화학공학소재연구정보센터
Biochemical and Biophysical Research Communications, Vol.283, No.4, 726-731, 2001
DNA-dependent protein kinase is inhibited by trifluoperazine
The DNA-dependent protein kinase (DNA-PK) is a serine/threonine nuclear kinase, important for the repair of DNA double strand breaks (DSB). Cells defective in DNA PK show increased sensitivity to ionising radiation and different DNA-damaging drugs, such as cisplatinum. Increased sensitivity to cisplatinum has previously been noted in the presence of phenothiazines. We tested a panel of phenothiazines and one thioxanthen for any influence upon the activity and expression of DNA-PK in a nonsmall cell lung cancer cell line, U-1810. The activity of DNA-PK was completely inhibited in cell lysate and in purified enzyme by 200 muM TFP. DNA-PKcs and Ku86 cleavage were evident in U-1810 cells after 30 min incubation with 100 muM TFP, along with changes in the cells consistent with apoptosis. Our study suggests that phenothiazines and thioxanthens, acting through DNA-PK, have the potential to enhance the effects of DNA damaging agents.