title: Preparation and characterization of polymeric nanoparticles for siRNA delivery to down-regulate the expressions of exogenous and endogenous target genes.
abstract: Gene silencing induced by RNA interference using small interfering RNA (siRNA) provides a promising therapeutic approach for cancers. However, the lack of siRNA delivery vector has limited the development of siRNA therapy. The purpose of this study was to use the novel copolymer (mPEG5k-PCL1.2k)1.4-g-PEl10k to prepare siRNA-loaded nanoparticles for siRNA delivery. The results suggested that (mPEG5k-PCL1.2k)1.4-g-PEl10k could load siRNA to form nanoparticles with particle size less than 200 nm in a narrow distribution. Moreover, a certain density of positive charge existed onto the surfaces of nanoparticles. MTT assay results demonstrated that (mPEG5k-PCL1.2k)1.4-g-PEl10k/siRNA nanoparticles showed very low cytotoxicity. The gene silencing efficiency of (mPEG5k-PCL1.2k)1.4-g-PEl10k/siRNA nanoparticles was investigated through luciferase reporter gene assays. The expression of exogenous luciferase gene was significantly downregulated at a range of N/P ratio from 50 to 125, and was maximally inhibited at the N/P ratio of 125 with 54% and 59% reduction in MCF-7 and HepG2 cells, respectively. In the 4T1-luc cell line expressing luciferase stably, the silencing of endogenous luciferase gene also has a similar overall profile with maximal 54% reduction of luciferase expression. These results suggested that (mPEG5k-PCL1.2k)1.4-g-PEI10k/SiRNA nanoparticles could serve as a kind of highly efficient siRNA delivery system for down-regulating the expression of exogenous and endogenous target genes.
authors.affiliation: State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Huang
authors.forename: Ming
authors.initials: M
authors.lastname: Lv
authors.forename: Zhong-Gao
authors.initials: ZG
authors.lastname: Gao
authors.forename: Ming-Ji
authors.initials: MJ
authors.lastname: Jin
authors.forename: Yuan-Ji
authors.initials: YJ
authors.lastname: Xu
authors.forename: Xiao-Dan
authors.initials: XD
authors.lastname: Yu
authors.forename: Zhe-Hu
authors.initials: ZH
authors.lastname: Jin
authors.forename: Xue-Zhe
authors.initials: XZ
authors.lastname: Yin
mesh_terms: D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004396:Coloring Agents; D015536:Down-Regulation / Q000187:drug effects; D016503:Drug Delivery Systems; D015870:Gene Expression / Q000187:drug effects; D020868:Gene Silencing / Q000187:drug effects; D018390:Gene Targeting; D018014:Gene Transfer Techniques; D006801:Humans; D053758:Nanoparticles; D010957:Plasmids / Q000187:drug effects / Q000235:genetics; D011091:Polyesters; D011092:Polyethylene Glycols; D011108:Polymers / Q000737:chemistry*; D034741:RNA, Small Interfering / Q000008:administration & dosage*; D013778:Tetrazolium Salts; D013844:Thiazoles
chemical_list: D004396:Coloring Agents; D011091:Polyesters; D011108:Polymers; D034741:RNA, Small Interfering; D013778:Tetrazolium Salts; D013844:Thiazoles; C439611:methoxy poly(ethylene glycol-co-epsilon-caprolactone); D011092:Polyethylene Glycols; C022616:thiazolyl blue