Clusterin knockdown sensitizes prostate cancer cells to taxane by modulating mitosis
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE67256 | GEO | 2016/03/01
SECONDARY ACCESSION(S): PRJNA279355
REPOSITORIES: GEO
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Project description:Clusterin (CLU) is a stress-activated molecular chaperone that confers treatment resistance to taxanes when highly expressed. While CLU inhibition potentiates activity of taxanes and other anti-cancer therapies in preclinical models, progression to treatment resistant disease still occurs implicating additional compensatory survival mechanisms. Taxanes are believed to selectively target cells in mitosis, a complex mechanism controlled in part by balancing antagonistic roles of Cdc25C and Wee1 in mitosis progression. Our data indicate that CLU silencing induces a constitutive activation of Cdc25C, which delays mitotic exit and hence sensitizes cancer cells to mitotic-targeting agents such taxanes. Unchecked Cdc25C activation leads to mitotic catastrophe and cell death unless cells upregulate protective mechanisms mediated through the cell cycle regulators Wee1 and Cdc2. In this study we show that CLU silencing induces a constitutive activation of Cdc25C via the phosphatase PP2A but leads to relief of negative feedback inhibition and activation of Wee1-Cdc2 to promote survival and limit therapeutic efficacy. Simultaneous inhibition of CLU-regulated cell cycle effectors, like PP2A and Wee1, may improve synergistic responses of biologically rational combinatorial regimens using taxanes and CLU inhibitors Biological triplicate of PC3 treated with siClusterin were compared to biological trplicate of PC3 treated with siScramblein
2016-03-01 | E-GEOD-67256 | biostudies-arrayexpress
Project description:The G2 DNA damage checkpoint inhibits Cdc2 and mitotic entry through the dual regulation of Wee1 and Cdc25 by the Chk1 effector kinase. Up-regulation of Chk1 by mutation or overexpression bypasses the requirement for up-stream regulators or DNA damage to promote a G2 cell cycle arrest. We screened in fission yeast for mutations that rendered cells resistant to overexpressed Chk1. We identified a mutation in tra1, which encodes one of two homologs of TRRAP, an ATM/R-related pseudokinase that scaffolds several histone acetyltransferase (HAT) complexes. Inhibition of histone deacetylases reverts the resistance to overexpressed Chk1, suggesting this phenotype is due to a HAT activity, though expression of checkpoint and cell cycle genes is not greatly affected. Cells with mutant or deleted tra1 activate Chk1 normally and are checkpoint proficient. However, these cells are semi-wee even when overexpressing Chk1, and accumulate inactive Wee1 protein. The Cdr (changed division response) kinases Cdr1 and Cdr2 are negative regulators of Wee1, and while best characterized in the cellular response to limited nutrition, we show that they are required for the Tra1-dependent alterations to Wee1 function. This identifies Tra1 as another component controlling the timing of entry into mitosis via Cdc2 activation. Two and three independent microaaray experiments were done for wild type and the mutant (tra1-1) respectively.
2010-04-11 | E-GEOD-12674 | biostudies-arrayexpress
Project description:The G2 DNA damage checkpoint inhibits Cdc2 and mitotic entry through the dual regulation of Wee1 and Cdc25 by the Chk1 effector kinase. Up-regulation of Chk1 by mutation or overexpression bypasses the requirement for up-stream regulators or DNA damage to promote a G2 cell cycle arrest. We screened in fission yeast for mutations that rendered cells resistant to overexpressed Chk1. We identified a mutation in tra1, which encodes one of two homologs of TRRAP, an ATM/R-related pseudokinase that scaffolds several histone acetyltransferase (HAT) complexes. Inhibition of histone deacetylases reverts the resistance to overexpressed Chk1, suggesting this phenotype is due to a HAT activity, though expression of checkpoint and cell cycle genes is not greatly affected. Cells with mutant or deleted tra1 activate Chk1 normally and are checkpoint proficient. However, these cells are semi-wee even when overexpressing Chk1, and accumulate inactive Wee1 protein. The Cdr (changed division response) kinases Cdr1 and Cdr2 are negative regulators of Wee1, and while best characterized in the cellular response to limited nutrition, we show that they are required for the Tra1-dependent alterations to Wee1 function. This identifies Tra1 as another component controlling the timing of entry into mitosis via Cdc2 activation.
2010-04-11 | GSE12674 | GEO
Project description:During mitosis, TATA-binding protein(TBP), which remains bound to DNA during mitosis, recruits PP2A and also interacts with a subunit of the condensin complex to allow efficient dephosphorylation and inactivation of condensin near these promoters to inhibit their compaction. These result suggest that TBP function is not only important for expression of genes transcribed bDuring mitosis, TATA-binding protein(TBP), which remains bound to DNA during mitosis, recruits PP2A and also interacts with a subunit of the condensin complex to allow efficient dephosphorylation and inactivation of condensin near these promoters to inhibit their compaction. These result suggest that TBP function is not only important for expression of genes transcribed by all three RNA polymerase during interphase, but also for transmitting the memory of gene activity through mitosis to daughter cellsy all three RNA polymerase during interphase, but also for transmitting the memory of gene activity through mitosis to daughter cells We use ChIP-chip approach to identify TBP-bindind sites in mitotic Jurkat cells at genome-wide level. Input DNA fragments and DNA fragments immunoprecipitated by TBP antibodies by ChIP assay on mitotic Jurkat cells were used to probe the Affymetrix Genechip human tiling 2.0c to identift TBP-binding sites in mitotic Jurkat cells. Input and ChIP sample were replicated three times as following: Input rep1, TBP ChIP1, Input rep2, TBP ChIP2, Input rep3, TBP ChIP3.
2010-04-03 | E-GEOD-12256 | biostudies-arrayexpress
Project description:Two mitotic Cyclins, A and B, exist in higher eukaryotes, but their specialised functions in mitosis are poorly understood. Using degron tags we analyse how acute depletion of these proteins affects mitosis. Loss of Cyclin A in G2-phase prevents the initial activation of Cdk1. Cells lacking Cyclin B can enter mitosis and phosphorylate most mitotic proteins, because of parallel PP2A:B55 phosphatase inactivation by Greatwall kinase. The final barrier to mitotic establishment corresponds to nuclear envelope breakdown that requires a decisive shift in the balance of Cdk1 and PP2A:B55 activity. Beyond this point Cyclin B/Cdk1 is essential to phosphorylate a distinct subset mitotic Cdk1 substrates that are essential to complete cell division. Our results identify how Cyclin A, B and Greatwall coordinate mitotic progression by increasing levels of Cdk1-dependent substrate phosphorylation. The phosphoproteomics dataset aims to identify substrates that are affected specifically by acute depletion of Cyclin Bprotein.
2020-05-21 | PXD012100 | Pride
Project description:While effective anti-cancer drugs targeting the CHK1 kinase are advancing in the clinic, drug resistance is rapidly emerging. Here, we demonstrate that CRISPR-mediated knockout of the little-known gene FAM122A confers cellular resistance to CHK1 inhibitors and cross-resistance to ATR inhibitors. Knockout of FAM122A results in activation of PP2A-B55α, a phosphatase which dephosphorylates the WEE1 protein and rescues WEE1 from Ubiquitin-mediated degradation. The resulting increase in WEE1 protein expression reduces replication stress, activates the G2/M checkpoint, and confers cellular resistance to CHK1 inhibitors. Interestingly, in tumor cells with oncogene-driven replication stress, CHK1 can directly phosphorylate FAM122A, leading to activation of the PP2A-B55α phosphatase and increased WEE1 expression. A combination of a CHK1 inhibitor plus a WEE1 inhibitor can overcome CHK1 inhibitor resistance of these tumor cells, thereby enhancing anti-cancer activity. The FAM122A expression level in a tumor cell can serve as a useful biomarker for predicting CHK1 inhibitor sensitivity or resistance.
2021-01-01 | GSE158338 | GEO
Project description:Goldbeter1991 - Min Mit Oscil
Minimal cascade model for the mitotic oscillator involving cyclin and cdc2 kinase.
This model has been generated by MathSBML 2.4.6 (14-January-2005) 14-January-2005 18:33:39.806932.
This model is described in the article:
A minimal cascade model for the mitotic oscillator involving cyclin and cdc2 kinase.
Goldbeter A.
Proc. Natl. Acad. Sci. U.S.A. 1991; 88(20):9107-11
Abstract:
A minimal model for the mitotic oscillator is presented. The model, built on recent experimental advances, is based on the cascade of post-translational modification that modulates the activity of cdc2 kinase during the cell cycle. The model pertains to the situation encountered in early amphibian embryos, where the accumulation of cyclin suffices to trigger the onset of mitosis. In the first cycle of the bicyclic cascade model, cyclin promotes the activation of cdc2 kinase through reversible dephosphorylation, and in the second cycle, cdc2 kinase activates a cyclin protease by reversible phosphorylation. That cyclin activates cdc2 kinase while the kinase triggers the degradation of cyclin has suggested that oscillations may originate from such a negative feedback loop [Félix, M. A., Labbé, J. C., Dorée, M., Hunt, T. & Karsenti, E. (1990) Nature (London) 346, 379-382]. This conjecture is corroborated by the model, which indicates that sustained oscillations of the limit cycle type can arise in the cascade, provided that a threshold exists in the activation of cdc2 kinase by cyclin and in the activation of cyclin proteolysis by cdc2 kinase. The analysis shows how miototic oscillations may readily arise from time lags associated with these thresholds and from the delayed negative feedback provided by cdc2-induced cyclin degradation. A mechanism for the origin of the thresholds is proposed in terms of the phenomenon of zero-order ultrasensitivity previously described for biochemical systems regulated by covalent modification.
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2024-09-02 | BIOMD0000000003 | BioModels
Project description:Treating wild-type S. pombe cells and ∆wee1 mutant with 20mM H2O2, we observed that aberrant Cdc2 activity, as in case of ∆wee1 cells can lead to major changes in the Spc1 dependent global transcriptional response to oxidative stress.
2021-05-04 | GSE173744 | GEO
Project description:The G1/S cell-cycle checkpoint is frequently dysregulated in cancer, leaving cancer cells particularly reliant on a functional G2/M checkpoint to prevent excessive DNA damage. Inhibiting regulators of the G2/M checkpoint can therefore drive cancer cells into premature mitosis, ultimately causing cell death by mitotic catastrophe. One such regulator is Wee1, a nuclear tyrosine kinase that delays mitotic entry by phosphorylating CDK1 at Tyr15. Previous drug development efforts targeting Wee1 resulted in the clinical-grade inhibitor, AZD1775. However, AZD1775 is burdened by dose- limiting adverse events, and has off-target PLK1 activity. In an attempt to overcome these limitations, we designed small molecule degraders of Wee1 by conjugating AZD1775 to the cereblon (CRBN)- binding ligand, pomalidomide, as informed by molecular docking. The resulting lead compound, ZNL- 02-096, degrades Wee1 while sparing PLK1, induces G2/M phase accumulation at up to 10-fold lower concentrations than AZD1775, and potently synergizes with Olaparib in ovarian cancer cell lines. We demonstrate that ZNL-02-096 has CRBN-dependent pharmacology that is distinct from the conventional catalytic inhibitor, AZD1775, which justifies further evaluation of selective Wee1 degraders.
2019-11-18 | PXD015513 | Pride
Project description:Patients with small-cell lung cancer (SCLC) are in dire need of more effective therapeutic options. Frequent disruption of the G1 checkpoint in SCLC cells creates a greater dependency of these cells on the G2/M checkpoint to maintain genomic integrity. Indeed, in pre-clinical models, inhibiting the G2/M kinase WEE1 shows promise in inhibiting SCLC growth. However, toxicity and acquired resistance limit the clinical effectiveness of this strategy. Here we conducted CRISPR/Cas9 knockout screens to identify genes influencing the response of SCLC cells to WEE1 kinase inhibition. These screens uncovered a role for the GCN2 amino acid-sensing pathway in modulating the response of SCLC cells to WEE1 inhibition. Rapid activation of GCN2 upon WEE1 inhibition triggers a stress response. Pharmacological activation of the GCN2 pathway synergizes with WEE1 inhibition. Thus, activation of the GCN2 amino acid-sensing pathway represents a novel approach for augmenting the efficacy of WEE1 inhibitors in SCLC.
2024-07-16 | GSE246354 | GEO