Effect of Plasma-Derived Exosomes of Refractory/Relapsed or Responsive Patients with Diffuse Large B-Cell Lymphoma on Natural Killer Cells Functions (original) (raw)

Cancer exosomes and natural killer cells dysfunction: biological roles, clinical significance and implications for immunotherapy

Molecular Cancer

Tumor-derived exosomes (TDEs) play pivotal roles in several aspects of cancer biology. It is now evident that TDEs also favor tumor growth by negatively affecting anti-tumor immunity. As important sentinels of immune surveillance system, natural killer (NK) cells can recognize malignant cells very early and counteract the tumor development and metastasis without a need for additional activation. Based on this rationale, adoptive transfer of ex vivo expanded NK cells/NK cell lines, such as NK-92 cells, has attracted great attention and is widely studied as a promising immunotherapy for cancer treatment. However, by exploiting various strategies, including secretion of exosomes, cancer cells are able to subvert NK cell responses. This paper reviews the roles of TDEs in cancer-induced NK cells impairments with mechanistic insights. The clinical significance and potential approaches to nullify the effects of TDEs on NK cells in cancer immunotherapy are also discussed.

The Interplay of Exosomes and NK Cells in Cancer Biology

Cancers

Natural killer (NK) cells are innate lymphoid cells involved in tumor surveillance. These immune cells have the potential to fight cancer growth and metastasis, as such, their deregulation can result in tumor immune escape. Recently exosomes were described as mediators of intercellular communication between cancer and NK cells. The exact role of this subclass of extracellular vesicles (EVs), which transport genetic and molecular material to recipient cells, in NK cell biology in the context of cancer, is still an open question. Several reports have demonstrated that tumor-derived exosomes (TDEs) can exert immunomodulatory activities, including immunosuppression, thus promoting cancer progression. Some reports demonstrate that the interplay between cancer exosomes and NK cells allows tumors to escape immune regulation. On the other hand, tumor exosomes were also described to activate NK cells. Additionally, studies show that NK cell exosomes can modulate the immune system, opening up...

Natural Killer Cell Cytotoxicity Is Suppressed by Exposure to the Human NKG2D Ligand MICA*008 That Is Shed by Tumor Cells in Exosomes

Cancer Research, 2010

The MHC class I-related chain (MIC) A and MICB ligands for the activating receptor NKG2D can be shed from tumor cells, and the presence of these soluble molecules in sera is related with compromised immune response and progression of disease. Recently, thiol disulphide isomerases and members of the ADAM (a disintegrin and metalloproteinase) gene family were identified as key enzymes in mediating MICA/B shedding from cells. Here, we report shedding of the most frequently expressed MICA allele in human populations (MICA*008) into exosomes, small membrane vesicles that are secreted upon fusion with the plasma membrane. Although similar to other MICA/B molecules in the extracellular domain, the predicted transmembrane and cytoplasmic domains of MICA*008 are quite different, and this difference seemed to be critical for the mode of release from tumor cells. Treatment of natural killer (NK) cells with exosomes containing MICA*008 molecules not only triggered downregulation of NKG2D from the cell surface but also provoked a marked reduction in NK cytotoxicity that is independent of NKG2D ligand expression by the target cell. Our findings reveal a mechanism of NK suppression in cancer that may facilitate immune escape and progression.

Lysis of human B-lymphocyte-derived lymphoma/leukemia cells of established cell lines by interferon-activated natural killer (NK) cells

International Journal of Cancer, 1981

Cultured cell lines derived from malignant Epstein-Barr virus (EBVFnegative B cells, and representative of the more common types of naturally occurring non-Hodgkin lymphomas and related leukemias, were found to be sensitive to lysis by human natural killer (NK) cells. The observed lysis of such cell lines was mediated by a population of interferon-augmentable, FcR-positive, non-adherent lymphoid cells, which were also able to kill the "standard" NK targets K562 and Molt-4. When the NK susceptibility of the neoplastic, EBV-negative B cells was compared to that of diploid, EBV-carrying, non-neoplastic B lymphoblastoid cell lines (BLCLC) and of the "standard" NK target K562, several distinct patterns were observed. The killing of the neoplastic B cell lines was significantly less than that of K562, but significantly greater than that of the EBV-derived BLCLS of non-neoplastic origin. An additional finding was a similar NK susceptibility profile for the neoplastic, true histiocytic cell line U-937 (i.e., K562>U937> BLCLC). Furthermore, all cell lines, with the exception of the BLCLC, could effectively compete for the observed killing in cold target inhibition assays. The implications of these findings are discussed in relation to both neoplastic and non-neoplastic targets of NK lysis.

Novel alternatives to extracellular vesicle-based immunotherapy – exosome mimetics derived from natural killer cells

Artificial Cells, Nanomedicine, and Biotechnology, 2018

Exosomes are endogenous nanocarriers that can deliver biological information between cells. They are secreted by all cell types, including immune cells such as natural killer (NK) cells. However, mammalian cells release low quantities of exosomes, and the purification of exosomes is difficult. Here, nanovesicles were developed by extrusion of NK cells through filters with progressively smaller pore sizes to obtain exosome mimetics (NK-EM). The anti-tumour effect of the NK-EM was confirmed in vitro and in vivo. The morphological features of the NK-EM were revealed by transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA) and Western blot. In vitro, the cytotoxicity of the NK-EM to cancer cells (glioblastoma, breast carcinoma, anaplastic thyroid cancer and hepatic carcinoma) was assessed using bioluminescence imaging (BLI) and CCK-8 assay. For in vivo study, a xenograft glioblastoma mouse model was established. The anti-tumour activity of NK-EM was confirmed in vivo by the significant decreases of BLI, size and weight (all p < .001) of the tumour compared with the control group. Moreover, NK-EM cytotoxicity for glioblastoma cells that related with decreased levels of the cell survival markers pERK and p-AKT, and increased levels of apoptosis protein markers cleaved-caspase 3, cytochrome-c and cleaved-PARP was confirmed. All those results suggest that NK-EM exert stronger killing effects to cancer cells compared with the traditional NK-Exo, at the same time, the tumour targeting ability of the NK-EM was obtained in vivo. Therefore, NK-EM might be a promising immunotherapeutic agent for treatment of cancer.

Characterization of Human NK Cell-Derived Exosomes: Role of DNAM1 Receptor in Exosome-Mediated Cytotoxicity against Tumor

Cancers

Despite the pivotal role of natural killer (NK) cells in defenses against tumors, their exploitation in cancer treatment is still limited due to their reduced ability to reaching tumor sites and the inhibitory effects of tumor microenvironment (TME) on their function. In this study, we have characterized the exosomes from IL2- or IL15-cultured human NK cells. Both cytokines induced comparable amounts of exosomes with similar cargo composition. Analysis of molecules contained within or exposed at the exosome surface, allowed the identification of molecules playing important roles in the NK cell function including IFN-γ, Lymphocyte Function-Associated Antigen (LFA-1), DNAX Accessory Molecule-1 (DNAM1) and Programmed Cell Death Protein (PD-1). Importantly, we show that DNAM1 is involved in exosome-mediated cytotoxicity as revealed by experiments using blocking antibodies to DNAM1 or DNAM1 ligands. In addition, antibody-mediated inhibition of exosome cytotoxicity results in a delay in t...

Role of Exosomes Released by Dendritic Cells and/or by Tumor Targets: Regulation of NK Cell Plasticity

Frontiers in Immunology, 2014

Exosomes are endosomal-derived nanovesicles released by normal and tumor cells, which transfer functionally active proteins, lipids, and nucleic acids between cells.They are important mediators of intercellular communication and act on the adjacent stroma as well as in the periphery. Recently, exosomes have been recognized to play a pathophysiological role in various diseases such as cancer or infectious diseases. Tumor cell-derived exosomes (Tex) have been shown to act as tumor promotors by educating non-malignant cells to provide a tumor supporting microenvironment, which helps to circumvent immune detection by the host and supports metastasis. However, Tex with anti-tumor, immune-activating properties were also described reflecting the complexity of exosomes. Here, we assess the role of extracellular microvesicles/exosomes as messengers affecting NK cell function in health and disease and discuss the molecular basis for the differential impact of exosomes on NK cell activity. The molecular composition/load of exosomes and the mechanisms regulating their release remain unclear and need to be further analyzed to facilitate the development of new treatment options targeting the exosomal machinery.

Dendritic Cell-Derived Exosomes Promote Natural Killer Cell Activation and Proliferation: A Role for NKG2D Ligands and IL-15Rα

PLoS ONE, 2009

Dendritic cell (DC) derived-exosomes (Dex) are nanomeric vesicles harboring functional MHC/peptide complexes promoting T cell-dependent tumor rejection. In the first Phase I trial using peptide-pulsed Dex, the observation of clinical regressions in the absence of T cell responses prompted the search for alternate effector mechanisms. Mouse studies unraveled the bioactivity of Dex on NK cells. Indeed, Dex promoted an IL-15Ra-and NKG2D-dependent NK cell proliferation and activation respectively, resulting in anti-metastatic effects mediated by NK1.1 + cells. In humans, Dex express functional IL-15Ra which allow proliferation and IFNc secretion by NK cells. In contrast to immature DC, human Dex harbor NKG2D ligands on their surface leading to a direct engagement of NKG2D and NK cell activation ex vivo. In our phase I clinical trial, we highlight the capacity of Dex based-vaccines to restore the number and NKG2D-dependent function of NK cells in 7/14 patients. Altogether, these data provide a mechanistic explanation on how Dex may stimulate non MHC restricted-anti-tumor effectors and induce tumor regression in vivo.

Prostate Tumor-Derived Exosomes Down-Regulate NKG2D Expression on Natural Killer Cells and CD8+ T Cells: Mechanism of Immune Evasion

PLoS ONE, 2014

Tumor-derived exosomes, which are nanometer-sized extracellular vesicles of endosomal origin, have emerged as promoters of tumor immune evasion but their role in prostate cancer (PC) progression is poorly understood. In this study, we investigated the ability of prostate tumor-derived exosomes to downregulate NKG2D expression on natural killer (NK) and CD8 + T cells. NKG2D is an activating cytotoxicity receptor whose aberrant loss in cancer plays an important role in immune suppression. Using flow cytometry, we found that exosomes produced by human PC cells express ligands for NKG2D on their surface. The NKG2D ligand-expressing prostate tumor-derived exosomes selectively induced downregulation of NKG2D on NK and CD8 + T cells in a dose-dependent manner, leading to impaired cytotoxic function in vitro. Consistent with these findings, patients with castration-resistant PC (CRPC) showed a significant decrease in surface NKG2D expression on circulating NK and CD8 + T cells compared to healthy individuals. Tumor-derived exosomes are likely involved in this NKG2D downregulation, since incubation of healthy lymphocytes with exosomes isolated from serum or plasma of CRPC patients triggered downregulation of NKG2D expression in effector lymphocytes. These data suggest prostate tumor-derived exosomes as down-regulators of the NKG2D-mediated cytotoxic response in PC patients, thus promoting immune suppression and tumor escape. Citation: Lundholm M, Schrö der M, Nagaeva O, Baranov V, Widmark A, et al. (2014) Prostate Tumor-Derived Exosomes Down-Regulate NKG2D Expression on Natural Killer Cells and CD8 + T Cells: Mechanism of Immune Evasion. PLoS ONE 9(9): e108925.