leading up to the current state‐of‐the‐art in the field, with a particular emphasis on contributions from our own laboratory. This review is part of a series of articles on immunology in Scandinavia, published in conjunction with the 50th anniversary of the Scandinavian Society for Immunology.

Natural Killer Cells in Immunotherapy: Are We Nearly There?

Natural killer (NK) cells are potent anti-tumor and anti-microbial cells of our innate immune system. They are equipped with a vast array of receptors that recognize tumor cells and other pathogens. The innate immune activity of NK cells develops faster than the adaptive one performed by T cells, and studies suggest an important immunoregulatory role for each population against the other. The association, observed in acute myeloid leukemia patients receiving haploidentical killer-immunoglobulin-like-receptor-mismatched NK cells, with induction of complete remission was the determinant to begin an increasing number of clinical studies administering NK cells for the treatment of cancer patients. Unfortunately, even though transfused NK cells demonstrated safety, their observed efficacy was poor. In recent years, novel studies have emerged, combining NK cells with other immunotherapeutic agents, such as monoclonal antibodies, which might improve clinical efficacy. Moreover, genetically-modified NK cells aimed at arming NK cells with better efficacy and persistence have appeared as another option. Here, we review novel pre-clinical and clinical studies published in the last five years administering NK cells as a monotherapy and combined with other agents, and we also review chimeric antigen receptor-modified NK cells for the treatment of cancer patients. We then describe studies regarding the role of NK cells as anti-microbial effectors, as lessons that we could learn and apply in immunotherapy applications of NK cells; these studies highlight an important immunoregulatory role performed between T cells and NK cells that should be considered when designing immunotherapeutic strategies. Lastly, we highlight novel strategies that could be combined with NK cell immunotherapy to improve their targeting, activity, and persistence.

Umbilical Cord Blood and iPSC-Derived Natural Killer Cells Demonstrate Key Differences in Cytotoxic Activity and KIR Profiles

Natural killer (NK) cells derived or isolated from different sources have been gaining in importance for cancer therapies. In this study, we evaluate and compare key characteristics between NK cells derived or isolated from umbilical cord blood, umbilical cord blood hematopoietic stem/progenitor cells, peripheral blood, and induced pluripotent stem cells (iPSCs). Specifically, we find CD56⁺ NK cells isolated and expanded directly from umbilical cord blood (UCB56) and NK cells derived from CD34⁺ hematopoietic stem/progenitors in umbilical cord blood (UCB34) differ in their expression of markers associated with differentiation including CD16, CD2, and killer Ig-like receptors (KIRs). UCB56-NK cells also displayed a more potent cytotoxicity compared to UCB34-NK cells. NK cells derived from iPSCs (iPSC-NK cells) were found to have variable KIR expression, with certain iPSC-NK cell populations expressing high levels of KIRs and others not expressing KIRs. Notably, KIR expression on UCB56 and iPSC-NK cells had limited effect on cytotoxic activity when stimulated by tumor target cells that express high levels of cognate HLA class I, suggesting that in vitro differentiation and expansion may override the KIR-HLA class I mediated inhibition when used across HLA barriers. Together our results give a better understanding of the cell surface receptor, transcriptional, and functional differences between NK cells present in umbilical cord blood and hematopoietic progenitor-derived NK cells which may prove important in selecting the most active NK cell populations for treatment of cancer or other therapies.

NK-Cell-Mediated Targeting of Various Solid Tumors Using a B7-H3 Tri-Specific Killer Engager In Vitro and In Vivo

We improved the bispecific antibody platform that primarily engages natural killer (NK) cells to kill cancer cells through antibody-dependent cellular cytotoxicity (ADCC) by adding IL-15 as a crosslinker that expands and self-sustains the effector NK cell population. The overall goal was to target B7-H3, an established marker predominantly expressed on cancer cells and minimally expressed on normal cells, and prove that it could target cancer cells in vitro and inhibit tumor growth in vivo. The tri-specific killer engager (TriKE^TM) was assembled by DNA shuffling and ligation using DNA encoding a camelid anti-CD16 antibody fragment, a wild-type IL-15 moiety, and an anti-B7-H3 scFv (clone 376.96). The expressed and purified cam1615B7H3 protein was tested for in vitro NK cell activity against a variety of tumors and in vivo against a tagged human MA-148 ovarian cancer cell line grafted in NSG mice. cam1615B7H3 showed specific NK cell expansion, high killing activity across a range of B7-H3+ carcinomas, and the ability to mediate growth inhibition of aggressive ovarian cancer in vivo. cam1615B7H3 TriKE improves NK cell function, expansion, targeted cytotoxicity against various types of B7-H3-positive human cancer cell lines, and delivers an anti-cancer effect in vivo in a solid tumor setting.

Metabolic Reprograming via Deletion of CISH in Human iPSC-Derived NK Cells Promotes In Vivo Persistence and Enhances Anti-tumor Activity

Cytokine-inducible SH2-containing protein (CIS; encoded by the gene CISH) is a key negative regulator of interleukin-15 (IL-15) signaling in natural killer (NK) cells. Here, we develop human CISH-knockout (CISH-/-) NK cells using an induced pluripotent stem cell-derived NK cell (iPSC-NK cell) platform. CISH-/- iPSC-NK cells demonstrate increased IL-15-mediated JAK-STAT signaling activity. Consequently, CISH-/- iPSC-NK cells exhibit improved expansion and increased cytotoxic activity against multiple tumor cell lines when maintained at low cytokine concentrations. CISH-/- iPSC-NK cells display significantly increased in vivo persistence and inhibition of tumor progression in a leukemia xenograft model. Mechanistically, CISH-/- iPSC-NK cells display improved metabolic fitness characterized by increased basal glycolysis, glycolytic capacity, maximal mitochondrial respiration, ATP-linked respiration, and spare respiration capacity mediated by mammalian target of rapamycin (mTOR) signaling that directly contributes to enhanced NK cell function. Together, these studies demonstrate that CIS plays a key role to regulate human NK cell metabolic activity and thereby modulate anti-tumor activity.

Genome engineering of induced pluripotent stem cells to manufacture natural killer cell therapies

Natural killer (NK) cells play a crucial role in host immunity by detecting cells that downregulate MHC class I presentation and upregulate stress ligands, as commonly seen in cancers. Current NK therapies using primary NK cells are prone to manufacturing issues related to expansion and storage. Alternative cell sources utilizing immortalized NK cell lines require irradiation and are dependent on systemic IL-2 administration, which has been associated with adverse effects. In contrast, NK cells differentiated from induced pluripotent stem cells (iPSC-NK cells) offer an off-the-shelf alternative that may overcome these bottlenecks. The development of a serum-free and feeder-free differentiation protocol allows for the manufacturing of clinically adaptable iPSC-NK cells that are equally as effective as primary NK cells and the NK-92 cell line for many indications. Moreover, genetic modifications targeting NK-mediated antibody-dependent cellular cytotoxicity capabilities, cytotoxicity, and checkpoint inhibitors may increase the therapeutic potential of iPSC-NK products. This review will highlight the current sources for NK therapies and their respective constraints, discuss recent developments in the manufacturing and genetic engineering of iPSC-NK cells, and provide an overview of ongoing clinical trials using NK cells.

Immunology and ovarian cancers

The current standard therapy of epithelial ovarian cancer (EOC) is the combination of surgery and multiagent chemotherapy with/without adding targeted therapy. After treatment, response rate is high and nearly all patients can achieve complete remission, even though they are advanced diseases; however, the majority of patients will relapse and subsequently die of diseases within several years after initial treatment. When treatment options are limited, there is the urgent need for new novel therapeutic approaches for precise cancer control. The development of chemoresistance and evading of the anticancer immune response may be one of the important causes contributing to the therapeutic failure, and therefore, it represents a paradigm shift in cancer research. An individual's immune response and interaction with EOC cells might be one of the key factors for cancer treatment. There are many interventions, including targeting certain type immunogenic EOC-associated antigens, immune checkpoint blockade, and adoptive cellular therapy, which present a profound opportunity to revolutionize EOC treatment. This review will encompass the interaction between EOC and immune system and highlight recent data regarding the research of immunotherapy in EOC.

Directed Differentiation of Mobilized Hematopoietic Stem and Progenitor Cells into Functional NK cells with Enhanced Antitumor Activity

Obtaining sufficient numbers of functional natural killer (NK) cells is crucial for the success of NK-cell-based adoptive immunotherapies. While expansion from peripheral blood (PB) is the current method of choice, ex vivo generation of NK cells from hematopoietic stem and progenitor cells (HSCs) may constitute an attractive alternative. Thereby, HSCs mobilized into peripheral blood (PB-CD34⁺) represent a valuable starting material, but the rather poor and donor-dependent differentiation of isolated PB-CD34⁺ cells into NK cells observed in earlier studies still represents a major hurdle. Here, we report a refined approach based on ex vivo culture of PB-CD34⁺ cells with optimized cytokine cocktails that reliably generates functionally mature NK cells, as assessed by analyzing NK-cell-associated surface markers and cytotoxicity. To further enhance NK cell expansion, we generated K562 feeder cells co-expressing 4-1BB ligand and membrane-anchored IL-15 and IL-21. Co-culture of PB-derived NK cells and NK cells that were ex-vivo-differentiated from HSCs with these feeder cells dramatically improved NK cell expansion, and fully compensated for donor-to-donor variability observed during only cytokine-based propagation. Our findings suggest mobilized PB-CD34⁺ cells expanded and differentiated according to this two-step protocol as a promising source for the generation of allogeneic NK cells for adoptive cancer immunotherapy.

Tumor Microenvironment-Associated Extracellular Matrix Components Regulate NK Cell Function

The tumor microenvironment (TME) is composed of multiple infiltrating host cells (e.g., endothelial cells, fibroblasts, lymphocytes, and myeloid cells), extracellular matrix, and various secreted or cell membrane-presented molecules. Group 1 innate lymphoid cells (ILCs), which includes natural killer (NK) cells and ILC1, contribute to protecting the host against cancer and infection. Both subsets are able to quickly produce cytokines such as interferon gamma (IFN-γ), chemokines, and other growth factors in response to activating signals. However, the TME provides many molecules that can prevent the potential effector function of these cells, thereby protecting the tumor. For example, TME-derived tumor growth factor (TGF)-β and associated members of the superfamily downregulate NK cell cytotoxicity, cytokine secretion, metabolism, proliferation, and induce effector NK cells to upregulate ILC1-like characteristics. In concert, a family of carbohydrate-binding proteins called galectins, which can be produced by different cells composing the TME, can downregulate NK cell function. Matrix metalloproteinase (MMP) and a disintegrin and metalloproteinase (ADAM) are also enzymes that can remodel the extracellular matrix and shred receptors from the tumor cell surface, impairing the activation of NK cells and leading to less effective effector functions. Gaining a better understanding of the characteristics of the TME and its associated factors, such as infiltrating cells and extracellular matrix, could lead to tailoring of new personalized immunotherapy approaches. This review provides an overview of our current knowledge on the impact of the TME and extracellular matrix-associated components on differentiation, impairment, and function of NK cells.