title: Redox and pH dual responsive poly(amidoamine) dendrimer-poly(ethylene glycol) conjugates for intracellular delivery of doxorubicin.
abstract: To solve the contradiction between long circulation time and effective intracellular drug release, redox and pH-responsive drug delivery system was developed by incorporated redox-sensitive disulfide linkage between poly(amidoamine) dendrimers (PAMAM) and poly(ethylene glycol) (PEG). Doxorubicin (DOX) was loaded into the hydrophobic core of the conjugates to prepare PAMAM-SS-PEG/DOX complexes (PSSP/DOX). In vitro release studies suggested that DOX release from PSSP/DOX complexes followed an redox and acid-triggered manner and increased with increasing PEGylation degree. In vitro cytotoxicity of PSSP/DOX complexes against B16 tumor cells increased with, while cellular uptake decreased with increasing PEGylation degree. Further, intracellular DOX release observation and measurement indicate that the intracellular DOX release played a critical role for the cytotoxicity of DOX-loaded PSSP conjugates. In addition, cellular entry mechanism of the PSSP/DOX study demonstrated that both clathrin- and caveolae-mediated endocytosis were the primary pathways for cellular entry of PSSP/DOX. Finally, in vivo study of PSSP/DOX complexes in B16 tumor-bearing mice indicate that PSSP/DOX could significantly improve antitumor efficiency and present a good safety. The redox and pH-responsive drug delivery system has been demonstrated to be a promising candidate for solid tumor therapy.
  
  
  
  In previous research, pH-sensitive diblock polymer of poly(ethylene glycol)-poly(2,4,6-trimethoxybenzylidene-pentaerythritol carbonate) (PEG-PTMBPEC) was synthesized to facilitate the intracellular anticancer drug release. However, the nanoparticles based on PEG-PTMBPEC get into the tumor cells just relying on the EPR-mediated passive targeting resulting in the low drug accumulation. Therefore, cRGD peptide modified PEG-PTMBPEC polymeric micelles were developed for specific targeted delivery of doxorubicin (DOX) to neovascular cells and tumor cells simultaneously. The precise intracellular target site and effective drug concentration will contribute to enhancing the antitumor toxicity and reducing the systematic toxicity of DOX. The cRGD modified pH-sensitive micellar system is a promising vehicle for intracellular drug delivery to αvβ3 integrin receptor overexpressed tumor cells and neovascular cells.
authors.affiliation: Department of Pharmaceutics, College of Pharmaceutical Sciences, Soochow University, Suzhou 215123, China; Yangtze River Pharmaceutical Group, Taizhou 225321, China.
authors.forename: Wen
authors.initials: W
authors.lastname: Hu
authors.affiliation: Department of Pharmaceutics, School of Pharmaceutical Sciences, Jiangnan University, Wuxi 214122, China.
authors.forename: Lipeng
authors.initials: L
authors.lastname: Qiu
authors.affiliation: Department of Pharmaceutics, College of Pharmaceutical Sciences, Soochow University, Suzhou 215123, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Cheng
authors.affiliation: Department of Pharmaceutics, College of Pharmaceutical Sciences, Soochow University, Suzhou 215123, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Hu
authors.affiliation: School of Pharmacy, Nanjing Medical University, Nanjing 210029, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Pharmaceutics, College of Pharmaceutical Sciences, Soochow University, Suzhou 215123, China.
authors.forename: Ziyang
authors.initials: Z
authors.lastname: Hu
authors.affiliation: Department of Pharmaceutics, College of Pharmaceutical Sciences, Soochow University, Suzhou 215123, China. Electronic address: chendawei@suda.edu.cn.
authors.forename: Dawei
authors.initials: D
authors.lastname: Chen
authors.affiliation: Department of Pharmaceutics, College of Pharmaceutical Sciences, Soochow University, Suzhou 215123, China. Electronic address: chenglifang0803@126.com.
authors.forename: Lifang
authors.initials: L
authors.lastname: Cheng
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D050091:Dendrimers / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology; D004317:Doxorubicin / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology; D016503:Drug Delivery Systems / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D051379:Mice; D009374:Neoplasms, Experimental / Q000188:drug therapy* / Q000378:metabolism; D010084:Oxidation-Reduction; D011073:Polyamines / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology; D011092:Polyethylene Glycols / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology
chemical_list: D050091:Dendrimers; C104700:PAMAM Starburst; C531249:Poly(amidoamine); D011073:Polyamines; D011092:Polyethylene Glycols; D004317:Doxorubicin
keywords: Antitumor activity; Cellular uptake; Dual responsive; Poly(amidoamine) dendrimers; Poly(ethylene glycol)