Adenovirus-mediated expression of Tob1 sensitizes breast cancer cells to ionizing radiation1
Aim: To investigate the effect of the Tob1 gene, a member of the Transducing Molecule of ErbB2/B-cell Translocation Ggene (TOB/BTG) family, by using the adenovirus-mediated expression of Tob1 on radiosensitivity in a human breast cancer cell line MDA-MB-231. Methods: Cell survival was determined by clonogenic assay. Apoptosis was evaluated by DNA fragmentation gel electrophoresis and terminal deoxynucleotidyl transferase-mediated nick end labeling assay. Protein expression was analyzed by Western blot assay and DNA repair was measured by a host cell reactivation assay. Results: We demonstrated that pre-irradiation treatment with Ad5–Tob1 significantly increased radiosensitivity, accompanying the increased induction of apoptosis and the repression of DNA damage repair. Furthermore, Ad5-Tob1-mediated radiosensitivity correlates with the upregulation of the pro-apoptotic protein Bax and the downregulation of several DNA double strand break repair proteins, including DNA-dependent protein kinases, Ku70 and Ku80, and X-ray-sensitive complementation group 4. Conclusion: Tob1, as a new radiosensitizer, is a new target in the radiotherapy of breast cancer via increasing apoptosis and suppressing DNA repair.
Document Type: Research Article
Affiliations: 1: School of Radiology and Public Health, Soochow University, Suzhou 215123, China 2: Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington DC 20057, USA
Publication date: 2007-10-01