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Cancer development is a highly complicated process in which tumour growth depends on the development of its vascularization system. To support their own growth, tumour cells significantly modify their microenvironment. One of such modifications inflicted by tumours is stimulation of endothelial cell migration and proliferation. There is accumulating evidence that extracellular vesicles (EVs) secreted by tumour cells (tumour-derived EVs, TEVs) may be regarded as “messengers” with the potential for affecting the biological activities of target cells. Interaction of TEVs with different cell types occurs in an auto- and paracrine manner and may lead to changes in the function of the latter, e.g., promoting motility, proliferation, etc. This study analysed the proangiogenic activity of EVs derived from human pancreatic adenocarcinoma cell line (HPC-4, TEVHPC) in vitro and their effect in vivo on Matrigel matrix vascularization in severe combined immunodeficient (SCID) mice. TEVHPC enhanced proliferation of HPC-4 cells and induced their motility. Moreover, TEVHPC stimulated human umbilical vein endothelial cell (HUVEC) proliferation and migration in vitro. Additionally, TEVHPC influenced secretion of proangiogenic factors (IL-8, VEGF) by HUVEC cells and supported Matrigel matrix haemoglobinization in vivo. These data show that TEVs may support tumour propagation in an autocrine manner and may support vascularization of the tumour. The presented data are in line with the theory that tumour cells themselves are able to modulate the microenvironment via TEVs to maximize their growth potential. [ABSTRACT FROM AUTHOR]

Studying viral infections necessitates well-designed cell culture models to deepen our understanding of diseases and develop effective treatments. In this study, we present a readily available ex vivo 3D co-culture model replicating the human intestinal mucosa. The model combines fully differentiated human intestinal epithelium (HIE) with human monocyte-derived macrophages (hMDMs) and faithfully mirrors the in vivo structural and organizational properties of intestinal mucosal tissues. Specifically, it mimics the lamina propria, basement membrane, and the air-exposed epithelial layer, enabling the pioneering observation of macrophage migration through the tissue to the site of viral infection. In this study, we applied the HIE-hMDMs model for the first time in viral infection studies, infecting the model with two globally significant viruses: severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and human norovirus GII.4. The results demonstrate the model's capability to support the replication of both viruses and show the antiviral role of macrophages, determined by their migration to the infection site and subsequent direct contact with infected epithelial cells. In addition, we evaluated the production of cytokines and chemokines in the intestinal niche, observing an increased interleukin-8 production during infection. A parallel comparison using a classical in vitro cell line model comprising Caco-2 and THP-1 cells for SARS-CoV-2 experiments confirmed the utility of the HIE-hMDMs model in viral infection studies. Our data show that the ex vivo tissue models hold important implications for advances in virology research.IMPORTANCEThe fabrication of intricate ex vivo tissue models holds important implications for advances in virology research. The co-culture model presented here provides distinct spatial and functional attributes not found in simplified models, enabling the evaluation of macrophage dynamics under severe acute respiratory syndrome coronavirus 2 and human norovirus (HuNoV) infections in the intestine. Moreover, these models, comprised solely of primary cells, facilitate the study of difficult-to-replicate viruses such as HuNoV, which cannot be studied in cell line models, and offer the opportunity for personalized treatment evaluations using patient cells. Similar co-cultures have been established for the study of bacterial infections and different characteristics of the intestinal tissue. However, to the best of our knowledge, a similar intestinal model for the study of viral infections has not been published before.

Globally, an increasing prevalence of colorectal cancer (CRC) prompts a need for the development of new methods for early tumor detection. MicroRNAs (also referred to as miRNAs) are short non-coding RNA molecules that play a pivotal role in the regulation of gene expression. MiRNAs are effectively transferred to extracellular vesicle (EVs) membrane sacs commonly released by cells. Our study aimed to examine the expression of miRNAs in four CRC cell lines and EVs derived from them (tumor EVs) in comparison to the normal colon epithelium cell line and its EVs. EVs were isolated by ultracentrifugation from the culture supernatant of SW480, SW620, SW1116, HCT116 and normal CCD841CoN cell lines and characterized according to the MISEV2023 guidelines. MiRNAs were analyzed by small RNA sequencing and validated by quantitative PCR. The performed analysis revealed 22 common miRNAs highly expressed in CRC cell lines and effectively transferred to tumor EVs, including miR-9-5p, miR-182-5p, miR-196b-5p, miR-200b-5p, miR-200c-3p, miR-425-5p and miR-429, which are associated with development, proliferation, invasion and migration of colorectal cancer cells, as well as in vesicle maturation and transport-associated pathways. In parallel, normal cells expressed miRNAs, such as miR-369 and miR-143, which play a role in proinflammatory response and tumor suppression. The analysis of selected miRNAs in plasma-derived EVs and tumor samples from CRC patients showed the similarity of miRNA expression profile between the patients' samples and CRC cell lines. Moreover, miR-182-5p, miR-196-5p, miR-425-5p and miR-429 were detected in several EV samples isolated from patients' plasma. Our results suggest that miR-182-5p, miR-196b-5p and miR-429 are differentially expressed between EVs from CRC patients and healthy donors, which might have clinical implications.

Selective IgA deficiency (SIgAD) is the most common form and common variable immunodeficiency (CVID) is the most symptomatic form of predominant antibody deficiency. Despite differences in the clinical picture, a similar genetic background is suggested. A common feature of both disorders is the occurrence of autoimmune conditions. Regulatory T cells (T regs ) are the major immune cell type that maintains autoimmune tolerance. As the different types of abnormalities of T reg cells have been associated with autoimmune disorders in primary immunodeficiency (PID) patients, in our study we aimed to analyze the gene expression profiles of T reg cells in CVID and SIgAD patients compared to age-matched healthy controls. The transcriptome-wide gene profiling was performed by microarray technology. As a result, we analyzed and visualized gene expression patterns of isolated population of T reg cells. We showed the differences at the gene level between patients with and without autoimmunizations. Our findings suggest that the gene signatures of T reg cells isolated from SIgAD and CVID patients differ from age-matched healthy controls and from each other, presenting transcriptional profiles enriched in innate immune or Th response, respectively. The occurrence of autoimmunity in both types of PID is associated with down-regulation of class I IFNs signaling pathways. In summary, our findings improve our understanding of T reg dysfunctions in patients with common PIDs and associated autoimmunity.

Extracellular vesicles (EVs) and neutrophil extracellular traps (NETs) are pivotal bioactive structures involved in various processes including inflammation. Herein we report the interactions between EVs and NETs during murine endotoxemia studied in situ directly in the vasculature (cremaster muscle, liver sinusoids) using intravital microscopy (IVM). We captured NETs and EV release in real time by both non- and polarized neutrophils in liver but not in cremaster vasculature. When comparing numbers of circulating EVs of various origin (nanoparticle tracking analysis-NTA, flow cytometry) with those interacting with endothelium and NETs (IVM) we observed that whereas platelet and monocyte/macrophage-derived EVs dominate in blood and peritoneal lavage, respectively, mostly neutrophil-derived EVs interact with the vascular lining, NETs and leukocytes. Despite the interaction, NETs do not affect EV formation as NET release inhibition did not alter EV release. However, EVs inhibit NETs formation and in particular, erythrocyte-derived EVs downregulate NET release and this effect is mediated via Siglec-E-dependent interactions with neutrophils. Overall, we report that EVs are present in NETs in vivo and they do modulate their release but the process in not bidirectional. Moreover, EVs isolated from body fluids might not reflect their importance in direct endothelial- and leukocyte-related interactions., (© 2024. The Author(s).)

The antioxidant and anti-inflammatory activities of acylated and decarboxylated gomphrenins, as well as Basella alba L. fruit extract, were investigated in relation to gomphrenin, known for its high biological potential. The most abundant natural acylated gomphrenins, namely, 6'- O - E -caffeoyl-gomphrenin (malabarin) and 6'- O - E -4-coumaroyl-gomphrenin (globosin), were isolated from B. alba extract for the studies. In addition, controlled thermal decarboxylation of gomphrenin in the purified B. alba extract at 65-75 °C resulted in the formation of the most prevalent decarboxylated products, including 17-decarboxy-gomphrenin and 2,17-bidecarboxy-gomphrenin, along with their isoforms. The structures of the decarboxylated pigments were confirmed by NMR analyses. Exploring the matrix effect on pigment reactivity revealed a tremendous increase in the stability of all betacyanins after the initial stage of extract purification using a cation exchanger under various conditions. This indicates the removal of a substantial portion of the unfavorable matrix from the extract, which presumably contains reactive species that could otherwise degrade the pigments. Furthermore, the high concentration of citrates played a significant role in favoring the formation of 2-decarboxy-gomphrenin to a considerable extent. In vitro screening experiments revealed that the tested compounds demonstrated strong anti-inflammatory properties in lipopolysaccharide (LPS)-activated human macrophages. This effect encompassed the selective inhibition of cytokine and chemokine release from activated macrophages, modulation of the chemotactic activity of immune cells, and the regulation of tissue remodeling mediators' release.

Allogeneic transplantation is a multi-step process involving many clinicians and laboratory personnel working together to achieve a common goal-to maximize the recipients' chance of survival and to improve their quality of life. One of the key elements of the process is to ensure high quality, accuracy, and reliability of histocompatibility testing. This manuscript presents: the development and organizational principles of the national system of supervision and control of histocompatibility laboratories in Poland, problems faced by these laboratories, availabe proficiency testing schemes, as well as suggestions and prospects for the future raised by members of the Polish histocompatibility community., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The authors declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (Copyright © 2024 Uhrynowska-Tyszkiewicz, Bogunia-Kubik, Baj-Krzyworzeka and Piątosa.)

During tumor progression, monocytes circulating in the blood or infiltrating tissue may be exposed to tumor-derived extracellular vesicles (TEVs). The first stage of such interactions involves binding of TEVs to the surface of monocytes, followed by their internalization. The present study examines the role of CD44 molecules in the interactions between monocytes and EVs derived from colon cancer cell lines (HCT116 and SW1116). The efficiency of the attachment and engulfment of TEVs by monocytes is linked to the number of TEVs and time of exposure/interaction. The two investigated TEVs, TEVs HCT116 and TEVs SW1116 , originating from HCT116 and SW1116 cells, respectively, differ in hyaluronan (HA) cargo, which reflects HA secretion by parental cancer cells. HA-rich TEVs HCT116 are internalized more effectively in comparison with HA-low TEVs SW1116 . Blocking of CD44 molecules on monocytes by anti-CD44 monoclonal antibody significantly decreased the engulfment of TEVs HCT116 but not that of TEVs SW1116 after 30 min contact, suggesting the involvement of the HA-CD44 axis. The three subsets of monocytes, classical, intermediate and non-classical, characterized by gradual changes in the expression of CD14 and CD16 markers, also differ in the expression of CD44. The highest expression of CD44 molecules was observed in the intermediate monocyte subset. Blocking of CD44 molecules decreased the internalization of HA-rich TEVs in all three subsets, which is associated with CD44 expression level. It was hypothesized that HA carried by TEVs, potentially as a component of the 'corona' coating, may facilitate the interaction between subsets of monocytes and TEVs, which may influence the fate of TEVs (such as the rate of TEVs adhesion and engulfment) and change monocyte activity., Competing Interests: The authors declare that they have no competing interests., (Copyright: © Babula et al.)

Introduction: Natural killer (NK) cells plays a pivotal role in the control of viral infections, and their function depend on the balance between their activating and inhibitory receptors. The immune dysregulation observed in COVID-19 patients was previously associated with downregulation of NK cell numbers and function, yet the mechanism of inhibition of NK cell functions and the interplay between infected cells and NK cells remain largely unknown., Methods: In this study we show that SARS-CoV-2 infection of airway epithelial cells can directly influence NK cell phenotype and functions in the infection microenvironment. NK cells were co-cultured with SARS-CoV-2 infected epithelial cells, in a direct contact with A549 ACE2/TMPRSS2 cell line or in a microenvironment of the infection in a 3D ex vivo human airway epithelium (HAE) model and NK cell surface expression of a set of most important receptors (CD16, NKG2D, NKp46, DNAM-1, NKG2C, CD161, NKG2A, TIM-3, TIGIT, and PD-1) was analyzed., Results: We observed a selective, in both utilized experimental models, significant downregulation the proportion of CD161 (NKR-P1A or KLRB1) expressing NK cells, and its expression level, which was followed by a significant impairment of NK cells cytotoxicity level against K562 cells. What is more, we confirmed that SARS-CoV-2 infection upregulates the expression of the ligand for CD161 receptor, lectin-like transcript 1 (LLT1, CLEC2D or OCIL), on infected epithelial cells. LLT1 protein can be also detected not only in supernatants of SARS-CoV-2 infected A549 ACE2/TMPRSS2 cells and HAE basolateral medium, but also in serum of COVID-19 patients. Finally, we proved that soluble LLT1 protein treatment of NK cells significantly reduces i) the proportion of CD161+ NK cells, ii) the ability of NK cells to control SARS-CoV-2 infection in A549 ACE2/TMPRSS2 cells and iii) the production of granzyme B by NK cells and their cytotoxicity capacity, yet not degranulation level., Conclusion: We propose a novel mechanism of SARS-CoV-2 inhibition of NK cell functions via activation of the LLT1-CD161 axis., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Lenart, Górecka, Bochenek, Barreto-Duran, Szczepański, Gałuszka-Bulaga, Mazur-Panasiuk, Węglarczyk, Siwiec-Koźlik, Korkosz, Łabaj, Baj-Krzyworzeka, Siedlar and Pyrc.)

Extracellular vesicles (EVs) are a heterogeneous population of membrane vesicles released by cells in vitro and in vivo. Their omnipresence and significant role as carriers of biological information make them intriguing study objects, requiring reliable and repetitive protocols for their isolation. However, realizing their full potential is difficult as there are still many technical obstacles related to their research (like proper acquisition). This study presents a protocol for the isolation of small EVs (according to the MISEV 2018 nomenclature) from the culture supernatant of tumor cell lines based on differential centrifugation. The protocol includes guidelines on how to avoid contamination with endotoxins during the isolation of EVs and how to properly evaluate them. Endotoxin contamination of EVs can significantly hinder subsequent experiments or even mask their true biological effects. On the other hand, the overlooked presence of endotoxins may lead to incorrect conclusions. This is of particular importance when referring to cells of the immune system, including monocytes, because monocytes constitute a population that is especially sensitive to endotoxin residues. Therefore, it is highly recommended to screen EVs for endotoxin contamination, especially when working with endotoxin-sensitive cells such as monocytes, macrophages, myeloid-derived suppressor cells, or dendritic cells.

Atherosclerosis, a common age-related disease, is characterized by intense immunological activity. Atherosclerotic plaque is composed of endothelial cells, vascular smooth muscle cells (VSMCs), lipids and immune cells infiltrating from the blood. During progression of the disease, VSMCs undergo senescence within the plaque and secrete SASP (senescence-associated secretory phenotype) factors that can actively modulate plaque microenvironment. We demonstrated that senescent VSMCs secrete increased number of extracellular vesicles (senEVs). Based on unbiased proteomic analysis of VMSC-derived EVs and of the soluble fraction of SASP (sSASP), more than 900 proteins were identified in each of SASP compartments. Comparison of the composition of VMSC-derived EVs with the SASP atlas revealed several proteins, including Serpin Family F Member 1 (SERPINF1) and Thrombospondin 1 (THBS1), as commonly upregulated components of EVs secreted by senescent VSMCs and fibroblasts. Among soluble SASP factors, only Growth Differentiation Factor 15 (GDF15) was universally increased in the secretome of senescent VSMCs, fibroblasts, and epithelial cells. Bioinformatics analysis of EV proteins distinguished functionally organized protein networks involved in immune cell function regulation. Accordingly, EVs released by senescent VSMCs induced secretion of IL-17, INFγ, and IL-10 by T cells and of TNFα produced by monocytes. Moreover senEVs influenced differentiation of monocytes favoring mix M1/M2 polarization with proinflammatory characteristics. Altogether, our studies provide a complex, unbiased analysis of VSMC SASP and prove that EVs derived from senescent VSMCs influence the cytokine milieu by modulating immune cell activity. Our results strengthen the role of senescent cells as an important inducer of inflammation in atherosclerosis., (© 2022. The Author(s).)

Cervical cancer is the fourth most common type of cancer in females worldwide. Infection with a human papillomavirus is crucial to the etiopathogenesis of cervical cancer. The natural trajectory of HPV infection comprises HPV acquisition, HPV persistence versus clearance, and progression to precancer and invasive cancer. The majority of HPV infections are cleared and controlled by the immune system within 2 years, but some infections may become quiescent or undetectable. The persistence of high-risk HPV infection for a longer period of time enhances the risk of malignant transformation of infected cells; however, the mechanisms responsible for the persistence of infection are not yet well-understood. It is estimated that 10-15% of infections do persist, and the local microenvironment is now recognized as an important cofactor promoting infection maintenance. Extracellular vesicles (EVs) are small membrane vesicles derived from both normal cells and cancer cells. EVs contain various proteins, such as cytoskeletal proteins, adhesion molecules, heat shock proteins, major histocompatibility complex, and membrane fusion proteins. EVs derived from HPV-infected cells also contain viral proteins and nucleic acids. These biologically active molecules are transferred via EVs to target cells, constituting a kind of cell-to-cell communication. The viral components incorporated into EVs are transmitted independently of the production of infectious virions. This mode of transfer makes EVs a perfect vector for viruses and their components. EVs participate in both physiological and pathological conditions; they have also been identified as one of the mediators involved in cancer metastasis. This review discusses the potential role of EVs in remodeling the cervical cancer microenvironment which may be crucial to tumor development and the acquisition of metastatic potential. EVs are promising as potential biomarkers in cervical cancer.

Monocytes represent a heterogeneous population of blood cells that provide a link between innate and adaptive immunity. The unique potential of monocytes as both precursors (e.g., of macrophages) and effector cells (as phagocytes or cytotoxic cells) makes them an interesting research and therapeutic target. At the site of a tumor, monocytes/macrophages constitute a major population of infiltrating leukocytes and, depending on the type of tumor, may play a dual role as either a bad or good indicator for cancer recovery. The functional activity of monocytes and macrophages derived from them is tightly regulated at the transcriptional and post-transcriptional level. This review summarizes the current understanding of the role of small regulatory miRNA in monocyte formation, maturation and function in health and cancer development. Additionally, signatures of miRNA-based monocyte subsets and the influence of exogenous miRNA generated in the tumor environment on the function of monocytes are discussed.

MicroRNAs (miRNAs) are small single-stranded molecules of RNA (21-23 nucleotides) which regulate the expression of different genes on a posttranscriptional level through binding to mRNA. miRNA regulate a number of biological processes such as: proliferation, differentiation, angiogenesis, migration, apoptosis or oncogenesis. Many studies have proved involvement of miRNA in cancer progression from its initial stage to metastasis. Wide range of genes regulated by miRNA in the course of the cancer disease allowed to distinguish two classes of miRNA: suppressors and oncomirs. Monitoring the changes in expression profile of chosen miRNA could help in early identification of cancer cells and serve as a prediction factor of the disease or treatment. Defining target genes of deregulated miRNA in cancer cells and developing methods of their selective silencing is a promising therapeutic strategy. This paper presents selected studies focused on the use of miRNA as a diagnostic marker and a potential target of modern cancer therapies.

Cancer metastasis, the final stage of tumor progression, is a complex process governed by the interplay of multiple types of cells and the tumor microenvironment. One of the aspects of this interplay involves the release of various factors by the tumor cells alone or by forcing other cells to do so. As a consequence of these actions, tumor cells are prepared in favorable conditions for their dissemination and spread to other sites/organs, which guarantees their escape from immunosurveillance and further progression. Tumor-derived extracellular vesicles (TEVs) represent a heterogeneous population of membrane-bound vesicles that are being actively released by different tumors. The array of proteins (i.e., receptors, cytokines, chemokines, etc.) and nucleic acids (i.e., mRNA, miR, etc.) that TEVs can transfer to other cells is often considered beneficial for the tumor's survival and proliferation. One of the proteins that is associated with many different tumors as well as their TEVs is a cluster of differentiation 44 in its standard (CD44s) and variant (CD44v) form. This review covers the present information regarding the TEVs-mediated CD44s/CD44v transfer/interaction in the context of cancer metastasis. The content and the impact of the transferred cargo by this type of TEVs also are discussed with regards to tumor cell dissemination.

Colon cancer constitutes 33% of all cancer cases in humans and the majority of patients with metastatic colon cancer still have poor prognosis. An important role in cancer development is the communication between cancer and normal cells. This may occur, among others, through extracellular vesicles (including microvesicles) (MVs), which are being released by both types of cells. MVs may regulate a diverse range of biological processes and are considered as useful cancer biomarkers. Herein, we show that similarity in the general chemical composition between colon cancer cells and their corresponding tumor-derived microvesicles (TMVs) does exist. These results have been confirmed by spectroscopic methods for four colon cancer cell lines: HCT116, LoVo, SW480, and SW620 differing in their aggressiveness/metastatic potential. Our results show that Raman and Fourier Transform InfraRed (FTIR) analysis of the cell lines and their corresponding TMVs did not differ significantly in the characterization of their chemical composition. However, hierarchical cluster analysis of the data obtained by both of the methods revealed that only Raman spectroscopy provides results that are in line with the molecular classification of colon cancer, thus having potential clinical relevance.

Tumor‑derived microvesicles (TMVs) interact with a variety of different cell types within the immune system, including lymphocytes, monocytes, dendritic cells and tumor cells that they have originated from. In the present study, the effects of autologous‑TMVs (auto‑TMVs) on gene expression, chemotaxis, intercellular signaling and cellular metabolism were examined in cells of the gastric cancer (GC) cell line 1415 (GC1415). The effects of auto‑TMVs on mRNA gene expression in GC1415 cells were assessed using pathway‑focused PCR arrays. A chemotaxis assay was performed using the HoloMonitor M4 System. Signaling pathways were evaluated using western blot analysis, and cellular respiration was measured using the Seahorse XF Cell Mito Stress Test. Exposure of the GC1415 cells to auto‑TMVs led to the overexpression (75 genes) and underexpression (96 genes) of genes that are associated with signal transduction, metabolism, chemotaxis, angiogenesis and metastasis. The auto‑TMVs were indicated to induce chemotaxis and activate the PI3K/AKT signaling pathway in GC1415 cells. However, the MAPK/ERK signaling pathway was not indicated to be activated. Furthermore, studies on cellular respiration in GC1415 cells exposed to auto‑TMVs demonstrated a metabolic shift to glycolysis. The results of the current study thus indicate that auto‑TMVs may exert an effect on tumor cell function.

The need for more effective therapies of chronic and acute diseases has led to the attempts of developing more adequate and less invasive treatment methods. Regenerative medicine relies mainly on the therapeutic potential of stem cells. Mesenchymal stem cells (MSCs), due to their immunosuppressive properties and tissue repair abilities, seem to be an ideal tool for cell-based therapies. Taking into account all available sources of MSCs, perinatal tissues become an attractive source of allogeneic MSCs. The allogeneic MSCs provide "off-the-shelf" cellular therapy, however, their allogenicity may be viewed as a limitation for their use. Moreover, some evidence suggests that MSCs are not as immune-privileged as it was previously reported. Therefore, understanding their interactions with the recipient's immune system is crucial for their successful clinical application. In this review, we discuss both autologous and allogeneic application of MSCs, focusing on current approaches to allogeneic MSCs therapies, with a particular interest in the role of human leukocyte antigens (HLA) and HLA-matching in allogeneic MSCs transplantation. Importantly, the evidence from the currently completed and ongoing clinical trials demonstrates that allogeneic MSCs transplantation is safe and seems to cause no major side-effects to the patient. These findings strongly support the case for MSCs efficacy in treatment of a variety of diseases and their use as an "off-the-shelf" medical product.

WNT signaling plays an important role in fibrotic processes in the heart. Recently, exosomes have been proposed as novel extracellular transporters for WNT proteins. In this study, we analyzed whether WNT3a and WNT5a carried by exosomes could activate downstream molecular pathways in human cardiac fibroblasts. Exosomes were isolated from conditioned medium of control, WNT3a- and WNT5a-producing L cells by differential ultracentrifugations. Obtained exosomes showed size ranging between 20⁻150 nm and expressed exosomal markers ALG-2-interacting protein X (ALIX) and CD63. Treatment with WNT3a-rich exosomes inhibited activity of glycogen synthase kinase 3β (GSK3β), induced nuclear translocation of β-catenin, and activated T-cell factor (TCF)/lymphoid enhancer factor (LEF) transcription factors as well as expression of WNT/β-catenin responsive genes in cardiac fibroblasts, but did not coactivate extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and activator protein 1 (AP-1) signaling pathways. In contrast, exosomes produced by WNT5a-producing L cells failed to activate β-catenin-dependent response, but successfully triggered phosphorylation of ERK1/2 and JNK and stimulated IL-6 production. In conclusion, exosomes containing WNT proteins can functionally contribute to cardiac fibrosis by activating profibrotic WNT pathways on cardiac fibroblasts and may represent a novel mechanism of spreading profibrotic signals in the heart.

Introduction: CD44H is a transmembrane molecule important for cell-cell and cell-extracellular matrix interactions. In monocytes, CD44H is implicated in phagocytosis of particles coated by hyaluronan (HA). HA fragments were shown to induce chemokine secretion by monocytes. Tumour derived microvesicles (TMVs), which are small membrane fragments derived from tumour cells can carry fragments of HA. The aim of the study was to examine whether monocyte's CD44H is involved in the engulfment of pancreatic adenocarcinoma-derived microvesicles and in the production of chemokines induced by TMVs., Materials and Methods: TMVs engulfment and chemokines' secretion stimulated with TMVs were determined in control human monocytes and cells incubated with anti-CD44H monoclonal antibody (mAb) by flow cytometry and ELISA, respectively. Phosphorylation of STAT3, transcription factor essential for chemokines' production and CD44 signal transduction, was determined by Western blotting., Results: Blocking of CD44H by anti-CD44H mAb on monocytes decreased the engulfment of TMVs and the secretion of CCL4 and CCL5, but had no effect on CCL2, CCL3 and CXCL8. STAT-3 phosphorylation in monocytes incubated with TMVs after CD44 blocking was also reduced., Conclusion: The results suggest that tumour-derived microvesicles (TMVs) may carry bioactive cargo(s) which induces STAT3 dependent signalling pathway in human monocytes via CD44 molecules.

The three cell lines, designated as gastric cancer (GC)1401, GC1415 and GC1436 were derived from peritoneal effusions from patients with gastric adenocarcinoma. Cell lines were established in tissue culture and in immunodeficient, non-obese diabetic/severe combined immunodeficiency (NOD/SCID) mice. All cell lines were cultured in Dulbecco's modified Eagle's medium supplemented with 5% fetal bovine serum. These cell lines were grown as an adherent monolayer with doubling time ranging between 25 h (GC1436 cell line) and 30-34 h (GC1401 and GC1415, respectively). All cells showed morphological features of epithelial-like cells, forming sheets of polygonal cells. Chromosomal analysis showed that the modal numbers ranged from 52 (GC1401), 51-56 (GC1415) and 106 (GC1436). High heterogeneity, resulting from several structural and numerical chromosomal abnormalities were evident in all cell lines. The surface marker expression suggested a tumor origin of the cells, and indicated the intestinal phenotype of a GC (CD10 + , MUC1). All three cell lines were tumorigenic but not metastatic, in vivo , in NOD/SCID mice. The lack of metastatic potential was suggested by the lack of aldehyde dehydrogenase 1A1 activity. In conclusion, these newly established GC cell lines widen the feasibility of the functional studies on biology of GC as well as drug testing for potential therapeutic purposes.

INTRODUCTION    A different clinical course and pattern of skeletal involvement in peripheral and axial spondyloarthritis (SpA) suggests a distinct pathophysiology of these 2 phenotypic manifestations of SpA. Monocytes, as part of the innate immune system, seem to play an important role in the pathogenesis of SpA, but the exact inflammatory pathways remain to be elucidated. Regulatory T lymphocytes (Treg) and Th17 lymphocytes are also known to influence proinflammatory and anti‑inflammatory reactions. OBJECTIVES    The aim of our study was to compare the absolute numbers of monocyte subpopulations, Treg, and Th17 lymphocytes with clinical measures of disease activity in patients with peripheral and axial SpA. PATIENTS AND METHODS    We enrolled 21 patients with peripheral SpA and 27 patients with axial SpA diagnosed according to the Assessment of SpondyloArthritis International Society classification criteria, as well as 23 healthy controls. Patients were under 45 years, naïve to synthetic and biological disease‑modifying antirheumatic drugs and without the administration of systemic glucocorticoids. The absolute numbers of classical, intermediate, nonclassical monocytes, Treg, and Th17 in peripheral blood were analyzed. Disease activity was assessed using the Ankylosing Spondylitis Disease Activity Score (ASDAS-CRP), Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), and Disease Activity Score 28 (DAS28). RESULTS    In patients with SpA, the number of circulating nonclassical monocytes was decreased in comparison with controls. Only in the peripheral SpA group, a significant negative correlation was found between the concentration of nonclassical monocytes and DAS28 and the number of swollen joints. The 3 groups did not differ in terms of the concentrations of classical or intermediate monocytes and Treg or Th17 lymphocytes. CONCLUSIONS    Nonclassical monocytes may play a role in induction and perpetuation of peripheral joint inflammation, at least in peripheral SpA, as cells infiltrating the synovium.

In recent years, extracellular vesicles (EVs) have become a subject of intense study. These membrane-enclosed spherical structures are secreted by almost every cell type and are engaged in the transport of cellular content (cargo) from parental to target cells. The impact of EVs transfer has been observed in many vital cellular processes including cell-to-cell communication and immune response modulation; thus, a fast and precise characterization of EVs may be relevant for both scientific and diagnostic purposes. In this review, the most popular analytical techniques used in EVs studies are presented with the emphasis on exosomes and microvesicles characterization.

Tumor-derived microvesicles (TMV) can mimic effects of tumor cells leading to an increased anti-inflammatory cytokine production, such as interleukin 10 (IL-10), by tumor-infiltrating monocytes and macrophages. Yet, the mechanism of IL-10 induction by TMV in monocytes remains unclear. The co-incubation of TMV derived from the human pancreas carcinoma cell line (HPC-4) with human monocytes resulted in a nearly 30-fold increase in IL-10 protein production. This effect operates at the level of transcription since monocytes transduced with an adenovirus containing IL-10-promoter luciferase reporter gene showed a 5-fold induction of luciferase activity after treatment with TMV. Since tumor cells can express hyaluronan (HA), which participates in tumor invasion and metastases, we have tested its effect on IL-10 expression. We showed that HA at the concentration of 100μg/ml induces IL-10 protein expression and the IL-10 promoter activation in monocytes. Moreover, hyaluronidase treatment of TMV reduced IL-10 protein production by 50% and promoter activity by 40%. Inhibitors of the PI3K/Akt/mTOR pathway reduced both, TMV-induced IL-10 promoter activity and protein production, and the same was observed in monocytes when stimulated by HPC-4 cells or HA. Inhibition of PI3K activity down-regulated phosphorylation of the Akt and (to a lesser extent) mTOR proteins in monocytes following TMV or HA stimulation. When comparing monocyte subsets, TMV induced IL-10 protein and mRNA synthesis only in classical CD14 ++ CD16 - but not in CD16-positive monocytes. Our data show that TMV induce IL-10 synthesis in human classical monocytes via HA, which, in turn, activates the PI3K/Akt/mTOR pathway., (Copyright © 2015 Elsevier GmbH. All rights reserved.)

Background: Tumour-derived microvesicles (TMVs) are important players in tumour progression, modulating biological activity of immune cells e.g. lymphocytes, monocytes and macrophages. This phenomenon is particularly interesting in the progression of colon cancer, as macrophages in this type of tumour are relevant for the recovery processes. In the present study, the role of colon cancer cell-derived microvesicles in monocyte differentiation and activity profile (polarization) was investigated., Methods: Monocyte-derived macrophages (MDM) were differentiated in vitro in the presence of TMVs obtained from colon cancer: Caco-2, SW620, LoVo or SW480 cell lines and analysed according to their morphology and biological functions, as defined by cytokine secretion, reactive oxygen intermediate (ROI) production and cytotoxic activity against respective colon cancer cells., Results: Monocytes differentiated with TMVs exhibited morphological and phenotypical characteristics of macrophages. An early contact (beginning with the first day of the in vitro culture) of monocytes with TMVs resulted in increased IL-10 secretion and only slightly elevated TNF release. Early, or prolonged contact resulted in low ROI production and low cytotoxicity against tumour cells. On the other hand, late contact of MDM with TMVs, stimulated MDM to significant TNF and IL-12 secretion, ROI production and enhanced cytotoxicity against tumour cells in vitro. In addition, differences in MDM response to TMVs from different cell lines were observed (according to cytokine secretion, ROI production and cytotoxicity against tumour cells in vitro). Biological activity, STATs phosphorylation and microRNA profiling of MDMs indicated differences in their polarization/activation status which may suggest mixed polarization type M1/M2 with the predominance of proinflammatory cells after late contact with TMVs., Conclusions: Macrophage activity (polarization status) may be regulated by contact with not only tumour cells but also with TMVs. Their final polarization status depends on the contact time, and probably on the vesicle "cargo", as signified by the distinct impact of TMVs which enabled the switching of MDM maturation to regulatory macrophages.

Introduction: Gastric cancer is one of the most common cancer-related causes of death. This is mainly due to the lack of good noninvasive method/biomarkers suitable for early-tumour diagnosis and planning of further therapy modalities. Chemokines play an important role in cancer progression and metastasis formation. In gastric cancer patients, clinical relevance of CXCL12 and CCL5 level has been postulated., Aim of the Study: Efforts were undertaken to examine whether expanded chemokine range may be relevant for evaluation of preoperative staging of gastric cancer patients., Material and Methods: Plasma from 66 gastric cancer patients and 11 healthy controls was obtained, and CCL2, CCL3, CCL4, CCL5, CXCL8, CXCL9, and CXCL10 levels were determined by flow cytometry FlexSet system., Results: In gastric cancer patients' plasma an increased level of CCL2, CCL4, CCL5, CXCL8, CXCL9, and CXCL10 was observed. In the case of CCL2, CXCL9, and CXCL10, the chemokine levels correlated with advanced (III and IV in TNM classification) disease stage. In the case of CCL4, CCL5, and CXCL8, elevated levels were observed in all cancer patients in comparison to healthy donors., Conclusions: The accuracy of preoperative diagnosis in gastric cancer may include the monitoring of a wide range of chemokines in patients' plasma. Increased levels of chemokines may warn that the disease is more advanced than conventional diagnostic procedures suggest., Competing Interests: The authors declare no conflict of interest.

Background: Tumour cells release membrane micro(nano)fragments called tumour-derived microvesicles (TMV) that are believed to play an important role in cancer progression. TMV suppress/modify antitumour response of the host, but there is also some evidence for their direct interaction with cancer cells. In cancer patients TMV are present in body fluid and tumour microenvironment. The present study aimed at characterization of whole types/subpopulations, but not only exosomes, of TMV from newly established gastric cancer cell line (called GC1415) and to define their interactions with autologous cells., Methods: TMV were isolated from cell cultures supernatants by centrifugation at 50,000×g and their phenotype was determined by flow cytometry. The size of TMV was analysed by dynamic light scattering and nanoparticle tracking analysis, while morphology by transmission electron microscopy and atomic force microscopy. Interactions of TMV with cancer cells were visualized using fluorescence-activated cell sorter, confocal and atomic force microscopy, biological effects by xenografts in NOD SCID mice., Results: Isolated TMV showed expression of CD44H, CD44v6 (hyaluronian receptors), CCR6 (chemokine receptor) and HER-2/neu molecules, exhibited different shapes and sizes (range 60-900 nm, highest frequency of particles with size range of 80-120 nm). TMV attached to autologous cancer cells within 2 h and then were internalized by them at 24 h. CD44H, CD44v6 and CCR6 molecules may play a role in attachment of TMV to cancer cells, while HER-2 associated with CD24 be involved in promoting cancer cells growth. Pre-exposure of cancer cells to TMV resulted in enhancement of tumour growth and cancer cell-induced angiogenesis in NOD SCID mice model., Conclusions: TMV interact directly with cancer cells serving as macro-messengers and molecular cargo transfer between gastric cancer cells resulting in enhancement of tumour growth. TMV should be considered in future as target of anticancer therapy.

Micro(nano)vesicles (MV) are regarded as important messengers in cell-to-cell communication. There is also evidence for their pivotal role in cancer progression. Circulating MV are of different body cells origin, including tumor cell‑derived MV (TMV) in cancer patients. Determination of circulating TMV is of importance because of their potential diagnostic and therapeutic applications. In the present study, an analysis of circulating MV in colorectal cancer (CRC) patients was undertaken. Plasma from healthy donors was used as the control. In order to define MV characteristics, two plasma fractions: obtained by sequential centrifugation at 15,000 x g (MV15) and 50,000 x g (MV50) were used for analysis. The two fractions possessed a large range of sizes: 70(80)-1,300(1,400) nm and the most common particles with sizes 70-90 nm, both in patients and controls. Atomic force microscopy images of MV50 revealed a heterogeneous population of particles with different shapes and sizes. MV15 contained an increased level of CD41+ and CD61+ particles, suggesting their platelet origin. No difference between patients and controls was observed. A more precise analysis of MV50 showed the increased level of particles expressing EGFR (HER-1/Erb B1), HER-2/neu and Mucin1 (MUC1), suggesting their tumor origin. The total level of MV50‑expressing EGFR, HER-2/neu and MUC1 was enhanced in CRC patients. MV50 both of patients and controls attached to a colon cancer cell line (SW480) and to isolated blood monocytes at 2 h and were engulfed at 24 h. This uptake showed the lack of specificity. Thus, apart from the direct delivery of MV to the tumor site by plasma, monocytes carrying MV may also be involved in their transportation. Taken together, the presented data indicate that MV15 contain mainly platelet‑derived particles, while MV50 from CRC patients are enriched in TMV. Interaction of MV with cancer cells may pin-point their role in communication between tumor cells, resulting in molecular cargo exchange between them.

The discovery of extracellular vesicles (EVs) has revised the interpretation of intercellular communication. It is now well established that EVs play a significant role in coagulation, inflammation, cancer and stem cell renewal and expansion. Their release presents an intriguing, transporting/trafficking network of biologically active molecules, which are able to reach and modulate the function/behavior of the target cells in a variety of ways. Moreover, the presence of EVs in various body fluids points to their potential for use as biomarkers and prognostic indicators in the surveillance/monitoring of a variety of diseases. Although vast knowledge on the subject of EVs has accumulated over the years, there are still fundamental issues associated with the correct approach for their isolation. This review comprises the knowledge on EV isolation techniques that are currently available. The aim of this reveiw was to make both experienced researchers and newcomers to the field aware that different types of EVs require unique isolation approaches. The realization of this 'uniqueness' is the first step in the right direction for the complete assessment of EVs.

Motivation: Extracellular vesicles (EVs) are spherical bilayered proteolipids, harboring various bioactive molecules. Due to the complexity of the vesicular nomenclatures and components, online searches for EV-related publications and vesicular components are currently challenging., Results: We present an improved version of EVpedia, a public database for EVs research. This community web portal contains a database of publications and vesicular components, identification of orthologous vesicular components, bioinformatic tools and a personalized function. EVpedia includes 6879 publications, 172 080 vesicular components from 263 high-throughput datasets, and has been accessed more than 65 000 times from more than 750 cities. In addition, about 350 members from 73 international research groups have participated in developing EVpedia. This free web-based database might serve as a useful resource to stimulate the emerging field of EV research., Availability and Implementation: The web site was implemented in PHP, Java, MySQL and Apache, and is freely available at http://evpedia.info., (© The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.)

Extracellular vesicles (EV) form a heterogeneous population of mostly spherical membrane structures released by almost all cells, including tumour cells, both in vivo and in vitro. Their size varies from 30 nm to 1 μm, and size is one of the main criteria of the selection of two categories of EV: small (30-100 nm), more homogeneous exosomes and larger fragments (0.1-1 μm) called membrane microvesicles or ectosomes. The presence of EV has already been detected in many human body fluids: blood, urine, saliva, semen and amniotic fluid. Formation of EV is tightly controlled, and their function and biochemical composition depend on the cell type they originate from. EV are the "vehicles" of bioactive molecules, such as proteins, mRNA and microRNA, and may play an important role in intercellular communication and modulation of e.g. immune system cell activity. In addition, on the surface of tumour-derived microvesicles (TMV), called oncosomes, several markers specific for cancer cells were identified, which indicates a role of TMV in tumour growth and cancer development. On the other hand, TMV may be an important source of tumour-associated antigens (TAA) which can be potentially useful as biomarkers with prognostic value, as well as in development of new forms of targeted immunotherapy of cancer.

The tumour microenvironment represents a dynamic complex milieu, which includes tumour cells, cells of the immune system and other (cellular and non-cellular) components. The role of these particular 'puzzle pieces' may change substantially due to their mutual interactions. The present review concerns different opinions on interactions that occur between monocytes, tumour cells and TMVs (tumour-derived microvesicles).

Monocytes and their subsets (CD14(++)CD16(+) and CD14(+)CD16(-)) generated from cord blood CD34(+) progenitor cells were used for determination of their capacity to interact with tumor cells in vitro and in vivo. The studies in vitro included adhesion to human umbilical vein endothelial cells, cytotoxicity, production of toxic mediators: reactive oxygen and nitrogen intermediates (ROI and RNI, respectively), and finally their effect on transplantable human tumor growth in nonobese diabetic severe combined immunodeficient mice. The CD14(++)CD16(+) subset exhibited an increased adherence to human umbilical vein endothelial cells and cytotoxicity toward tumor cells in vitro. CD14(+)CD16(-) monocytes showed a higher production of reactive oxygen and nitrogen intermediates after stimulation with tumor cells, and more pronounced inhibition of tumor growth in vivo. The results revealed significant differences in the behavior of CD14(++)CD16(+) and CD14(+)CD16(-) monocyte subsets toward tumor cells, thus providing further evidence that CD34(+) cell-derived monocytes differ in this respect from blood monocytes. The protocol for generation of monocytes with antitumor reactivity described here may be useful to obtain monocytes from CD34(+) progenitor cells of cancer patients. This might offer a basis for a novel approach for various forms of cellular immunotherapy of cancer., (Copyright © 2012 ISEH - Society for Hematology and Stem Cells. Published by Elsevier Inc. All rights reserved.)

Background: The chemokine-chemokine receptor (CR) network is involved in the regulation of cellular infiltration of tumours. Cancer cells and infiltrating macrophages produce a whole range of chemokines. This study explored the expression of some CR and chemokine production by cord blood stem cell-derived CD34(+) monocytes and their novel CD14(++)CD16(+) and CD14(+)CD16(-) subsets in response to tumour cells., Material and Methods: CR expression was determined by flow cytometry and their functional activity by migration to chemoattractants. Monocytes were cultured with tumour cells and the chemokine content was assessed in culture supernatants., Results: CD14(++)CD16(+) monocytes exhibited increased expression of chemokine (C-C) receptor (CCR) 1, while CD14(+)CD16(-) of CCR2, chemokine (C-X-C) receptor (CXCR) 1, 2 and 4. The increased expression of CCR2 on CD14(+)CD16(-) monocytes was associated with their enhanced migration to monocyte chemoattractant protein-1 (CCL2), MCP-3 (CCL7), MCP-2 (CCL8) and MCP-4 (CCL13), while that of CXCR1 and 2 to interleukin 8 (CXCL8), and CXCR4 to stromal cell-derived factor-1 (CXCL12). Tumour cells induced production of macrophage inflammatory protein-1α (CCL3) MIP-1β and regulated on activation normal T-cells expressed and secreted (CCL5) but not CCL2 or CXCL8, monokine induced by gamma interferon (CXCL9), interferon gamma-induced protein 10 (CXCL10)., Conclusion: The studied monocyte subsets, in comparison to those from blood, exhibit different expression of CRs and response to the stimuli that occur from tumour cells.

We have studied the effect of intravenous immunoglobulins (IVIG) on monocyte subpopulations and cytokine production in patients with CVID. The absolute number of CD14(+)CD16(++) monocytes decreased on average 2.5-fold 4h after IVIG and after 20h returned to the baseline. The cytokine level in the supernatants of peripheral blood mononuclear cells (PBMC) after ex vivo LPS stimulation demonstrated the >2-fold decrease in TNF production 4h after IVIG. The TNF expression, which is higher in the CD14(+)CD16(++) monocytes, was decreased in these cells by IVIG in 4/7 CVID cases. In vitro exposure of the healthy individuals' monocytes to the IVIG preparation resulted in reduced TNF production, which was overcome by blockade of the FcγRIIB in the CD14(+)CD16(++) CD32B(high) monocytes. Our data suggest that reduction in the number of CD14(+)CD16(++) monocytes and the blockade of their cytokine production via triggering CD32B can contribute to the anti-inflammatory action of IVIG., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Background: Tumour-derived microvesicles (TMVs) may interact with cells of the immune system. Our previous observations indicated that TMVs modulate production of cytokines and reactive oxygen species (ROS) by monocytes. This study was designed to determine the role of TMVs in stimulation of chemokine production by human monocytes., Materials and Methods: Chemokines at the mRNA and protein level were detected by real-time PCR and by Western blot, respecively. Chemokine release and chemotaxis of blood leukocytes were analysed by flow cytometry. Matrigel assay was used to determine angiogenesis in a NOD-SCID mice model., Results: TMVs induced secretion of interleukin-8 (CXCL8), monocyte chemoattractant protein-1 (CCL2), macrophage inflammatory protein-1α (CCL3) and MIP-1β (CCL4), and regulated on activation normal T-cells expressed and secreted (CCL5) chemokines and accumulation of their mRNA in monocytes. Moreover, TMVs enhanced angiogenesis in NOD-SCID mice by delivering chemokines and via stimulation of monocytes. In addition, TMVs may be storage for chemokines thus inducing chemotaxis of blood leukocytes., Conclusion: These results further support the role of TMVs in modulation of monocyte biological activity.

Background: Monocytes/macrophages may be affected by tumour cells via cell-to-cell contact, soluble factors and by tumour-derived microvesicles (TMV). Previous observations indicate that TMV interact with monocytes and alter their immunophenotype and activity. This study was designed to determine interactions of TMV with subpopulations (CD14(++)CD16(-) and CD14(+)CD16(++)) of human monocytes., Methods: Engulfment of TMV by subsets of monocytes was analysed by flow cytometry. Moreover cytokine release and production of reactive oxygen intermediates (ROI) and reactive nitrogen intermediates (RNI) by CD14(++)CD16(-) and CD14(+)CD16(++) cells after TMV stimulation was determined., Results: It was found that TMV are engulfed more efficiently by CD14(++)CD16(-) than CD14(+)CD16(++) cells. TMV-activated CD14(++)CD16(-) cells produce more ROI and interleukin -10 (IL-10) than CD14(++)CD16(+). CD14(+)CD16(++) cells following TMV stimulation showed an increased release of tumour necrosis factor alpha, IL-12p40 and RNI., Conclusion: TMV significantly modulate biological activity of monocyte subsets with a pattern similar to tumour cells. Therefore, TMV mimic the activating effect of tumour cells on monocytes as assessed by release of cytokines, ROI and RNI.

Cell membrane microfragments called microvesicles (MV) originating from different cells are circulating in the blood of healthy subjects and their elevated numbers are found in different diseases, including cancer. This study was designed to characterise MV present in plasma of gastric cancer patients. Since majority of MV in blood are platelets-derived (PMV), plasma samples deprived of PMV were used. In comparison to control, the number of MV in patients was significantly elevated in all stages, higher in more advanced disease. Patients' MV showed an increased membrane expression of CCR6 and HER-2/neu. The proportion of MV carrying some leucocyte determinants was low and similar in patients and control. Transmission electron microscopy showed their substantial heterogeneity in size and shape. The size determined by dynamic light scattering analysis confirmed this heterogeneity. The MV size distribution in patients was broader within the range of 10-800 nm, while in control MV showed 3-mode distribution within the range of 10-400 nm. Atomic force microscopy confirmed MV size heterogeneity with implication that larger objects represented aggregates of smaller microparticles. Patients' MV exhibited increased absolute values of zeta potential, indicating a higher surface charge. Tumour markers HER-2/neu, MAGE-1, c-MET and EMMPRIN were detected both in control and patients' samples with stronger expression in the latter. Significantly higher expression of MAGE-1 and HER-2/neu mRNA was observed in individual patients. All together, it suggests that at least some MV in plasma of gastric cancer patients are tumour-derived. However, their role in cancer requires further studies.

Background: Monocytes/macrophages exhibit antitumour potential, but clinicopathological evidence suggests that they may both inhibit and enhance tumour growth. The purpose of this study was to determine the effect of monocytes on the growth of human pancreatic cancer (HPC-4) in severe combined immunodeficient (SCID) mice., Materials and Methods: Freshly isolated human monocytes or CD14+ cells from cocultures with tumour cells were coengrafted, at various ratios, with HPC-4 cells into SCID mice. The tumour size and angiogenesis were determined., Results: At a high ratio of monocytes to cancer cells the enhancement and, at a low ratio, the inhibition of tumour growth was observed. Multiple intratumoral applications of monocytes in large numbers also enhanced tumour growth. Deactivation of monocytes by a short pre-exposure to tumour cells in vitro before engraftment led to increased tumour growth. Monocytes used in large numbers and deactivated monocytes in low doses enhanced tumour-induced angiogenesis., Conclusion: Monocytes may both facilitate and suppress the growth of human tumours in SCID mice and both the number of monocytes, as well as the state of monocyte deactivation are critical for the final outcome of monocyte-tumour interactions.

Tumour cells are shedding membrane fragments (tumour-derived microvesicles, TMV) that may interact with cells of immune system. Our previous observations indicated that TMV carry several surface determinants and mRNA of tumour cells and transfer some of them to monocytes. This study determined the effect of TMV on biological activity of human monocytes as the precursors of tumour infiltrating macrophages (TIM). It was found that TMV activated monocytes as shown by an increased HLA-DR expression, induced production of ROI (reactive oxygen intermediates) and of tumour necrosis factor (TNF), interleukin (IL)-10, IL-12p40 accumulation of mRNA and their secretion. Induction of TNF synthesis was CD44 dependent as blocking of CD44 on monocytes abolished its secretion. TMV-treated monocytes showed an increased antitumour activity as judged by enhanced cytotoxicity/cytostasis against tumour cells in vitro. Taken together, these results indicate that TMV significantly modulate biological activity of monocytes and thus mimic the effect of tumour cells on them. This may suggest that tumour cells interact with TIM not only via direct contact, soluble factors, but also TMV.

This study was designed to determine the characteristics of tumour cell-derived microvesicles (TMV) and their interactions with human monocytes. TMV were shed spontaneously by three different human cancer cell lines but their release was significantly increased upon activation of the cells with phorbol 12-myristate 13-acetate (PMA). TMV showed the presence of several surface determinants of tumour cells, e.g. HLA class I, CD29, CD44v7/8, CD51, chemokine receptors (CCR6, CX3CR1), extracellular matrix metalloproteinase inducer (EMMPRIN), epithelial cell adhesion molecule (EpCAM), but their level of expression differed from that on cells they originated from. TMV also carried mRNA for growth factors: vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF), interleukin-8 (IL-8) and surface determinants (CD44H). TMV were localized at the monocytes surface following their short exposure to TMV, while at later times intracellularly. TMV transferred CCR6 and CD44v7/8 to monocytes, exerted antiapoptotic effect on monocytes and activated AKT kinase (Protein Kinase B). Thus, TMV interact with monocytes, alter their immunophenotype and biological activity. This implicates the novel mechanism by which tumour infiltrating macrophages may be affected by tumour cells not only by a direct cell to cell contact, soluble factors but also by TMV.

Immunotherapy with Mycobacterium vaccae as an adjuvant to chemotherapy has recently been applied to treatment of patients with cancer. One of the mechanisms of antitumour activity of Mycobacterium bovis bacillus Calmette-Guérin (BCG), the prototype immunomodulator, is associated with activation of monocytes/macrophages. These studies were undertaken to determine how M. vaccae affects monocyte tumour cell interactions and, in particular, whether it can prevent or reverse deactivation of monocytes that occurrs following their contact with tumour cells during coculture in vitro. Deactivation is characterised by the impaired ability of monocytes to produce tumour necrosis factor alpha (TNF-alpha), interleukin 12 (IL-12), and enhanced IL-10 secretion following their restimulation with tumour cells. To see whether deactivation of monocytes can be either prevented or reversed, three different strains of M. vaccae--B 3805, MB 3683, and SN 920--and BCG were used to stimulate monocytes before or after exposure to tumour cells. Pretreatment of monocytes with M. vaccae MB 3683, SN 920 and BCG before coculture resulted in increased TNF-alpha and decreased IL-10 production. All strains of M. vaccae and BCG used for treatment of deactivated monocytes enhanced depressed TNF-alpha secretion. Strain SN 920 and BCG increased IL-12 release but only BCG treatment inhibited an enhanced IL-10 production by deactivated monocytes. Thus, although some strains of M. vaccae may either prevent or reverse tumour-induced monocyte deactivation, none of them appears to be more effective than BCG.

Upon contact with tumor cells when cocultured in vitro, human monocytes become unresponsive (deactivated) to restimulation and demonstrate decreased production of TNF-alpha and IL-12, and enhanced IL-10 secretion. The present study was undertaken to determine whether immunomodulatory agents (proinflammatory cytokines and PPD of tuberculin) could either prevent or reverse the deactivation of monocytes. Monocytes were treated with the agents either before or after being cocultured with tumor cells. Pretreatment of monocytes with IFN-gamma, either alone or in combination with TNF-alpha, GM-CSF, or PPD, significantly enhanced TNF-alpha and IL-12 production by deactivated monocytes. TNF-alpha, GM-CSF, and PPD alone were inactive. Treatment of monocytes following coculture with IFN-gamma, TNF-alpha, GM-CSF, PPD or IFN-gamma in combination with these agents reversed the depressed TNF-alpha release, whereas IL-12 production was enhanced by IFN-gamma alone. All the agents had no or only a limited effect on the enhanced IL-10 secretion by deactivated monocytes. However, treatment of cocultured monocytes with anti-IL-10 mAb significantly increased the production of TNF-alpha and IL-12 by deactivated monocytes. Moreover, coengraftment of deactivated monocytes with human pancreatic carcinoma cells into SCID mice caused an enhancement of the tumor growth that was alleviated by the treatment of monocytes in vitro with IFN-gamma alone or in combination with GM-CSF or PPD. These results suggest that activation of monocytes with certain proinflammatory cytokines and/or selective inhibition of IL-10 by a mAb may prevent or reverse monocyte deactivation caused by tumor cells.

Objective: Two main subpopulations of human blood monocytes are distinguished on the basis of CD14 and CD16 expression: the major population with enhanced expression of CD14 (CD14++ monocytes) and the minor one with a weak expression of CD14 coexpressing CD16 (CD14+/CD16+ monocytes). As monocytes and macrophages are involved in antitumor response of the host, we assessed the ability of CD14+/CD16+ monocytes to produce cytokines (intracellular expression, release) and reactive oxygen and nitrogen (ROI, RNI) intermediates following stimulation in vitro with tumor cells., Materials and Methods: Monocytes were isolated by elutriation and their subpopulations by FACS sorting. Monocytes and their subpopulations were cocultured with tumor cells. Cytokine (TNF-alpha, IL-12, and IL-10) production was assessed by determination of intracellular protein expression by flow cytometry, and release by ELISA. ROI induction was detected by chemiluminescence and O2- production by flow cytometry, whereas RNI by intracellular expression of inducible NO synthase (iNOS) and nitric oxide (NO) release assessed colorimetrically., Results: CD14+/CD16+ monocytes stimulated with tumor cells showed significantly enhanced production of TNF-alpha, IL-12p40, IL-12p70 (intracellular expression, release), whereas little IL-10 release was observed. CD14+/CD16+ subpopulation did not produce ROI, but showed an increased iNOS expression and NO release. CD14+/CD16+ monocytes also exhibited enhanced cytotoxic and cytostatic activities against tumor cells., Conclusions: CD14+/CD16+ cells constitute the main subpopulation of blood monocytes involved in antitumor response as judged by enhanced production of proinflammatory cytokines, RNI, and increased cytotoxic/cytostatic activity.

Although blood monocytes exhibit significant cytotoxic activity against tumor cells, the function of tumor infiltrating macrophages (TIM) is depressed in cancer patients. This study addresses the question of how the antitumor response of human monocytes, assessed by production of cytokines (tumor necrosis factor alpha, TNF; IL-10; IL-12p40) and cytotoxicity, is altered by exposure to cancer cells. Tumor cell--pre-exposed monocytes restimulated with tumor cells showed significantly decreased production of TNF, IL-12, increased IL-10 (mRNA and release) and inhibition of IL-1 receptor-associated kinase-1 (IRAK-1) expression. This down-regulation of cytokine production was selective, as the response of pre-exposed monocytes to lipopolysaccharide (LPS) was unaffected. Treatment of tumor cell--pre-exposed monocytes with hyaluronidase (HAase) improved their depressed production of TNF, while HAase-treated cancer cells did not cause monocyte dysfunction. The response of hyaluronan (HA)--pre-exposed monocytes to stimulation with tumor cells was also inhibited. Cytotoxic activity of monocytes pretreated with cancer cells was also decreased. This study shows that tumor cells selectively deactivate monocytes and suggests that tumor cell-derived HA by blocking CD44 on monocytes inhibits their antitumor response. These observations may provide some explanation for the depressed function of TIM in human malignancy.