Caffeine inhibits homology-directed repair of I-SceI-induced DNA double-strand breaks

Wang, Huichen; Boecker, Wilfried; Wang, Hongyan; Wang, Xiang; Guan, Jun; Thompson, Larry H.; Nickoloff, Jac A.; Iliakis, George

doi:10.1038/sj.onc.1207168

Cited by 45 publications

(49 citation statements)

References 83 publications

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“…It is thought that this drug exerts its effect either by its capacity to inactivate multiple DNA damage-responsive cell cycle checkpoints (Cortez, 2003;Rowley, 1992;Schlegel and Pardee, 1986) or by its ability to directly inhibit DNA repair (Arlett et al, 1975;Asaad et al, 2000;Buhl and Regan, 1974;Wang et al, 2004). A widely held view is that caffeine inhibits cell-cycle checkpoint activation by targeting the checkpoint kinases ATM and ATR (Blasina et al, 1999;Sarkaria et al, 1999).…”

Section: Ssdna Focus Formation In Response To Uv-irradiationmentioning

confidence: 99%

Promyelocytic leukemia nuclear bodies are predetermined processing sites for damaged DNA

Bøe

Haave

Jul-Larsen

et al. 2006

Journal of Cell Science

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The promyelocytic leukemia protein (PML) participates in several cellular functions, including transcriptional regulation, apoptosis and maintenance of genomic stability. A key feature of this protein is its ability to induce the assembly of nuclear compartments termed PML-nuclear bodies (PML-NBs). Here we show that these nuclear structures recruit single-stranded DNA (ssDNA) molecules in response to exogenous DNA damage. ssDNA was readily detected in PML-NBs within 1 hour following exposure of cells to UV light. Confocal real-time imaging of cells expressing YFP-tagged PML did not reveal de novo formation of new PML-NBs following UV-irradiation, which shows that ssDNA focus formation occurred within pre-existing PML-NBs. Moreover, siRNA-mediated depletion of PML prevented ssDNA focus formation and sensitized cells to UV-induced apoptosis. PML-dependent ssDNA focus formation was found to be particularly efficient during S-phase of the cell cycle, and PML-depleted cells became retarded in S-phase upon growth in the presence of etoposide. In addition, we found that caffeine and the poly(ADP-ribose) polymerase (PARP) inhibitor NU1027 enhanced UV-induced recruitment of ssDNA to PML-NBs. Together, our results show that PML-NBs have the capacity to accommodate DNA metabolic activities that are associated with processing of damaged DNA.

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Section: Ssdna Focus Formation In Response To Uv-irradiationmentioning

confidence: 99%

Promyelocytic leukemia nuclear bodies are predetermined processing sites for damaged DNA

Bøe

Haave

Jul-Larsen

et al. 2006

Journal of Cell Science

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“…The fact that caffeine affects DNA double-strand break repair, both HR and nonhomologous end joining (Block et al, 2004;Wang et al, 2004), but not centrosome fragmentation, is figure) were analysed. Cells were fixed in methanol for 15 min at À201C and permeabilized with acetone.…”

Section: Impact On Centrosome Fragmentation and Chromosome Stability mentioning

confidence: 99%

Genetic interactions between RAD51 and its paralogues for centrosome fragmentation and ploidy control, independently of the sensitivity to genotoxic stresses

2005

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We evaluate here whether RAD51 and its paralogues XRCC2 and XRCC3 act via a common pathway for sensitivity to genotoxic stress, centrosome fragmentation and chromosome stability. We expressed the RAD51 dominant-negative SMRAD51 in irs1 and irs1SF cells, defective for XRCC2 and XRCC3, respectively, and in their corresponding wild-type cells (V79 and AA8, respectively). V79-SMRAD51 cells are sensitive to mitomycin C (MMC), but SMRAD51 did not further sensitize irs1 cells to MMC, showing that SMRAD51 and XRCC2 act on the same pathway for resistance to MMC. However, in contrast to irs1 and irs1SF cells, SMRAD51-V79 and SMRAD51-AA8 cells are not sensitive to c-rays or UV-C. Despite these differences in sensitivity, SMRAD51-expressing cells and xrcc2-or xrcc3-defective cells show similar increased levels of centrosome fragmentation. This spontaneous centrosome fragmentation is resistant to caffeine, suggesting that ATM and ATR are not involved. Consistent with centrosome fragmentation, increased aneuploidy was measured in irs1 and SMRAD51-expressing cells. Expression of SMRAD51 in irs1 or irs1SF cells did not increase further the frequency of multipolar cells. Thus, RAD51, XRCC2 and XRCC3 act in the same pathway for centrosome fragmentation, independently of the sensitivity to exogenous genotoxic stresses and of the ATM/ATR pathway.

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“…For example, genetic manipulations of a checkpoint-defective and radiosensitive cell line could restore the checkpoint defects without affecting radiosensitivity (19). Moreover, caffeine was shown to inhibit DNA repair (20), and its radiosensitizing effect may be due to defective repair rather than checkpoint abrogation. UCN-01, which was originally synthesized as a staurosporine analog, caused apoptosis in human cancer cells when combined with IR (21).…”

Section: Introductionmentioning

confidence: 99%

Inhibition of Chk1 by CEP-3891 Accelerates Mitotic Nuclear Fragmentation in Response to Ionizing Radiation

et al. 2004

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The human checkpoint kinase Chk1 has been suggested as a target for cancer treatment. Here, we show that a new inhibitor of Chk1 kinase, CEP-3891, efficiently abrogates both the ionizing radiation (IR)-induced S and G 2 checkpoints. When the checkpoints were abrogated by CEP-3891, the majority (64%) of cells showed fragmented nuclei at 24 hours after IR (6 Gy). The formation of nuclear fragmentation in IR-treated human cancer cells was directly visualized by time-lapse video microscopy of U2-OS cells expressing a green fluorescent protein-tagged histone H2B protein. Nuclear fragmentation occurred as a result of defective chromosome segregation when irradiated cells entered their first mitosis, either prematurely without S and G 2 checkpoint arrest in the presence of CEP-3891 or after a prolonged S and G 2 checkpoint arrest in the absence of CEP-3891. The nuclear fragmentation was clearly distinguishable from apoptosis because caspase activity and nuclear condensation were not induced. Finally, CEP-3891 not only accelerated IR-induced nuclear fragmentation, it also increased the overall cell killing after IR as measured in clonogenic survival assays. These results demonstrate that transient Chk1 inhibition by CEP-3891 allows premature mitotic entry of irradiated cells, thereby leading to accelerated onset of mitotic nuclear fragmentation and increased cell death.

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Caffeine inhibits homology-directed repair of I-SceI-induced DNA double-strand breaks

Cited by 45 publications

References 83 publications

Promyelocytic leukemia nuclear bodies are predetermined processing sites for damaged DNA

Promyelocytic leukemia nuclear bodies are predetermined processing sites for damaged DNA

Genetic interactions between RAD51 and its paralogues for centrosome fragmentation and ploidy control, independently of the sensitivity to genotoxic stresses

Inhibition of Chk1 by CEP-3891 Accelerates Mitotic Nuclear Fragmentation in Response to Ionizing Radiation

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