Search results for: CultreCoat Collagen IV 96 Well CA Plate
#19847623 
2009/07/15
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The invasiveness of five medulloblastoma cell lines in collagen gels.
Local recurrence continues to limit survival in medulloblastoma patients, largely related to the persistence of invasive cells at the site of tumour resection and leptomeningeal dissemination. Given the relative dearth of understanding of causative mechanisms behind the invasiveness of medulloblastomas, and a general lack of validated in vitro models with which to study them, our objectives were (1) to obtain quantitative data on the invasiveness of five distinct medulloblastoma cell lines within a 3-dimensional in vitro collagen-based model; and (2) to characterize some of the mechanisms behind invasion, specifically striving to identify proteolytic processes that occur as medulloblastoma cells disrupt and thereby invade the normal tissue surrounding them, and specific inhibitors of these proteolytic enzymes. Five different medulloblastoma cell lines (UW228-1, 2 and 3; Daoy, and Madsen) were implanted onto a 3-dimensional, type I collagen gel assay to assess tumour invasion distance and mean doubling time over 5 days. Proteolytic activity was assessed against collagen types I and IV by measuring the degradation of 3H-collagen I and IV to products soluble in 100% w/v trichloroacetic acid; and general (neutral) proteolytic activity evaluated by measuring the degradation of 3H-albumin. In other experiments, cells were pre-exposed to a variety of protease inhibitors, including inhibitors of metalloproteinases and cysteine, serine and aspartic proteases, and then plated to identify any inhibition of invasion. Inter-group differences in mean invasion distance were assessed by means of Student's t-tests for non-paired subjects, with P < 0.05 set as the threshold for statistical significance. For the inhibitor studies, an inhibition index, called the inhibitory concentration 50, IC-50, was calculated by performing a regression analysis for each inhibitor tested over a range of concentrations, for each cell line. Within hours of implantation, individual cells readily detached from the surface of the cell aggregates and invaded the collagen matrix, to distances of up to 1,200 mum and at rates of up to 300-mum per day; the UW228-1 cell line clearly was less invasive than the other four cell lines. Proteolytic activity was identified against collagen type I, but not against collagen type IV or albumin; but there was no apparent correlation between invasion distance and either cell doubling time or the amount of collagen type I proteolytic activity. Both metalloproteinase inhibitors suppressed tumour invasion, as did one of two cysteine protease inhibitors; but there was no tumour suppression with either serine or aspartic protease inhibition. MMP-1 and 2, and TIMP-1 and 2 all were detectable by Western blot analysis. Medulloblastoma cell invasiveness within the 3-dimensional model used here appears to depend upon a combination of metalloproteinase and cysteine protease activity, a finding that may suggest areas for potential future clinical investigation and therapy.Adrianna Ranger, Warren McDonald, Emi Moore, Rolando Delmaestro
2279 related Products with: The invasiveness of five medulloblastoma cell lines in collagen gels.
96 samples24 tests96 samples24 tests24 tests1100 plates100ug Lyophilized400 ug
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#11172338 //
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Sinusoidal ultrastructure evaluated during the revascularization of regenerating rat liver.
Sinusoidal endothelial cell (SEC) porosities were compared between the periportal (zone 1) and pericentral (zone 3) regions of the rat liver during regeneration following partial hepatectomy (PHx). SEC porosities and fenestration diameters were measured in control livers, as well as at 5 minutes, 24, 48, 72, 96, 120 hours, and 14 days following PHx. Bimodal maximums in both porosity and fenestration diameters were observed in both zones at 5 minutes and 5 days following PHx. SEC porosities increased significantly in both zones 1 and 3 within 5 minutes following PHx, but the increase was maintained only in zone 1 at 24 hours after resection. Following the initial rise, both zones displayed a gradual decrease to less than half their porosity values at 72 hr post-PHx. After 72 hours, porosities increased to over control levels and remained elevated until 14 days after PHx. The decrease in porosity at 72 hr post-PHx is accompanied by ultrastructural changes within the sinusoid at this time. Vascular corrosion casting and transmission electron microscopy (TEM) show sinusoid compression resulting from increased hepatic plate widths due to hepatocyte proliferation in the absence of SEC proliferation. Also at this time, we observed many SEC completely enveloped by stellate cells. The zonal variations observed for porosities throughout regeneration did not correlate with changes in laminin, collagen I and IV, or fibronectin deposition within the space of Disse. Taken together, the data reveal that SEC are dynamic regulators of porosity that respond rapidly and locally to environmental zonal stimuli during liver regeneration.K E Wack, M A Ross, V Zegarra, L R Sysko, S C Watkins, D B Stolz
2669 related Products with: Sinusoidal ultrastructure evaluated during the revascularization of regenerating rat liver.
1.00 flask1.00 flask1.00 flask200 assays250ul1500ml10 μg2
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#7491298 //
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Unsaturated fatty acid effects on human breast cancer cell adhesion.
Polyunsaturated fatty acids influence several steps involved in metastasis formation in animal tumor models. During the process of metastasis from the primary site, tumor cells adhere to the endothelium and underlying basement membrane before extravasation and secondary growth. The purpose of this study was to determine the effect of unsaturated fatty acids on adhesion of human breast cancer cell lines to components of the basement membrane. Cells were cultured in low-serum medium for five days with or without added unsaturated fatty acids. Adhesion assays were conducted by incubating cells with basement membrane substrates coated on 96-well plates, washing to remove nonadherent cells, and staining adherent cells with crystal violet. Linoleic acid (LA) and eicosapentaenoic acid increased adhesion of the metastatic cell line MDA-MB-231 to Matrigel and type IV collagen, while eicosapentaenoic acid decreased adhesion of the less metastatic cell line SK-BR-3 to these two basement membrane substrates. Oleic acid increased adhesion of MDA-MB-231 cells to Matrigel and fibronectin. Nordihydroguaiaretic acid and high concentrations of indomethacin, each of which inhibits the lipoxygenase pathway of arachidonate metabolism, were effective in reversing the stimulatory effect of LA on MDA-MB-231 cell adhesion. A protein kinase C inhibitor likewise suppressed the increase in adhesion observed when MDA-MB-231 cells were incubated in media with added LA. Unsaturated fatty acids modified the adhesive properties of human breast cancer cell lines in vitro, and LA appeared to increase human breast cancer cell adhesion to extracellular matrix components by activating lipoxygenase and/or protein kinase C pathways.G L Johanning, T Y Lin