| 41. |
- Wang, Yusheng, et al.
(författare)
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Mast cell-derived tumour necrosis factor-alpha mediates macrophage inflammatory protein-2-induced recruitment of neutrophils in mice.
- 2005
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Ingår i: British Journal of Pharmacology. - : Wiley. - 1476-5381 .- 0007-1188. ; 145:8, s. 1062-1068
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Tidskriftsartikel (refereegranskat)abstract
- 1 Recent studies have indicated that mast cells play an intermediate role in chemokine-induced neutrophil recruitment in vivo. 2 The aim of the present investigation was to determine the role of tumour necrosis factor-alpha (TNF-alpha) in neutrophil recruitment provoked by the CXC chemokine macrophage inflammatory protein-2 (MIP-2). For this purpose, we used mast cell- and TNF-alpha-deficient mice and studied neutrophil adhesion to endothelial cells in vitro and neutrophil recruitment in the mouse cremaster muscle in vivo. 3 In contrast to the classical chemoattractant formyl-methionine-leucine-phenylalanin ( fMLP), MIP-2 dose dependently increased neutrophil accumulation in vivo. This MIP-2-regulated neutrophil recruitment was abolished in mast cell- deficient mice. 4 TNF-alpha increased E-selectin mRNA expression in both wild-type (WT) and mast cell-deficient mice. In contrast, MIP-2 challenge increased gene expression of E-selectin in WT but not in mast cell-deficient animals. Moreover, MIP-2-provoked extravascular accumulation of neutrophils was reduced by 78% in mice lacking TNF-alpha. 5 In order to better define the role of mast cell-derived TNF-alpha in neutrophil responses to MIP-2, we used an in vitro endothelial cell adhesion assay with and without mast cells. Interestingly, MIP-2-induced neutrophil adhesion to endothelial cells was decreased by 58% using TNF-alpha-deficient compared to WT mast cells. Moreover, mast cell secretion of TNF-alpha increased by more than 71% in response to challenge with MIP-2. 6 Taken together, our results suggest that MIP-2-induced neutrophil recruitment is mediated by TNF-alpha released from local mast cells. These findings help to explain the complex molecular interactions between chemokines, mast cell activation and neutrophil infiltration in vivo.
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| 42. |
- Zawadzki, Antoni, et al.
(författare)
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Verapamil Inhibits L-type Calcium Channel Mediated Apoptosis in Human Colon Cancer Cells.
- 2008
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Ingår i: Diseases of the Colon & Rectum. - : Ovid Technologies (Wolters Kluwer Health). - 0012-3706. ; 51, s. 1696-1702
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: Treatment with calcium channel blockers have been associated with increased colon cancer mortality in epidemiologic studies. We examined the potential expression and function of calcium channels in two human colon cancer cell lines. METHODS: Both primary (collected at operation) and commercially-available human colon cancer cell lines were used. The colon cancer cells were incubated with a calcium channel blocker (verapamil) and a calcium channel agonist (BayK 8644) at clinically relevant concentrations. L-type calcium channel mRNA was determined by reverse-transcription polymerase chain reaction. Intracellular calcium ion levels were measured with fluorometry and apoptosis with flow cytometry. RESULTS: Both types of cells expressed L-type calcium channel mRNA, comprising an alpha-1D and a beta-3 subunit, whereas the cells were negative for N-type and P-type channels. The selective calcium channel agonist (BayK 8644), dose-dependently increased intracellular calcium ion levels and the level of apoptosis in primary human colon cancer cells. Pretreatment with verapamil completely abolished both calcium channel agonist-induced influx of calcium and apoptosis in these cells. CONCLUSIONS: These data demonstrate that human colon cancer cells express L-type calcium channels that mediate calcium influx and apoptosis, which warrants further studies to determine whether calcium channel blockers may promote colon cancer growth.
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