scholarly journals Aurora Kinase Inhibitor ZM447439 Blocks Chromosome-induced Spindle Assembly, the Completion of Chromosome Condensation, and the Establishment of the Spindle Integrity Checkpoint inXenopusEgg Extracts

2005 ◽  
Vol 16 (3) ◽  
pp. 1305-1318 ◽  
Author(s):  
Bedrick B. Gadea ◽  
Joan V. Ruderman
Keyword(s):  
Cell Cycle ◽  
Mitotic Spindle ◽  
Kinase Inhibitor ◽  
Spindle Assembly ◽  
Aurora Kinase ◽  
Chromosome Morphology ◽  
Chromosome Condensation ◽  
Embryonic Cell ◽  
Cell Cycle Regulators ◽  
Cell Cycles

The Aurora family kinases contribute to accurate progression through several mitotic events. ZM447439 (“ZM”), the first Aurora family kinase inhibitor to be developed and characterized, was previously found to interfere with the mitotic spindle integrity checkpoint and chromosome segregation. Here, we have used extracts of Xenopus eggs, which normally proceed through the early embryonic cell cycles in the absence of functional checkpoints, to distinguish between ZM's effects on the basic cell cycle machinery and its effects on checkpoints. ZM clearly had no effect on either the kinetics or amplitude in the oscillations of activity of several key cell cycle regulators. It did, however, have striking effects on chromosome morphology. In the presence of ZM, chromosome condensation began on schedule but then failed to progress properly; instead, the chromosomes underwent premature decondensation during mid-mitosis. ZM strongly interfered with mitotic spindle assembly by inhibiting the formation of microtubules that are nucleated/stabilized by chromatin. By contrast, ZM had little effect on the assembly of microtubules by centrosomes at the spindle poles. Finally, under conditions where the spindle integrity checkpoint was experimentally induced, ZM blocked the establishment, but not the maintenance, of the checkpoint, at a point upstream of the checkpoint protein Mad2. These results show that Aurora kinase activity is required to ensure the maintenance of condensed chromosomes, the generation of chromosome-induced spindle microtubules, and activation of the spindle integrity checkpoint.

scholarly journals Aurora kinases A and B are up-regulated by Myc and are essential for maintenance of the malignant state

Blood ◽  
2010 ◽  
Vol 116 (9) ◽  
pp. 1498-1505 ◽  
Author(s):  
Jürgen den Hollander ◽  
Sara Rimpi ◽  
Joanne R. Doherty ◽  
Martina Rudelius ◽  
Andreas Buck ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Kinase Activity ◽  
Kinase Inhibitor ◽  
Aurora Kinase ◽  
Cell Cycle Regulators ◽  
Aurora Kinase Inhibitor ◽  
Aurora Kinases ◽  
Protein Levels ◽  
Malignant State ◽  
E Boxes

Myc oncoproteins promote continuous cell growth, in part by controlling the transcription of key cell cycle regulators. Here, we report that c-Myc regulates the expression of Aurora A and B kinases (Aurka and Aurkb), and that Aurka and Aurkb transcripts and protein levels are highly elevated in Myc-driven B-cell lymphomas in both mice and humans. The induction of Aurka by Myc is transcriptional and is directly mediated via E-boxes, whereas Aurkb is regulated indirectly. Blocking Aurka/b kinase activity with a selective Aurora kinase inhibitor triggers transient mitotic arrest, polyploidization, and apoptosis of Myc-induced lymphomas. These phenotypes are selectively bypassed by a kinase inhibitor-resistant Aurkb mutant, demonstrating that Aurkb is the primary therapeutic target in the context of Myc. Importantly, apoptosis provoked by Aurk inhibition was p53 independent, suggesting that Aurka/Aurkb inhibitors will show efficacy in treating primary or relapsed malignancies having Myc involvement and/or loss of p53 function.

scholarly journals Targeting the Id1-Kif11 Axis in Triple-Negative Breast Cancer Using Combination Therapy

Biomolecules ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1295
Author(s):  
Archana P. Thankamony ◽  
Reshma Murali ◽  
Nitheesh Karthikeyan ◽  
Binitha Anu Varghese ◽  
Wee S. Teo ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cell Cycle ◽  
Triple Negative Breast Cancer ◽  
Large Scale ◽  
Triple Negative ◽  
Genomic Analysis ◽  
Aurora Kinase ◽  
Cell Cycle Regulators ◽  
Tumor Models ◽  
Tnbc Subtype

The basic helix-loop-helix (bHLH) transcription factors inhibitor of differentiation 1 (Id1) and inhibitor of differentiation 3 (Id3) (referred to as Id) have an important role in maintaining the cancer stem cell (CSC) phenotype in the triple-negative breast cancer (TNBC) subtype. In this study, we aimed to understand the molecular mechanism underlying Id control of CSC phenotype and exploit it for therapeutic purposes. We used two different TNBC tumor models marked by either Id depletion or Id1 expression in order to identify Id targets using a combinatorial analysis of RNA sequencing and microarray data. Phenotypically, Id protein depletion leads to cell cycle arrest in the G0/G1 phase, which we demonstrate is reversible. In order to understand the molecular underpinning of Id proteins on the cell cycle phenotype, we carried out a large-scale small interfering RNA (siRNA) screen of 61 putative targets identified by using genomic analysis of two Id TNBC tumor models. Kinesin Family Member 11 (Kif11) and Aurora Kinase A (Aurka), which are critical cell cycle regulators, were further validated as Id targets. Interestingly, unlike in Id depletion conditions, Kif11 and Aurka knockdown leads to a G2/M arrest, suggesting a novel Id cell cycle mechanism, which we will explore in further studies. Therapeutic targeting of Kif11 to block the Id1–Kif11 axis was carried out using small molecular inhibitor ispinesib. We finally leveraged our findings to target the Id/Kif11 pathway using the small molecule inhibitor ispinesib in the Id+ CSC results combined with chemotherapy for better response in TNBC subtypes. This work opens up exciting new possibilities of targeting Id targets such as Kif11 in the TNBC subtype, which is currently refractory to chemotherapy. Targeting the Id1–Kif11 molecular pathway in the Id1+ CSCs in combination with chemotherapy and small molecular inhibitor results in more effective debulking of TNBC.

scholarly journals Microtubule Cytoskeleton Remodeling by Acentriolar Microtubule-organizing Centers at the Entry and Exit from Mitosis in Drosophila Somatic Cells

2009 ◽  
Vol 20 (11) ◽  
pp. 2796-2808 ◽  
Author(s):  
Sara Moutinho-Pereira ◽  
Alain Debec ◽  
Helder Maiato
Keyword(s):  
Cell Cycle ◽  
Mitotic Spindle ◽  
De Novo ◽  
Animal Cell ◽  
Somatic Cells ◽  
Spindle Assembly ◽  
Entry And Exit ◽  
Down Regulation ◽  
Microtubule Organizing Centers ◽  
Cytoskeleton Remodeling

Cytoskeleton microtubules undergo a reversible metamorphosis as cells enter and exit mitosis to build a transient mitotic spindle required for chromosome segregation. Centrosomes play a dominant but dispensable role in microtubule (MT) organization throughout the animal cell cycle, supporting the existence of concurrent mechanisms that remain unclear. Here we investigated MT organization at the entry and exit from mitosis, after perturbation of centriole function in Drosophila S2 cells. We found that several MTs originate from acentriolar microtubule-organizing centers (aMTOCs) that contain γ-tubulin and require Centrosomin (Cnn) for normal architecture and function. During spindle assembly, aMTOCs associated with peripheral MTs are recruited to acentriolar spindle poles by an Ncd/dynein-dependent clustering mechanism to form rudimentary aster-like structures. At anaphase onset, down-regulation of CDK1 triggers massive formation of cytoplasmic MTs de novo, many of which nucleated directly from aMTOCs. CDK1 down-regulation at anaphase coordinates the activity of Msps/XMAP215 and the kinesin-13 KLP10A to favor net MT growth and stability from aMTOCs. Finally, we show that microtubule nucleation from aMTOCs also occurs in cells containing centrosomes. Our data reveal a new form of cell cycle–regulated MTOCs that contribute for MT cytoskeleton remodeling during mitotic spindle assembly/disassembly in animal somatic cells, independently of centrioles.

Activity of the Aurora Kinase Inhibitor, MLN8237 (alisertib) Alone or in Combination with Ponatinib Against Imatinib-Resistant BCR-ABL-Positive Cells

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 1333-1333
Author(s):  
Seiichi Okabe ◽  
Tetsuzo Tauchi ◽  
Seiichiro Katagiri ◽  
Yuko Tanaka ◽  
Kazuma Ohyashiki
Keyword(s):  
Cell Cycle ◽  
Cell Growth ◽  
Growth Inhibition ◽  
Kinase Inhibitor ◽  
K562 Cells ◽  
Aurora Kinase ◽  
Dependent Manner ◽  
Cell Growth Inhibition ◽  
Cycle Arrest ◽  
T315i Mutation

Abstract Abstract 1333 Chronic myeloid leukemia (CML) is characterized by cytogenetic aberration (Philadelphia chromosome: Ph) and chimeric tyrosine kinase BCR-ABL. ABL tyrosine kinase inhibitor, imatinib has demonstrated the potency against CML patients. However, resistance to imatinib can develop in CML patients due to BCR-ABL point mutations. One of T315I mutation is resistant to currently available ABL tyrosine kinase inhibitors. Therefore, new approach against T315I mutant may improve the outcome of Ph-positive leukemia patients. Aurora kinases are serine/threonine kinases and upregulated in many malignancies including leukemia, and play an important role in cell cycle control and tumor proliferations. Because Aurora kinases are overexpressed in leukemia cells, Aurora kinases may present attractive targets for leukemia treatment. One of Aurora kinase inhibitor, MLN8237 (alisertib) is an oral and selective Aurora kinase A inhibitor and is currently being investigated in a pivotal phase 3 clinical trial against hematological malignancies. We suggested that alisertib mediated inhibition Aurora kinase activity and in combination with ponatinib, also known as AP24534 may abrogate the proliferation and survival of Ph-positive cells including T315I mutation. In this study, we investigated the combination therapy with a ponatinib and an alisertib by using the BCR-ABL positive cell line, K562, murine Ba/F3 cell line which was transfected with T315I mutant, ponatinib resistant Ba/F3 cells and T315I primary sample. Protein expression of Aurora A and B were increased in Ph-positive leukemia cells. 72 hours treatment of alisertib exhibits cell growth inhibition and induced apoptosis against K562 cells in a dose dependent manner. Alisertib also induced cell cycle arrest. The treatment of ponatinib exhibits cell growth inhibition partially against K562 cells in the presence of feeder cell (HS-5) conditioned media. We found that the treatment of alisertib abrogated the protective effects of HS-5 conditioned media in K562 cells. We investigated the alisertib activity against T315I positive cells. Alisertib potently induced cell growth inhibition of Ba/F3 cells ectopically expressing T315I mutation and induced cell cycle arrest. We investigated the efficacy between ponatinib and alisertib by using these cell lines. Combined treatment of Ba/F3 T315I cells with ponatinib and alisertib caused significantly more cytotoxicity than each drug alone. Ponatinib and alisertib were also effective against T315I primary samples. We examined the intracellular signaling of alisertib. Phosphorylation of Aurora A was inhibited in a time dependent manner. We also found the phosphorylation of histone H3 was also reduced in a dose dependent manner suggested that high concentration of alisertib also inhibits Aurora B activity. We next investigated by using ponatinib resistant Ba/F3 cells. In the ponatinib resistant cell lines, IC50 of ponatinib was up to 200 nM. BCR-ABL triple point mutations (T315I, E255K and Y253H) were detected by direct sequence analysis. The treatment of alisertib exhibits cell growth inhibition against Ba/F3 ponatinib resistant cells in the dose dependent manner. Alisertib induced cell cycle arrest in ponatinib resistant cells. Combined treatment of Ba/F3 ponatinib resistant cells with ponatinib and alisertib caused significantly more cytotoxicity. To assess the activity of alisertib and ponatinib, we performed to test on CML tumor formation in mice. We injected nude mice subcutaneously with 1×107 Ba/F3 T315I cells. A dose of 30 mg/kg/day p.o of ponatinib and 30 mg/kg/day p.o of alisertib inhibited tumor growth and reduced tumor volume compared with control mice. The treatments were well tolerated with no animal health concerns observed indicating the feasibility of alisertib combination strategies in the clinic. Data from this study suggested that administration of the ponatinib and Aurora inhibitor, alisertib may be a powerful strategy against BCR-ABL mutant cells including T315I. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Chromosome Association of Minichromosome Maintenance Proteins in Drosophila Mitotic Cycles

1997 ◽  
Vol 139 (1) ◽  
pp. 13-21 ◽  
Author(s):  
Tin Tin Su ◽  
Patrick H. O'Farrell
Keyword(s):  
Cell Cycle ◽  
Cyclin E ◽  
Embryonic Cell ◽  
Cyclin B ◽  
Chromatin Interaction ◽  
G1 Phase ◽  
Minichromosome Maintenance ◽  
Cell Cycles ◽  
Mcm Proteins ◽  
Replication Factors

Minichromosome maintenance (MCM) proteins are essential DNA replication factors conserved among eukaryotes. MCMs cycle between chromatin bound and dissociated states during each cell cycle. Their absence on chromatin is thought to contribute to the inability of a G2 nucleus to replicate DNA. Passage through mitosis restores the ability of MCMs to bind chromatin and the ability to replicate DNA. In Drosophila early embryonic cell cycles, which lack a G1 phase, MCMs reassociate with condensed chromosomes toward the end of mitosis. To explore the coupling between mitosis and MCM–chromatin interaction, we tested whether this reassociation requires mitotic degradation of cyclins. Arrest of mitosis by induced expression of nondegradable forms of cyclins A and/or B showed that reassociation of MCMs to chromatin requires cyclin A destruction but not cyclin B destruction. In contrast to the earlier mitoses, mitosis 16 (M16) is followed by G1, and MCMs do not reassociate with chromatin at the end of M16. dacapo mutant embryos lack an inhibitor of cyclin E, do not enter G1 quiescence after M16, and show mitotic reassociation of MCM proteins. We propose that cyclin E, inhibited by Dacapo in M16, promotes chromosome binding of MCMs. We suggest that cyclins have both positive and negative roles in controlling MCM–chromatin association.

scholarly journals Cell Cycle Interference Contributes to the Anticancer Synergy Between Radiotherapy and Aurora Kinase Inhibitor VE-465 in Hepatocellular Carcinoma

2014 ◽  
Vol 25 ◽  
pp. ii20
Author(s):  
Lin Zhong-Zhe ◽  
Chou Chia-Hung ◽  
Cheng Ann-Lii ◽  
Liu Wei-Lin ◽  
Cheng Jason Chia-Hsien
Keyword(s):  
Hepatocellular Carcinoma ◽  
Cell Cycle ◽  
Kinase Inhibitor ◽  
Aurora Kinase ◽  
Aurora Kinase Inhibitor

scholarly journals Excess histone H3 is a Chk1 inhibitor that controls embryonic cell cycle progression

2020 ◽  
Author(s):  
Yuki Shindo ◽  
Amanda A. Amodeo
Keyword(s):  
Cell Cycle ◽  
Cell Fate ◽  
Cell Cycle Progression ◽  
Histone H3 ◽  
Embryonic Cell ◽  
Cycle Progression ◽  
Cell Cycles ◽  
Embryonic Cell Cycle

AbstractThe early embryos of many species undergo a switch from rapid, reductive cleavage divisions to slower, cell fate-specific division patterns at the Mid-Blastula Transition (MBT). The maternally loaded histone pool is used to measure the increasing ratio of nuclei to cytoplasm (N/C ratio) to control MBT onset, but the molecular mechanism of how histones regulate the cell cycle has remained elusive. Here, we show that excess histone H3 inhibits the DNA damage checkpoint kinase Chk1 to promote cell cycle progression in the Drosophila embryo. We find that excess H3-tail that cannot be incorporated into chromatin is sufficient to shorten the embryonic cell cycle and reduce the activity of Chk1 in vitro and in vivo. Removal of the Chk1 phosphosite in H3 abolishes its ability to regulate the cell cycle. Mathematical modeling quantitatively supports a mechanism where changes in H3 nuclear concentrations over the final cell cycles leading up to the MBT regulate Chk1-dependent cell cycle slowing. We provide a novel mechanism for Chk1 regulation by H3, which is crucial for proper cell cycle remodeling during early embryogenesis.

scholarly journals CCNE1 and E2F1 Partially Suppress G1 Phase Arrest Caused by Spliceostatin A Treatment

2021 ◽  
Vol 22 (21) ◽  
pp. 11623
Author(s):  
Kei Kikuchi ◽  
Daisuke Kaida
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Kinase Inhibitor ◽  
G1 Phase ◽  
Cell Cycle Regulators ◽  
Protein Levels ◽  
Cyclin Dependent Kinase Inhibitor ◽  
Phase Arrest ◽  
G1 Phase Arrest ◽  
Spliceostatin A

The potent splicing inhibitor spliceostatin A (SSA) inhibits cell cycle progression at the G1 and G2/M phases. We previously reported that upregulation of the p27 cyclin-dependent kinase inhibitor encoded by CDKN1B and its C-terminal truncated form, namely p27*, which is translated from CDKN1B pre-mRNA, is one of the causes of G1 phase arrest caused by SSA treatment. However, the detailed molecular mechanism underlying G1 phase arrest caused by SSA treatment remains to be elucidated. In this study, we found that SSA treatment caused the downregulation of cell cycle regulators, including CCNE1, CCNE2, and E2F1, at both the mRNA and protein levels. We also found that transcription elongation of the genes was deficient in SSA-treated cells. The overexpression of CCNE1 and E2F1 in combination with CDKN1B knockout partially suppressed G1 phase arrest caused by SSA treatment. These results suggest that the downregulation of CCNE1 and E2F1 contribute to the G1 phase arrest induced by SSA treatment, although they do not exclude the involvement of other factors in SSA-induced G1 phase arrest.

Cell cycle regulators in Drosophila: downstream and part of developmental decisions

1997 ◽  
Vol 110 (5) ◽  
pp. 523-528 ◽  
Author(s):  
C.F. Lehner ◽  
M.E. Lane
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Molecular Mechanisms ◽  
Eukaryotic Cell ◽  
Embryonic Cell ◽  
Developmental Phase ◽  
Cell Cycle Regulators ◽  
Egg Extracts ◽  
Extensive Growth ◽  
New Perspective

The molecular identification of an evolutionarily conserved set of cell cycle regulators in yeast, Xenopus egg extracts, and vertebrate cell culture has opened up a new perspective for understanding the mechanisms that regulate cell proliferation during metazoan development. Now we can study how the crucial regulators of eukaryotic cell cycle progression, the various cyclin/cdk complexes (for a recent review see Nigg (1995) BioEssays 17, 471–480), are turned on or off during development. In Drosophila, this analysis is most advanced, in particular in the case of the rather rigidly programmed embryonic cell cycles that generate the cells of the larvae. In addition, this analysis has revealed how the mitotic cycle is transformed into an endocycle which allows the extensive growth of larvae and oocytes. In contrast, we know little about cyclin/cdk regulation during the imaginal proliferation that generates the cells of the adult. Nevertheless, we will also consider this second developmental phase with its conspicuous regulative character, because it will be of great interest for the analysis of the molecular mechanisms that integrate growth and proliferation during development.

A Novel Aurora-a Kinase Inhibitor MLN8237 Induces Cytotoxicity and Cell Cycle Arrest in Experimental Multiple Myeloma Models.

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 1719-1719 ◽  
Author(s):  
Gullu Gorgun ◽  
Elisabetta Calabrese ◽  
Mala Mani ◽  
Teru Hideshima ◽  
Hiroshi Ikeda ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Multiple Myeloma ◽  
Cell Lines ◽  
Mitotic Spindle ◽  
Kinase Inhibitor ◽  
Thymidine Incorporation ◽  
Significant Inhibition ◽  
Aurora A Kinase ◽  
Aurora A ◽  
Resistant Line

Abstract Multiple myeloma (MM) is an incurable bone marrow derived plasma cell malignancy. Despite significant improvements in treating patients suffering from this disease, MM remains uniformly fatal owing to intrinsic or acquired drug resistance. Thus, additional modalities for treating MM are required. In this study, we examined the anti-tumor activity of MLN8237, a small molecule Aurora-A kinase inhibitor, in experimental models of MM. Aurora-A is a mitotic kinase that localizes to centrosomes and the proximal mitotic spindle and functions in mitotic spindle formation and in regulating chromatid congression and segregation. Aurora-A gene amplification and protein overexpression is a common event in many cancers, and has been experimentally linked to genetic instability and tumorigenesis. In MM, increased Aurora-A gene expression has previously been correlated with centrosome amplification and a worsened disease prognosis. Thus, inhibition of Aurora A in MM may prove to be therapeutically beneficial. Here we show that Aurora-A protein is highly expressed in eight distinct MM cell lines. The affect of Aurora-A inhibition in these cell lines was examined in cytotoxicity (MTT viability) and proliferation (3[H]thymidine incorporation) assays by treating with MLN8237 (0.25 mM −32 mM) for 24, 48 and 72h. Although there was no significant inhibition of cell viability and proliferation at 24h, a marked effect occurred 48 and 72h after compound addition at concentrations as low as 0.25 mM. Interestingly, the melphalan resistant line (LR5) and Doxorubucin resistant line (Dox40) were among the least sensitive to MLN8237 induced cell cytotoxicity. The affect of MLN8237 on peripheral blood mononuclear cells (PBMCs) from healthy donors was also examined at the same concentrations and exposure time used for the MM cell lines. In healthy PBMCs, MLN8237 did not induce cytotoxicity as measured by the MTT assay, but there was a significant inhibition of proliferation at 48 and 72h as measured by the 3[H]thymidine incorporation assay at concentrations above 4uM. To delineate the mechanisms of cytotoxicity and growth inhibitory activity of MLN8237, apoptotic markers and cell cycle profiles were examined in the MM cell lines. Fluorescence conjugated-Annexin V and propidium iodide (PI) co-staining of MM cell lines after culturing in the presence or absence of MLN8237 at 1 mM (IC50) for 24, 48 and 72h demonstrated that MLN8237 induces apoptosis in these lines. This finding was corroborated by demonstrating increased capase-9 expression by Western blot analysis. Cell cycle analysis by flow cytometry demonstrated that MLN8237 results in an accumulation of tetraploid cells, presumably by abrogating G2/M progression. These results suggest that MLN8237 represents a possible novel agent for treating MM patients. Additional studies are ongoing to assess the anti-tumor effects of MLN8237 alone and in combination with other therapeutic agents in xenograft models of MM.

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