Aim: The present study was designed to explore the radiation-resistance mechanism by interfering in checkpoints kinase 1 (CHK1) and DNA-activated protein kinase (DNA-PK) genes with short hairpin RNA (shRNA) transfection into Skov3 cells derived from ovarian cancer and HeLa cells derived from cervical cancer.
Materials and methods: The cultured Skov3 and HeLa cells were transfected with plasmid vectors containing CHK1 shRNA and DNA-PK shRNA, respectively, through Lipofectimine™ 2000 mediation, and cultured for 20 hours before exposure to 2 Gy X-radiation. The cells were harvested 4 and 28 after X-irradiation respectively then washed 3 times with PBS. These cells were stained with Annexin V/PI and applied by flow cytometer to analyze alteration of apoptosis with software CellQuest.
Results: The apoptotic response in Skov3 cells to X-radiation was significantly lower than that in HeLa cells at 4 hour (t = 15.22, P < 0.001) and 28 hours (t = 15.78, P < 0.001) of post-irradiation. The shRNA might not affect the apoptosis of Skov3 and HeLa cells, while shRNA-transfection significantly enhanced the apoptotic response in Skov3 cells to X-radiation as compared with that in HeLa cells.
Conclusions: The present work suggests that the CHK1 and DNA-PK genes are very likely to play a role in developing a radiation resistance in ovarian cancer.