In vivo adenoviral-mediated human p53 tumor suppressor gene transfer and expression in rat liver after resection.

BACKGROUND

The aim of this study was to establish a clinically relevant model for gene transfer to liver with an adenoviral vector encoding wild-type p53 as a first step toward use of this class of gene products in the treatment of primary and metastatic liver tumors.

METHODS

Full-size or 50% hepatectomized rat livers were subjected to asanguineous portal perfusion with a replication-defective adenoviral vector encoding wild-type p53 (Ad5p53), whereas control animals received adenoviral vector encoding Escherichia coli beta-galactosidase (beta-gal) (Ad5LacZ) or Ringer's lactate only. Liver biopsy specimens, blood samples, and liver weight were serially obtained. Gene transfer and expression were confirmed by X-Gal staining for gamma-gal, DNA/RNA polymerase chain reaction, (PCR) and Western blots for p53 and beta-gal. Liver integrity was assessed by histologic findings, serum transaminase levels, and synthetic function.

RESULTS

The gene transfer rate in whole liver and after hepatectomy ranged from 20% to 40%. DNA PCR showed Ad sequences in livers transduced with Ad5p53 and Ad5LacZ. RNA PCR and Western blot confirmed expression and production of recombinant wild-type p53. Liver regeneration was not affected by p53 gene transduction. Liver histologic findings and synthetic function were not different between transduced and control groups.

CONCLUSIONS

Ad5p53 gene transfer to full-size or hepatectomized livers is efficient. Liver regeneration and hepatocyte function are unaffected by overexpression of p53. Adenovirus-mediated tumor-suppressor transduction of the liver is a safe and promising adjuvant in cancer gene therapy.