scholarly journals Genome-scale genetic interactions position the Mitotic Exit Network as a major antagonist of transient Topoisomerase II deficiency

2017 ◽  
Author(s):  
Ramos-Pérez Cristina ◽  
Grant W Brown ◽  
Machín Félix
Keyword(s):  
Cell Cycle Progression ◽  
Topoisomerase Ii ◽  
Gene Array ◽  
Mitotic Exit ◽  
Mitotic Catastrophe ◽  
Cycle Progression ◽  
Anaphase Bridges ◽  
Yeast Strains ◽  
Mitotic Exit Network ◽  
Genome Scale

AbstractTopoisomerase II (Top2) is the essential protein that resolves DNA catenations. When the Top2 is inactivated, mitotic catastrophe results from massive entanglement of chromosomes. Top2 is also the target of many first-line anticancer drugs, the so-called Top2 poisons. Often, tumours become resistant to these drugs by downregulating Top2. Here, we have compared two isogenic yeast strains carrying top2 thermosensitive alleles that differ in their resistance to Top2 poisons, the broadly-used poison-sensitive top2-4 and the poison-resistant top2-5. We found that top2-5 transits through anaphase faster than top2-4. In order to define the biological importance of this difference, we performed genome-scale Synthetic Gene Array (SGA) analyses during chronic sublethal Top2 downregulation and acute, yet transient, Top2 inactivation. We find that downregulation of cell cycle progression, especially the Mitotic Exit Network (MEN), protects against Top2 deficiency. In all conditions, genetic protection was stronger in top2-5, and this correlated with destabilization of anaphase bridges by execution of MEN. We suggest that mitotic exit may be a therapeutic target to hypersensitize cancer cells carrying downregulating mutations in TOP2.

scholarly journals Budding yeast PAK kinases regulate mitotic exit by two different mechanisms

2003 ◽  
Vol 160 (6) ◽  
pp. 857-874 ◽  
Author(s):  
Elena Chiroli ◽  
Roberta Fraschini ◽  
Alessia Beretta ◽  
Mariagrazia Tonelli ◽  
Giovanna Lucchini ◽  
...  
Keyword(s):  
Cell Cycle Progression ◽  
Budding Yeast ◽  
Mitotic Exit ◽  
Dominant Negative ◽  
Anaphase Promoting Complex ◽  
Gene Encoding ◽  
Cycle Progression ◽  
Mitotic Exit Network ◽  
P21 Activated Kinase

We report the characterization of the dominant-negative CLA4t allele of the budding yeast CLA4 gene, encoding a member of the p21-activated kinase (PAK) family of protein kinases, which, together with its homologue STE20, plays an essential role in promoting budding and cytokinesis. Overproduction of the Cla4t protein likely inhibits both endogenous Cla4 and Ste20 and causes a delay in the onset of anaphase that correlates with inactivation of Cdc20/anaphase-promoting complex (APC)–dependent proteolysis of both the cyclinB Clb2 and securin. Although the precise mechanism of APC inhibition by Cla4t remains to be elucidated, our results suggest that Cla4 and Ste20 may regulate the first wave of cyclinB proteolysis mediated by Cdc20/APC, which has been shown to be crucial for activation of the mitotic exit network (MEN). We show that the Cdk1-inhibitory kinase Swe1 is required for the Cla4t-dependent delay in cell cycle progression, suggesting that it might be required to prevent full Cdc20/APC and MEN activation. In addition, inhibition of PAK kinases by Cla4t prevents mitotic exit also by a Swe1-independent mechanism impinging directly on the MEN activator Tem1.

scholarly journals Evolutionary trade-offs between unicellularity and multicellularity in budding yeast

2018 ◽  
Author(s):  
Jennie J. Kuzdzal-Fick ◽  
Lin Chen ◽  
Gábor Balázsi
Keyword(s):  
Mitotic Exit ◽  
Fundamental Question ◽  
Bet Hedging ◽  
Evolutionary Transitions ◽  
Wild Yeast ◽  
Yeast Strains ◽  
Trade Offs ◽  
Mitotic Exit Network ◽  
Multicellular Organisms ◽  
Benefits And Costs

ABSTRACTMulticellular organisms appeared on Earth through several independent major evolutionary transitions. Are such transitions reversible? Addressing this fundamental question entails understanding the benefits and costs of multicellularity versus unicellularity. For example, some wild yeast strains form multicellular clumps, which might be beneficial in stressful conditions, but this has been untested. Here we show that unicellular yeast evolves from clump-forming ancestors by propagating samples from suspension after larger clumps have settled. Unicellular yeast strains differed from their clumping ancestors mainly by mutations in the AMN1 (Antagonist of Mitotic exit Network) gene. Ancestral yeast clumps were more resistant to freeze/thaw, hydrogen peroxide, and ethanol stressors than their unicellular counterparts, while unicellularity was advantageous without stress. These findings inform mathematical models, jointly suggesting a trade-off between the benefits and downsides of multicellularity, causing bet-hedging by regulated phenotype switching as a survival strategy in unexpected stress.

Proteomic Analysis of Acute Promyelocytic Leukemia Reveals That PML-RARalpha Induces Cell Cycle Progression and Mitotic Exit by Increased Expression and Decreased Ser63 Phosphorylation of OP18.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2028-2028
Author(s):  
A. PeerZada ◽  
M. Geletu ◽  
J. Pullikan ◽  
V. Reddy ◽  
W. Hiddemann ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Acute Promyelocytic Leukemia ◽  
Cell Cycle Progression ◽  
Promyelocytic Leukemia ◽  
Mitotic Exit ◽  
Cycle Progression ◽  
2D Gel ◽  
First Time ◽  
Common Cell

Abstract We applied a mass spectrometry based approach to explore the proteins differentially regulated by PML-RARalpha, a translocation characteristic of acute promyelocytic leukemia (APL). Bioinformatic pathway analysis placed the 46 identified PML-RARalpha regulated proteins into three major networks, OP18-MAPK1, HSP-STAT3 and CCT-MYC. Using this approach, we were able to generate a common cell cycle network of the proteins in these pathways. Further analysis indicated that mRNA expression of OP18, which belonged to this network, was elevated in APL patients and the increased OP18 protein expression upon PML-RARalpha induction was overcome by retinoic acid treatment. Here we also report, for the first time a novel role of PML-RARalpha in cell cycle progression and mitotic exit. RNA interference experiments revealed that siRNA against OP18 overcomes PML-RARalpha effects on cell cycle progression. In addition to increased OP18 expression by PML-RARalpha, 2D gel electrophoresis revealed an isomer of OP18, subsequently confirmed by 2D-western as ser63 phosphomer to be downregulated by PML-RARalpha. Based on these findings, point mutation experiments indicated that decreased phosphorylation of ser63 in OP18 is important for PML-RARalpha mediated cell cycle and mitotic index effects since a constitutive phosphorylated mutant (ser63/asp) of OP18 overcame the PML-RARalpha effects in U9/PR cells, NB4 and APL patients. In summary, our results demonstrate that the effect of PML-RARalpha on cell cycle progression and mitotic exit is via two mechanisms: increasing the expression of OP18 and decreasing the phosphorylation of OP18 at ser63.

scholarly journals Effects of conditional depletion of topoisomerase II on cell cycle progression in mammalian cells

Cell Cycle ◽  
2011 ◽  
Vol 10 (20) ◽  
pp. 3505-3514 ◽  
Author(s):  
Ruth E. Gonzalez ◽  
Chang-Uk Lim ◽  
Kelly Cole ◽  
Christine Hanko Bianchini ◽  
Gary P. Schools ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Mammalian Cells ◽  
Cell Cycle Progression ◽  
Topoisomerase Ii ◽  
Cycle Progression

scholarly journals Wee1 Rather Than Plk1 Is Inhibited by AZD1775 at Therapeutically Relevant Concentrations

Cancers ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 819 ◽  
Author(s):  
Angela Flavia Serpico ◽  
Giuseppe D’Alterio ◽  
Cinzia Vetrei ◽  
Rosa Della Monica ◽  
Luca Nardella ◽  
...  
Keyword(s):  
Cell Cycle Progression ◽  
Mitotic Catastrophe ◽  
Cyclin Dependent Kinase ◽  
Cycle Progression ◽  
Replication Checkpoint ◽  
Dna Damaging Agents ◽  
Dna Replication Checkpoint ◽  
Wee1 Kinase ◽  
Damaged Dna

Wee1 kinase is an inhibitor of cyclin-dependent kinase (cdk)s, crucial cell cycle progression drivers. By phosphorylating cdk1 at tyrosine 15, Wee1 inhibits activation of cyclin B-cdk1 (Cdk1), preventing cells from entering mitosis with incompletely replicated or damaged DNA. Thus, inhibiting Wee1, alone or in combination with DNA damaging agents, can kill cancer cells by mitotic catastrophe, a tumor suppressive response that follows mitosis onset in the presence of under-replicated or damaged DNA. AZD1775, an orally available Wee1 inhibitor, has entered clinical trials for cancer treatment following this strategy, with promising results. Recently, however, AZD1775 has been shown to inhibit also the polo-like kinase homolog Plk1 in vitro, casting doubts on its mechanism of action. Here we asked whether, in the clinically relevant concentration range, AZD1775 inhibited Wee1 or Plk1 in transformed and non-transformed human cells. We found that in the clinically relevant, nanomolar, concentration range AZD1775 inhibited Wee1 rather than Plk1. In addition, AZD1775 treatment accelerated mitosis onset overriding the DNA replication checkpoint and hastened Plk1-dependent phosphorylation. On the contrary selective Plk1 inhibition exerted opposite effects. Thus, at therapeutic concentrations, AZD1775 inhibited Wee1 rather than Plk1. This information will help to better interpret results obtained by using AZD1775 both in the clinical and experimental settings and provide a stronger rationale for combination therapies.

scholarly journals Overdosage of balanced protein complexes reduces proliferation rate in aneuploid cells

2018 ◽  
Author(s):  
Ying Chen ◽  
Siyu Chen ◽  
Ke Li ◽  
Yuliang Zhang ◽  
Xiahe Huang ◽  
...  
Keyword(s):  
Molecular Basis ◽  
Cell Cycle Progression ◽  
Protein Complexes ◽  
Diploid Cell ◽  
Proliferation Rate ◽  
Cycle Progression ◽  
Protein Levels ◽  
Yeast Strains ◽  
Wide Range ◽  
In Cells

SUMMARYCells with complex aneuploidies, such as tumor cells, display a wide range of phenotypic abnormalities. However, molecular basis for this has been mainly studied in trisomic (2n+1) and disomic (n+1) cells. To determine how karyotype affects proliferation rate in cells with complex aneuploidies we generated forty 2n+x yeast strains in which each diploid cell has an extra 5 to 12 chromosomes and found that these strains exhibited abnormal cell-cycle progression. Proliferation rate was negatively correlated with the number of protein complexes in which all subunits were at the 3-copy level, but not with the number of imbalanced complexes made up of a mixture of 2-copy and 3-copy genes. Proteomics revealed that most 3-copy members of imbalanced complexes were expressed at only 2n protein levels whereas members of complexes in which all subunits are stoichiometrically balanced at 3 copies per cell had 3n protein levels. We identified individual protein complexes for which overdosage reduces proliferation rate, and found that deleting one copy of each member partially restored proliferation rate in cells with complex aneuploidies. Lastly, we validated this finding using orthogonal datasets from both yeast and from human cancers. Taken together, our study provides a novel explanation how aneuploidy affects phenotype.

Potent cytotoxicity and inhibition of pan-cell cycle progression by Alchemix, a novel alkylating anthraquinone

2006 ◽  
Vol 24 (18_suppl) ◽  
pp. 12030-12030
Author(s):  
A. A. Epenetos ◽  
K. Pors ◽  
P. J. Smith ◽  
L. H. Patterson
Keyword(s):  
Cell Cycle ◽  
Cell Line ◽  
Cell Lines ◽  
Cell Cycle Progression ◽  
Topoisomerase Ii ◽  
Human Tumors ◽  
Drug Resistant ◽  
Cycle Progression ◽  
Topo Ii

12030 Introduction: DNA topoisomerase II (topo II) is crucial to the maintenance of cancer cells in a proliferative state. DNA intercalation is a crucial part of topo II inhibition by DNA affinic anthraquinones. Potent cytotoxicity of anthraquinones, is related to their slow rate of dissociation from DNA, the kinetics of which favours long-term trapping of the topo-DNA complexes. Currently available DNA interacting agents at best promote a transient inhibition of topo II, since the topo-drug-DNA ternary complex is reversed by removal of the intracellular drug pool. Results: Alchemix cell cycle events: DNA content and Cyclin B1 expression were measured using flow cytometry and a p53 functional human osteosarcoma cell line (U2-OS) The results indicate: (ii) slow pan-cell cycle progression and mitotic commitment with a limited expression of G2 arrest, (iii) B1 cyclin tracking reveals that escape from Alchemix-induced cell cycle arrest in G2 is forcing some cells to enter polyploidy via an aberrant mitosis in keeping with topoisomerase II inhibition. Alchemix in vitro activity against the NCI human cell line panel including several drug resistant cancer cell lines had a mean IG50 = 49 nM. 11 of the 24 cell lines tested have an IG50 of <10 nM. Alchemix retains potent activity against chemotherapy resistant tumors including drug resistant ones. Conclusions: Alchemix possesses potent activity across a variety of different human tumors and significantly shows potent activity in cisplatin and anthracyline resistant human tumors Alchemix has pan-cell cycle effects. Multilevel targeting by Alchemix reduces the probability of evasion of cell cycle related pharmacodynamic responses. Results help explain the activity of Alchemix in both cisplatin and anthracycline resistant tumors in vitro and in vivo. [Table: see text]

scholarly journals Human cells lacking CDC14A and CDC14B show differences in ciliogenesis but not in mitotic progression

2020 ◽  
pp. jcs.255950
Author(s):  
Patrick Partscht ◽  
Borhan Uddin ◽  
Elmar Schiebel
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Cell Cycle Progression ◽  
Cell Cycle Control ◽  
Mitotic Exit ◽  
Human Cells ◽  
Mitotic Progression ◽  
Cycle Progression ◽  
Double Deletion ◽  
Redundant Functions

Budding yeast Cdc14 phosphatase has a central role in mitotic exit and cytokinesis. Puzzlingly, a uniform picture for the three human CDC14 paralogues hCDC14A, B and C in cell cycle control has not emerged to date. Redundant functions between the three hCDC14 phosphatases could explain this unclear picture. To address the possibility of redundancy, we tested expression of hCDC14 and analysed cell cycle progression of cells with single- and double-deletion in hCDC14 genes. Our data suggest that hCDC14C is not expressed in human RPE1 cells excluding a function in this cell line. Single- and double-knockouts (KO) of hCDC14A and hCDC14B in RPE1 cells indicate that both phosphatases are not important for the timing of mitotic phases, cytokinesis and cell proliferation. However, cycling hCDC14A KO and hCDC14B KO cells show altered ciliogenesis compared to WT cells. The cilia of cycling hCDC14A KO cells are longer, whereas hCDC14B KO cilia are more frequent and disassemble faster. In conclusion, this study demonstrates that the cell cycle functions of CDC14 proteins are not conserved between yeast and human cells.

scholarly journals Cell Cycle-Dependent Control and Roles of DNA Topoisomerase II

Genes ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 859 ◽  
Author(s):  
Joyce H. Lee ◽  
James M. Berger
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Topoisomerase Ii ◽  
Type Ii ◽  
Dna Topoisomerase Ii ◽  
Dna Topoisomerase ◽  
Cycle Progression ◽  
Double Stranded Dna ◽  
Topo Ii ◽  
Cycle Dependent

Type II topoisomerases are ubiquitous enzymes in all branches of life that can alter DNA superhelicity and unlink double-stranded DNA segments during processes such as replication and transcription. In cells, type II topoisomerases are particularly useful for their ability to disentangle newly-replicated sister chromosomes. Growing lines of evidence indicate that eukaryotic topoisomerase II (topo II) activity is monitored and regulated throughout the cell cycle. Here, we discuss the various roles of topo II throughout the cell cycle, as well as mechanisms that have been found to govern and/or respond to topo II function and dysfunction. Knowledge of how topo II activity is controlled during cell cycle progression is important for understanding how its misregulation can contribute to genetic instability and how modulatory pathways may be exploited to advance chemotherapeutic development.

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