scholarly journals FBXO45-MYCBP2 regulates mitotic cell fate by targeting FBXW7 for degradation

2018 ◽  
Author(s):  
Kai T. Richter ◽  
Yvonne T. Kschonsak ◽  
Barbara Vodicska ◽  
Ingrid Hoffmann
Keyword(s):  
Cell Death ◽  
Cell Fate ◽  
Chemotherapy Resistance ◽  
Mitotic Cell ◽  
Mitotic Arrest ◽  
Protein Levels ◽  
Mitotic Slippage ◽  
Microtubule Targeting Agents ◽  
Fate Decision ◽  
F Box Protein

SUMMARYCell fate decision upon prolonged mitotic arrest induced by microtubule targeting agents depends on the activity of the tumor suppressor and F-box protein FBXW7. FBXW7 promotes mitotic cell death and prevents premature escape from mitosis through mitotic slippage. Mitotic slippage is a process that can cause chemoresistance and tumor relapse. Therefore, understanding the mechanisms that regulate the balance between mitotic cell death and mitotic slippage is an important task. Here we report that FBXW7 protein levels markedly decline during extended mitotic arrest. FBXO45 binds to a conserved acidic N-terminal motif of FBXW7 specifically under a prolonged delay in mitosis, leading to ubiquitylation and subsequent proteasomal degradation of FBXW7 by the FBXO45-MYCBP2 E3 ubiquitin ligase. Moreover, we find that FBXO45-MYCBP2 counteracts FBXW7 in that it promotes mitotic slippage and prevents cell death in mitosis. Targeting this interaction represents a promising strategy to prevent chemotherapy resistance.

scholarly journals The cytoplasmic DNA sensor cGAS promotes mitotic cell death

2017 ◽  
Author(s):  
Christian Zierhut ◽  
Hironori Funabiki
Keyword(s):  
Cell Death ◽  
Nuclear Envelope ◽  
Cell Fate ◽  
Mitotic Cell ◽  
Mitotic Arrest ◽  
Innate Immune ◽  
Target Cells ◽  
Cytoplasmic Dna ◽  
Mitotic Abnormalities

AbstractThe cyclic GMP-AMP (cGAMP) synthase cGAS counteracts infections by detecting and binding foreign cytoplasmic DNA1. DNA-induced synthesis of cGAMP activates innate immune signalling and apoptosis through the cGAMP receptor STING and the downstream effector IRF31–7. During interphase the nuclear envelope protects chromosomal self-DNA from cGAS, but the consequences of exposing chromosomes to cGAS following mitotic nuclear envelope disassembly are unknown. Here we demonstrate that cGAS associates with chromosomes during mitosis and binds nucleosomes with even higher affinity than naked DNA in vitro. Nucleosomes nevertheless competitively inhibit the DNA-dependent stimulation of cGAS, and accordingly, chromosomal cGAS does not affect mitotic progression under normal conditions. This suggests that nucleosomes prevent the inappropriate activation of cGAS during mitosis by acting as a signature of self-DNA. During prolonged mitotic arrest, however, cGAS becomes activated to promote cell death, limiting the fraction of cells that can survive and escape mitotic arrest induced by the chemotherapeutic drug taxol. Induction of mitotic cell death involves cGAMP synthesis by cGAS, as well as signal transduction to IRF3 by STING. We thus propose that cGAS plays a previously unappreciated role in guarding against mitotic errors, promoting cell death during prolonged mitotic arrest. Our data also indicate that the cGAS pathway, whose activity differs widely among cell lines, impacts cell fate determination upon treatment with taxol and other anti-mitotic drugs. Thus, we propose the innate immune system may be harnessed to selectively target cells with mitotic abnormalities.

scholarly journals Antagonizing the spindle assembly checkpoint silencing enhances paclitaxel and Navitoclax-mediated apoptosis with distinct mechanistic

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ana C. Henriques ◽  
Patrícia M. A. Silva ◽  
Bruno Sarmento ◽  
Hassan Bousbaa
Keyword(s):  
Cell Death ◽  
Cancer Cells ◽  
Cell Fate ◽  
Spindle Assembly Checkpoint ◽  
Spindle Assembly ◽  
Time Lapse ◽  
Antimitotic Drugs ◽  
Mitotic Slippage ◽  
Mitotic Death ◽  
Chronic Activation

AbstractAntimitotic drugs arrest cells in mitosis through chronic activation of the spindle assembly checkpoint (SAC), leading to cell death. However, drug-treated cancer cells can escape death by undergoing mitotic slippage, due to premature mitotic exit. Therefore, overcoming slippage issue is a promising chemotherapeutic strategy to improve the effectiveness of antimitotics. Here, we antagonized SAC silencing by knocking down the MAD2-binding protein p31comet, to delay mitotic slippage, and tracked cancer cells treated with the antimitotic drug paclitaxel, over 3 days live-cell time-lapse analysis. We found that in the absence of p31comet, the duration of mitotic block was increased in cells challenged with nanomolar concentrations of paclitaxel, leading to an additive effects in terms of cell death which was predominantly anticipated during the first mitosis. As accumulation of an apoptotic signal was suggested to prevent mitotic slippage, when we challenged p31comet-depleted mitotic-arrested cells with the apoptosis potentiator Navitoclax (previously called ABT-263), cell fate was shifted to accelerated post-mitotic death. We conclude that inhibition of SAC silencing is critical for enhancing the lethality of antimitotic drugs as well as that of therapeutic apoptosis-inducing small molecules, with distinct mechanisms. The study highlights the potential of p31comet as a target for antimitotic therapies.

scholarly journals Consequences of mitotic slippage for antimicrotubule drug therapy

2017 ◽  
Vol 24 (9) ◽  
pp. T97-T106 ◽  
Author(s):  
Bing Cheng ◽  
Karen Crasta
Keyword(s):  
Cell Death ◽  
Spindle Assembly Checkpoint ◽  
Mitotic Cell ◽  
G1 Arrest ◽  
Front Line ◽  
Cell Fates ◽  
Mitotic Slippage ◽  
Drug Treatment Outcomes ◽  
Antimicrotubule Agents ◽  
Sustained Activation

Antimicrotubule agents are commonly utilised as front-line therapies against several malignancies, either by themselves or as combination therapies. Cell-based studies have pinpointed the anti-proliferative basis of action to be a consequence of perturbation of microtubule dynamics leading to sustained activation of the spindle assembly checkpoint, prolonged mitotic arrest and mitotic cell death. However, depending on the biological context and cell type, cells may take an alternative route besides mitotic cell death via a process known as mitotic slippage. Here, mitotically arrested cells ‘slip’ to the next interphase without undergoing proper chromosome segregation and cytokinesis. These post-slippage cells in turn have two main cell fates, either cell death or a G1 arrest ensuing in senescence. In this review, we take a look at the factors determining mitotic cell death vs mitotic slippage, post-slippage cell fates and accompanying features, and their consequences for antimicrotubule drug treatment outcomes.

scholarly journals BUB1 mediation of caspase-independent mitotic death determines cell fate

2007 ◽  
Vol 178 (2) ◽  
pp. 283-296 ◽  
Author(s):  
Yohei Niikura ◽  
Amruta Dixit ◽  
Ray Scott ◽  
Guy Perkins ◽  
Katsumi Kitagawa
Keyword(s):  
Cell Death ◽  
Cell Fate ◽  
Cell Lines ◽  
Chromosome Instability ◽  
Spindle Checkpoint ◽  
Mitotic Cell ◽  
Endonuclease G ◽  
Colon Tumors ◽  
Mitotic Death ◽  
Apoptosis Inducing Factor

The spindle checkpoint that monitors kinetochore–microtubule attachment has been implicated in tumorigenesis; however, the relation between the spindle checkpoint and cell death remains obscure. In BUB1-deficient (but not MAD2-deficient) cells, conditions that activate the spindle checkpoint (i.e., cold shock or treatment with nocodazole, paclitaxel, or 17-AAG) induced DNA fragmentation during early mitosis. This mitotic cell death was independent of caspase activation; therefore, we named it caspase-independent mitotic death (CIMD). CIMD depends on p73, a homologue of p53, but not on p53. CIMD also depends on apoptosis-inducing factor and endonuclease G, which are effectors of caspase-independent cell death. Treatment with nocodazole, paclitaxel, or 17-AAG induced CIMD in cell lines derived from colon tumors with chromosome instability, but not in cells from colon tumors with microsatellite instability. This result was due to low BUB1 expression in the former cell lines. When BUB1 is completely depleted, aneuploidy rather than CIMD occurs. These results suggest that cells prone to substantial chromosome missegregation might be eliminated via CIMD.

scholarly journals Precisely control mitochondria with light to manipulate cell fate decision

2018 ◽  
Author(s):  
Patrick Ernst ◽  
Ningning Xu ◽  
Jing Qu ◽  
Herbert Chen ◽  
Matthew S. Goldberg ◽  
...  
Keyword(s):  
Cell Death ◽  
Cell Fate ◽  
Cell Function ◽  
Apoptotic Cell ◽  
Light Illumination ◽  
Mitochondrial Depolarization ◽  
Inner Mitochondrial Membrane ◽  
Cell Type Specificity ◽  
Spatiotemporal Resolution ◽  
Fate Decision

ABSTRACTMitochondrial dysfunction has been implicated in many pathological conditions and diseases. The normal functioning of mitochondria relies on maintaining the inner mitochondrial membrane (IMM) potential (a.k.a. ΔΨm) that is essential for ATP synthesis, Ca2+ homeostasis, redox balance and regulation of other key signaling pathways such as mitophagy and apoptosis. However, the detailed mechanisms by which ΔΨm regulates cellular function remain incompletely understood, partially due to difficulty of manipulating ΔΨm with spatiotemporal resolution, reversibility, or cell type specificity. To address this need, we have developed a next-generation optogenetic-based technique for controllable mitochondrial depolarization with light. We demonstrate successful targeting of the heterologous Channelrhodopsin-2 (ChR2) fusion protein to the IMM and formation of functional cationic channels capable of light-induced selective ΔΨm depolarization and mitochondrial autophagy. Importantly, we for the first time show that optogenetic-mediated mitochondrial depolarization can be well-controlled to differentially influence the fate of cells expressing mitochondrial ChR2: while sustained moderate light illumination induces substantial apoptotic cell death, transient mild light illumination elicits cytoprotection via mitochondrial preconditioning. Finally, we show that Parkin overexpression exacerbates, instead of ameliorating, mitochondrial depolarization-mediated cell death in HeLa cells. In summary, we provide evidence that the described mitochondrial-targeted optogenetics may have a broad application for studying the role of mitochondria in regulating cell function and fate decision.

scholarly journals BET Inhibition Suppresses S100A8 and S100A9 Expression in Acute Myeloid Leukemia Cells and Synergises with Daunorubicin in Causing Cell Death

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Helen J. S. Stewart ◽  
Sabah Chaudry ◽  
Asante Crichlow ◽  
Freya Luiling Feilding ◽  
Timothy J. T. Chevassut
Keyword(s):  
Cell Death ◽  
Myeloid Leukemia ◽  
Chemotherapy Resistance ◽  
Time Dependent ◽  
Leukemia Cells ◽  
Myeloid Differentiation ◽  
S100 Family ◽  
Protein Levels ◽  
Acute Myeloid Leukemia Cells ◽  
S100a9 Expression

S100A8 and S100A9 are both members of the S100 family and have been shown to play roles in myeloid differentiation, autophagy, apoptosis, and chemotherapy resistance. In this study we demonstrate that the BET-bromodomain inhibitor JQ1 causes rapid suppression of S100A8 and S100A9 mRNA and protein in a reversible manner. In addition, we show that JQ1 synergises with daunorubicin in causing AML cell death. Daunorubicin alone causes a dose- and time-dependent increase in S100A8 and S100A9 protein levels in AML cell lines which is overcome by cotreatment with JQ1. This suggests that JQ1 synergises with daunorubicin in causing apoptosis via suppression of S100A8 and S100A9 levels.

scholarly journals Cell-to-cell variability in inducible Caspase9-mediated cell death

2021 ◽  
Author(s):  
Yuan Yuan ◽  
Huixia Ren ◽  
Yanjun Li ◽  
Shanshan Qin ◽  
Xiaojing Yang ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Cell Death ◽  
Cell Fate ◽  
Single Cells ◽  
Suicide Gene ◽  
Significant Heterogeneity ◽  
Cell Therapies ◽  
Protein Levels ◽  
Multiple Round ◽  
Cell To Cell Variability

iCasp9 suicide gene has been widely used as a promising killing strategy in various cell therapies. However, different cells show significant heterogeneity in response to apoptosis inducer, posing challenges in clinical applications of killing strategy. The cause of the heterogeneity remains elusive so far. Here, by simultaneously monitoring the dynamics of iCasp9 dimerization, Caspase3 activation and cell fate in single cells, we found that the heterogeneity was mainly due to cell-to-cell variability in initial iCasp9 expression and XIAP/Caspase3 ratio. Moreover, multiple-round drugging cannot increase the killing efficiency. Instead, it will place selective pressure on protein levels, especially on the level of initial iCasp9, leading to drug resistance. We further show this resistance can be largely eliminated by combinatorial drugging with XIAP inhibitor at the end, but not at the beginning, of the multiple-round treatments. Our results unveil the source of cell fate heterogeneity and drug resistance in iCasp9-mediated cell death, which may enlighten better therapeutic strategies for optimized killing.

scholarly journals Dual Function Microtubule- and Mitochondria-Associated Proteins Mediate Mitotic Cell Death

2009 ◽  
Vol 31 (5) ◽  
pp. 393-405
Author(s):  
Leyuan Liu ◽  
Rui Xie ◽  
Chaofeng Yang ◽  
Wallace L. McKeehan
Keyword(s):  
Cell Death ◽  
Mitotic Cell ◽  
Mitotic Arrest ◽  
Dual Function ◽  
Associated Proteins ◽  
Irreversible Aggregation ◽  
The Common ◽  
Spindle Microtubules ◽  
Segregation Of Chromosomes ◽  
Mitotic Cells

Background: Survival and evolution of aneuploid cells after an asymmetric segregation of chromosomes at mitosis may be the common initiating event and underlying cause of the genetic diversity and adaptability of cancers. We hypothesize that mechanisms exist to detect impending aneuploidy and prevent it before completion of an aberrant mitosis.Methods: The distribution of isoforms of C19ORF5, an interactive partner with mitochondria-associated LRPPRC and tumor suppressor RASSF1A, state of spindle microtubules and mitochondrial aggregation was analyzed in synchronized mitotic cells and cells stalled in mitosis after treatment with paclitaxel.Results: C19ORF5 distributed broadly across the mitotic spindle and reversibly accumulated during reversible mitotic arrest. Prolonged stabilization of microtubules caused an accumulation of a C19ORF5 product with dual MAP and MtAP properties that caused irreversible aggregation of mitochondria and death of mitotic cells.Conclusions: Dual function microtubule-associated (MAP) and mitochondria-associated (MtAP) proteins generated by prolonged mitotic arrest trigger mitochondrial-induced mitotic cell death. This is a potential mechanism to prevent minimal survivable aneuploidy resulting from an aberrant cell division and cancers in general at their earliest common origin.

scholarly journals A hydraulic instability drives the cell death decision in the nematode germline

2020 ◽  
Author(s):  
N. T. Chartier ◽  
A. Mukherjee ◽  
J. Pfanzelter ◽  
S. Fürthauer ◽  
B. T. Larson ◽  
...  
Keyword(s):  
Decision Making ◽  
Cell Death ◽  
Cell Fate ◽  
Germ Cells ◽  
Cell Fate Decision ◽  
Homogeneous Population ◽  
C Elegans ◽  
The Common ◽  
Fate Decision ◽  
Cell Volumes

AbstractOocytes are large and resourceful. During oogenesis some germ cells grow, typically at the expense of others that undergo apoptosis. How germ cells are selected to live or die out of a homogeneous population remains unclear. Here we show that this cell fate decision in C. elegans is mechanical and related to tissue hydraulics. Germ cells become inflated when the pressure inside them is lower than in the common cytoplasmic pool. This condition triggers a hydraulic instability which amplifies volume differences and causes some germ cells to grow and others to shrink. Shrinking germ cells are extruded and die, as we demonstrate by reducing germ cell volumes via thermoviscous pumping. Together, this reveals a robust mechanism of mechanochemical cell fate decision making in the germline.

scholarly journals A hydraulic instability drives the cell death decision in the nematode germline

2021 ◽  
Author(s):  
Nicolas T. Chartier ◽  
Arghyadip Mukherjee ◽  
Julia Pfanzelter ◽  
Sebastian Fürthauer ◽  
Ben T. Larson ◽  
...  
Keyword(s):  
Cell Death ◽  
Germ Cell ◽  
Cell Fate ◽  
Germ Cells ◽  
Cell Fate Decision ◽  
Present Evidence ◽  
Life And Death ◽  
Fate Decision ◽  
Cell Volumes ◽  
Material Fluxes

AbstractOocytes are large cells that develop into an embryo upon fertilization1. As interconnected germ cells mature into oocytes, some of them grow—typically at the expense of others that undergo cell death2–4. We present evidence that in the nematode Caenorhabditis elegans, this cell-fate decision is mechanical and related to tissue hydraulics. An analysis of germ cell volumes and material fluxes identifies a hydraulic instability that amplifies volume differences and causes some germ cells to grow and others to shrink, a phenomenon that is related to the two-balloon instability5. Shrinking germ cells are extruded and they die, as we demonstrate by artificially reducing germ cell volumes via thermoviscous pumping6. Our work reveals a hydraulic symmetry-breaking transition central to the decision between life and death in the nematode germline.

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