Fig. 4.

IL-6 knocked down CD133+ cells showed lower expression of DNA repair-associated molecules. a Higher expression of γ-H2AX indicating unrepaired DNA damage was found in IL-6 knocked down CD133+ cell cultures measured by IF staining. CD133+ cells of A549IL-6si/sc and H157IL-6si/sc pairs were irradiated with 6 Gy gamma rays and γ-H2AX IF staining was performed at 3 h after irradiation. b Higher DNA strand breaks were detected in CD133+ cells of IL-6si cells than those of sc cells. CD133+ and CD133- cells were obtained from A549IL-6si/sc and H157IL-6si/sc cell pairs, irradiated (6 Gy), and DNA strand breaks were analyzed at 0 and 30 min after radiation in Comet assay. The ratio of head diameter to comet length of 50 cells were measured in each sample analysis and used in quantitation shown on right. c Lower expression of DNA repair associated proteins, ATM, CHK2, p-ATM, and p-p53 were detected in CD133+ cells of IL-6 knocked down cell line than those of sc counterparts (IF staining). CD133+ and CD133- cells of A549IL-6si/sc and H157IL-6si/sc pairs were irradiated with 6 Gy gamma rays and IF staining was performed at 2 h after irradiation using antibodies of ATM, CHK2, p-ATM, and p-p53. d qPCR analysis. CD133+ cells of A549IL-6si/sc and H157IL-6si/sc pairs were irradiated with 6 Gy gamma rays and total RNAs were obtained for qPCR analyses at 6 h after irradiation. e ATM-luc assay. 293HEK and H1299 cells were transfected with ATM-luc and cultured with various concentrations of IL-6. At the end of 48 h of incubation, luciferase activities were measured