ABSTRACT
Glycosaminoglycan (GAG) sequences that selectively target heparin cofactor II (HCII), a key serpin present in human plasma, remain unknown. Using a computational strategy on a library of 46 656 heparan sulfate hexasaccharides we identified a rare sequence consisting of consecutive glucuronic acid 2-O-sulfate residues as selectively targeting HCII. This and four other unique hexasaccharides were chemically synthesized. The designed sequence was found to activate HCII ca. 250-fold, while leaving aside antithrombin, a closely related serpin, essentially unactivated. This group of rare designed hexasaccharides will help understand HCII function. More importantly, our results show for the first time that rigorous use of computational techniques can lead to discovery of unique GAG sequences that can selectively target GAG-binding protein(s), which may lead to chemical biology or drug discovery tools.
Subject(s)
Glucuronates/pharmacology , Heparin Cofactor II/agonists , Heparitin Sulfate/pharmacology , Drug Discovery , Glucuronates/chemistry , Heparin Cofactor II/metabolism , Heparitin Sulfate/chemistry , Humans , Protein Binding , Small Molecule Libraries/chemistry , Small Molecule Libraries/pharmacologyABSTRACT
Prostate cancer is a leading cause of cancer-related death in men and RNA interference (RNAi) has emerged as a potential therapeutic option. However, the absence of a safe and specific delivery vector remains a major obstacle to the clinical application of RNAi. Cyclodextrin derivatives are known to be efficient delivery systems with low toxicity in a variety of cell types. In this study, a cationic cyclodextrin derivative was synthesized to complex siRNA. The nanoparticle was then further modified by exploiting the ability of the ß-cyclodextrin cavity to form an inclusion complex with the hydrophobic molecule adamantane. PEGylated adamantane derivatives were synthesized with and without the anisamide-targeting ligand on the terminal end of the PEG chain. Anisamide is known to bind specifically to the sigma receptor which is overexpressed on the surface of prostate cancer cells. The resulting nanocomplexes were slightly cationic and less than 300 nm in size. They successfully protected siRNA from serum-induced nuclease degradation and were non-toxic to prostate cancer cells. In addition, the targeted nanoparticles mediated high levels of siRNA cellular uptake and corresponding PLK1 gene knockdown in prostate cancer cells in vitro. To our knowledge, this is the first time that the ability of cyclodextrins to form inclusion complexes with adamantane derivatives has been exploited for the targeted delivery of siRNA to prostate cancer cells via the sigma receptor.
Subject(s)
Nanoparticles , Prostatic Neoplasms/genetics , RNA, Small Interfering/administration & dosage , Receptors, sigma/genetics , Adamantane/chemistry , Cations , Cell Cycle Proteins/genetics , Cell Line, Tumor , Gene Knockdown Techniques , Gene Transfer Techniques , Humans , Male , Particle Size , Protein Serine-Threonine Kinases/genetics , Proto-Oncogene Proteins/genetics , RNA Interference , beta-Cyclodextrins/chemistry , Sigma-1 Receptor , Polo-Like Kinase 1ABSTRACT
A new series of amphiphilic cyclodextrins containing cationic groups at the 6-positions and alkyl or biolabile ester groups at the 2-positions has been synthesised. Selective 2-O-allylation followed by photochemical addition of lipophilic thiols made it possible to control lipophilicity in these mesomolecules and allow solubility and self-assembly in water. The cationic groups are cysteamine-derived, while the alkyl and ester groups are C(1)-C(16) and benzyl ester groups. This is a new general synthetic route to a potentially wide range of polycationic cyclodextrins capable of acting as gene delivery vectors by condensing DNA and forming liquid crystalline complexes with oligonucleotides.
Subject(s)
Cyclodextrins/chemistry , Cyclodextrins/chemical synthesis , Sulfides/chemistry , Sulfides/chemical synthesis , beta-Cyclodextrins/chemistry , beta-Cyclodextrins/chemical synthesis , Cyclodextrins/metabolism , Drug Design , Esters/chemistry , Gene Transfer Techniques , Magnetic Resonance Spectroscopy , Spectrometry, Mass, Electrospray Ionization , Sulfides/metabolism , beta-Cyclodextrins/metabolismABSTRACT
New amphiphilic cyclodextrins fully substituted with sugar residues on the primary face have been synthesised and enzymatically modified.
