title: Comparison of anti-EGFR-Fab' conjugated immunoliposomes modified with two different conjugation linkers for siRNa delivery in SMMC-7721 cells.
abstract: BACKGROUND
  Targeted liposome-polycation-DNA complex (LPD), mainly conjugated with antibodies using functionalized PEG derivatives, is an effective nanovector for systemic delivery of small interference RNA (siRNA). However, there are few studies reporting the effect of different conjugation linkers on LPD for gene silencing. To clarify the influence of antibody conjugation linkers on LPD, we prepared two different immunoliposomes to deliver siRNA in which DSPE-PEG-COOH and DSPE-PEG-MAL, the commonly used PEG derivative linkers, were used to conjugate anti-EGFR Fab' with the liposome.
  
  
  METHODS
  First, 600 μg of anti-EGFR Fab' was conjugated with 28.35 μL of a micelle solution containing DSPE-PEG-MAL or DSPE-PEG-COOH, and then post inserted into the prepared LPD. Various liposome parameters, including particle size, zeta potential, stability, and encapsulation efficiency were evaluated, and the targeting ability and gene silencing activity of TLPD-FPC (DSPE-PEG-COOH conjugated with Fab') was compared with that of TLPD-FPM (DSPE-PEG-MAL conjugated with Fab') in SMMC-7721 hepatocellular carcinoma cells.
  
  
  RESULTS
  There was no significant difference in particle size between the two TLPDs, but the zeta potential was significantly different. Further, although there was no significant difference in siRNA encapsulation efficiency, cell viability, or serum stability between TLPD-FPM and TLPD-FPC, cellular uptake of TLPD-FPM was significantly greater than that of TLPD-FPC in EGFR-overexpressing SMMC-7721 cells. The luciferase gene silencing efficiency of TLPD-FPM was approximately three-fold high than that of TLPD-FPC.
  
  
  CONCLUSIONS
  Different conjugation linkers whereby antibodies are conjugated with LPD can affect the physicochemical properties of LPD and antibody conjugation efficiency, thus directly affecting the gene silencing effect of TLPD. Immunoliposomes prepared by DSPE-PEG-MAL conjugation with anti-EGFR Fab' are more effective than TLPD containing DSPE-PEG-COOH in targeting hepatocellular carcinoma cells for siRNA delivery.
authors.affiliation: Department of Pharmaceutical Science, China.
authors.forename: Li
authors.initials: L
authors.lastname: Deng
authors.forename: Yingying
authors.initials: Y
authors.lastname: Zhang
authors.forename: Lulu
authors.initials: L
authors.lastname: Ma
authors.forename: Xiaolong
authors.initials: X
authors.lastname: Jing
authors.forename: Xingfa
authors.initials: X
authors.lastname: Ke
authors.forename: Jianhao
authors.initials: J
authors.lastname: Lian
authors.forename: Qiang
authors.initials: Q
authors.lastname: Zhao
authors.forename: Bo
authors.initials: B
authors.lastname: Yan
authors.forename: Jinfeng
authors.initials: J
authors.lastname: Zhang
authors.forename: Jianzhong
authors.initials: J
authors.lastname: Yao
authors.forename: Jianming
authors.initials: J
authors.lastname: Chen
mesh_terms: D000911:Antibodies, Monoclonal; D006528:Carcinoma, Hepatocellular / Q000235:genetics* / Q000276:immunology* / Q000628:therapy; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000235:genetics; D003432:Cross-Linking Reagents / Q000737:chemistry; D066246:ErbB Receptors / Q000276:immunology*; D015316:Genetic Therapy / Q000379:methods; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000737:chemistry / Q000276:immunology*; D008081:Liposomes / Q000138:chemical synthesis* / Q000276:immunology; D008422:Materials Testing; D034741:RNA, Small Interfering / Q000008:administration & dosage* / Q000737:chemistry / Q000235:genetics*
chemical_list: D000911:Antibodies, Monoclonal; D003432:Cross-Linking Reagents; D007140:Immunoglobulin Fab Fragments; D008081:Liposomes; D034741:RNA, Small Interfering; C512478:EGFR protein, human; D066246:ErbB Receptors
keywords: anti-EGFR Fab’; conjugation technology; hepatocellular carcinoma; immunoliposomes; liposome-polycation-DNA; small interfering RNA delivery
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