Hypoxia targeted bifunctional suicide gene expression enhances radiotherapy in vitro and in vivo

Xiaorong Sun, Ligang Xing, Xuelong Deng, Hung Tsung Hsiao, Akiko Manami, Jason A. Koutcher, C. Clifton Ling, Gloria C. Li

Research output: Contribution to journalArticlepeer-review

19 Citations (Scopus)


Purpose: To investigate whether hypoxia targeted bifunctional suicide gene expression-cytosine deaminase (CD) and uracil phosphoribosyltransferase (UPRT) with 5-FC treatments can enhance radiotherapy. Materials and methods: Stable transfectants of R3327-AT cells were established which express a triple-fusion-gene: CD, UPRT and monomoric DsRed (mDsRed) controlled by a hypoxia inducible promoter. Hypoxia-induced expression/function of CDUPRTmDsRed was verified by western blot, flow cytometry, fluorescent microscopy, and cytotoxicity assay of 5-FU and 5-FC. Tumor-bearing mice were treated with 5-FC and local radiation. Tumor volume was monitored and compared with those treated with 5-FC or radiation alone. In addition, the CDUPRTmDsRed distribution in hypoxic regions of tumor sections was visualized with fluorescent microscopy. Results: Hypoxic induction of CDUPRTmDsRed protein correlated with increased sensitivity to 5-FC and 5-FU. Significant radiosensitization effects were detected after 5-FC treatments under hypoxic conditions. In the tumor xenografts, the distribution of CDUPRTmDsRed expression visualized with fluorescence microscopy was co-localized with the hypoxia marker pimonidazole positive staining cells. Furthermore, administration of 5-FC to mice in combination with local irradiation resulted in significant tumor regression, as in comparison with 5-FC or radiation treatments alone. Conclusions: Our data suggest that the hypoxia-inducible CDUPRT/5-FC gene therapy strategy has the ability to specifically target hypoxic cancer cells and significantly improve the tumor control in combination with radiotherapy.

Original languageEnglish
Pages (from-to)57-63
Number of pages7
JournalRadiotherapy and Oncology
Issue number1
Publication statusPublished - 2012 Oct

All Science Journal Classification (ASJC) codes

  • Hematology
  • Oncology
  • Radiology Nuclear Medicine and imaging


Dive into the research topics of 'Hypoxia targeted bifunctional suicide gene expression enhances radiotherapy in vitro and in vivo'. Together they form a unique fingerprint.

Cite this