title: Exploring the HYDRAtion method for loading siRNA on liposomes: the interplay between stability and biological activity in human undiluted ascites fluid.
abstract: Delivery of small interfering RNA (siRNA) is recently gaining tremendous attention for the treatment of ovarian cancer. The present study investigated the potential of different liposomal formulations composed of (2,3-dioleoyloxy-propyl)-trimethylammonium (DOTAP) and 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) encapsulating siRNA (hydration method) for their ability to knockdown luciferase (Luc) activity in human ovarian cancer SKOV-3 cells. Fluorescence single particle tracking (fSPT) and fluorescence correlation spectroscopy (FCS) in human-undiluted ascites fluid obtained from a peritoneal carcinomatosis patient revealed that cationic hydra-lipoplexes (HYDRA-LPXs) and HYDRA-LPXs decorated with stable DSPE-PEG (DSPE HYDRA-LPXs) showed high stability during at least 24 h. HYDRA-LPXs decorated with sheddable C8 and C16 PEG-Ceramides (Cer HYDRA-LPXs) resulted in rapid and premature release of siRNA already in the first hours. Despite their role in preventing aggregation in vivo, liposomes decorated with stable PEG residues resulted in a poor transfection compared to the ones decorated with sheddable PEG residues in reduced serum conditions. Yet, the transfection efficiency of both Cer HYDRA-LPXs significantly decreased following 1 h of incubation in ascites fluid due to a drastic drop in the cellular uptake, while DSPE HYDRA-LPXs are still taken up by cells, but too stable to induce efficient gene silencing.
authors.affiliation: Ghent Research Group on Nanomedicines, Laboratory for General Biochemistry and Physical Pharmacy, Faculty of Pharmaceutical Sciences, Ghent University, Ottergemsesteenweg 460, 9000, Ghent, Belgium.
authors.forename: George R
authors.initials: GR
authors.lastname: Dakwar
authors.affiliation: Ghent Research Group on Nanomedicines, Laboratory for General Biochemistry and Physical Pharmacy, Faculty of Pharmaceutical Sciences, Ghent University, Ottergemsesteenweg 460, 9000, Ghent, Belgium.|Centre for Nano- and Biophotonics, Ghent University, 9000, Ghent, Belgium.
authors.forename: Kevin
authors.initials: K
authors.lastname: Braeckmans
authors.affiliation: Department of Surgery, Ghent University Hospital, De Pintelaan 185, 9000, Ghent, Belgium.
authors.forename: Wim
authors.initials: W
authors.lastname: Ceelen
authors.affiliation: Ghent Research Group on Nanomedicines, Laboratory for General Biochemistry and Physical Pharmacy, Faculty of Pharmaceutical Sciences, Ghent University, Ottergemsesteenweg 460, 9000, Ghent, Belgium. stefaan.desmedt@ugent.be.
authors.forename: Stefaan C
authors.initials: SC
authors.lastname: De Smedt
authors.affiliation: Ghent Research Group on Nanomedicines, Laboratory for General Biochemistry and Physical Pharmacy, Faculty of Pharmaceutical Sciences, Ghent University, Ottergemsesteenweg 460, 9000, Ghent, Belgium. Katrien.Remaut@ugent.be.
authors.forename: Katrien
authors.identifier: 0000-0002-2244-1339
authors.initials: K
authors.lastname: Remaut
mesh_terms: D001201:Ascites; D045744:Cell Line, Tumor; D002470:Cell Survival; D005229:Fatty Acids, Monounsaturated / Q000737:chemistry; D006801:Humans; D008081:Liposomes; D008156:Luciferases / Q000235:genetics; D010714:Phosphatidylethanolamines / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D034741:RNA, Small Interfering / Q000008:administration & dosage / Q000737:chemistry
chemical_list: D005229:Fatty Acids, Monounsaturated; D008081:Liposomes; D010714:Phosphatidylethanolamines; D000644:Quaternary Ammonium Compounds; D034741:RNA, Small Interfering; C107570:polyethylene glycol-distearoylphosphatidylethanolamine; D011092:Polyethylene Glycols; C020888:1,2-dielaidoylphosphatidylethanolamine; D008156:Luciferases; C070046:1,2-dioleoyloxy-3-(trimethylammonium)propane
keywords: Ascites; Peritoneal metastasis; Sheddable PEG; siRNA delivery; siRNA encapsulation