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Overcoming cisplatin resistance of ovarian cancer cells by targeted liposomes in vitro.
Int J Pharm. 2010 Apr 15;389(1-2):10-7
Authors: Krieger ML, Eckstein N, Schneider V, Koch M, Royer HD, Jaehde U, Bendas G
The clinical application of cisplatin to treat solid tumours is often limited by the development of tumour cell resistance against this cytostatic agent. Although liposomal carriers of cisplatin are currently in clinical development, approaches to functionally overcome cisplatin resistance by liposomes have hardly been reported. We prepared PEGylated cisplatin-containing liposomes with diameters of about 110 nm and targetability to transferrin receptors (TfR) to correlate cisplatin cell uptake with cytotoxicity in sensitive and cisplatin resistant ovarian cancer cells A2780 compared to the free drug. Whereas the cell entry of free cisplatin was reduced by factor 4 after 24h in resistant cells, liposomal uptake was similar in both cell lines and not affected by resistance. Cytotoxicity was clearly related to intracellular platinum levels, which were even higher for liposomal vs. free cisplatin in the resistant cells after 24, 48, and 72 h and slightly lower in the sensitive cells. However, TfR targeting was of less impact on activity in comparison to non-targeted liposomes. Detection of cellular ATP levels within 24h allowed postulations on the intracellular fate of the liposomes. Altogether, this study strongly supports approaches to overcome cisplatin resistance by a liposomal application of the drug.
PMID: 20060458 [PubMed - indexed for MEDLINE]
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Biotin-directed assembly of targeted modular lipoplexes and their transfection of human hepatoma cells in vitro.
Drug Deliv. 2010 May 14;
Authors: Singh A, Ariatti M, Singh M, Hawtrey A, Naidoo R
The asialoglycoprotein receptor, which is abundantly and near exclusively expressed on hepatocytes, has received much attention in the design of non-viral hepatotropic DNA delivery systems. Thus, asialoglycoproteins and hexopyranosyl ligands have been coupled to DNA-binding cationic polymers and liposomes in the assembly of complexes intended for uptake by liver parenchymal cells. The aim of the study was to construct a hepatocyte-targeted multimodular liposome-based transfecting complex, in which the biotin-streptavidin interaction provides the cohesive force between the ligand asialorosomucoid and the liposome bilayer, and to evaluate its transfection capabilities in the hepatocyte-derived human transformed cell line HepG2. Dibiotinylated asialoorosomucoid was attached to cationic liposomes constructed from 3beta[N-(N',N'-dimethylaminopropane)-carbamoyl] cholesterol (Chol-T):dioleoylphosphatidylethanolamine:biotinylcholesterylformylhydrazide (MSB1) (48:50:2 mole ratio) through streptavidin interposition. Liposome-pGL3 DNA interactions were studied by gel band shift and ethidium displacement assays. The cytotoxicity of assemblies was evaluated in the HepG2 cell line and transfection capabilities determined by measuring the activity of the transgene luciferase. Binding assays showed that all DNA was liposome associated at a DNA (negative):liposome (positive) charge ratio of 1:1. Accommodation of a streptavidin dibiotinylated asialoorosomucoid assembly was achieved at a DNA:liposome:streptavidin dibiotinylated asialoorosomucoid ratio of 1:4:9 (weight basis). Complexes showed optimal transfection activity at this ratio, which was reduced 10-fold by the presence of the competing ligand asialofetuin. The streptavidin-biotin interaction has been applied for the first time to the assembly of hepatocyte-targeted lipoplexes that display asialoorosomucoid and that are well tolerated by a human hepatoma cell line in which transfection is demonstrably achieved by receptor mediation. Favorable size and charge ratio characteristics suggest that this system may be suitable for in vivo application.
PMID: 20469969 [PubMed - as supplied by publisher]
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Expression of endostatin mediated by a novel non-viral delivery system inhibits human umbilical vein endothelial cells in vitro.
Mol Biol Rep. 2010 Apr;37(4):1755-62
Authors: Zhang C, Zhang X, Liu C, Wang J, Liu X, Li H, Wang J, Wu C
Ultrasound (US)-mediated microbubble destruction is recognized to have considerable potential for gene delivery, whereas, there is few report of its effect on enhancing liposomal transfection. In this study, we used pIRES2-EGFP/hES containing human endostatin (hES) cDNA as target gene to test the hypothesis that US exposure with microbubbles could improve liposomal transfection, and to investigate the possibility of intracellular delivery of ES gene using this method. Under the controlled US exposure condition with microbubbles, the plasmid:liposome was transferred into COS-7 cells. The transfection rate, the expression of endostatin and the inhibition effect of transfection-endostatin on endothelial cells were assessed. The results revealed that US-mediated microbubble destruction together with liposome could significantly enhance gene transfection without obvious cell damage. By this means, endostatin gene could be efficiently transferred into COS-7 cells and expressed. The transfection-endostatin could inhibit endothelial proliferation and migration, which suggests that the non-viral method might be useful in anti-angiogenesis therapy in the future.
PMID: 19585274 [PubMed - in process]
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