Abstract: BACKGROUND ＆ AIM: The cell model of suppressed DNA-PKcs expression by siRNA was constructed and used to study the function of DNA-PKcs. MATERIAL AND METHODS: DNA-PKcs siRNA expression vectors were constructed and HeLa cells were transfected by lipofectamine. Western blot was used to measure the expression of DNA-PKcs and the rate of growth of cells was used to analyze the changes of radiosensitivity. RESULTS: Three stable transfectants were selected from the DNA-PKcs siRNA transfected HeLa cells. Western blot analysis indicated that the expression of DNA-PKcs was suppressed by the siRNA. The sensitivity of cells to UV radiation and ionizing radiation was markedly increased. The growth of tumor cells was inhibited. CONCLUSION: We successfully established the cell model of suppressed DNA-PKcs expression by siRNA. The inhibition of DNA-PKcs could influence the radiosensitivity and growth of tumor cells. DNA-PKcs; siRNA; radiosensitivity; cell proliferation

Key words: DNA-PKcs, siRNA, radiosensitivity, cell proliferation