Role of TDP2 in the repair of DNA damage induced by the radiomimetic drug Bleomycin
Abstract Background Bleomycin (Bleo) is a glycopeptide with potent antitumor activity that induces DNA double-strand breaks (DSBs) through free radical generation, similar to ionizing radiation (IR). Therefore, Bleo is considered a radiomimetic drug. However, differences in DNA repair mechanisms bet...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
BMC
2025-03-01
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| Series: | Genes and Environment |
| Subjects: | |
| Online Access: | https://doi.org/10.1186/s41021-025-00329-9 |
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| Summary: | Abstract Background Bleomycin (Bleo) is a glycopeptide with potent antitumor activity that induces DNA double-strand breaks (DSBs) through free radical generation, similar to ionizing radiation (IR). Therefore, Bleo is considered a radiomimetic drug. However, differences in DNA repair mechanisms between IR- and Bleo-induced DNA damage have not been fully elucidated. Therefore, in the present study, we examined a panel of repair-deficient human TK6 cell lines to elucidate the relative contributions of individual repair factors. Results Our comprehensive profiling indicated that both non-homologous end joining (NHEJ) and homologous recombination (HR) contributed to DSB repair induced by X-rays and Bleo. Furthermore, tyrosyl-DNA phosphodiesterase (TDP)-related repair was a significant factor for cellular sensitivity to Bleo treatment. TDP1 −/− /TDP2 −/− cells exhibited greater sensitivity to Bleo than TDP1 −/− or TDP2 −/− cells, but not to X-rays. In addition, we determined whether TDP2 is involved in the repair of Bleo-induced DSBs using a neutral comet assay. In TDP1-deficient cells, knockout of TDP2 resulted in a significant delay in the repair kinetics of DSBs induced by Bleo, but not by X-rays. Conclusions The contribution of the TDP-related pathway to DSB repair significantly differed between IR and radiomimetic drugs. The discovery of this novel TDP2-dependent repair of DSBs resulting from radiomimetic drug exposure indicates that TDP1 and TDP2 inhibition in combination with radiomimetic drugs represents a strategy for cancer treatment. |
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| ISSN: | 1880-7062 |