title: Sheddable ternary nanoparticles for tumor acidity-targeted siRNA delivery.
abstract: Drug delivery systems for cancer therapy usually need to be sterically stabilized by a poly(ethylene glycol) (PEG) layer during blood circulation to minimize nonspecific interactions with serum components. However, PEGylation significantly reduces cellular uptake of the delivery systems after they accumulate at the tumor site, which markedly impairs the in vivo antitumor efficiency. Here, we develop a ternary small interfering RNA (siRNA) delivery system with tumor acidity-activated sheddable PEG layer to overcome the challenge. The sheddable nanoparticle is fabricated by introducing a tumor acidity-responsive PEGylated anionic polymer to the surface of positively charged polycation/siRNA complexes via electrostatic interaction. We show clear evidence that introducing the PEGylated anionic polymer to the surface of a nanoparticle markedly reduces its nonspecific interactions with protein. We further demonstrate that the nanoparticle is capable of deshielding the PEG layer at the slightly acidic tumor extracellular microenvironment to facilitate the delivery of siRNA to the tumor cells after accumulation at the tumor site. Accordingly, this promotes the RNA-interfering efficiencies and enhances the inhibition of tumor growth. Such delivery system with the ability to deshield the PEG layer at the target tissues has remarkable potential in cancer therapy.
authors.affiliation: CAS Key Laboratory of Brain Function and Disease, and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, People's Republic of China.
authors.forename: Xian-Zhu
authors.initials: XZ
authors.lastname: Yang
authors.forename: Jin-Zhi
authors.initials: JZ
authors.lastname: Du
authors.forename: Shuang
authors.initials: S
authors.lastname: Dou
authors.forename: Cheng-Qiong
authors.initials: CQ
authors.lastname: Mao
authors.forename: Hong-Yan
authors.initials: HY
authors.lastname: Long
authors.forename: Jun
authors.initials: J
authors.lastname: Wang
mesh_terms: D045744:Cell Line, Tumor; D006801:Humans; D006863:Hydrogen-Ion Concentration; D053769:Nanocapsules / Q000737:chemistry*; D009374:Neoplasms, Experimental / Q000235:genetics* / Q000628:therapy*; D011092:Polyethylene Glycols / Q000737:chemistry*; D034741:RNA, Small Interfering / Q000008:administration & dosage* / Q000235:genetics*
chemical_list: D053769:Nanocapsules; D034741:RNA, Small Interfering; D011092:Polyethylene Glycols