Oxidative DNA damage is involved in ochratoxin A-induced G2 arrest through ataxia telangiectasia-mutated (ATM) pathways in human gastric epithelium GES-1 cells in vitro

2013 ◽  
Vol 87 (10) ◽  
pp. 1829-1840 ◽  
Author(s):  
Jinfeng Cui ◽  
Jing Liu ◽  
Sha Wu ◽  
Yuan Wang ◽  
Haitao Shen ◽  
...  
Keyword(s):  
Dna Damage ◽  
Ochratoxin A ◽  
Ataxia Telangiectasia ◽  
Oxidative Dna Damage ◽  
Gastric Epithelium ◽  
Ataxia Telangiectasia Mutated ◽  
G2 Arrest

scholarly journals Tethering DNA Damage Checkpoint Mediator Proteins Topoisomerase IIβ-binding Protein 1 (TopBP1) and Claspin to DNA Activates Ataxia-Telangiectasia Mutated and RAD3-related (ATR) Phosphorylation of Checkpoint Kinase 1 (Chk1)

2011 ◽  
Vol 286 (22) ◽  
pp. 19229-19236 ◽  
Author(s):  
Laura A. Lindsey-Boltz ◽  
Aziz Sancar
Keyword(s):  
Dna Damage ◽  
Ataxia Telangiectasia ◽  
Mammalian Cells ◽  
Binding Protein ◽  
Effector Proteins ◽  
Ataxia Telangiectasia Mutated ◽  
Checkpoint Kinase ◽  
Atr Kinase

The ataxia-telangiectasia mutated and RAD3-related (ATR) kinase initiates DNA damage signaling pathways in human cells after DNA damage such as that induced upon exposure to ultraviolet light by phosphorylating many effector proteins including the checkpoint kinase Chk1. The conventional view of ATR activation involves a universal signal consisting of genomic regions of replication protein A-covered single-stranded DNA. However, there are some indications that the ATR-mediated checkpoint can be activated by other mechanisms. Here, using the well defined Escherichia coli lac repressor/operator system, we have found that directly tethering the ATR activator topoisomerase IIβ-binding protein 1 (TopBP1) to DNA is sufficient to induce ATR phosphorylation of Chk1 in an in vitro system as well as in vivo in mammalian cells. In addition, we find synergistic activation of ATR phosphorylation of Chk1 when the mediator protein Claspin is also tethered to the DNA with TopBP1. Together, these findings indicate that crowding of checkpoint mediator proteins on DNA is sufficient to activate the ATR kinase.

scholarly journals Threonine-11, Phosphorylated by Rad3 and ATM In Vitro, Is Required for Activation of Fission Yeast Checkpoint Kinase Cds1

2001 ◽  
Vol 21 (10) ◽  
pp. 3398-3404 ◽  
Author(s):  
Katsunori Tanaka ◽  
Michael N. Boddy ◽  
Xiao-Bo Chen ◽  
Clare H. McGowan ◽  
Paul Russell
Keyword(s):  
Dna Damage ◽  
Dna Replication ◽  
Fission Yeast ◽  
Ataxia Telangiectasia ◽  
Null Mutant ◽  
Ataxia Telangiectasia Mutated ◽  
Tolerance Mechanisms ◽  
Checkpoint Kinase ◽  
And Function

ABSTRACT Fission yeast Cds1 is phosphorylated and activated when DNA replication is interrupted by nucleotide starvation or DNA damage. Cds1 enforces the S-M checkpoint that couples mitosis (M) to the completion of DNA synthesis (S). Cds1 also controls replicational stress tolerance mechanisms. Cds1 is regulated by a group of proteins that includes Rad3, a kinase related to human checkpoint kinase ATM (ataxia telangiectasia mutated). ATM phosphorylates serine or threonine followed by glutamine (SQ or TQ). Here we show that in vitro, Rad3 and ATM phosphorylate the N-terminal domain of Cds1 at the motif T11Q12. Substitution of threonine-11 with alanine (T11A) abolished Cds1 activation that occurs when DNA replication is inhibited by hydroxyurea (HU) treatment. Thecds1-T11A mutant was profoundly sensitive to HU, although not quite as sensitive as a cds1− null mutant. Cds1T11A was unable to enforce the S-M checkpoint. These results strongly suggest that Rad3-dependent phosphorylation of Cds1 at threonine-11 is required for Cds1 activation and function.

scholarly journals Sterigmatocystin-Induced DNA Damage Triggers G2 Arrest via an ATM/p53-Related Pathway in Human Gastric Epithelium GES-1 Cells In Vitro

PLoS ONE ◽  
2013 ◽  
Vol 8 (5) ◽  
pp. e65044 ◽  
Author(s):  
Donghui Zhang ◽  
Yu Cui ◽  
Haitao Shen ◽  
Lingxiao Xing ◽  
Jinfeng Cui ◽  
...  
Keyword(s):  
Dna Damage ◽  
Gastric Epithelium ◽  
G2 Arrest ◽  
Related Pathway

Ochratoxin A induced oxidative DNA damage and micronuclei as sensitive indicators of its genotoxic effects in vitro

2006 ◽  
Vol 164 ◽  
pp. S288-S289 ◽  
Author(s):  
Gisela H. Degen ◽  
Yury Lektarau ◽  
Ülkü Ündeger ◽  
Claudia Behm ◽  
Wolfram Foellmann
Keyword(s):  
Dna Damage ◽  
Ochratoxin A ◽  
Oxidative Dna Damage ◽  
Genotoxic Effects

230 Oxidative DNA damage induced by the carcinogenic mycotoxin ochratoxin a in vitro and in vivo

2003 ◽  
Vol 144 ◽  
pp. s65
Author(s):  
H.G. Kamp ◽  
R. Turesky ◽  
J. Schlatter ◽  
G. Eisenbrand ◽  
C. Janzowski
Keyword(s):  
Dna Damage ◽  
Ochratoxin A ◽  
Oxidative Dna Damage

scholarly journals Anti-Tumor Effect of Inhibition of DNA Damage Response Proteins, ATM and ATR, in Endometrial Cancer Cells

Cancers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1913 ◽  
Author(s):  
Makoto Takeuchi ◽  
Michihiro Tanikawa ◽  
Kazunori Nagasaka ◽  
Katsutoshi Oda ◽  
Yoshiko Kawata ◽  
...  
Keyword(s):  
Dna Damage ◽  
Endometrial Cancer ◽  
Cancer Cells ◽  
Dna Damage Response ◽  
Ataxia Telangiectasia ◽  
Synthetic Lethality ◽  
Ataxia Telangiectasia Mutated ◽  
Checkpoint Kinase ◽  
Damage Response

While the incidence of endometrial cancer continues to rise, the therapeutic options remain limited for advanced or recurrent cases, and most cases are resistant to therapy. The anti-tumor effect of many chemotherapeutic drugs and radiotherapy depends on the induction of DNA damage in cancer cells; thus, activation of DNA damage response (DDR) pathways is considered an important factor affecting resistance to therapy. When some DDR pathways are inactivated, inhibition of other DDR pathways can induce cancer-specific synthetic lethality. Therefore, DDR pathways are considered as promising candidates for molecular-targeted therapy for cancer. The crosstalking ataxia telangiectasia mutated and Rad3 related and checkpoint kinase 1 (ATR-Chk1) and ataxia telangiectasia mutated and Rad3 related and checkpoint kinase 2 (ATM-Chk2) pathways are the main pathways of DNA damage response. In this study, we investigated the anti-tumor effect of inhibitors of these pathways in vitro by assessing the effect of the combination of ATM or ATR inhibitors and conventional DNA-damaging therapy (doxorubicin (DXR), cisplatin (CDDP), and irradiation) on endometrial cancer cells. Both the inhibitors enhanced the sensitivity of cells to DXR, CDDP, and irradiation. Moreover, the combination of ATR and Chk1 inhibitors induced DNA damage in endometrial cancer cells and inhibited cell proliferation synergistically. Therefore, these molecular therapies targeting DNA damage response pathways are promising new treatment strategies for endometrial cancer.

scholarly journals Requirement of ATM for Rapid p53 Phosphorylation at Ser46 without Ser/Thr-Gln Sequences

2010 ◽  
Vol 30 (7) ◽  
pp. 1620-1633 ◽  
Author(s):  
Masami Kodama ◽  
Chihiro Otsubo ◽  
Toru Hirota ◽  
Jun Yokota ◽  
Masato Enari ◽  
...  
Keyword(s):  
Dna Damage ◽  
Ataxia Telangiectasia ◽  
Early Phase ◽  
Phosphorylation Site ◽  
Phase Response ◽  
Ataxia Telangiectasia Mutated ◽  
Serine Residue ◽  
Atm Kinase ◽  
Atp Analogues

ABSTRACT p53 phosphorylation at Ser46 following DNA damage is important for preferential transactivation of proapoptotic genes. Here, we report that ataxia-telangiectasia mutated (ATM) kinase is responsible for Ser46 phosphorylation of p53 during early-phase response to DNA damage. To elucidate the direct phosphorylation of p53 at Ser46 by ATM, an ATM mutant (ATM-AS) sensitive to ATP analogues was engineered. In vitro kinase assays revealed that p53 was phosphorylated at Ser46 by ATM-AS, even when ATP analogues were used as phosphate donors, although this phosphorylation site is not in an SQ motif, a consensus ATM site. Furthermore, Ser46 phosphorylation by ATM was dependent on the N- and C-terminal domains of p53, unlike Ser15 phosphorylation. Immunofluorescence analyses showed that Ser46-phosphorylated p53 was observed as foci in response to DNA damage and colocalized with γ-H2AX or Ser1981-phosphorylated ATM. These results suggest that ATM phosphorylates a noncanonical serine residue on p53 by mechanisms different from those for the phosphorylation of Ser15.

scholarly journals Ionizing radiation induces ataxia telangiectasia mutated kinase (ATM)-mediated phosphorylation of LKB1/STK11 at Thr-366

2002 ◽  
Vol 368 (2) ◽  
pp. 507-516 ◽  
Author(s):  
Gopal P. SAPKOTA ◽  
Maria DEAK ◽  
Agnieszka KIELOCH ◽  
Nick MORRICE ◽  
Aaron A. GOODARZI ◽  
...  
Keyword(s):  
Dna Damage ◽  
Protein Kinase ◽  
Ionizing Radiation ◽  
Ataxia Telangiectasia ◽  
Cellular Responses ◽  
Ataxia Telangiectasia Mutated ◽  
Cancer Syndrome ◽  
Phosphoinositide 3 Kinase

The serine/threonine protein kinase LKB1 functions as a tumour suppressor, and mutations in this enzyme lead to the inherited Peutz—Jeghers cancer syndrome. We previously found that LKB1 was phosphorylated at Thr-366 in vivo, a residue conserved in mammalian, Xenopus and Drosophila LKB1, located on a C-terminal non-catalytic moiety of the enzyme. Mutation of Thr-366 to Ala or Asp partially inhibited the ability of LKB1 to suppress growth of G361 melanoma cells, but did not affect LKB1 activity in vitro or LKB1 localization in vivo. As a first step in exploring the role of this phosphorylation further, we have generated a phosphospecific antibody specifically recognizing LKB1 phosphorylated at Thr-366 and demonstrate that exposure of cells to ionizing radiation (IR) induced a marked phosphorylation of LKB1 at Thr-366 in the nucleus. Thr-366 lies in an optimal phosphorylation motif for the phosphoinositide 3-kinase-like kinases DNA-dependent protein kinase (DNA-PK), ataxia telangiectasia mutated kinase (ATM) and ataxia telangiectasia-related kinase (ATR), which function as sensors for DNA damage in cells and mediate cellular responses to DNA damage. We demonstrate that both DNA-PK and ATM efficiently phosphorylate LKB1 at Thr-366 in vitro and provide evidence that ATM mediates this phosphorylation in vivo. This is based on the finding that LKB1 is not phosphorylated in a cell line lacking ATM in response to IR, and that agents which induce cellular responses via ATR in preference to ATM poorly induce phosphorylation of LKB1 at Thr-366. These observations provide the first link between ATM and LKB1 and suggest that ATM could regulate LKB1.

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