betadex and Fibrosarcoma

This research is aimed to develop a kind of hollow nanosphere based on β-cyclodextrin-grafted α, β-poly(aspartic acid) (β-CD-graft-PAsp) as drug carrier to enhance the stability of camptothecin (CPT) in aqueous media. Firstly, mono(6-(2-aminoethyl) amino-6-deoxy)-β-cyclodextrin (β-CDen) was synthesized by a substitution reaction between mono-6-deoxy-6-(p-tolylsulfonyl)-β-cyclodextrin (6-OTs-β-CD) and ethylenediamine; and then, the five-member rings in poly(L-succinimide) (PSI) were successively opened by β-CDen to obtain β-CD-graft-PAsp. The synthesized β-CD-graft-PAsp was found to form the unique hollow nanosphere with the internal hole of about 17 nm and many β-CD cavities of 0.7 nm interspersed on the shell. The drug-loading behavior of the hollow nanosphere was also evaluated by using CPT as guest molecule of β-CD. It was worth of note that the β-CD-graft-PAsp hollow nanosphere as carrier enhanced the stability of CPT in aqueous media, and the CPT from the β-CD-graft-PAsp hollow nanosphere displayed a sustained release profile and hence resulted in the essential decrease of cytotoxicity to L929 cell line. Furthermore, almost no cytotoxicity of the β-CD-graft-PAsp is desirable for the application of drug carrier. As a result, the β-CD-graft-PAsp hollow nanosphere showed a great potential as the carrier of CPT.

Topics: Animals; Antineoplastic Agents, Phytogenic; Aspartic Acid; beta-Cyclodextrins; Biopolymers; Camptothecin; Cell Survival; Cells, Cultured; Drug Carriers; Drug Compounding; Fibrosarcoma; Mice; Nanospheres; Tumor Cells, Cultured; Water

Unstimulated human fibrosarcoma cells (HT1080) constitutively secrete matrix metalloproteinase 2 (MMP 2) as a proenzyme requiring proteolytic cleavage by membrane type-1 MMP (MT1 MMP) for activation. Physiological and pharmacological stimuli induce clustering of MT1 MMP/tissue inhibitor of MMP 2 "receptors", promoting binding and activation of MMP 2. We now report that cholesterol depleted HT1080 cells accumulated MT1 MMP on the cell surface and activated MMP 2. A specific inhibitor of mitogen activated protein kinase kinase 1/2 inhibited both MMP 2 activation and extracellular signal-related kinase phosphorylation induced by cholesterol depletion. Our data indicate that the cholesterol content of unstimulated cells is critical for secretion of MMP 2 as an inactive zymogen and control of pericellular proteolysis.

Topics: beta-Cyclodextrins; Cell Line, Tumor; Cell Membrane; Cholesterol; Cyclodextrins; Enzyme Activation; Fibrosarcoma; Humans; MAP Kinase Kinase 1; MAP Kinase Signaling System; Matrix Metalloproteinase 2; Matrix Metalloproteinase Inhibitors; Matrix Metalloproteinases, Membrane-Associated; Metalloendopeptidases; Mitogen-Activated Protein Kinase Kinases; Mitogen-Activated Protein Kinases; Phosphorylation; Protease Inhibitors; Tissue Inhibitor of Metalloproteinase-2