Methods for Studying Checkpoint Kinases – Chk1

2011 ◽  
pp. 171-179 ◽  
Author(s):  
Claudia Tapia-Alveal ◽  
Matthew J. O’Connell
Keyword(s):  
Checkpoint Kinases

EFFECT OF ARYL HYDROCARBON RECEPTOR AGONISTS AND LIPOPOLYSACCHARIDE ON BENZO(A)PYRENE GENOTOXICITY MARKERS

2019 ◽  
pp. 19-25 ◽  
Author(s):  
V. N. Babakov ◽  
N. Yu. Rogovskaya ◽  
I. D. Kurdyukov ◽  
P. P. Beltyukov ◽  
S. A. Dulov ◽  
...  
Keyword(s):  
Dna Repair ◽  
Aryl Hydrocarbon Receptor ◽  
P53 Protein ◽  
Control Level ◽  
Repair System ◽  
Human Hepatoma Cells ◽  
Kinase Activation ◽  
Receptor Agonists ◽  
Checkpoint Kinases ◽  
Aryl Hydrocarbon

The effect of aryl hydrocarbon receptor agonists (FICZ and ITE), as well as lipopolysaccharide under the toxic action of benzo(a)pyrene in HepaRG human hepatoma cells was evaluated. Active forms of the key stress-activated kinase cascades and DNA repair system proteins were used as markers of the genotoxic action of benzo(a)pyrene. A mixture of lipopolysaccharide with benzo(a)pyrene increases benzo(a)pyrene cytotoxicity and reduces the activation of DNA repair system proteins below the control level. Aryl hydrocarbon receptor agonists (FICZ and ITE) exhibit a cytoprotective effect against benzo(a) pyrene, enhance Akt1 kinase activation, and downregulate activation of the p53 protein and Chk1 and Chk2 checkpoint kinases. Thus, FICZ and ITE reduce the genotoxicity of benzo(a)pyrene.

scholarly journals Acceleration or Brakes: Which Is Rational for Cell Cycle-Targeting Neuroblastoma Therapy?

Biomolecules ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 750
Author(s):  
Kiyohiro Ando ◽  
Akira Nakagawara
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Cell Cycle Progression ◽  
Parp Inhibitors ◽  
Cell Cycle Checkpoint ◽  
Mitotic Catastrophe ◽  
Malignant Neoplasms ◽  
Checkpoint Kinases ◽  
Molecular Features ◽  
Cycle Checkpoint

Unrestrained proliferation is a common feature of malignant neoplasms. Targeting the cell cycle is a therapeutic strategy to prevent unlimited cell division. Recently developed rationales for these selective inhibitors can be subdivided into two categories with antithetical functionality. One applies a “brake” to the cell cycle to halt cell proliferation, such as with inhibitors of cell cycle kinases. The other “accelerates” the cell cycle to initiate replication/mitotic catastrophe, such as with inhibitors of cell cycle checkpoint kinases. The fate of cell cycle progression or arrest is tightly regulated by the presence of tolerable or excessive DNA damage, respectively. This suggests that there is compatibility between inhibitors of DNA repair kinases, such as PARP inhibitors, and inhibitors of cell cycle checkpoint kinases. In the present review, we explore alterations to the cell cycle that are concomitant with altered DNA damage repair machinery in unfavorable neuroblastomas, with respect to their unique genomic and molecular features. We highlight the vulnerabilities of these alterations that are attributable to the features of each. Based on the assessment, we offer possible therapeutic approaches for personalized medicine, which are seemingly antithetical, but both are promising strategies for targeting the altered cell cycle in unfavorable neuroblastomas.

scholarly journals The mitotic checkpoint is a targetable vulnerability of carboplatin-resistant triple negative breast cancers

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Stijn Moens ◽  
Peihua Zhao ◽  
Maria Francesca Baietti ◽  
Oliviero Marinelli ◽  
Delphi Van Haver ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Triple Negative ◽  
Breast Cancer Subtype ◽  
Mitotic Checkpoint ◽  
Breast Cancers ◽  
Checkpoint Kinases ◽  
Xenograft Models ◽  
Potential Strategy ◽  
Shrna Screen ◽  
Resistant Cells

AbstractTriple-negative breast cancer (TNBC) is the most aggressive breast cancer subtype, lacking effective therapy. Many TNBCs show remarkable response to carboplatin-based chemotherapy, but often develop resistance over time. With increasing use of carboplatin in the clinic, there is a pressing need to identify vulnerabilities of carboplatin-resistant tumors. In this study, we generated carboplatin-resistant TNBC MDA-MB-468 cell line and patient derived TNBC xenograft models. Mass spectrometry-based proteome profiling demonstrated that carboplatin resistance in TNBC is linked to drastic metabolism rewiring and upregulation of anti-oxidative response that supports cell replication by maintaining low levels of DNA damage in the presence of carboplatin. Carboplatin-resistant cells also exhibited dysregulation of the mitotic checkpoint. A kinome shRNA screen revealed that carboplatin-resistant cells are vulnerable to the depletion of the mitotic checkpoint regulators, whereas the checkpoint kinases CHEK1 and WEE1 are indispensable for the survival of carboplatin-resistant cells in the presence of carboplatin. We confirmed that pharmacological inhibition of CHEK1 by prexasertib in the presence of carboplatin is well tolerated by mice and suppresses the growth of carboplatin-resistant TNBC xenografts. Thus, abrogation of the mitotic checkpoint by CHEK1 inhibition re-sensitizes carboplatin-resistant TNBCs to carboplatin and represents a potential strategy for the treatment of carboplatin-resistant TNBCs.

scholarly journals Regulation of Pkc1 Hyper-Phosphorylation by Genotoxic Stress

2021 ◽  
Vol 7 (10) ◽  
pp. 874
Author(s):  
Li Liu ◽  
Jiri Veis ◽  
Wolfgang Reiter ◽  
Edwin Motari ◽  
Catherine E. Costello ◽  
...  
Keyword(s):  
Dna Damage ◽  
Cell Wall ◽  
Protein Kinase ◽  
Transcriptional Response ◽  
Genotoxic Stress ◽  
Telomere Maintenance ◽  
Phosphorylation Sites ◽  
Casein Kinase 1 ◽  
Checkpoint Kinases ◽  
Radiation Repair

The cell wall integrity (CWI) signaling pathway is best known for its roles in cell wall biogenesis. However, it is also thought to participate in the response to genotoxic stress. The stress-activated protein kinase Mpk1 (Slt2, is activated by DNA damaging agents through an intracellular mechanism that does not involve the activation of upstream components of the CWI pathway. Additional observations suggest that protein kinase C (Pkc1), the top kinase in the CWI signaling cascade, also has a role in the response to genotoxic stress that is independent of its recognized function in the activation of Mpk1. Pkc1 undergoes hyper-phosphorylation specifically in response to genotoxic stress; we have found that this requires the DNA damage checkpoint kinases Mec1 (Mitosis Entry Checkpoint) and Tel1 (TELomere maintenance), but not their effector kinases. We demonstrate that the casein kinase 1 (CK1) ortholog, Hrr25 (HO and Radiation Repair), previously implicated in the DNA damage transcriptional response, associates with Pkc1 under conditions of genotoxic stress. We also found that the induced association of Hrr25 with Pkc1 requires Mec1 and Tel1, and that Hrr25 catalytic activity is required for Pkc1-hyperphosphorylation, thereby delineating a pathway from the checkpoint kinases to Pkc1. We used SILAC mass spectrometry to identify three residues within Pkc1 the phosphorylation of which was stimulated by genotoxic stress. We mutated these residues as well as a collection of 13 phosphorylation sites within the regulatory domain of Pkc1 that fit the consensus for CK1 sites. Mutation of the 13 Pkc1 phosphorylation sites blocked hyper-phosphorylation and diminished RNR3 (RiboNucleotide Reductase) basal expression and induction by genotoxic stress, suggesting that Pkc1 plays a role in the DNA damage transcriptional response.

Potential for inhibition of checkpoint kinases 1/2 in pulmonary fibrosis and secondary pulmonary hypertension

Thorax ◽  
2021 ◽  
pp. thoraxjnl-2021-217377
Author(s):  
Wen-Hui Wu ◽  
Sébastien Bonnet ◽  
Tsukasa Shimauchi ◽  
Victoria Toro ◽  
Yann Grobs ◽  
...  
Keyword(s):  
Dna Damage ◽  
Pulmonary Hypertension ◽  
Animal Models ◽  
Pulmonary Fibrosis ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Therapeutic Option ◽  
Checkpoint Kinases ◽  
Medical Needs ◽  
Secondary Pulmonary Hypertension

BackgroundIdiopathic pulmonary fibrosis (IPF) is a chronic lung disease characterised by exuberant tissue remodelling and associated with high unmet medical needs. Outcomes are even worse when IPF results in secondary pulmonary hypertension (PH). Importantly, exaggerated resistance to cell death, excessive proliferation and enhanced synthetic capacity are key endophenotypes of both fibroblasts and pulmonary artery smooth muscle cells, suggesting shared molecular pathways. Under persistent injury, sustained activation of the DNA damage response (DDR) is integral to the preservation of cells survival and their capacity to proliferate. Checkpoint kinases 1 and 2 (CHK1/2) are key components of the DDR. The objective of this study was to assess the role of CHK1/2 in the development and progression of IPF and IPF+PH.Methods and resultsIncreased expression of DNA damage markers and CHK1/2 were observed in lungs, remodelled pulmonary arteries and isolated fibroblasts from IPF patients and animal models. Blockade of CHK1/2 expression or activity-induced DNA damage overload and reverted the apoptosis-resistant and fibroproliferative phenotype of disease cells. Moreover, inhibition of CHK1/2 was sufficient to interfere with transforming growth factor beta 1-mediated fibroblast activation. Importantly, pharmacological inhibition of CHK1/2 using LY2606368 attenuated fibrosis and pulmonary vascular remodelling leading to improvement in respiratory mechanics and haemodynamic parameters in two animal models mimicking IPF and IPF+PH.ConclusionThis study identifies CHK1/2 as key regulators of lung fibrosis and provides a proof of principle for CHK1/2 inhibition as a potential novel therapeutic option for IPF and IPF+PH.

DNA damage checkpoint kinases in cancer

2020 ◽  
Vol 22 ◽  
Author(s):  
Hannah L. Smith ◽  
Harriet Southgate ◽  
Deborah A. Tweddle ◽  
Nicola J. Curtin
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Environmental Dna ◽  
Cell Cycle Checkpoint ◽  
Checkpoint Control ◽  
Integrated Network ◽  
Checkpoint Kinases ◽  
G1 Checkpoint ◽  
Cycle Checkpoint ◽  
High Level

Abstract DNA damage response (DDR) pathway prevents high level endogenous and environmental DNA damage being replicated and passed on to the next generation of cells via an orchestrated and integrated network of cell cycle checkpoint signalling and DNA repair pathways. Depending on the type of damage, and where in the cell cycle it occurs different pathways are involved, with the ATM-CHK2-p53 pathway controlling the G1 checkpoint or ATR-CHK1-Wee1 pathway controlling the S and G2/M checkpoints. Loss of G1 checkpoint control is common in cancer through TP53, ATM mutations, Rb loss or cyclin E overexpression, providing a stronger rationale for targeting the S/G2 checkpoints. This review will focus on the ATM-CHK2-p53-p21 pathway and the ATR-CHK1-WEE1 pathway and ongoing efforts to target these pathways for patient benefit.

scholarly journals Overexpression of Cyclin E1 or Cdc25A leads to replication stress, mitotic aberrancies, and increased sensitivity to replication checkpoint inhibitors

Oncogenesis ◽  
2020 ◽  
Vol 9 (10) ◽  
Author(s):  
Yannick P. Kok ◽  
Sergi Guerrero Llobet ◽  
Pepijn M. Schoonen ◽  
Marieke Everts ◽  
Arkajyoti Bhattacharya ◽  
...  
Keyword(s):  
Genomic Instability ◽  
Checkpoint Inhibitors ◽  
Replication Stress ◽  
Underlying Mechanism ◽  
Dna Lesions ◽  
Mitotic Catastrophe ◽  
Replication Checkpoint ◽  
Cyclin E1 ◽  
Checkpoint Kinases ◽  
Increased Sensitivity

Abstract Oncogene-induced replication stress, for instance as a result of Cyclin E1 overexpression, causes genomic instability and has been linked to tumorigenesis. To survive high levels of replication stress, tumors depend on pathways to deal with these DNA lesions, which represent a therapeutically actionable vulnerability. We aimed to uncover the consequences of Cyclin E1 or Cdc25A overexpression on replication kinetics, mitotic progression, and the sensitivity to inhibitors of the WEE1 and ATR replication checkpoint kinases. We modeled oncogene-induced replication stress using inducible expression of Cyclin E1 or Cdc25A in non-transformed RPE-1 cells, either in a TP53 wild-type or TP53-mutant background. DNA fiber analysis showed Cyclin E1 or Cdc25A overexpression to slow replication speed. The resulting replication-derived DNA lesions were transmitted into mitosis causing chromosome segregation defects. Single cell sequencing revealed that replication stress and mitotic defects upon Cyclin E1 or Cdc25A overexpression resulted in genomic instability. ATR or WEE1 inhibition exacerbated the mitotic aberrancies induced by Cyclin E1 or Cdc25A overexpression, and caused cytotoxicity. Both these phenotypes were exacerbated upon p53 inactivation. Conversely, downregulation of Cyclin E1 rescued both replication kinetics, as well as sensitivity to ATR and WEE1 inhibitors. Taken together, Cyclin E1 or Cdc25A-induced replication stress leads to mitotic segregation defects and genomic instability. These mitotic defects are exacerbated by inhibition of ATR or WEE1 and therefore point to mitotic catastrophe as an underlying mechanism. Importantly, our data suggest that Cyclin E1 overexpression can be used to select patients for treatment with replication checkpoint inhibitors.

scholarly journals CDK and Mec1/Tel1-catalyzed phosphorylation of Sae2 regulate different responses to DNA damage

2019 ◽  
Vol 47 (21) ◽  
pp. 11238-11249 ◽  
Author(s):  
Tai-Yuan Yu ◽  
Valerie E Garcia ◽  
Lorraine S Symington
Keyword(s):  
Dna Damage ◽  
Dna Damage Response ◽  
Phosphorylation Site ◽  
Physiological Role ◽  
Checkpoint Signaling ◽  
Strand Breaks ◽  
Checkpoint Kinases ◽  
Damage Response ◽  
End Resection

Abstract Sae2 functions in the DNA damage response by controlling Mre11-Rad50-Xrs2 (MRX)-catalyzed end resection, an essential step for homology-dependent repair of double-strand breaks (DSBs), and by attenuating DNA damage checkpoint signaling. Phosphorylation of Sae2 by cyclin-dependent kinase (CDK1/Cdc28) activates the Mre11 endonuclease, while the physiological role of Sae2 phosphorylation by Mec1 and Tel1 checkpoint kinases is not fully understood. Here, we compare the phenotype of sae2 mutants lacking the main CDK (sae2-S267A) or Mec1 and Tel1 phosphorylation sites (sae2-5A) with sae2Δ and Mre11 nuclease defective (mre11-nd) mutants. The phosphorylation-site mutations confer DNA damage sensitivity, but not to the same extent as sae2Δ. The sae2-S267A mutation is epistatic to mre11-nd for camptothecin (CPT) sensitivity and synergizes with sgs1Δ, whereas sae2-5A synergizes with mre11-nd and exhibits epistasis with sgs1Δ. We find that attenuation of checkpoint signaling by Sae2 is mostly independent of Mre11 endonuclease activation but requires Mec1 and Tel1-dependent phosphorylation of Sae2. These results support a model whereby CDK-catalyzed phosphorylation of Sae2 activates resection via Mre11 endonuclease, whereas Sae2 phosphorylation by Mec1 and Tel1 promotes resection by the Dna2-Sgs1 and Exo1 pathways indirectly by dampening the DNA damage response.

Keeping checkpoint kinases in line: new selective inhibitors in clinical trials

2008 ◽  
Vol 17 (9) ◽  
pp. 1331-1340 ◽  
Author(s):  
Susan Ashwell ◽  
James W Janetka ◽  
Sonya Z abludoff
Keyword(s):  
Clinical Trials ◽  
Selective Inhibitors ◽  
Checkpoint Kinases
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