RNA干扰靶向沉默Ku70对人肺腺癌耐药细胞细胞周期与凋亡的影响

Objective In this paper ,to explore the role of Ku70 in the regulation of drug-resistance in lung cancer, we examined the changes of cell cycle and apoptosis of A549DDP by silencing Ku70 using small interfering RNA (SiRNA) . Methods Expression of Ku70mRNA and Ku70 protein were measured in parental A549 and A549DDP by RT-PCR and Western Blot. A549DDP was transfected with Ku70 siRNA targeting Ku70. The changes of the inhibition rate of cell morphology,cell cycle , apoptosis and caspase-3 activity were observed by flow cytometry and spectrophotometer.Results 1.The Ku70mRNA and protein expression were higher in A549DDP cells compared with those in A549 cells; 2.The expression of Ku70 mRNA and protein in A549DDP were downregulated after the siRNA plasmid transfected. With the equal concentrations of DDP the apoptosis rate increased;mitochondrial membrane potential declined;cell cycle arrested at S phase; and activity of caspase-3 increased ;more changes of apoptotic cells in morphology in Ku70 silencing A549. Conclusions Our data provide the functional study of Ku70 as an apoptosis and drug-resistance modulator , which show Ku70 might be involved in the development of drug resistance of lung cancer. Ku70 siRNA downregulated the expression of Ku70 and promted the apoptosis of A549DDP .Therefore, Ku70 may be the marker of resistance to chemotherapy for tumor and a new target that reverses the chemotherapy-resistant of lung cancer.