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Soluble CD163 (sCD163) is a circulating inflammatory mediator, indicative of acute and chronic, systemic and non-systemic inflammatory conditions. It is the cleavage outcome, consisting of almost the entire extracellular domain, of the CD163, a receptor expressed in monocytic lineages. Its expression is proportional to the abundance of CD163+ macrophages. Various mechanisms trigger the shedding of the CD163 receptor or the accumulation of CD163-expressing macrophages, inducing the sCD163 concentration in the circulation and bodily fluids. The activities of sCD163 range from hemoglobin (Hb) scavenging, macrophage marker, decoy receptor for cytokines, participation in immune defense mechanisms, and paracrine effects in various tissues, including the endothelium. It is an established marker of macrophage activation and thus participates in many diseases, including chronic inflammatory conditions, such as atherosclerosis, asthma, and rheumatoid arthritis; acute inflammatory conditions, such as sepsis, hepatitis, and malaria; insulin resistance; diabetes; and tumors. The sCD163 levels have been correlated with the severity, stage of the disease, and clinical outcome for many of these conditions. This review article summarizes the expression and role of sCD163 and its precursor protein, CD163, outlines the sCD163 generation mechanisms, the biological activities, and the known underlying molecular mechanisms, with an emphasis on its impact on the endothelium and its contribution in the pathophysiology of human diseases. [ABSTRACT FROM AUTHOR]

In this study, liposomes coated with novel multifunctional polymers were proposed as an innovative platform for tumor targeted drug delivery. Novel Folic acid–Cysteine-Thiolated chitosan (FTC) derivatives possessing active targeting ability and redox responsivity were synthesized, characterized, and employed to develop FTC-coated liposomes. Liposomes were characterized for size, surface charge and drug encapsulation efficiency before and after coating. The formation of a coating layer on liposomal surface was confirmed by the slight increase in particle size and by zeta-potential changes. FTC-coated liposomes showed a redox-dependent drug release profile: good stability at physiological conditions and rapid release of liposome-entrapped calcein in presence of glutathione. Moreover, the uptake and cytotoxic activity of doxorubicin-loaded FTC-coated liposomes was evaluated on murine B16-F10 and human SKMEL2 melanoma cancer cells. Results demonstrated enhanced uptake and antitumor efficacy of FTC-coated liposomes compared to control chitosan-coated liposomes in both cancer lines, which is attributed to higher cellular uptake via folate receptor-mediated endocytosis and to triggered drug release by the reductive microenvironment of tumor cells. The proposed novel liposomes show great potential as nanocarriers for targeted therapy of cancer. [ABSTRACT FROM AUTHOR]

Protein tyrosine phosphatase receptor zeta 1 (PTPRZ1) is a transmembrane tyrosine phosphatase (TP) expressed in endothelial cells and required for stimulation of cell migration by vascular endothelial growth factor A165 (VEGFA165) and pleiotrophin (PTN). It is also over or under‐expressed in various tumor types. In this study, we used genetically engineered Ptprz1−/− and Ptprz1+/+ mice to study mechanistic aspects of PTPRZ1 involvement in angiogenesis and investigate its role in lung adenocarcinoma (LUAD) growth. Ptprz1−/− lung microvascular endothelial cells (LMVEC) have increased angiogenic features compared with Ptprz1+/+ LMVEC, in line with the increased lung angiogenesis and the enhanced chemically induced LUAD growth in Ptprz1−/− compared with Ptprz1+/+ mice. In LUAD cells isolated from the lungs of urethane‐treated mice, PTPRZ1 TP inhibition also enhanced proliferation and migration. Expression of beta 3 (β3) integrin is decreased in Ptprz1−/− LMVEC, linked to enhanced VEGF receptor 2 (VEGFR2), c‐Met tyrosine kinase (TK) and Akt kinase activities. However, only c‐Met and Akt seem responsible for the enhanced endothelial cell activation in vitro and LUAD growth and angiogenesis in vivo in Ptprz1−/− mice. A selective PTPRZ1 TP inhibitor, VEGFA165 and PTN also activate c‐Met and Akt in a PTPRZ1‐dependent manner in endothelial cells, and their stimulatory effects are abolished by the c‐Met TK inhibitor (TKI) crizotinib. Altogether, our data suggest that low PTPRZ1 expression is linked to worse LUAD prognosis and response to c‐Met TKIs and uncover for the first time the role of PTPRZ1 in mediating c‐Met activation by VEGFA and PTN. [ABSTRACT FROM AUTHOR]

Mast cells (MCs) have been identified in various tumors; however, the role of these cells in tumorigenesis remains controversial. Here, we quantified MCs in human and murine malignant pleural effusions (MPEs) and evaluated the fate and function of these cells in MPE development. Evaluation of murine MPE-competent lung and colon adenocarcinomas revealed that these tumors actively attract and subsequently degranulate MCs in the pleural space by elaborating CCL2 and osteopontin. MCs were required for effusion development, as MPEs did not form in mice lacking MCs, and pleural infusion of MCs with MPE-incompetent cells promoted MPE formation. Once homed to the pleural space, MCs released tryptase AB1 and IL-1[beta], which in turn induced pleural vasculature leakiness and triggered NF-[kappa]B activation in pleural tumor cells, thereby fostering pleural fluid accumulation and tumor growth. Evaluation of human effusions revealed that MCs are elevated in MPEs compared with benign effusions. Moreover, MC abundance correlated with MPE formation in a human cancer cell-induced effusion model. Treatment of mice with the c-KIT inhibitor imatinib mesylate limited effusion precipitation by mouse and human adenocarcinoma cells. Together, the results of this study indicate that MCs are required for MPE formation and suggest that MC-dependent effusion formation is therapeutically addressable., Introduction Inflammation was recently recognized as an enabling hallmark of cancer that may mediate tumor growth and dissemination instead of tumor eradication (1). Inflammatory signaling networks in the tumor microenvironment [...]

Increased expression of osteopontin (secreted phosphoprotein 1, SPP1) is associated with aggressive human lung adenocarcinoma (LADC), but its function remains unknown. Our aim was to determine the role of SPP1 in smoking-induced LADC. We combined mouse models of tobacco carcinogen-induced LADC, of deficiency of endogenous Spp1 alleles, and of adoptive pulmonary macrophage reconstitution to map the expression of SPP1 and its receptors and determine its impact during carcinogenesis. Co-expression of Spp1 and mutant Kras G12C in benign cells was employed to investigate SPP1/KRAS interactions in oncogenesis. Finally, intratracheal adenovirus encoding Cre recombinase was delivered to LSL.KRAS G12D mice lacking endogenous or overexpressing transgenic Spp1 alleles. SPP1 was overexpressed in experimental and human LADC and portended poor survival. In response to two different smoke carcinogens, Spp1 -deficient mice developed fewer and smaller LADC with decreased cellular survival and angiogenesis. Both lung epithelial- and macrophage-secreted SPP1 drove tumor-associated inflammation, while epithelial SPP1 promoted early tumorigenesis by fostering the survival of KRAS -mutated cells. Finally, loss and overexpression of Spp1 was, respectively, protective and deleterious for mice harboring KRAS G12D-driven LADC. Our data support that SPP1 is functionally involved in early stages of airway epithelial carcinogenesis driven by smoking and mutant KRAS and may present an important therapeutic target. [ABSTRACT FROM AUTHOR]