Synthetic emmprin peptides with chitobiose substitution stimulate MMP-2 production by fibroblasts

<p>Abstract</p> <p>Background</p> <p>Emmprin, a glycoprotein containing two Ig domains, is enriched on tumor cell surfaces and stimulates matrix metalloproteinase (MMP) production by adjacent stromal cells. Its first Ig domain (ECI) contains the biologically active site. The dependence of emmprin activity on N-glycosylation is controversial. We investigated whether synthetic ECI with the shortest sugar is functionally active.</p> <p>Methods</p> <p>The whole ECI peptides carrying sugar chains, a chitobiose unit or N-linked core pentasaccharide, were synthesized by the thioester method and added to fibroblasts to examine whether they stimulate MMP-2 production.</p> <p>Results</p> <p>ECI carrying a chitobiose unit, ECI-(GlcNAc) ₂, but not ECI without a chitobiose unit or the chitobiose unit alone, dose-dependently stimulated MMP-2 production by fibroblasts. ECI with longer chitobiose units, ECI-[(Man)₃(GlcNAc)₂], also stimulated MMP-2 production, but the extent of its stimulation was lower than that of ECI-(GlcNAc)₂.</p> <p>Conclusions</p> <p>Our results indicate that ECI can mimic emmprin activity when substituted with chitobiose, the disaccharide with which N-glycosylation starts.</p

Taxonomy and Description of Policy Combination Methods

To control complicated and decomposable networking functions, such as Diffserv, two or more policies must cooperate. Combining two or more mutually dependent policies for a specific purpose is called policy combination. Methods of passing information between combined policies can be classified into real tags and virtual tags, or labels and attributes. Policy combinations can be classified into concatenation, parallel application, selection, and repetition. Explicitly specifying policy combinations makes policy systems semantically clearer and better suited to general use, extends the range of functionality, and improves the possibility of optimization. If policy combinations can be specified in a policy system, two types of policy organizations can be distinguished: homogeneous and heterogeneous. Heterogeneous organization is more service-oriented and seems to meet service-management requirements, but homogeneous organization is more device-oriented and may provide better performance