| First Author | Kruszewski M | Year | 1998 |
| Journal | Mutat Res | Volume | 409 |
| Issue | 1 | Pages | 31-6 |
| PubMed ID | 9806500 | Mgi Jnum | J:52738 |
| Mgi Id | MGI:1330094 | Doi | 10.1016/s0921-8777(98)00040-8 |
| Citation | Kruszewski M, et al. (1998) Differential inhibitory effect of OK-1035 on DNA repair in L5178Y murine lymphoma sublines with functional or defective repair of double strand breaks. Mutat Res 409(1):31-6 |
| abstractText | Radiosensitive L5178Y-S (LY-S) subline and its parental, more radioresistant L5178Y-R (LY-R) subline differ in DNA double strand break (DSB) rejoining. In this work we examined by comet assay the repair of X-ray-induced DNA damage in LY cells treated with OK-1035, a potent DNA-PK inhibitor. The unirradiated cells differ: the respective tail moment values for LY-R and LY-S cells were 9.62+/-2.84 and 3.52+/-0.1, reflecting the susceptibility to lysis conditions as well as the possible endogenous (oxidative) damage level. The level of initial DNA damage measured after irradiation (8 Gy) at DNA-denaturing pH was the same in both LY sublines: the mean tail moment values +/- SD were 92.93+/-10.39 for LY-R cells and 94.93+/-12.94 for LY-S cells. In LY-S cells the repair of 8 Gy X-ray-induced damage proceeded identically in the presence or absence of 2 mM OK-1035 to the same level of residual damage. In contrast, the level of residual damage in inhibitor treated LY-R cells was considerably higher than that in the untreated cells. Moreover, the inhibitor affected LY-R cells in G1 and S phases and not those in G2, in agreement with cell-cycle specificity of DNA-PK. These results may indicate that the DSB repair defect previously identified in LY-S cells is due to a lack of function of DNA-PK or its impaired activation in the irradiated cells. |
