ABSTRACT
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.
Subject(s)
Carcinoma, Pancreatic Ductal/pathology , Extracellular Vesicles/pathology , Pancreatic Neoplasms/pathology , Animals , Autocrine Communication , Cell Division , Cell Line, Tumor , Chemotaxis , Collagen , Drug Combinations , Human Umbilical Vein Endothelial Cells , Humans , Interleukin-8/genetics , Interleukin-8/metabolism , Laminin , Mice , Mice, SCID , Neoplasm Transplantation , Neovascularization, Pathologic/etiology , Proteoglycans , RNA, Messenger/biosynthesis , Tumor Microenvironment , Vascular Endothelial Growth Factor A/genetics , Vascular Endothelial Growth Factor A/metabolismABSTRACT
Immune cells may take part in the renin-angiotensin-aldosterone system (RAAS), which plays a pivotal role in the regulation of vascular tone and blood pressure. The aim of the study was to analyse the expression and activity of angiotensin-converting enzyme type 1 (ACE1) and ACE2 in human monocytes (MO) and their subsets. The highest relative level of ACE1-, as well as ACE2-mRNA expression, was observed in CD14(++)CD16(-) (classical) MO. Moreover, in these cells, mean level of ACE2-mRNA was almost two times higher than that of ACE1-mRNA (11.48 versus 7.073 relative units, respectively). In peripheral blood mononuclear cells (PBMC), MO and classical MO, ACE1 and ACE2 protein expression was stronger compared to other MO subpopulations. The highest level of Ang II generated from Ang I in vitro was observed in classical MO. In this setting, generation of Ang-(1-9) by PBMC and classical MO was higher when compared to the whole MO population (P < 0.05). The generation rate of vasoprotective Ang-(1-7) was comparable in all analysed cell populations. However, in CD14(+)CD16(++) (non-classical) MO, formation of Ang-(1-7) was significantly greater than Ang II (P < 0.001). We suggest that in physiological conditions MO (but also lymphocytes forming the rest of PBMC pool) may be involved in the regulation of vessel wall homeostasis via the RAAS-related mechanisms. Moreover, non-classical MO, which are associated preferentially with the vascular endothelium, express the vasoprotective phenotype.
Subject(s)
Monocytes/enzymology , Peptidyl-Dipeptidase A/metabolism , Angiotensin-Converting Enzyme 2 , GPI-Linked Proteins/immunology , Healthy Volunteers , Humans , Lipopolysaccharide Receptors/immunology , Monocytes/immunology , Peptidyl-Dipeptidase A/genetics , RNA, Messenger/biosynthesis , Receptors, IgG/immunology , Renin-Angiotensin System/immunologyABSTRACT
OBJECTIVE: This study addressed the role of the pattern recognition receptors (PRR), which recognize different molecular structures present on microorganisms, apoptotic, senescent and tumor cells, in the stimulation of human monocyte and monocyte-derived macrophages (MDM) for the production of intracellular cytokines. MATERIALS AND METHODS: Monocytes and MDM were stimulated with different ligands of scavenger receptors (SR) and mannose receptor (MR). Production of intracellular cytokines: tumor necrosis factor alpha (TNF alpha), interleukin 10 and 12 (IL-10, IL-12) was determined by flow cytometry following staining with anti-cytokine monoclonal antibodies (mAbs). RESULTS: The ligands of SR type A: fucoidan, polyguanylic acid (polyG), chemically modified low density lipoproteins (LDL), ligands of SR-B: native and chemically modified LDL, and ligand of mannose receptor (MR)-mannan induced strong expression of intracellular TNF alpha and weaker IL-10 in monocytes, while phosphatidylserine (PdS) was without effect. IL-12 was stimulated only by fucoidan and polyG. The induction of cytokine m-RNA generally followed the pattern and the magnitude of intracellular cytokine production. In MDM, intracellular TNF alpha and IL-12 expression was induced by mannan, native and modified LDL, but not other ligands. Expression of IL-10 was less pronounced and occurred following stimulation with fucoidan, polyG and modified, but not native, LDL. CONCLUSIONS: These results suggest that some PRR ligands may be involved in activation of monocytes/MDM for the production of mainly proinflammatory cytokines (TNF alpha, IL-12) implicating their role in the response to microbial and tumor invasion.
