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

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.

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

10.1101/834259 ◽

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

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Alternative Cdc20 translational isoforms bypass the spindle assembly checkpoint to control mitotic arrest duration

10.1101/2021.10.24.465552 ◽

2021 ◽

Author(s):

Mary Jane Tsang ◽

Iain M Cheeseman

Keyword(s):

Translational Regulation ◽

Spindle Assembly Checkpoint ◽

Critical Role ◽

Spindle Assembly ◽

Mitotic Arrest ◽

Mitotic Exit ◽

Regulatory Control ◽

Cycle Arrest ◽

Anaphase Onset ◽

Mitotic Slippage

Mitotic chromosome segregation defects activate the Spindle Assembly Checkpoint (SAC), which inhibits the APC/C co-activator Cdc20 to induce a prolonged cell cycle arrest. Once errors are corrected, the SAC is silenced thereby allowing anaphase onset and mitotic exit to proceed. However, in the presence of persistent, unresolvable errors, cells can undergo "mitotic slippage", exiting mitosis into a tetraploid G1 state and escaping the cell death that results from a prolonged arrest. The molecular logic that allows cells to balance these dueling mitotic arrest and slippage behaviors remains unclear. Here we demonstrate that human cells modulate their mitotic arrest duration through the presence of conserved, alternative Cdc20 translational isoforms. Translation initiation at downstream start sites results in truncated Cdc20 isoforms that are resistant to SAC-mediated inhibition and promote mitotic exit even in the presence of mitotic perturbations. Targeted molecular changes or naturally-occurring mutations in cancer cells that alter the relative Cdc20 isoform levels or its translational regulatory control modulate both mitotic arrest duration and anti-mitotic drug sensitivity. Our work reveals a critical role for the differential translational regulation of Cdc20 in mitotic arrest timing, with important implications for the diagnosis and treatment of human cancers.

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

Open Biology ◽

10.1098/rsob.160134 ◽

2016 ◽

Vol 6 (8) ◽

pp. 160134 ◽

Cited By ~ 14

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.

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Inhibitor of the spindle assembly checkpoint surpasses apoptosis sensitizer in synergy with taxanes

10.1101/414359 ◽

2018 ◽

Author(s):

Teng-Long Han ◽

Zhi-Xin Jiang ◽

Yun-Tian Li ◽

Deng-Shan Wu ◽

Jun Ji ◽

...

Keyword(s):

Cell Death ◽

Treatment Response ◽

Tumor Cells ◽

Spindle Assembly Checkpoint ◽

Spindle Checkpoint ◽

Spindle Assembly ◽

Mitotic Slippage ◽

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. Thus, apoptosis sensitizers which inhibit antiapoptotic Bcl-2 family proteins has been shown to enhance taxanes-induced cell death. By contrast, spindle checkpoint disruption facilitates mitotic slippage and is thought to promote taxanes resistance. Notably, other modes of cell death also contribute to treatment outcomes. Here we show that inhibition of the spindle checkpoint suppresses taxanes induced apoptosis but increases terminal growth arrest of tumor cells with features of cellular senescence. By using clonogenic assay which measures the net result of multiple forms of cell death and is more reflective of therapeutic response, our finding suggests apoptosis is not a major determinant of antitumor efficacy of taxanes, whereas spindle checkpoint inhibitor displays a long-term advantage over apoptosis sensitizer in blocking colony outgrowth of tumor cells when combined with different microtubule toxins, therefore represents a superior therapeutic strategy.SIGNIFICANCEApoptosis has long been regarded as the primary mechanism of anti-cancer efficacy of taxanes, while the role of the spindle assembly checkpoint (SAC) in treatment response to taxanes has been controversial. Either apoptosis sensitizer or inhibitor of SAC has been reported to synergize with taxanes. While inhibitor of antiapoptotic proteins potentiates taxanes induced apoptosis, inhibitor of SAC suppresses apoptosis by facilitating mitotic slippage, that is why it is implicated in taxanes resistance. By demonstrating that apoptotic rates are not associate with long-term treatment response, not only do we find that inhibitor of SAC displays a long-term advantage over apoptosis sensitizer in combination with taxanes, but we also resolve the dispute around the role of SAC in cellular response to taxanes.

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Annona muricata silver nanoparticles exhibit strong anticancer activities against cervical and prostate adenocarcinomas through regulation of CASP9 and the CXCL1/CXCR2 genes axis

Tumor Biology ◽

10.3233/tub-200058 ◽

2021 ◽

Vol 43 (1) ◽

pp. 37-55

Author(s):

Yahaya Gavamukulya ◽

Esther N. Maina ◽

Hany A. El-Shemy ◽

Amos M. Meroka ◽

Geoffrey K. Kangogo ◽

...

Keyword(s):

Silver Nanoparticles ◽

Anticancer Drugs ◽

Hela Cells ◽

Selectivity Index ◽

Annona Muricata ◽

Anticancer Activities ◽

Apoptosis Pathway ◽

Migration Assay ◽

Intrinsic Apoptosis Pathway ◽

In Cells

BACKGROUND: Green synthesized nanoparticles have been earmarked for use in nanomedicine including for the development of better anticancer drugs. OBJECTIVE: The aim of this study was to undertake biochemical evaluation of anticancer activities of green synthesized silver nanoparticles (AgNPs) from ethanolic extracts of fruits (AgNPs-F) and leaves (AgNPs-L) of Annona muricata. METHODS: Previously synthesized silver nanoparticles were used for the study. The effects of the AgNPs and 5-Fluorouracil were studied on PC3, HeLa and PNT1A cells. The resazurin, migration and colonogenic assays as well as qRT-PCR were employed. RESULTS: The AgNPs-F displayed significant antiproliferative effects against HeLa cells with an IC50 of 38.58μg/ml and PC3 cells with an IC50 of 48.17μg/ml but selectively spared normal PNT1A cells (selectivity index of 7.8), in comparison with first line drug 5FU and AgNPs-L whose selectivity index were 3.56 and 2.26 respectively. The migration assay revealed potential inhibition of the metastatic activity of the cells by the AgNPs-F while the colonogenic assay indicated the permanent effect of the AgNPs-F on the cancer cells yet being reversible on the normal cells in contrast with 5FU and AgNPs-L. CASP9 was significantly over expressed in all HeLa cells treated with the AgNPs-F (1.53-fold), AgNPs-L (1.52-fold) and 5FU (4.30-fold). CXCL1 was under expressed in HeLa cells treated with AgNPs-F (0.69-fold) and AgNPs-L (0.58-fold) and over expressed in cells treated with 5FU (4.95-fold), but the difference was not statistically significant. CXCR2 was significantly over expressed in HeLa cells treated with 5FU (8.66-fold) and AgNPs-F (1.12-fold) but under expressed in cells treated with AgNPs-L (0.76-fold). CONCLUSIONS: Here we show that biosynthesized AgNPs especially AgNPs-F can be used in the development of novel and better anticancer drugs. The mechanism of action of the AgNPs involves activation of the intrinsic apoptosis pathway through upregulation of CASP9 and concerted down regulation of the CXCL1/ CXCR2 gene axis.

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

Scientific Reports ◽

10.1038/s41598-021-83743-7 ◽

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.

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SMBA1, a Bax Activator, Induces Cell Cycle Arrest and Apoptosis in Malignant Glioma Cells

Pharmacology ◽

10.1159/000500292 ◽

2019 ◽

Vol 105 (3-4) ◽

pp. 164-172

Author(s):

Shuangbo Fan ◽

Qian Xu ◽

Liang Wang ◽

Yulin Wan ◽

Sheng Qiu

Keyword(s):

Cell Cycle ◽

Cell Cycle Arrest ◽

Biological Effects ◽

Cyclin B1 ◽

Dependent Manner ◽

Apoptosis Pathway ◽

Cycle Arrest ◽

Intrinsic Apoptosis Pathway ◽

Induced Apoptosis ◽

Dose Dependent

SMBA1 (small-molecule Bax agonists 1), a small molecular activator of Bax, is a potential anti-tumour agent. In the present study, we investigated the biological effects of SMBA1 on glioblastoma (GBM) cells. SMBA1 reduced the viabilities of U87MG, U251 and T98G cells in a time- and dose-dependent manner. Moreover, treatment with SMBA1 induced cell cycle arrest at the G2/M phase transition, accompanied by the downregulation of Cdc25c and cyclin B1 and the upregulation of p21. SMBA1 also induced apoptosis of GBM cells in a dose-dependent manner. Mechanistically, SMBA1 induced apoptosis via the intrinsic pathway. Silencing of Bax or ectopic expression of Bcl-2 significantly inhibited SMBA1-induced apoptosis. Moreover, SMBA1 inhibited the growth of U87MG xenograft tumours in vivo. Overall, SMBA1 shows anti-proliferative effects against GBM cells through activation of the intrinsic apoptosis pathway.

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Encephalitozoon cuniculi and Vittaforma corneae (Phylum Microsporidia) inhibit staurosporine-induced apoptosis in human THP-1 macrophages in vitro

Parasitology ◽

10.1017/s0031182018001968 ◽

2018 ◽

Vol 146 (5) ◽

pp. 569-579 ◽

Cited By ~ 1

Author(s):

Yuliya Y. Sokolova ◽

Lisa C. Bowers ◽

Xavier Alvarez ◽

Elizabeth S. Didier

Keyword(s):

Expression Profiles ◽

Life Cycles ◽

Host Cells ◽

Human Macrophage ◽

Inflammasome Activation ◽

Encephalitozoon Cuniculi ◽

Apoptosis Pathway ◽

Intrinsic Apoptosis Pathway ◽

Induced Apoptosis

AbstractObligately intracellular microsporidia regulate their host cell life cycles, including apoptosis, but this has not been evaluated in phagocytic host cells such as macrophages that can facilitate infection but also can be activated to kill microsporidia. We examined two biologically dissimilar human-infecting microsporidia species, Encephalitozoon cuniculi and Vittaforma corneae, for their effects on staurosporine-induced apoptosis in the human macrophage-differentiated cell line, THP1. Apoptosis was measured after exposure of THP-1 cells to live and dead mature organisms via direct fluorometric measurement of Caspase 3, colorimetric and fluorometric TUNEL assays, and mRNA gene expression profiles using Apoptosis RT2 Profiler PCR Array. Both species of microsporidia modulated the intrinsic apoptosis pathway. In particular, live E. cuniculi spores inhibited staurosporine-induced apoptosis as well as suppressed pro-apoptosis genes and upregulated anti-apoptosis genes more broadly than V. corneae. Exposure to dead spores induced an opposite effect. Vittaforma corneae, however, also induced inflammasome activation via Caspases 1 and 4. Of the 84 apoptosis-related genes assayed, 42 (i.e. 23 pro-apoptosis, nine anti-apoptosis, and 10 regulatory) genes were more affected including those encoding members of the Bcl2 family, caspases and their regulators, and members of the tumour necrosis factor (TNF)/TNF receptor R superfamily.

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Slip slidin’ away of mitosis with CRL2Zyg11

The Journal of Cell Biology ◽

10.1083/jcb.201609086 ◽

2016 ◽

Vol 215 (2) ◽

pp. 143-145 ◽

Cited By ~ 1

Author(s):

Michael Brandeis

Keyword(s):

Spindle Assembly Checkpoint ◽

E3 Ligase ◽

Spindle Assembly ◽

Cyclin B1 ◽

Anaphase Promoting Complex ◽

Cell Biol ◽

Mitotic Slippage ◽

Mitotic Cells

The spindle assembly checkpoint arrests mitotic cells by preventing degradation of cyclin B1 by the anaphase-promoting complex/cyclosome, but some cells evade this checkpoint and slip out of mitosis. Balachandran et al. (2016. J. Cell Biol. http://dx.doi.org/10.1083/jcb.201601083) show that the E3 ligase CRL2ZYG11 degrades cyclin B1, allowing mitotic slippage.

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