Cancer extracellular vesicles as novel regulators of NK cell response
Graphical abstract
Introduction
Extracellular vesicles (EVs) have recently emerged as important modulators of the immune response in the context of cancer development [1]. Although for years the main mediators for the tumour cell-to-cell communication were attributed to soluble molecules such as cytokines, growth factors and chemokines, recent work has pointed out EVs as novel and crucial regulators of this process [2]. EVs can transmit information to acceptor cells by acting at the cell surface or through delivery of their content. In the tumor microenvironment, cancer-secreted vesicles can bind to and/or transfer their cargo not only to neoplastic cells but also to stromal and immune cells, thus contributing to the modulation of the anti-tumor immune response.
Natural killer (NK) cells represent innate lymphoid cells that play a major role in the immune surveillance against tumors through both the direct killing of tumor cells and the secretion of cytokines and chemokines [3]. A number of surface activating and inhibitory receptors tightly regulate NK cell activation, with the latter (KIRs, CD94/NKG2A) mainly recognizing Major Histocompatibility Complex (MHC) class I molecules. NK cell recognition of induced self ligands on tumor cells involves several activating receptors such as NK group 2D (NKG2D/CD314), DNAX accessory molecule-1 (DNAM-1/CD226), and the natural cytotoxicity receptors (NCRs) namely NKp30/CD337, NKp44/CD336 and NKp46/CD335. In addition to activation by cell surface ligands, the acquisition of optimal effector activity by NK cells is driven by cytokines and other signals. Among the signals, tumor-derived extracellular vesicles have the capability to either promote or suppress NK cell-mediated functions, depending on the molecular composition and cargo.
Anti-cancer therapies seeking to sustain host anti-tumor immune response represent an appealing strategy to control tumor growth and avoid tumor immune escape. The establishment of the immunogenic cell death (ICD) by some chemotherapeutic agents and the concomitant release of damage-associated molecular patterns (DAMPs) is a mode to boost anti-tumor specific immune responses through the activation of innate immune cell populations, mainly dendritic cells (DCs), by a number of pattern recognition receptors (PRRs).
Over the last years, some of the most relevant therapeutic approaches aimed at potentiating NK cell activities against tumors have been based on the usage of sublethal doses of chemotherapeutic drugs in order to increase the immunogenicity of cancer cells by the enhancement of NK cell activating ligand expression on cancer cell surface [4]. Another important aspect to be considered relies on the activation of DNA damage response (DDR) and the induction of cellular senescence, a central response to cytotoxic chemotherapies (Chemotherapy-Induced Senescence or CIS) that culminates in a state of stable cell cycle arrest [5]. Of interest, NKG2D and DNAM-1 ligands have been shown to be preferentially expressed by drug-induced senescent cancer cells, uncovering a critical role of NK cells for the immune surveillance and clearance of senescent cells [[6], [7], [8]].
It is emerging that anti-cancer therapies strongly affect both the EV release and their contents; thus, the immunomodulatory action of extracellular vesicles can significantly change in response to anti-cancer treatments. In addition, several studies have shown that EVs represent important components of the senescent secretoma known as senescence-associated secretory phenotype (SASP) whose role in the modulation of the functional status of cells in the tumor microenvironment has been extensively described.
Herein, we will address the main mechanisms used by cancer-derived extracellular vesicles to modulate NK cell activity, and we will discuss how anti-cancer therapies might impact on the secretion and the immunomodulatory function of these vesicles.
Section snippets
Extracellular vesicles: general features
Extracellular vesicles (EVs), a general term that includes exosomes, microvesicles and apoptotic bodies, are membrane-enclosed vesicles secreted by all cell types, both in healthy and diseased conditions, and are found in most body fluids. Since their first observation in 1946 by Chargaff and West [9], they have been implicated in a plethora of functions, including intercellular communication on short and remote distance, maintenance of cell homeostasis by removal of drugs or molecular waste [10
Modulation of NK cell functions by tumour-derived extracellular vesicles
Over the last years a number of studies have shown that tumour-derived EVs can either stimulate or suppress the anti-tumor immune response via multiple mechanisms. As such, EVs containing native tumour antigens can be efficiently taken up by DCs for antigen processing and cross-presentation to tumour-specific cytotoxic T lymphocytes (CTLs), thus potentiating adaptive immune response [30,31]. In addition, tumor cells secrete vesicles that convey danger signals [32] like heat shock proteins
Modulation of extracellular vesicle release and content in response to cancer therapy
Although it is clear that EVs secreted by tumor cells play an important role in the communication between tumor-tumor and tumor-microenvironment, less is known about the impact that anti-tumor therapy has on the secretion and function of these vesicles. Recent studies have uncovered the role of different cancer therapies in modulating both qualitatively and quantitatively EV release from cancer cells. Many anticancer treatments activate key elements of the cellular stress response, a
Conclusions and perspectives
The field of intercellular communication via extracellular vesicles is a rapid evolving area and the effects of tumour-derived extracellular vesicles on immune cells have received increasing attention over the last years. NK cells are critical players in tumour immune surveillance, thus a better discerning of the mechanisms by which EVs influence the NK cell phenotype and functions can open new possibilities for the usage of these particles in cancer therapy to potentiate NK cell activity. As
Declaration of Competing Interest
The authors declare no competing financial interests.
Acknowledgements
This work was supported by grants of Italian Association for Cancer Research (AIRC Investigator Grant cod. 16014 and AIRC 5×1000) and grant by Sapienza University (RM1181642771A58E). E.V. is supported by a fellowship from AIRC.
Alessandra Soriani obtained her PhD in Immunological Sciences in 2003 at “Sapienza” University of Rome with a study on the role of integrins in the NK cell function regulation. She was a Postdoctoral Fellow (from 2003 to 2005) in Dr. Shattil’s laboratory at the SCRIPPS Research Institute first and UCSD later in San Diego, USA. At present, she is Associate Professor at “Sapienza” University of Rome. Her current scientific interest has been mainly aimed at understanding the immuno-mediated
References (111)
- et al.
Communication by extracellular vesicles: where we are and where we need to go
Cell
(2016) - et al.
ATM-ATR-dependent up-regulation of DNAM-1 and NKG2D ligands on multiple myeloma cells by therapeutic agents results in enhanced NK-cell susceptibility and is associated with a senescent phenotype
Blood
(2009) - et al.
The biological significance of the thromboplastic protein of blood
J. Biol. Chem.
(1946) - et al.
ARF6-regulated shedding of tumor cell-derived plasma membrane microvesicles
Curr. Biol.
(2009) - et al.
Exosome-dependent trafficking of HSP70: a novel secretory pathway for cellular stress proteins
J. Biol. Chem.
(2005) - et al.
Damage-associated molecular pattern markers HMGB1 and cell-Free fetal telomere fragments in oxidative-stressed amnion epithelial cell-derived exosomes
J. Reprod. Immunol.
(2017) - et al.
FLIM reveals alternative EV-mediated cellular up-take pathways of paclitaxel
J. Control. Release
(2018) - et al.
Exosome uptake depends on ERK1/2-heat shock protein 27 signaling and lipid Raft-mediated endocytosis negatively regulated by caveolin-1
J. Biol. Chem.
(2013) - et al.
Cellular uptake of extracellular vesicles is mediated by clathrin-independent endocytosis and macropinocytosis
J. Control. Release
(2017) - et al.
miR-210 and hypoxic microvesicles: two critical components of hypoxia involved in the regulation of killer cells function
Cancer Lett.
(2016)
Oral cancer-derived exosomal NAP1 enhances cytotoxicity of natural killer cells via the IRF-3 pathway
Oral Oncol.
Human leukocyte antigen-B-associated transcript 3 is released from tumor cells and engages the NKp30 receptor on natural killer cells
Immunity
Recognition of tumors by the innate immune system and natural killer cells
Adv. Immunol.
Guidelines for the nomenclature of the human heat shock proteins
Cell Stress Chaperones
Anticancer drugs cause release of exosomes with heat shock proteins from human hepatocellular carcinoma cells that elicit effective natural killer cell antitumor responses in vitro
J. Biol. Chem.
Soluble ligands for NK cell receptors promote evasion of chronic lymphocytic leukemia cells from NK cell anti-tumor activity
Blood
Efficient production and enhanced tumor delivery of engineered extracellular vesicles
Biomaterials
Bifacial effects of engineering tumour cell-derived exosomes on human natural killer cells
Exp. Cell Res.
Chemotherapy induces secretion of exosomes loaded with heparanase that degrades extracellular matrix and impacts tumor and host cell behavior
Matrix Biol.
Role for extracellular vesicles in the tumour microenvironment
Philos. Trans. R. Soc. Lond. B Biol. Sci.
Natural killer cells and other innate lymphoid cells in cancer
Nat. Rev. Immunol.
Natural killer cell response to chemotherapy-stressed cancer cells: role in tumor immunosurveillance
Front. Immunol.
Cellular senescence: when bad things happen to good cells
Nat. Rev. Mol. Cell Biol.
Natural killer cell recognition of in vivo drug-induced senescent multiple myeloma cells
Oncoimmunology
Genotoxic stress induces senescence-associated ADAM10-dependent release of NKG2D MIC ligands in multiple myeloma cells
J. Immunol.
Exosomes maintain cellular homeostasis by excreting harmful DNA from cells
Nat. Commun.
Abnormal lysosomal trafficking and enhanced exosomal export of cisplatin in drug-resistant human ovarian carcinoma cells
Mol. Cancer Ther.
Extracellular vesicles and matrix remodeling enzymes: the emerging roles in extracellular matrix remodeling, progression of diseases and tissue repair
Cells
Tumor-derived extracellular vesicles: molecular parcels that enable regulation of the immune response in cancer
J. Cell. Sci.
Exosomes: immune properties and potential clinical implementations
Semin. Immunopathol.
Biological properties of extracellular vesicles and their physiological functions
J. Extracell. Vesicles
Analysis of ESCRT functions in exosome biogenesis, composition and secretion highlights the heterogeneity of extracellular vesicles
J. Cell. Sci.
Multivesicular endosome biogenesis in the absence of ESCRTs
Traffic
New insights into the function of Rab GTPases in the context of exosomal secretion
Small GTPases
Mass spectrometry-based proteome profiling of extracellular vesicles and their roles in cancer biology
Exp. Mol. Med.
Post-translational add-ons mark the path in exosomal protein sorting
Cell. Mol. Life Sci.
Sumoylated hnRNPA2B1 controls the sorting of miRNAs into exosomes through binding to specific motifs
Nat. Commun.
Hypoxia-inducible factors and RAB22A mediate formation of microvesicles that stimulate breast cancer invasion and metastasis
Proc. Natl. Acad. Sci. U. S. A.
RhoA triggers a specific signaling pathway that generates transforming microvesicles in cancer cells
Oncogene
Biology and biogenesis of shed microvesicles
Small GTPases
Membrane bending by protein-protein crowding
Nat. Cell Biol.
High-resolution proteomic and lipidomic analysis of exosomes and microvesicles from different cell sources
J. Extracell. Vesicles
An ARF6-exportin-5 axis delivers pre-miRNA cargo to tumour microvesicles
Nat. Cell Biol.
Defining the morphologic features and products of cell disassembly during apoptosis
Apoptosis
Tumor-derived exosomes are a source of shared tumor rejection antigens for CTL cross-priming
Nat. Med.
From the antigen-presenting cell to the antigen-presenting vesicle: the exosomes
Curr. Opin. Mol. Ther.
Cancer exosomes as conveyors of stress-induced molecules: new players in the modulation of NK cell response
Int. J. Mol. Sci.
Double-stranded DNA in exosomes: a novel biomarker in cancer detection
Cell Res.
Exosome RNA unshielding couples stromal activation to pattern recognition receptor signaling in cancer
Cell
Blast-derived microvesicles in sera from patients with acute myeloid leukemia suppress natural killer cell function via membrane-associated transforming growth factor-beta1
Haematologica
Cited by (0)
Alessandra Soriani obtained her PhD in Immunological Sciences in 2003 at “Sapienza” University of Rome with a study on the role of integrins in the NK cell function regulation. She was a Postdoctoral Fellow (from 2003 to 2005) in Dr. Shattil’s laboratory at the SCRIPPS Research Institute first and UCSD later in San Diego, USA. At present, she is Associate Professor at “Sapienza” University of Rome. Her current scientific interest has been mainly aimed at understanding the immuno-mediated antitumor activities of several chemotherapeutic agents, that work through the modulation of ligands for NK cell activating receptors.
Elisabetta Vulpis joined the Prof Santoni’s laboratory (“Sapienza” University of Rome) in 2012, where she obtained her PhD in Immunology and Immunopathology in 2016 studying the immunomodulatory properties of multiple myeloma derived exosomes on NK cell-mediated functions. Since 2016 she is a postdoctoral fellow in Prof Santoni’s laboratory. In 2017 she was the winner of a three-years AIRC research fellowship on a project entitled: “Immunomodulatory role and autocrine effect of Multiple Myeloma cell-derived exosomes: implications for TLR2/Hsp70 axis”. Her research activity is mainly focused on the molecular mechanism underlying the interactions between multiple myeloma derived extracellular vesicles and NK cells, their uptake and the functional meaning of this interplay.
Lorenzo Cuollo obtained his M. Sc. degree in Molecular Biology in 2018 at University of Naples “Federico II”. His master thesis work, a study of p53 dynamics at single cell level, was conducted by Prof. Löwer’s laboratory of Systems Biology at the Technical University of Darmstadt (Germany). Currently he is PhD student by Prof. Santoni’s laboratory of Immunology and Immunopathology at “Sapienza” University of Rome; his main research focus is the effect of senescent tumoral cells on microenvironment and bystander cells in the context of multiple myeloma.
Alessandra Zingoni obtained her PhD in Immunology at “Sapienza” University of Rome studying the role of CD94/NKG2A inhibitory receptor in the modulation of NK cell-mediated functions. In 2000, She moved as post-doctoral fellow in the laboratory of Lewis Lanier at the University of San Francisco (CA, USA), where she found that NK cells have also an immunoregulatory role and can directly interact with T lymphocytes (2000–2002). In 2011 she received an Award from “Sapienza Ricerca” for the study: “Killer and beyond: NK–cell–mediated control of adaptive immune response”. Currently, she is Associate Professor at the Department of Molecular Medicine (“Sapienza” University of Rome) and her main scientific interest points to understand the complex interactions between NK cells and cancer cells focusing on the immunomodulatory action of either soluble factors and extracellular vesicles released by cancer cells.
Angela Santoni obtained her PhD in Biology at the University of Perugia in 1972. She was a Postdoctoral fellow in Dr. Herberman’s laboratory in the National Institutes of Health (NIH), USA, studying the role of Interferons in regulating proliferation and cytotoxicity of Natural Killer cells. Returning in Italy she established an independent research group at “Sapienza’’ University of Rome where her current position is Full Professor of Immunology. From 2009 to present she is the Scientific Director of the Pasteur Institute in Rome (Cenci Bolognetti Foundation), and from 2010 Head of the Department of Molecular Medicine at “Sapienza’’ University. She is Past President of the International Society for Natural Immunity, and member of Academia Medica, of the National Research Committee of the Welfare Ministry and of GAVI (Global alliance for Vaccination and Immunization) as Italian representative. Her research activity has been mainly aimed at understanding the mechanisms underlying the NK cell recognition, migration, and effector functions against tumor and viral infection. Ongoing studies are focused on the identification of the mechanisms regulating NK cell-mediated stress immunosurveillance and migration triggered by senescent cells.