[High sensitivity to cell death and low repair activity of DNA damages after exposure to oxidative stress in Cockayne syndrome (CS) patient-derived cells].

Objective: To investigate the protective function of Cockayne syndrome (CS) patient-derived cells against oxidative stress, we examined the sensitivity to cell death and the repair activity of DNA damages after exposure to oxidative stress in CS cells.

Methods: We used two CS cell lines, CS3BES (CSA defective) and CSIANS (CSB defective), the human cervical cancer cell line HeLa cells, and the human fibroblastic cell line RSa. Cells were exposed to oxidative stresses, such as X-ray irradiation and hydrogen peroxide treatment, and the sensitivity to cell death was examined using the colony survival assay and MTT assay. DNA lesions were analyzed using the comet assay.

Results: CS3BES and CS1ANS cells showed higher sensitivity to cell death induced by X ray and hydrogen peroxide than HeLa and RSa cells. Furthermore, after exposure to the stresses the levels of DNA damage were higher, or repair activity was lower in CS3BES cells when compared with HeLa cells.

Conclusions: The present results clearly show that the two CS cell lines are vulnerable to oxidative stress and suggest that both CSA and CSB proteins are involved in the protective response against oxidative injury.