The long-term objective is to develop a novel, non-invasive in vivo reporter system to measure gene transfer by gamma camera imaging using a 99mTc-labeled peptide. This will be accomplished by studying a model system that utilizes a recombinant adenoviral vector (Ad5) encoding the human type 2 somatostatin receptor (hSSTr2), together with 99mTc-labeled and 188Re-labeled peptides with high affinity for the receptor. Cancer cells transfected with the Ad5-hSSTr2 will express the receptor which can be measured by binding of the radiolabeled peptides. The proposed reporter system will be important as a part of a larger objective to treat cancer using gene therapy technology. The developed gene therapy vector will include both the reporter hSSTr2 gene and a therapeutic gene (cytosine deaminase, CD), the reporter allowing in vivo imaging of targeted gene delivery. The reporter gene will also be targeted with a 188Re-peptide for therapy, with concurrent imaging. Currently no reliable in vivo method exists to measure gene transfer and expression in cancer cells.
Specific aim 1 will use an existing Ad5-hSSTr2 to express high levels of the hSSTr2 protein in transfected cancer cell lines. As part of this aim, chimeric hSSTr2 will be produced with engineered domains to increase specificity and sensitivity of detection. The chimeric hSSTr2 genes will be placed in an Ad5 vector with the CD gene for therapy.
Specific aim 2 will evaluate the hSSTr2 protein and newly developed chimeras in vitro. Experiments will evaluate the receptor number, internalization, and recycling kinetics. The hSSTr2 protein will be targeted using the 99mTc-P829 (Diatide, currently in Phase III clinical trials for neuroendocrine cancer) and 188Re-P829 peptides with high affinity for induced hSSTr2 protein.
Specific aim 3 will consist of the in vivo testing of the Ad5 vectors encoding the hSSTr2 (and chimeras) using nude mice with tumors. Gamma camera imaging will be conducted in animal tumor models to measure the location and amount of expression of the transferred hSSTr2 gene constructs, by measuring the binding of the 99mTc- P829 peptide to the receptors. Therapy studies will be conducted using 5-flurocytosine, either alone, or in combination with 188Re-P829 targeting the hSSTr2 protein. Preliminary data presented herein indicate the feasibility of the approach. The proposed research is significant for the gene therapy field since the reporter system will eventfully be extended to human trials, and allow for non-invasive imaging of gene transfer, and provide an additional mechanism for therapy. The proposed reporter system will determine if gene therapy vectors are targeted to tumor, and when further gene therapy treatment is necessary.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
1R01CA080104-01A1
Application #
2899971
Study Section
Medical Biochemistry Study Section (MEDB)
Program Officer
Menkens, Anne E
Project Start
1999-07-06
Project End
2003-04-30
Budget Start
1999-07-06
Budget End
2000-04-30
Support Year
1
Fiscal Year
1999
Total Cost
Indirect Cost
Name
University of Alabama Birmingham
Department
Radiation-Diagnostic/Oncology
Type
Schools of Medicine
DUNS #
004514360
City
Birmingham
State
AL
Country
United States
Zip Code
35294
Buchsbaum, Donald J; Chaudhuri, Tandra R; Zinn, Kurt R (2005) Radiotargeted gene therapy. J Nucl Med 46 Suppl 1:179S-86S
Zinn, K R; Szalai, A J; Stargel, A et al. (2004) Bioluminescence imaging reveals a significant role for complement in liver transduction following intravenous delivery of adenovirus. Gene Ther 11:1482-6
Rogers, B E; Chaudhuri, T R; Reynolds, P N et al. (2003) Non-invasive gamma camera imaging of gene transfer using an adenoviral vector encoding an epitope-tagged receptor as a reporter. Gene Ther 10:105-14
Hemminki, Akseli; Zinn, Kurt R; Liu, Bin et al. (2002) In vivo molecular chemotherapy and noninvasive imaging with an infectivity-enhanced adenovirus. J Natl Cancer Inst 94:741-9
Zinn, Kurt R; Chaudhuri, Tandra R; Krasnykh, Victor N et al. (2002) Gamma camera dual imaging with a somatostatin receptor and thymidine kinase after gene transfer with a bicistronic adenovirus in mice. Radiology 223:417-25
Zinn, Kurt R; Chaudhuri, Tandra R (2002) The type 2 human somatostatin receptor as a platform for reporter gene imaging. Eur J Nucl Med Mol Imaging 29:388-99
Rogers, Buck E; Zinn, Kurt R; Lin, Chin-Yu et al. (2002) Targeted radiotherapy with [(90)Y]-SMT 487 in mice bearing human nonsmall cell lung tumor xenografts induced to express human somatostatin receptor subtype 2 with an adenoviral vector. Cancer 94:1298-305
Chaudhuri, T R; Rogers, B E; Buchsbaum, D J et al. (2001) A noninvasive reporter system to image adenoviral-mediated gene transfer to ovarian cancer xenografts. Gynecol Oncol 83:432-8
Chaudhuri, T R; Mountz, J M; Rogers, B E et al. (2001) Light-based imaging of green fluorescent protein-positive ovarian cancer xenografts during therapy. Gynecol Oncol 82:581-9
Zinn, K R; Chaudhuri, T R; Buchsbaum, D J et al. (2001) Simultaneous evaluation of dual gene transfer to adherent cells by gamma-ray imaging. Nucl Med Biol 28:135-44

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