title: Effect of poly(ethylene glycol)-block-polylactide nanoparticles on hepatic cells of mouse: low cytotoxicity, but efflux of the nanoparticles by ATP-binding cassette transporters.
abstract: The objective of this paper is to study the effects of poly(ethylene glycol)-block-polylactide (PLA-PEG) nanoparticles on hepatic cells of mouse. Blank PLA-PEG nanoparticles have been successfully prepared and MTT assay suggested that the nanoparticles with HepG2 cell co-culture model did not cause significant changes in membrane integrity in controlled concentration range (0.001-0.1 mg/ml). Immunohistochemical analysis demonstrated that large dose of PLA-PEG nanoparticles injection (42.04 mg/kg, i.v.) did not induce hepatic cell apoptosis. From biochemical assay experiments, although the levels of SOD decreased and those of MDA, NOS increased after treatment with large dose of PLA-PEG nanoparticles injection (42.04 mg/kg, i.v.), they were all not significant (p>0.05). Then Kunming mice were treated with large dose of PLA-PEG nanoparticles (42.04 mg/kg, i.v.) and after 4 days total RNA was isolated to elucidate patterns of gene expression using a mouse cDNA-microarray (SuperArray). Treatment with nanoparticles resulted in over-expression of a lot of ATP-binding cassette (ABC) transporters, especially two ABC transporters (ABCA8 and ABCC5/MRP5), and down-regulation of GSTP1, in comparison with the control. ABCA8 could extrude low molecular weight polymers after PLA-PEG nanoparticles hydrolysis outside the cells. We also discovered that ABCC5 expressed multidrug resistance protein 5 (MRP5) to pump out conjugate (GS-X) of PLA-PEG nanoparticles with GSH. The results were confirmed by RT-PCR. Results of in vitro accumulation and efflux experiments indicated that about 51-52% (51.5% and 52.0%) intracellular PLA-PEG nanoparticles was expulsed after mouse primary hepatocytes reached a saturation uptake of nanoparticles during the concentration range of 750-1000 microg/ml. The results suggested that ABC transporters (especially ABCA8) pump out the polymers after hydrolysis from mouse hepatic cells and large dose of PLA-PEG nanoparticles make mouse hepatic cells gain drug resistance to PLA-PEG nanoparticles.
authors.affiliation: Department of Biomedical Engineering, Central South University, Changsha, China.
authors.forename: Yangde
authors.initials: Y
authors.lastname: Zhang
authors.forename: Zhiyuan
authors.initials: Z
authors.lastname: Hu
authors.forename: Maoying
authors.initials: M
authors.lastname: Ye
authors.forename: Yifeng
authors.initials: Y
authors.lastname: Pan
authors.forename: Jiji
authors.initials: J
authors.lastname: Chen
authors.forename: Yulin
authors.initials: Y
authors.lastname: Luo
authors.forename: Yanqiong
authors.initials: Y
authors.lastname: Zhang
authors.forename: Lianxiang
authors.initials: L
authors.lastname: He
authors.forename: Jiwei
authors.initials: J
authors.lastname: Wang
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation; D004337:Drug Carriers; D005260:Female; D015870:Gene Expression / Q000187:drug effects; D020869:Gene Expression Profiling / Q000379:methods; D051549:Glutathione S-Transferase pi / Q000235:genetics / Q000378:metabolism; D022781:Hepatocytes / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D006868:Hydrolysis; D007773:Lactates / Q000378:metabolism / Q000494:pharmacology* / Q000633:toxicity; D051379:Mice; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000378:metabolism; D053758:Nanoparticles; D020411:Oligonucleotide Array Sequence Analysis; D010316:Particle Size; D011092:Polyethylene Glycols / Q000378:metabolism / Q000494:pharmacology* / Q000633:toxicity; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015854:Up-Regulation
chemical_list: D018528:ATP-Binding Cassette Transporters; D004337:Drug Carriers; D051549:Glutathione S-Transferase pi; D007773:Lactates; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D011092:Polyethylene Glycols; D012333:RNA, Messenger; C508626:Abca8b protein, mouse; C492376:Abcc5 protein, mouse; C088513:poly(lactic acid-ethylene glycol); C496557:Gstp1 protein, mouse