PEGylated adenovirus vectors containing RGD peptides on the tip of PEG show high transduction efficiency and antibody evasion ability.
BACKGROUND
PEGylation of adenovirus vectors (Ads) is an attractive strategy in gene therapy. Although many types of PEGylated Ad (PEG-Ads), which exhibit antibody evasion activity and long plasma half-life, have been developed, their entry into cells has been prevented by steric hindrance by polyethylene glycol (PEG) chains. Likewise, sufficient gene expression for medical treatment could not be achieved.


METHODS
A set of PEG-Ads, which have different PEG modification rates, was constructed, and gene expression was evaluated using A549 cells. A novel PEGylated Ad (RGD-PEG-Ad), which contained RGD (Arg-Gly-Asp) peptides on the tip of PEG, was developed. We evaluated gene expression both in Coxsackie-adenovirus receptor (CAR)-positive as well as -negative cells, and in vivo gene expression was also determined. Furthermore, the antibody evasion ability and the specificity of infection exhibited by this RGD-PEG-Ad were also evaluated.


RESULTS
Whereas PEG-Ads decreased gene expression in CAR-positive cells, RGD-PEG-Ad enhanced gene expression notably, to a level about 200-fold higher than that of PEG-Ads. Moreover, gene expression of RGD-PEG-Ad was almost equal to that of Ad-RGD, which contains an RGD-motif in the fiber and exhibits among the highest gene expression of CAR-positive and -negative cells. Furthermore, although Ad-RGD gene expression decreased remarkably in the presence of anti-Ad antiserum, RGD-PEG-Ad maintained its activity against antibodies. In vivo experiments also demonstrated that the modification of Ads with RGD-PEG induced efficient gene expression.


CONCLUSIONS
In the present study, we demonstrated that a new strategy, which combined integrin-targeting the RGD peptide on the tip of PEG and modified the Ad using this material, could enhance gene expression in both CAR-positive and -negative cells. At the same time, this novel PEGylated Ad maintained strong protective activity against antibodies. This strategy could also be easily modified for developing other vectors using other targeting molecules.
Eto
Yusuke
Y
Graduate School of Pharmaceutical Sciences, Osaka University, Japan.
Gao
Jian-Qing
JQ
Sekiguchi
Fumiko
F
Kurachi
Shinnosuke
S
Katayama
Kazufumi
K
Maeda
Mitsuko
M
Kawasaki
Koichi
K
Mizuguchi
Hiroyuki
H
Hayakawa
Takao
T
Tsutsumi
Yasuo
Y
Mayumi
Tadanori
T
Nakagawa
Shinsaku
S
D000256:Adenoviridae / Q000235:genetics*; D000818:Animals; D000914:Antibodies, Viral / Q000276:immunology*; D045744:Cell Line, Tumor; D005260:Female; D005822:Genetic Vectors; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics / Q000276:immunology / Q000628:therapy*; D008546:Melanoma, Experimental / Q000235:genetics / Q000276:immunology / Q000628:therapy*; D051379:Mice; D008807:Mice, Inbred BALB C; D008813:Mice, Inbred ICR; D009842:Oligopeptides / Q000627:therapeutic use*; D011092:Polyethylene Glycols / Q000008:administration & dosage* / Q000737:chemistry; D011422:Propionates / Q000008:administration & dosage / Q000737:chemistry; D012878:Skin Neoplasms / Q000235:genetics / Q000276:immunology / Q000628:therapy; D014161:Transduction, Genetic
D000914:Antibodies, Viral; D009842:Oligopeptides; D011422:Propionates; D011092:Polyethylene Glycols; C047981:arginyl-glycyl-aspartic acid; C028210:monomethoxypolyethylene glycol