Human eosinophil peroxidase enhances tumor necrosis factor and hydrogen peroxide release by human monocyte-derived macrophages

Transcriptomics and Immunological Analyses Reveal a Pro-Angiogenic and Anti-Inflammatory Phenotype for Decidual Endothelial Cells

Background: In pregnancy, excessive inflammation and break down of immunologic tolerance can contribute to miscarriage. Endothelial cells (ECs) are able to orchestrate the inflammatory processes by secreting pro-inflammatory mediators and bactericidal factors by modulating leakiness and leukocyte trafficking, via the expression of adhesion molecules and chemokines. The aim of this study was to analyse the differences in the phenotype between microvascular ECs isolated from decidua (DECs) and ECs isolated from human skin (ADMECs). Methods: DECs and ADMECs were characterized for their basal expression of angiogenic factors and adhesion molecules. A range of immunological responses was evaluated, such as vessel leakage, reactive oxygen species (ROS) production in response to TNF-α stimulation, adhesion molecules expression and leukocyte migration in response to TNF-α and IFN-γ stimulation. Results: DECs produced higher levels of HGF, VEGF-A and IGFBP3 compared to ADMECs. DECs expressed adhesion molecules, ICAM-2 and ICAM-3, and a mild response to TNF-α was observed. Finally, DECs produced high levels of CXCL9/MIG and CXCL10/IP-10 in response to IFN-γ and selectively recruited Treg lymphocytes. Conclusion: DEC phenotype differs considerably from that of ADMECs, suggesting that DECs may play an active role in the control of immune response and angiogenesis at the foetal-maternal interface.

Eosinophil peroxidase over-expression predicts the clinical outcome of patients with primary lung adenocarcinoma

Eosinophil peroxidase (EPO), a heme protein abundantly expressed in eosinophils, involves in the catalysis of cytotoxic oxidants associated with the pathogenesis of cancer, asthma, and allergic inflammatory disorders. To date, its roles in the pathogenesis of lung cancer are still not known. We determined the expression of EPO in the lung adenocarcinoma tissues and the normal adjacent lung tissues using Real-time PCR and Western blotting analysis, respectively. Also, EPO protein expression in 90 lung adenocarcinoma (AD) samples were confirmed with immunohistochemistry (IHC) using tissue microarrays. Meanwhile, we investigated the association between EPO and the clinicopathological characteristics and disease prognosis in the pulmonary adenocarcinoma patients, which demonstrated that EPO mRNA and protein were significantly higher in lung AD tissues that those of the adjacent normal lung tissues (P<0.05). EPO overexpression was significantly correlated with pathologic-tumour nodes metastasen stage (p-TNM stage, P=0.017) and lymph node metastasis (P=0.027). Patients with EPO overexpression showed shorter survival time than those with low EPO levels (P=0.017), according to the Kaplan-Meier survival curve. Furthermore, a multivariate Cox regression model was utilized to analyze the prognostic factors, which indicated that N stage (HR=0.965, 95% CI=0.328-1.359, P=0.008), p-TNM Stage (HR=3.127, 95% CI =2.463-5.015, P=0.021) and high EPO protein expression (HR=3.145, 95% CI=2.016-5.519, P=0.018) were independent factors for the prognosis of lung AD. In conclusion, increased EPO expression could be used as a biomarker for lung AD patients with poor prognosis.

Contribution of Adipose Tissue to Development of Cancer

Solid tumor growth and metastasis require the interaction of tumor cells with the surrounding tissue, leading to a view of tumors as tissue-level phenomena rather than exclusively cell-intrinsic anomalies. Due to the ubiquitous nature of adipose tissue, many types of solid tumors grow in proximate or direct contact with adipocytes and adipose-associated stromal and vascular components, such as fibroblasts and other connective tissue cells, stem and progenitor cells, endothelial cells, innate and adaptive immune cells, and extracellular signaling and matrix components. Excess adiposity in obesity both increases risk of cancer development and negatively influences prognosis in several cancer types, in part due to interaction with adipose tissue cell populations. Herein, we review the cellular and noncellular constituents of the adipose "organ," and discuss the mechanisms by which these varied microenvironmental components contribute to tumor development, with special emphasis on obesity. Due to the prevalence of breast and prostate cancers in the United States, their close anatomical proximity to adipose tissue depots, and their complex epidemiologic associations with obesity, we particularly highlight research addressing the contribution of adipose tissue to the initiation and progression of these cancer types. Obesity dramatically modifies the adipose tissue microenvironment in numerous ways, including induction of fibrosis and angiogenesis, increased stem cell abundance, and expansion of proinflammatory immune cells. As many of these changes also resemble shifts observed within the tumor microenvironment, proximity to adipose tissue may present a hospitable environment to developing tumors, providing a critical link between adiposity and tumorigenesis. © 2018 American Physiological Society. Compr Physiol 8:237-282, 2018.

Gamma-irradiation produces active chlorine species (ACS) in physiological solutions: Secoisolariciresinol diglucoside (SDG) scavenges ACS - A novel mechanism of DNA radioprotection

Background

Secoisolariciresinol diglucoside (SDG), the main lignan in whole grain flaxseed, is a potent antioxidant and free radical scavenger with known radioprotective properties. However, the exact mechanism of SDG radioprotection is not well understood. The current study identified a novel mechanism of DNA radioprotection by SDG in physiological solutions by scavenging active chlorine species (ACS) and reducing chlorinated nucleobases.

Methods

The ACS scavenging activity of SDG was determined using two highly specific fluoroprobes: hypochlorite-specific 3′-(p-aminophenyl) fluorescein (APF) and hydroxyl radical-sensitive 3′-(p-hydroxyphenyl) fluorescein (HPF). Dopamine, an SDG structural analog, was used for proton ¹H NMR studies to trap primary ACS radicals. Taurine N-chlorination was determined to demonstrate radiation-induced generation of hypochlorite, a secondary ACS. DNA protection was assessed by determining the extent of DNA fragmentation and plasmid DNA relaxation following exposure to ClO⁻ and radiation. Purine base chlorination by ClO⁻ and γ-radiation was determined by using 2-aminopurine (2-AP), a fluorescent analog of 6-aminopurine. Results: Chloride anions (Cl⁻) consumed >90% of hydroxyl radicals in physiological solutions produced by γ-radiation resulting in ACS formation, which was detected by ¹H NMR. Importantly, SDG scavenged hypochlorite- and γ-radiation-induced ACS. In addition, SDG blunted ACS-induced fragmentation of calf thymus DNA and plasmid DNA relaxation. SDG treatment before or after ACS exposure decreased the ClO⁻ or γ-radiation-induced chlorination of 2-AP. Exposure to γ-radiation resulted in increased taurine chlorination, indicative of ClO⁻ generation. NMR studies revealed formation of primary ACS radicals (chlorine atoms (Cl^•) and dichloro radical anions (Cl₂^−•)), which were trapped by SDG and its structural analog dopamine.

Conclusion

We demonstrate that γ-radiation induces the generation of ACS in physiological solutions. SDG treatment scavenged ACS and prevented ACS-induced DNA damage and chlorination of 2-aminopurine. This study identified a novel and unique mechanism of SDG radioprotection, through ACS scavenging, and supports the potential usefulness of SDG as a radioprotector and mitigator for radiation exposure as part of cancer therapy or accidental exposure.

Neutrophil elastase-dependent cleavage compromises the tumor suppressor role of EMILIN1

Proteolysis of the extracellular matrix (ECM) is a key event in tumor growth and progression. The breakdown of ECM can lead to the generation of bioactive fragments that promote cell growth and spread. EMILIN1, a multidomain glycoprotein expressed in several tissues, exerts a crucial regulatory function through the engagement of α4/α9 integrins. Unlike the majority of ECM molecules that elicit a proliferative program, the signals emitting from EMILIN1 engaged by α4/α9β1 integrins are antiproliferative. In this study, aimed to demonstrate if the suppressor role of EMILIN1 was related to its structural integrity, we tested the possibility that EMILIN1 could be specifically cleaved. Among the proteolytic enzymes released in the tumor microenvironment we showed that neutrophil elastase cleaved EMILIN1 in three/four major fragments. The consequence of this proteolytic process was the impairment of its anti-proliferative role. Accordingly, EMILIN1 was digested in sarcomas and ovarian cancers. Sarcoma specimens were infiltrated by neutrophils (PMNs) and stained positively for elastase. The present findings highlight the peculiar activity of PMN elastase in disabling EMILIN1 suppressor function.

Virulizin induces production of IL-17E to enhance antitumor activity by recruitment of eosinophils into tumors

Virulizin has demonstrated strong antitumor efficacy in a variety of human tumor xenograft models including melanoma, pancreatic cancer, breast cancer, ovarian cancer and prostate cancer. Our previous studies have demonstrated that macrophages, NK cells, and cytokines are important in the antitumor mechanism of Virulizin. Virulizin treatment of tumor bearing mice results in the expansion as well as increased activity of monocytes/macrophages and production of cytokines IL-12 and TNFalpha and activation of NK cells. In this study we show that the inflammatory cytokine IL-17E (IL-25) is induced by Virulizin treatment and is part of its antitumor mechanism. IL-17E is a proinflammatory cytokine, which induces a T(H)2 type immune response, associated with eosinophil expansion and infiltration into mucosal tissues. IL-17E was increased in sera of Virulizin-treated mice bearing human melanoma xenografts, compared to saline-treated controls, as shown by 2D gel electrophoresis and ELISA. Treatment of splenocytes in vitro with Virulizin resulted in increased IL-17E mRNA expression, which peaked between 24 and 32 h post-stimulation. Both in vitro and in vivo experiments demonstrated that B cells produced IL-17E in response to Virulizin treatment. Furthermore, Virulizin treatment in vivo resulted in increased blood eosinophilia and eosinophil infiltration into tumors. Finally, injection of recombinant IL-17E showed antitumor activity towards xenografted tumors, which correlated with increased eosinophilia in blood and tumors. Taken together, these results support another antitumor mechanism mediated by Virulizin, through induction of IL-17E by B cells, leading to recruitment of eosinophils into tumors, which may function in parallel with macrophages and NK cells in mediating tumor destruction.

Evidence of involvement of the mannose receptor in adhesion of Borrelia burgdorferi to monocyte/macrophages

The mannose receptor (MR) plays an important role in the recognition of some pathogens in nonopsonic phagocytosis and in antigen presentation to T cells. We found that Borrelia burgdorferi, the agent of Lyme borreliosis, adheres to monocyte-derived macrophages and to rat MR-transfected cells but not to untransfected cells. Antibodies to MR and sugars such as mannose, mannan, fucose, and some lectins significantly lowered the adhesion, confirming participation of the MR in the binding.

Intercellular cell adhesion molecule-1, vascular cell adhesion molecule-1, and regulated on activation normal T cell expressed and secreted are expressed by human breast carcinoma cells and support eosinophil adhesion and activation

Eosinophils are usually associated with parasitic and allergic diseases; however, eosinophilia is also observed in several types of human tumors, including breast carcinomas. In this study we examined several human breast carcinoma cell lines for adhesion molecule expression and the ability to bind and activate eosinophils. MDA-MB-435S and MDA-MB-468 cells constitutively expressed both intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) and this expression was enhanced by treatment with tumor necrosis factor-alpha (TNF-alpha). BT-20 and SK-BR-3 cells only expressed ICAM-1 or VCAM-1 after stimulation with TNF-alpha. Eosinophils constitutively bound to MDA-MB-435S cells, but not to BT-20 cells. Stimulation with TNF-alpha slightly enhanced eosinophil adhesion to MDA-MB-435S cells and dramatically increased adhesion to BT-20 cells. Greater than 80% of eosinophil adhesion to these cell lines was blocked with an anti-alpha4-integrin monoclonal antibody. Both MDA-MB-435S and BT-20 cells also released eosinophil activator(s). Supernatants from TNF-alpha-treated, but not control-treated, cell lines increased eosinophil adhesion to fibronectin and increased eosinophil transmigration across fibronectin-coated transwell plates. Enzyme-linked immunosorbent assays showed that TNF-alpha-stimulated breast carcinoma cells released the chemokine regulated on activation, T cell expressed and secreted (RANTES). Addition of an anti-RANTES antibody to breast carcinoma cell supernatants partially blocked eosinophil activation suggesting that RANTES in these supernatants was participating in eosinophil activation. These data show that TNF-alpha-stimulated breast carcinoma cells express mediators that can both bind and activate eosinophils, suggesting a mechanism for eosinophil localization to breast carcinoma sites.

Human neutrophils specifically interact with human monocyte-derived macrophage monolayers

Neutrophils and macrophages express on their membrane molecules which may, in principle, interact with each other, promote specific cell to cell adhesion, affect cell function and finally, as a consequence, modulate the progression of the inflammatory process. We tested therefore if human neutrophils specifically adhere to human monocyte-derived macrophage monolayer (MDMM). Our findings show that neutrophils significantly adhere to 4-day old MDMM and that the extent of adhesion is increased by LPS-activation of MDMM. The specificity of the interaction was shown by the very low extent of adhesion of neutrophils either to freshly prepared monocyte or other types of cell monolayers and by the low percent of adhesion showed by eosinophils exposed to 7-day old MDMM. A role for beta2 integrins, CD31 and PAF-receptor in the mechanism of neutrophil-MDMM interaction is suggested by specific antagonists. We suggest that the adhesion between the two cell types could lead to an increase in concentration of neutrophil- or macrophage released factors in the interaction site and in a mutual modulation of phagocyte functions.

The central role of CD4(+) T cells in the antitumor immune response

The induction of optimal systemic antitumor immunity involves the priming of both CD4(+) and CD8(+) T cells specific for tumor-associated antigens. The role of CD4(+) T helper cells (Th) in this response has been largely attributed to providing regulatory signals required for the priming of major histocompatibility complex class I restricted CD8(+) cytolytic T lymphocytes, which are thought to serve as the dominant effector cell mediating tumor killing. However, analysis of the effector phase of tumor rejection induced by vaccination with irradiated tumor cells transduced to secrete granulocyte/macrophage colony-stimulating factor indicates a far broader role for CD4(+) T cells in orchestrating the host response to tumor. This form of immunization leads to the simultaneous induction of Th1 and Th2 responses, both of which are required for maximal systemic antitumor immunity. Cytokines produced by these CD4(+) T cells activate eosinophils as well as macrophages that produce both superoxide and nitric oxide. Both of these cell types then collaborate within the site of tumor challenge to cause its destruction.

Eosinophil-Cryptococcus neoformans interactions in vivo and in vitro

Eosinophils are components of inflammatory responses to a variety of pathogens. Although a variety of beneficial and harmful functions have been ascribed to these cells, their role in protection against infectious agents remains uncertain. Previous studies have reported eosinophilic pneumonia in mice infected intratracheally with Cryptococcus neoformans. We confirmed this observation and studied the inflammatory response in the lung at day 14 by light and electron microscopy. Immunostaining for glucuronoxylomannan showed isolated cryptococci inside the eosinophilic cuffs. Eosinophils were found to be in close association with C. neoformans in vivo. Cryptococci were associated with eosinophils within eosinophilic perivascular cuffs, within granulomas, and lining the alveolar space. To further investigate this phenomenon in vitro, we isolated rat peritoneal eosinophils and studied cryptococcus-eosinophil interactions in the presence and absence of anti-capsular immunoglobulin G1 (IgG1) and IgE monoclonal antibody (MAb). Eosinophils phagocytosed C. neoformans only in the presence of specific antibody. Phagocytosis was rapid, and dense rings that appeared to consist of granule contents were formed around the organisms. Mast cells were observed to occasionally phagocytose C. neoformans in vitro in the presence of IgE MAb. Our observations suggest that eosinophils may be effector cells against C. neoformans.