Imaging adenoviral-mediated herpes virus thymidine kinase gene transfer and expression in vivo

Juri G. Tjuvajev, Shu Hsia Chen, Arjun Joshi, Revathi Joshi, Zong Sheng Guo, Julius Balatoni, Douglas Ballon, Jason Koutcher, Ronald Finn, Savio L. Woo, Ronald G. Blasberg

Research output: Contribution to journalArticle

149 Scopus citations

Abstract

The feasibility of noninvasive imaging of adenoviral-mediated herpes virus type one thymidine kinase (HSV1-tk) gene transfer and expression was assessed in a well-studied animal model of metastatic colon carcinoma of the liver. Tumors were produced in syngeneic BALB/c mice by intrahepatic injection of colon carcinoma cells (MCA-26). Seven days later, three different doses (3 x 108, 1 x 108, and 3 x 107 plaque-forming units (pfu) of the recombinant adenoviral vector ADV. Rous sarcoma virus (RSV)-tk bearing the HSV1-tk gene were administered by intratumoral injection in separate groups of mice. Two control groups of tumor-bearing mice received intratumoral injections of the control adenoviral vector dl-312 or buffer alone, respectively. T2-weighted magnetic resonance (MR) images of mice were obtained before administering the virus and provided an anatomical reference of hepatic tumor localization. Eighteen h after the virus injection, one group of animals was given i.v. injections of 300 μCi of no-carrier-added 5- [131I]-2'-fluoro-1-β-D-arabinofuranosyl-uracil (FIAU) and imaged 24 h later with a gamma camera. In some animals, the tumors were sampled and processed for histology and quantitative autoradiography (QAR). The gamma camera images demonstrated highly specific localization of [131I]FIAU- derived radioactivity to the area of ADV.RSV-tk-injected tumors in the liver, which was confirmed by coregistering the gamma camera and T2-weighted MR images. There was no accumulation of [131I]FIAU-derived radioactivity in tumors that were injected with the control vector or injection solution alone. A more precise distribution of radioactivity in the area of transfected tumor was obtained by histological and QAR comparisons. A heterogeneous pattern of radioactivity distribution in transfected tumors was observed. A punctate pattern of radioactivity distribution was observed in peritumoral liver tissue in animals given injections of 3 x 108 and 1 x 108 pfu of ADV.RSV-tk but not in animals given injections of 3 x 107 pfu nor in control animals. A QAR-microscopic comparison showed that the punctate areas of radioactivity colocalized with cholangial ducts. The level of [131I]FIAU-derived radioactivity accumulation (HSV1-tk expression) in the transfected tumors was vital dose-dependent. The vital dose-dependency of radioactivity accumulation was more pronounced in peritumoral liver, which was confirmed by reverse transcription-PCR analysis. A separate group of tumor-bearing animals received different doses of ADV.RSV-tk vector followed by treatment with ganciclovir (GCV), 10 mg/kg i.p. b.i.d, for 6 days. The ADV.RSV-tk transfected tumors significantly regressed with GCV treatment; the control tumors continued to grow. During the GCV treatment, the levels of liver transaminases (ALT and AST) were significantly increased in animals that received injections of 3 x 108 and 1 x 108 pfu of ADV.RSV-tk but not in animals that received injections of 3 x 107 pfu and in control animals. The observed liver toxicity confirms the results of gamma camera and QAR imaging, which demonstrated an unwanted spread of ADV.RSV-tk vector and HSV1- tk expression in peritumoral and remote liver tissue at higher doses. These and our previous results indicate that noninvasive imaging of adenoviral- mediated HSV1-tk gene expression is feasible for monitoring cancer gene therapy in patients.

Original languageEnglish (US)
Pages (from-to)5186-5193
Number of pages8
JournalCancer research
Volume59
Issue number20
StatePublished - Oct 15 1999

ASJC Scopus subject areas

  • Oncology
  • Cancer Research

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