Effect of a protein kinase CK2 inhibitor on intracellular levels of reactive oxygen species and DNA double-stand break in H460 cells / 中华放射肿瘤学杂志

ABSTRACT

Objective To evaluate the effect of a protein kinase CK2 inhibitor on intracellular levels of reactive oxygen species and DNA double?stand break in human non?small cell lung cancer H460 cells. Methods H460 cells were exposed to 0, 12?5, 25.0, and 50.0μmol/L quinalizarin, a specific inhibitor of protein kinase CK2, for 24 hours. The changes in protein and mRNA levels of CK2 subunits were measured. Flow cytometry was used to measure changes in the intracellular levels of reactive oxygen species in H460 cells after 4 or 24 hours of quinalizarin treatment. Immunofluorescence assays were performed to determine the effect of the CK2 inhibitor onγ?H2 AX expression and the average fluorescent number ofγ?H2 AX foci in H460 cells. Comparison was made by analysis of variance and t test. Results There were no significant differences in protein or mRNA levels of CK2 subunits in H460 cells after quinalizarin treatment ( CK2α,0μmol vs. 12?5 μmol/L, P=0?966;0 μmol/L vs. 25 μmol/L, P=0?355;0 μmol/L vs. 50 μmol/L, P=0?864, CK2α’ , 0 μmol/L vs. 12?5μmol/L,P=0?409;0μmol/L vs. 25μmol/L,P=0?833;0μmol/L vs. 50 μmol/L, P=0?0. 746, CK2β, 0 μmol/L vs. 12?5 μmol/L, P=0?532;0 μmol/L vs. 25 μmol/L, P=0?830;0 μmol/L vs. 50 μmol/L, P= 0?061 ) . The intracellular levels of reactive oxygen species were substantially elevated in H460 cells with the increase in quinalizarin concentration and treatment time. Different concentrations of quinalizarin resulted in dose?and time?dependent increases in the numbers of γ?H2 AX foci after 4 and 24 hours of treatment ( treated by Quianlizarin for 4 or 24 h, 0 μmol/L vs. 12?5μmol/L,12?5 μmol/L vs. 25 μmol/L, 25 μmol/L vs. 50 μmol/L, all P=0?000, concentration is 12?5μmol/L,25 μmol/L or 50 μmol/L, 4 h vs. 24 h, all all P=0?000 ) . Conclusions Quinalizarin can increase the intracellular levels of reactive oxygen species and DNA double?stand break in H460 cells by inhibition of protein kinase CK2 activity. This study provides a theoretical basis for using quinalizarin as a potential radiosensitizer for lung cancer.