Gene therapy by intrahepatic and intratumoral trafficking of p53-VP22 induces regression of liver tumors.
OBJECTIVE
VP22-mediated intercellular transport provides an approach to deliver functional chimeric proteins into a high percentage of target cells. The aim of this study was to evaluate the efficacy of p53/VP22 fusion protein in gene therapy of liver tumors.


METHODS
Expression vectors of N- and C-terminal fusion proteins of p53 and VP22 were subcloned and transcriptional properties of chimeric proteins were assessed by luciferase assays. Adenoviral vectors expressing p53 wild type (AdGFP/p53wt) and p53-VP22 (AdGFP/p53-VP22) were generated to investigate the VP22-mediated spreading in normal liver and in liver tumors in vivo by green fluorescent protein fluorescence and p53 immunohistochemistry. Gene therapy was investigated in subcutaneous and preclinical orthotopic animal tumor models after subcutaneous and intra-arterial administration of the adenoviruses, and tumor growth was assessed by direct calibration and magnetic resonance imaging.


RESULTS
p53-VP22 showed enhanced transcriptional activity compared with p53 wild type. VP22-mediated intercellular transport of p53 could be observed in the normal liver and in liver tumors in vivo and was correlated with increased antitumor efficacy of gene therapy and improved survival of the animals.


CONCLUSIONS
Fusion of VP22 to p53 strongly improves the results of p53 replacement gene therapy. Furthermore, the demonstrated VP22-mediated intercellular transport in the liver could be important for other strategies in liver gene therapy, providing a tool for enhancing the effect of gene therapy in liver diseases such as metabolic disorders or viral hepatitis.
Zender
Lars
L
Department of Gastroenterology and Hepatology, Medical School Hannover, Hannover, Germany.
Köck
Reiner
R
Eckhard
Matthias
M
Frericks
Bernd
B
Gösling
Thomas
T
Gebhardt
Thomas
T
Drobek
Susanne
S
Galanski
Michael
M
Kühnel
Florian
F
Manns
Michael
M
Kubicka
Stefan
S
D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D017209:Apoptosis; D016158:Genes, p53; D015316:Genetic Therapy; D005822:Genetic Vectors; D006801:Humans; D008114:Liver Neoplasms, Experimental / Q000628:therapy*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D011993:Recombinant Fusion Proteins / Q000235:genetics*; D015533:Transcriptional Activation; D014407:Tumor Cells, Cultured; D015678:Viral Structural Proteins / Q000235:genetics*
D011993:Recombinant Fusion Proteins; D015678:Viral Structural Proteins; C073413:herpes simplex virus type 1 protein VP22