title: Galactosylated 2-hydroxypropyl methacrylamide-s-3-guanidinopropyl methacrylamide copolymer as a small hairpin RNA carrier for inhibiting human telomerase reverse transcriptase expression.
abstract: BACKGROUND
  In the present study, a well-defined glucose and guanidine based copolymer, galactosylated 2-hydroxypropyl methacrylamide-s-3-guanidinopropyl methacrylamide (HPMA-s-GPMA) abbreviated as GGH was prepared and self-assembled with small hairpin RNA (shRNA) to inhibit human telomerase reverse transcriptase (hTERT) gene expression in vitro to develop a shRNA carrier.
  
  
  METHODS
  First, HPMA-s-APMA copolymers were synthesized by aqueous reversible addition-fragmentation chain transfer polymerization, followed by galactosylation and guanidinylation. Then, three target shRNAs containing green fluorescent protein gene as a reporter were combined with GGH to form shRNA/GGH polyplexes.
  
  
  RESULTS
  GGH copolymers could condense shRNA to form shRNA/GGH polyplex particles with a diameter in the range 122.8-331.6 nm in phosphate-buffered saline, and zeta potential values ranging from +3.7 to +16.5 mV at various charge ratios (N/P). That the cytotoxicity of GGH copolymers was significantly lower than that of PEI in human hepatocellular liver carcinoma cells (HepG2) and human cervix epithelial carcinoma cells. The transfection efficiency of shRNA/GGH polyplexes was higher than that of PEI at a charge ratio of 12 in the HepG2 cell line. Furthermore, shRNA/GGH polyplexes could effectively silence hTERT mRNA expression in serum-free medium (p < 0.01) and decrease the aggregation of protein in the medium with the presence of 10% serum. In addition, hTERT mRNA expression in HepG2 cells demosntrate a significant difference between siRNA/GGH polyplexes and blank samples (p < 0.05).
  
  
  CONCLUSIONS
  GGH copolymers could integrate advantages relating to galactose content for hepatocyte targeting, guanidino groups for cell penetration and HPMA component for shielding, showing great potential for effective hepatocyte targeting gene delivery.
authors: Biomaterials and Drug Delivery Laboratory, School of Chemistry and Chemical Engineering, Southeast University, Nanjing, China.
authors: Yang
authors: Y
authors: Wu
authors: Jingkai
authors: J
authors: Ji
authors: Ran
authors: R
authors: Yang
authors: Xiaoqiang
authors: X
authors: Zhang
authors: Yuanhui
authors: Y
authors: Li
authors: Yuepu
authors: Y
authors: Pu
authors: Xinsong
authors: X
authors: Li
mesh_terms: D000180:Acrylic Resins / Q000138:chemical synthesis / Q000737:chemistry*; D045744:Cell Line, Tumor; D004337:Drug Carriers / Q000138:chemical synthesis / Q000737:chemistry*; D015870:Gene Expression; D018014:Gene Transfer Techniques; D006146:Guanidines / Q000138:chemical synthesis / Q000737:chemistry*; D006367:HeLa Cells; D056945:Hep G2 Cells; D006801:Humans; D010316:Particle Size; D034622:RNA Interference; D012333:RNA, Messenger / Q000235:genetics; D034741:RNA, Small Interfering / Q000008:administration & dosage / Q000737:chemistry / Q000235:genetics*; D019098:Telomerase / Q000235:genetics*; D014162:Transfection
chemical_list: D000180:Acrylic Resins; D004337:Drug Carriers; D006146:Guanidines; C572241:N-3-guanidinopropyl methacrylamide-N-2-hydroxypropyl methacrylamide copolymer; D012333:RNA, Messenger; D034741:RNA, Small Interfering; C509186:TERT protein, human; D019098:Telomerase
keywords: gene silencing; hTERT; shRNA; targeting