Application of "Tissueoid Cell Culture System" Using a Silicate Fiber Scaffold for Cancer Research.

BACKGROUND: We developed a 3-dimensional (3D) culture system using a high-purity silica fiber scaffold of unwoven sheets called CellbedTM. METHODS: We used adherent colon and esophagogastric junction adenocarcinoma cells, tongue squamous cell carcinoma (SqCC) cells, and nonadherent gastric cancer cells. These cells were subjected to staining with various substances and observed by electron microscopy. To evaluate the effects of extracellular matrix in carcinoma tissues, SqCC cells were cultured in Cellbed coated with collagens I, III, and IV. RESULTS: Especially well-differentiated carcinoma cells cultured in this 3D system showed their own unique characteristics: luminal formation in adenocarcinoma cells and cell stratification and keratinization in SqCC cells. Scanning electron microscopy revealed the proliferation of cancer cells with cytoplasm entwined in Cellbed. Intercellular desmosomes in squamous epithelia were detected by transmission electron microscopy of vertical cross sections. SqCC cells cultured in Cellbed coated with collagen IV showed enhanced invasive and proliferative abilities. CONCLUSION: Because the morphology of cancer cells cultured in this 3D culture system is similar to that in living organisms, we called the system a "tissueoid cell culture system." Coating with collagen IV enables the modification of cell-matrix interactions as well as recapitulation of the in vivo microenvironment.

Effects of combination between web density and size of spider mite on predation by a generalist and a specialist phytoseiid mite.

Complicated three-dimensional webs of silk threads produced by Tetranychus spider mites provide protection from predation by many generalist phytoseiid mite species. Accessibility to prey may be the most significant criterion for successful predation in complicated webs. To assess the protective effects of combination between web size and density, we compared predation on eggs of the two-spotted spider mite, Tetranychus urticae, by a generalist (Euseius sojaensis) and a specialist (Neoseiulus womersleyi) phytoseiid mite in the laboratory under manipulated web size and density. Web sizes negatively affected to the predation. Significant interactions were found between phytoseiid mite species and prey distribution; egg consumption by E. sojaensis was more in uniform distribution, but that by N. womersleyi, in contrast, was larger in contagious distribution. However, the egg consumption by E. sojaensis and N. womersleyi were both mitigated in larger webs. This area size depending mitigation was more effective to the predation by E. sojaensis. Although the mechanism of web size depending mitigation is unknown, web sizes might affect prey searching efficiency of this phytoseiid mite. Consequently, combination between web density and size are likely to affect not only a generalist E. sojaensis but also a specialist N. wormersleyi.

Effects of regular exercise on neutrophil functions, oxidative stress parameters and antibody responses against 4-hydroxy-2-nonenal adducts in middle aged humans.

Regular exercise has recognized health benefits, partly because it reportedly lowers the levels of the oxidation products of proteins and DNA at rest, in contrast with the effect of acute exercise. However, when we compared oxidative response markers in active middle-aged subjects with those in sedentary ones, the level of urinary 8-OHdG was higher in active subjects. Because neutrophils are the first line of defense against a variety of infectious diseases, we then compared the cell density, functions and apoptosis of neutrophils in active subjects with those in sedentary ones. The cell density of neutrophils and phagocytosis of opsonized zymosan by neutrophils were higher in active subjects, being similar with the reported effects of acute exercise. To determine any beneficial effects of oxidative stress in active subjects, we then compared the levels of antibodies against 4-hydroxy-2-nonenal adducts in active subjects with those in sedentary ones, because 4-hydroxy-2-nonenal is one of the most common bioactive aldehyde products of oxidative stress, and because the IgM class of antibodies against oxidized low-density lipoprotein is associated with atheroprotective properties. The level of the IgM but not the IgG class of antibodies against 4-hydroxy-2-nonenal adducts was higher in active subjects. Overall, this study revealed that our active middle-aged subjects showed both oxidative responses and a higher IgM response to reactive carbonyl derivatives, possibly providing a basis for a health benefit by exercise in our active subjects.

Suppression of MIP-2 or IL-8 production by annexins A1 and A4 during coculturing of macrophages with late apoptotic human peripheral blood neutrophils.

Annexin A1 (ANXA1) is a well-known anti-inflammatory protein that is expressed on the surface of apoptotic cells. Annexin A4 (ANXA4) is also recruited from the nucleus to the cytoplasm in apoptotic cells, although it is not known whether or not ANXA4 is expressed on the surface of apoptotic cells. In this study, we obtained rabbit anti-human ANXA1 and ANXA4 antibodies, and then examined whether or not ANXA1 and ANXA4 are expressed on the surface of early and late human apoptotic cells. ANXA1 and, to a lesser extent, ANXA4 were detected on late but not early apoptotic HeLa cells, whereas ANXA1 and a small amount of ANXA4 were detected on both early and late apoptotic human neutrophils. We then examined the effects of the anti-human ANXA1 and ANXA4 antibodies on the mouse or human macrophage response to human apoptotic cells. Upon coculturing of mouse or human macrophages with late apoptotic human neutrophils, anti-human ANXA1 antibodies and, to a lesser extent, anti-human ANXA4 antibodies increased MIP-2 or IL-8 production significantly, suggesting that ANXA1 and ANXA4 suppress MIP-2 or IL-8 production by macrophages in response to late apoptotic human neutrophils.