Interactions of tumour-derived micro(nano)vesicles with human gastric cancer cells.

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.

Giant cell ependymoma: a case report.

Ependymomas account for 3-9% of all neuroepithelial tumors. A peculiar variant of ependymoma known as "giant cell ependymoma" ("GCE") is especially rarely reported, it may pose some difficulties for the diagnosing neuropathologist. Here we present a case of a giant cell ependymoma occuring in a 17-year-old patient with the history of 2-year recurrent headaches and a 1-month history of vision impairment. CT scanning demonstrated a mass in the left occipital lobe, arising from the occipital horn of the lateral ventricle. Histological, immunohistochemical and electron microscopic findings were consistent with high-grade ependymoma. Especially striking was the presence of bizzare pleomorphic giant cells which predominated in the tumor tissue. As a result the diagnosis of GCE was established. This type of neoplasm necessitates, at least in theory, differentiation with anaplastic oligodendroglioma, clear cell ependymoma, pleomorphic xanthoastrocytoma, giant cell glioblastoma, and subependymal giant cell astrocytoma. To date giant cell ependymomas (GCEs) were reported in seven cases in the literature. To the best of our knowledge this is the 8th case in the literature. In spite of apparently "worrisome" histology GCE seems to be a neoplasm with a relatively good prognosis.

The use of rigid, fibrillar Congo red nanostructures for scaffolding protein assemblies and inducing the formation of amyloid-like arrangement of molecules.

The ordered amyloid-like organization of protein aggregates was obtained using for their formation the rigid fibrillar nanostructures of Congo red as the scaffolding. The higher rigidity of used dye nanoparticles resulted from the stronger stacking of molecules at low pH (near the pK of the dye amino group) because of the decreased charge repulsion. The polylysine, human globin, and immunoglobulin L chain were arranged in this way to form deposits of amyloid properties. The scaffolding was introduced simply by mixing the dye and proteins at a low pH or the dye was used in the preorganized form by maintaining it in the electric field before and during protein addition. The polarization and electron microscopy studies confirmed the unidirectional organization of the complex. The precipitate of the complex was used for studies directly or after the partial or complete removal of the dye. The results suggest that the process of formation of amyloid-like deposits may bypass the nucleation step. It is possible if the protein aggregation occurs in unidirectionally organized (because of scaffolding) assembly of molecules, arranged prior to self-association. The recognition of the structure of amphoteric Congo red nanoparticles used for the scaffolding was based on the molecular dynamics simulation.

Tumour-derived microvesicles carry several surface determinants and mRNA of tumour cells and transfer some of these determinants to monocytes.

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.

Exposure of hop growers to bioaerosols.

Air sampling was performed during picking and sorting of hop (Humulus lupulus) cones on 19 hop farms located in eastern Poland. The concentration and composition of airborne microflora and the concentration of airborne dust and endotoxin were determined. Additionally, 7 samples of settled hop dust were collected and examined for the presence of microorganisms and endotoxin. Total concentrations of airborne microorganisms were within a range of 2.08-129.58 x 10(3) cfu/m(3). Gram-positive bacteria formed 22.2-96 % of the total count. Among them, prevailed corynebacteria and endospore-forming bacilli. Fungi constituted 3.7-65.4 % of the total count. The dominant species were Penicillium citrinum, Alternaria alternata, and Cladosporium epiphyllum. Thermophilic actinomycetes and Gram-negative bacteria were detected in the air of only 10 and 6 farms, respectively. Airborne dust concentrations at the workplace ranged from 0.17-31.67 mg/m(3). The concentrations of airborne endotoxin were in the range of 26-6250 ng/m(3). In the samples of settled dust, the concentrations of total microorganisms ranged from 0.25 x 10(6) to 2.87 x 10(8) cfu/g. Gram-positive and Gram-negative bacteria constituted respectively 3.2-98 % and 0-93.5 % of the total count. Fungi formed 0-30.3 % of the total count. The most common species were Penicillium spp. and Alternaria alternata. The concentrations of endotoxin were in the range of 312.5-6250 microg/g (median 6250 microg/g). The presence of microorganisms and endotoxin in the samples of settled dust was confirmed by electron microscopy. The hop growers seem to be exposed to lower concentrations of dust, microorganisms and endotoxin compared to other branches of agriculture. This may be partly due to antimicrobial properties of hop plant. Among microbial factors associated with hop dust, bacterial endotoxin and allergenic fungi pose the greatest potential hazard for exposed hop farmers.

Circulating CXCR4-positive stem/progenitor cells compete for SDF-1-positive niches in bone marrow, muscle and neural tissues: an alternative hypothesis to stem cell plasticity.

The trans-differentiation hypothesis of adult tissue-specific stem cells has been recently questioned because of insufficient proof that the so-called plasticity experiments were performed on pure populations of tissue-specific stem cells. It was shown recently, for example, that the formation of haematopoietic colonies by muscle cells depended on the presence of haematopoietic stem/progenitor cells residing within the muscle tissue and hence was not related to the plasticity of the muscle stem cells. The explanation for the presence in, or homing into, muscles of haematopoietic stem cells is, however, not clear. In our study, we hypothesised that muscle tissues secrete stromal-derived factor (SDF)- 1, an alpha-chemokine for haematopoietic stem cells (HSC), which could attract HSC circulating in peripheral blood into muscle tissue. We found, using RT-PCR and immunocytochemistry, that SDF-1 was expressed in human heart and skeletal muscles. Moreover, muscle satellite cells, which are pivotal for regeneration of muscle, highly expressed on their surface CXCR4, a G-protein-coupled receptor that binds SDF-1. To determine whether the CXCR4 receptor is functional on muscle satellite/progenitor cells, we stimulated murine satellite cells (the C2C12 cell line) with SDF-1 and demonstrated the phosphorylation of p42/44 MAPK and AKT serine-threonine kinase in these cells. Moreover, we showed that SDF-1 gradient chemoattracts these cells. We postulate that the CXCR4-positive muscle satellite and CXCR4-positive HSC circulating in the peripheral blood compete for occupancy of SDF-1-positive stem cell niches that are present in bone marrow and muscle tissues. Thus, we suggest that competition for common niches by various circulating CXCR4-positive stem cells and their ability to home to the SDF-1-positive niches in various organs, is a better explanation than stem cell plasticity of why (i) haematopoietic colonies can be cultured from muscles and (ii) early muscle progenitors could be cultured from bone marrow.