1. Hypoxia imaging predicts success of hypoxia-induced cytosine deaminase/5-fluorocytosine gene therapy in a murine lung tumor model.
- Author
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Lee, B-F, Lee, C-H, Chiu, N-T, Hsia, C-C, Shen, L-H, and Shiau, A-L
- Subjects
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LUNG tumors , *HYPOXEMIA , *CYTOSINE deaminase , *BIOMARKERS , *LABORATORY mice , *LUCIFERASES , *AUTORADIOGRAPHY , *GENE therapy - Abstract
Tc-99m-HL91 is a hypoxia imaging biomarker. The aim of this study was to investigate the value of Tc-99m-HL91 imaging for hypoxia-induced cytosine deaminase (CD)/5-fluorocytosine (5-FC) gene therapy in a murine lung tumor model. C57BL/6 mice were implanted with Lewis lung carcinoma cells transduced with the hypoxia-inducible promoter-driven CD gene (LL2/CD) or luciferase gene (LL2/Luc) serving as the control. When tumor volumes reached 100 mm3, pretreatment images were acquired after injection of Tc-99m-HL91. The mice were divided into low and high hypoxic groups based on the tumor-to-non-tumor ratio of Tc-99m-HL91. They were injected daily with 5-FC (500 mg kg−1) or the vehicle for 1 week. When tumor volumes reached 1000 mm3, autoradiography and histological examinations were performed. Treatment with 5-FC delayed tumor growth and enhanced the survival of mice bearing high hypoxic LL2/CD tumors. The therapeutic effect of hypoxia-induced CD/5-FC gene therapy was more pronounced in high hypoxic tumors than in low hypoxic tumors. This study provides the first evidence that Tc-99m-HL91 can serve as an imaging biomarker for predicting the treatment responses of hypoxia-regulated CD/5-FC gene therapy in animal tumor models. Our results suggest that hypoxia imaging using Tc-99m-HL91 has the predictive value for the success of hypoxia-directed treatment regimens. [ABSTRACT FROM AUTHOR]
- Published
- 2012
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