title: Secretory phospholipase A₂ responsive liposomes.
abstract: Secretory phospholipase A(2) (sPLA(2)) expression is increased in several cancers and has been shown to trigger release from some lipid carriers. This study used electrospray ionization mass spectrometry (ESI-MS) and release of 6-carboxyfluorescein (6-CF) to determine the effects of sPLA(2) on various liposome formulations. Different combinations of zwitterionic [1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine, 1,2-distearoyl-sn-glycero-3-phosphatidylcholine, and 1,2-distearoyl-sn-glycero-3-phosphatidylethanolamine (DSPE)] and anionic [1,2-distearoyl-sn-glycero-3-phosphatidic acid, 1,2-distearoyl-sn-glycero-3-phosphatidylglycerol (DSPG), 1,2-distearoyl-sn-glycero-3-phosphatidylserine, and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-poly(ethylene glycol) 2000 (DSPE-PEG)] phospholipids were examined. DSPG and DSPE were most susceptible to sPLA(2)-mediated degradation compared with other phospholipids. Increased 6-CF release was observed after inclusion of 10 mol % DSPE and anionic lipids into different liposome formulations. Group IIa sPLA(2)-mediated 6-CF release was less than Group III and relatively insensitive to cholesterol (Chol), whereas Chol reduced sPLA(2)-mediated release. Inclusion of DSPE-PEG increased sPLA(2)-mediated 6-CF release, whereas serum reduced lipid degradation and 6-CF release significantly. These data demonstrate that ESI-MS and 6-CF release were useful in determining the selectivity of sPLA(2) and release from liposomes, that differences in the activity of different sPLA(2) isoforms exist, and that DSPE-PEG enhanced sPLA(2)-mediated release of liposomal constituents. These findings will aid in the selection of lipids and optimization of the kinetics of drug release for the treatment of cancers and diseases of inflammation in which sPLA(2) expression is increased.
authors: Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, Georgia 30602.
authors: Guodong
authors: G
authors: Zhu
authors: Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, Georgia 30602.
authors: Jason N
authors: JN
authors: Mock
authors: Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, Georgia 30602; King Saud University, Riyadh, Saudi Arabia.
authors: Ibrahim
authors: I
authors: Aljuffali
authors: Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, Georgia 30602.
authors: Brian S
authors: BS
authors: Cummings
authors: Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, Georgia 30602. Electronic address: rarnold@rx.uga.edu.
authors: Robert D
authors: RD
authors: Arnold
mesh_terms: D000818:Animals; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D005452:Fluoresceins / Q000032:analysis; D005456:Fluorescent Dyes / Q000032:analysis; D054501:Group II Phospholipases A2 / Q000096:biosynthesis / Q000502:physiology*; D054520:Group III Phospholipases A2 / Q000096:biosynthesis / Q000502:physiology*; D008081:Liposomes; D015394:Molecular Structure; D053758:Nanoparticles; D004364:Pharmaceutical Preparations / Q000008:administration & dosage / Q000737:chemistry; D044367:Phase Transition; D010714:Phosphatidylethanolamines / Q000097:blood / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D005452:Fluoresceins; D005456:Fluorescent Dyes; D008081:Liposomes; D004364:Pharmaceutical Preparations; D010714:Phosphatidylethanolamines; C024098:6-carboxyfluorescein; D054501:Group II Phospholipases A2; D054520:Group III Phospholipases A2