title: Characterization of polyethylene glycol-grafted polyethylenimine and superparamagnetic iron oxide nanoparticles (PEG-g-PEI-SPION) as an MRI-visible vector for siRNA delivery in gastric cancer in vitro and in vivo.
abstract: BACKGROUND
  Gene therapy is a promising therapeutic method but is severely hampered due to its lack of an ideal delivery system. Therefore, in this study, a nonviral and magnetic resonance imaging (MRI) visible vector, polyethylene glycol-grafted polyethylenimine and superparamagnetic iron oxide nanoparticles (PEG-g-PEI-SPION) was used as a nanocarrier for small interfering RNA (siRNA) delivery in gastric cancer.
  
  
  METHODS
  Biophysical characterization of PEG-g-PEI-SPION was systematically analyzed, including size, zeta potential, siRNA condensation capacity, cell viability, transfection efficiency, cellular uptake, and MRI-visible function in vivo. Besides, CD44 variant isoform 6 (CD44v6), a protein marker for metastatic behavior in gastric cancer, and was chose as the target gene to further analyze the siRNA delivery function of PEG-g-PEI-SPION.
  
  
  RESULTS
  Under comprehensive analysis, the appropriate N/P ratio of PEG-g-PEI-SPION/siRNA was 10, and siRNA targeting at human CD44v6 (siCD44v6) transferred by PEG-g-PEI-SPION was effective at downregulating the CD44v6 expression of gastric carcinoma cell line SGC-7901 in vitro. Moreover, knockdown of CD44v6 impaired migrating and invasive abilities of SGC-7901 cells. Furthermore, PEG-g-PEI-SPION was a highly efficient contrast agent for MRI scan in vivo.
  
  
  CONCLUSIONS
  PEG-g-PEI-SPION was a promising nonviral vector with molecular image tracing capacity for cancer gene therapy. And CD44v6 was a potential target gene for the prevention and detection of metastatic behavior in gastric cancer.
authors.affiliation: Department of Gastroenterology, The Second Affiliated Hospital of Sun Yat-sen University, Guangzhou 510120, China.
authors.forename: Yinting
authors.initials: Y
authors.lastname: Chen
authors.forename: Guoda
authors.initials: G
authors.lastname: Lian
authors.forename: Chengde
authors.initials: C
authors.lastname: Liao
authors.forename: Weiwei
authors.initials: W
authors.lastname: Wang
authors.forename: Linjuan
authors.initials: L
authors.lastname: Zeng
authors.forename: Chenchen
authors.initials: C
authors.lastname: Qian
authors.forename: Kaihong
authors.initials: K
authors.lastname: Huang
authors.forename: Xintao
authors.initials: X
authors.lastname: Shuai
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D015536:Down-Regulation; D005260:Female; D005290:Ferric Compounds / Q000737:chemistry; D055785:Gene Knockdown Techniques; D018390:Gene Targeting; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors; D006801:Humans; D018960:Hyaluronan Receptors / Q000235:genetics*; D008279:Magnetic Resonance Imaging / Q000379:methods; D058185:Magnetite Nanoparticles / Q000737:chemistry; D008819:Mice, Nude; D009361:Neoplasm Invasiveness; D009362:Neoplasm Metastasis / Q000517:prevention & control; D011092:Polyethylene Glycols / Q000737:chemistry; D011094:Polyethyleneimine / Q000031:analogs & derivatives / Q000737:chemistry; D034741:RNA, Small Interfering / Q000008:administration & dosage*; D013274:Stomach Neoplasms / Q000473:pathology / Q000628:therapy*
chemical_list: C112697:CD44v6 antigen; D005290:Ferric Compounds; D018960:Hyaluronan Receptors; D058185:Magnetite Nanoparticles; D034741:RNA, Small Interfering; C544016:poly(ethylene glycol)-co-poly(ethyleneimine); C000499:ferric oxide; D011092:Polyethylene Glycols; D011094:Polyethyleneimine