scholarly journals Inhibition of Bcl-xL sensitizes cells to mitotic blockers, but not mitotic drivers

Open Biology ◽  
2016 ◽  
Vol 6 (8) ◽  
pp. 160134 ◽  
Author(s):  
Ailsa Bennett ◽  
Olivia Sloss ◽  
Caroline Topham ◽  
Louisa Nelson ◽  
Anthony Tighe ◽  
...  
Keyword(s):  
Cell Fate ◽  
Spindle Assembly Checkpoint ◽  
Spindle Assembly ◽  
Time Lapse ◽  
Intrinsic Apoptosis ◽  
Pharmacological Agents ◽  
Apoptosis Pathway ◽  
Combination Treatments ◽  
Intrinsic Apoptosis Pathway ◽  
Coupling Time

Cell fate in response to an aberrant mitosis is governed by two competing networks: the spindle assembly checkpoint (SAC) and the intrinsic apoptosis pathway. The mechanistic interplay between these two networks is obscured by functional redundancy and the ability of cells to die either in mitosis or in the subsequent interphase. By coupling time-lapse microscopy with selective pharmacological agents, we systematically probe pro-survival Bcl-xL in response to various mitotic perturbations. Concentration matrices show that BH3-mimetic-mediated inhibition of Bcl-xL synergises with perturbations that induce an SAC-mediated mitotic block, including drugs that dampen microtubule dynamics, and inhibitors targeting kinesins and kinases required for spindle assembly. By contrast, Bcl-xL inhibition does not synergize with drugs which drive cells through an aberrant mitosis by overriding the SAC. This differential effect, which is explained by compensatory Mcl-1 function, provides opportunities for patient stratification and combination treatments in the context of cancer chemotherapy.

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 Depletion of Survivin suppresses docetaxel-induced apoptosis in HeLa cells by facilitating mitotic slippage

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Teng-Long Han ◽  
Hang Sha ◽  
Jun Ji ◽  
Yun-Tian Li ◽  
Deng-Shan Wu ◽  
...  
Keyword(s):  
Hela Cells ◽  
Spindle Assembly Checkpoint ◽  
Spindle Assembly ◽  
Clonogenic Survival ◽  
Mitotic Arrest ◽  
Apoptosis Pathway ◽  
Mitotic Slippage ◽  
Intrinsic Apoptosis Pathway ◽  
Apoptosis Protein ◽  
Induced Apoptosis

AbstractThe anticancer effects of taxanes are attributed to the induction of mitotic arrest through activation of the spindle assembly checkpoint. Cell death following extended mitotic arrest is mediated by the intrinsic apoptosis pathway. Accordingly, factors that influence the robustness of mitotic arrest or disrupt the apoptotic machinery confer drug resistance. Survivin is an inhibitor of apoptosis protein. Its overexpression is associated with chemoresistance, and its targeting leads to drug sensitization. However, Survivin also acts specifically in the spindle assembly checkpoint response to taxanes. Hence, the failure of Survivin-depleted cells to arrest in mitosis may lead to taxane resistance. Here we show that Survivin depletion protects HeLa cells against docetaxel-induced apoptosis by facilitating mitotic slippage. However, Survivin depletion does not promote clonogenic survival of tumor cells but increases the level of cellular senescence induced by docetaxel. Moreover, lentiviral overexpression of Survivin does not provide protection against docetaxel or cisplatin treatment, in contrast to the anti-apoptotic Bcl-xL or Bcl-2. Our findings suggest that targeting Survivin may influence the cell response to docetaxel by driving the cells through aberrant mitotic progression, rather than directly sensitizing cells to apoptosis.

scholarly journals Suppression of Docetaxel induced apoptosis in Survivin-depleted cells due to failure of sustained mitotic block

2019 ◽  
Author(s):  
Teng-Long Han ◽  
Hang Sha ◽  
Zhi-Xin Jiang
Keyword(s):  
Drug Resistance ◽  
Spindle Assembly Checkpoint ◽  
Spindle Assembly ◽  
Mitotic Arrest ◽  
Apoptosis Pathway ◽  
Intrinsic Apoptosis Pathway ◽  
Apoptosis Protein ◽  
Mitotic Block ◽  
Docetaxel Treatment ◽  
Induced Apoptosis

AbstractThe antitumor effect of taxanes have been attributed to their ability to induce mitotic arrest through activation of the spindle assembly checkpoint. Cell death following prolonged mitotic arrest is mediated by the intrinsic apoptosis pathway. Accordingly, factors that influence the robustness of mitotic arrest or disrupt the apoptotic machinery might confer drug resistance. Survivin is an inhibitor of apoptosis protein. Its overexpression has been associated with resistance to multiple anticancer agents including taxanes, and its targeting led to drug sensitization. On the other hand, Survivin is a key regulator of mitosis, which is shown to be required for stable activation of the spindle assembly checkpoint. Since the sensitivity of taxanes depends on a functional spindle checkpoint, inhibition of Survivin may lead to drug resistance, which is the opposite effect of its anti-apoptotic function. Here we show that Survivin-depleted cells escape the mitotic block following Docetaxel treatment, thereby evading drug induced apoptosis. Moreover, Survivin depletion increases the level of mitotic catastrophe and cellular senescence induced by Docetaxel and enhanced its efficacy against clonogenic survival of tumor cells. Our finding suggests that inhibition of Survivin promotes non-apoptotic mechanisms following Docetaxel treatment rather than increases the sensitivity of apoptosis.

scholarly journals Amphiregulin Regulates Phagocytosis-Induced Cell Death in Monocytes via EGFR and the Bcl-2 Protein Family

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Christopher Platen ◽  
Stephan Dreschers ◽  
Jessica Wappler ◽  
Andreas Ludwig ◽  
Stefan Düsterhöft ◽  
...  
Keyword(s):  
Cell Death ◽  
Bacterial Infections ◽  
Caspase 3 ◽  
Inflammatory Responses ◽  
Inflammatory Diseases ◽  
Dependent Manner ◽  
Intrinsic Apoptosis ◽  
Caspase 9 ◽  
Apoptosis Pathway ◽  
Intrinsic Apoptosis Pathway

Neonates are extremely susceptible to bacterial infections, and evidences suggest that phagocytosis-induced cell death (PICD) is less frequently triggered in neonatal monocytes than in monocytes from adult donors. An insufficient termination of the inflammatory response, leading to a prolonged survival of neonatal monocytes with ongoing proinflammatory cytokine release, could be associated with the progression of various inflammatory diseases in neonates. Our previous data indicate that amphiregulin (AREG) is increasingly expressed on the cell surface of neonatal monocytes, resulting in remarkably higher soluble AREG levels after proteolytic shedding. In this study, we found that E. coli-infected neonatal monocytes show an increased phosphorylation of ERK, increased expression of Bcl-2 and Bcl-XL, and reduced levels of cleaved caspase-3 and caspase-9 compared to adult monocytes. In both cell types, additional stimulation with soluble AREG further increased ERK activation and expression of Bcl-2 and Bcl-XL and reduced levels of cleaved caspase-3 and caspase-9 in an EGFR-dependent manner. These data suggest that reduced PICD of neonatal monocytes could be due to reduced intrinsic apoptosis and that AREG can promote protection against PICD. This reduction of the intrinsic apoptosis pathway in neonatal monocytes could be relevant for severely prolonged inflammatory responses of neonates.

Alantolactone induces apoptosis in THP‐1 cells through STAT3, survivin inhibition, and intrinsic apoptosis pathway

2020 ◽  
Author(s):  
Bashir Ahmad ◽  
Yaser Gamallat ◽  
Pengyu Su ◽  
Akbar Husain ◽  
Ata Ur Rehman ◽  
...  
Keyword(s):  
Intrinsic Apoptosis ◽  
Apoptosis Pathway ◽  
Intrinsic Apoptosis Pathway

scholarly journals Cell death following the loss of ADAR1 mediated A-to-I RNA editing is not effected by the intrinsic apoptosis pathway

2019 ◽  
Vol 10 (12) ◽  
Author(s):  
Carl R. Walkley ◽  
Benjamin T. Kile
Keyword(s):  
Cell Death ◽  
Rna Editing ◽  
Rna Structure ◽  
Fetal Liver ◽  
Loss Of Function ◽  
Intrinsic Apoptosis ◽  
Triple Mutant ◽  
Apoptosis Pathway ◽  
Mitochondrial Apoptosis Pathway ◽  
Intrinsic Apoptosis Pathway

AbstractModifications of RNA, collectively termed as the epitranscriptome, are widespread, evolutionarily conserved and contribute to gene regulation and protein diversity in healthy and disease states. There are >160 RNA modifications described, greatly exceeding the number of modifications to DNA. Of these, adenosine-to-inosine (A-to-I) RNA editing is one of the most common. There are tens of thousands of A-to-I editing sites in mouse, and millions in humans. Upon translation or sequencing an inosine base is decoded as guanosine, leading to A-to-G mismatches between the RNA and DNA. Inosine has different base pairing properties to adenosine and as a result editing not only alters the RNA code but can also change the RNA structure. In mammals A-to-I editing is performed by ADAR1 and ADAR2. A feature of murine loss of function ADAR1 alleles is cell death and a failure to survive embryogenesis. Adar1−/− and editing deficient (Adar1E861A/E861A) mice die between E11.75–13.5 of failed hematopoiesis. Strikingly this phenotype is rescued by the deletion of the cytosolic dsRNA sensor MDA5 or its downstream adaptor MAVS, a mechanism conserved in human and mouse. Current literature indicates that the loss of ADAR1 leads to cell death via apoptosis, yet this has not been genetically established. We report that blockade of the intrinsic (mitochondrial) apoptosis pathway, through the loss of both BAK and BAX, does not rescue or modify the cellular phenotype of the fetal liver or extend the lifespan of ADAR1 editing deficient embryos. We had anticipated that the loss of BAK and BAX would rescue, or at least significantly extend, the gestational viability of Adar1E861A/E861A embryos. However, the triple mutant Adar1E861A/E861ABak−/−Bax−/− embryos that were recovered at E13.5 were indistinguishable from the Adar1E861A/E861A embryos with BAK and BAX. The results indicate that cell death processes not requiring the intrinsic apoptosis pathway are triggered by MDA5 following the loss of ADAR1.

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