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 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 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.

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

Pharmacology ◽  
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.

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

Parasitology ◽  
2018 ◽  
Vol 146 (5) ◽  
pp. 569-579 ◽  
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.

scholarly journals DNA Damage during the Spindle-Assembly Checkpoint Degrades CDC25A, Inhibits Cyclin–CDC2 Complexes, and Reverses Cells to Interphase

2003 ◽  
Vol 14 (10) ◽  
pp. 3989-4002 ◽  
Author(s):  
Jeremy P.H. Chow ◽  
Wai Yi Siu ◽  
Tsz Kan Fung ◽  
Wan Mui Chan ◽  
Anita Lau ◽  
...  
Keyword(s):  
Dna Damage ◽  
Spindle Assembly Checkpoint ◽  
Histone H3 ◽  
Ectopic Expression ◽  
Spindle Assembly ◽  
Cyclin B1 ◽  
Chemotherapeutic Agents ◽  
Cell Cycle Checkpoints ◽  
Dependent Manner ◽  
Mitotic Block

Cell cycle checkpoints that monitor DNA damage and spindle assembly are essential for the maintenance of genetic integrity, and drugs that target these checkpoints are important chemotherapeutic agents. We have examined how cells respond to DNA damage while the spindle-assembly checkpoint is activated. Single cell electrophoresis and phosphorylation of histone H2AX indicated that several chemotherapeutic agents could induce DNA damage during mitotic block. DNA damage during mitotic block triggered CDC2 inactivation, histone H3 dephosphorylation, and chromosome decondensation. Cells did not progress into G1 but seemed to retract to a G2-like state containing 4N DNA content, with stabilized cyclin A and cyclin B1 binding to Thr14/Tyr15-phosphorylated CDC2. The loss of mitotic cells was not due to cell death because there was no discernible effect on caspase-3 activation, DNA fragmentation, or viability. Extensive DNA damage during mitotic block inactivated cyclin B1-CDC2 and prevented G1 entry when the block was removed. The mitotic DNA damage responses were independent of p53 and pRb, but they were dependent on ATM. CDC25A that accumulated during mitosis was rapidly destroyed after DNA damage in an ATM-dependent manner. Ectopic expression of CDC25A or nonphosphorylatable CDC2 effectively inhibited the dephosphorylation of histone H3 after DNA damage. Hence, although spindle disruption and DNA damage provide conflicting signals to regulate CDC2, the negative regulation by the DNA damage checkpoint could overcome the positive regulation by the spindle-assembly checkpoint.

scholarly journals Acetylshikonin Sensitizes Hepatocellular Carcinoma Cells to Apoptosis through ROS-Mediated Caspase Activation

Cells ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 1466 ◽  
Author(s):  
Ming Hong ◽  
Jinke Li ◽  
Siying Li ◽  
Mohammed M.Almutairi
Keyword(s):  
Hepatocellular Carcinoma ◽  
Dna Damage ◽  
Hepg2 Cell ◽  
Cancer Cell ◽  
Ros Production ◽  
Apoptosis Pathway ◽  
Intrinsic Apoptosis Pathway ◽  
Shikonin Derivatives ◽  
Intracellular Ros ◽  
Induced Apoptosis

The tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has shown strong and explicit cancer cell-selectivity, which results in little toxicity toward normal tissues, and has been recognized as a potential, relatively safe anticancer agent. However, several cancers are resistant to the apoptosis induced by TRAIL. A recent study found that shikonin b (alkannin, 5,8-dihydroxy-2-[(1S)-1-hydroxy-4-methylpent-3-en-1-yl]naphthalene-1,4-dione) might induce apoptosis in TRAIL-resistant cholangiocarcinoma cells through reactive oxygen species (ROS)-mediated caspases activation. However, the strong cytotoxic activity has limited its potential as an anticancer drug. Thus, the current study intends to discover novel shikonin derivatives which can sensitize the liver cancer cell to TRAIL-induced apoptosis while exhibiting little toxicity toward the normal hepatic cell. The trypan blue exclusion assay, western blot assay, 4′,6-diamidino-2-phenylindole (DAPI) staining and the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay as well as the ‘comet’ assay, were used to study the underlying mechanisms of cell death and to search for any mechanisms of an enhancement of TRAIL-mediated apoptosis in the presence of ASH. Herein, we demonstrated that non-cytotoxic doses of acetylshikonin (ASH), one of the shikonin derivatives, in combination with TRAIL, could promote apoptosis in HepG2 cells. Further studies showed that application of ASH in a non-cytotoxic dose (2.5 μM) could increase intracellular ROS production and induce DNA damage, which might trigger a cell intrinsic apoptosis pathway in the TRAIL-resistant HepG2 cell. Combination treatment with a non-cytotoxic dose of ASH and TRAIL activated caspase and increased the cleavage of PARP-1 in the HepG2 cell. However, when intracellular ROS production was suppressed by N-acetyl-l-cysteine (NAC), the synergistic effects of ASH and TRAIL on hepatocellular carcinoma (HCC) cell apoptosis was abolished. Furthermore, NAC could alleviate p53 and the p53 upregulated modulator of apoptosis (PUMA) expression induced by TRAIL and ASH. Small (or short) interfering RNA (siRNA) targeting PUMA or p53 significantly reversed ASH-mediated sensitization to TRAIL-induced apoptosis. In addition, Bax gene deficiency also abolished ASH-induced TRAIL sensitization. An orthotopical HCC implantation mice model further confirmed that co-treated ASH overcomes TRAIL resistance in HCC cells without exhibiting potent toxicity in vivo. In conclusion, the above data suggested that ROS could induce DNA damage and activating p53/PUMA/Bax signaling, and thus, this resulted in the permeabilization of mitochondrial outer membrane and activating caspases as well as sensitizing the HCC cell to apoptosis induced by TRAIL and ASH treatment.

scholarly journals Aurora Kinase-A Inactivates DNA Damage-Induced Apoptosis and Spindle Assembly Checkpoint Response Functions of p73

Cancer Cell ◽  
2012 ◽  
Vol 21 (2) ◽  
pp. 196-211 ◽  
Author(s):  
Hiroshi Katayama ◽  
Jin Wang ◽  
Warapen Treekitkarnmongkol ◽  
Hidehiko Kawai ◽  
Kaori Sasai ◽  
...  
Keyword(s):  
Dna Damage ◽  
Spindle Assembly Checkpoint ◽  
Spindle Assembly ◽  
Aurora Kinase ◽  
Response Functions ◽  
Checkpoint Response ◽  
Aurora Kinase A ◽  
Induced Apoptosis ◽  
Kinase A

scholarly journals Probing Spindle Assembly Mechanisms with Monastrol, a Small Molecule Inhibitor of the Mitotic Kinesin, Eg5

2000 ◽  
Vol 150 (5) ◽  
pp. 975-988 ◽  
Author(s):  
Tarun M. Kapoor ◽  
Thomas U. Mayer ◽  
Margaret L. Coughlin ◽  
Timothy J. Mitchison
Keyword(s):  
Small Molecule ◽  
Spindle Assembly Checkpoint ◽  
Spindle Assembly ◽  
Small Molecule Inhibitor ◽  
Mitotic Arrest ◽  
Molecule Inhibitor ◽  
Egg Extracts ◽  
A Cell ◽  
Kinesin Eg5 ◽  
Mitotic Kinesin Eg5

Monastrol, a cell-permeable small molecule inhibitor of the mitotic kinesin, Eg5, arrests cells in mitosis with monoastral spindles. Here, we use monastrol to probe mitotic mechanisms. We find that monastrol does not inhibit progression through S and G2 phases of the cell cycle or centrosome duplication. The mitotic arrest due to monastrol is also rapidly reversible. Chromosomes in monastrol-treated cells frequently have both sister kinetochores attached to microtubules extending to the center of the monoaster (syntelic orientation). Mitotic arrest–deficient protein 2 (Mad2) localizes to a subset of kinetochores, suggesting the activation of the spindle assembly checkpoint in these cells. Mad2 localizes to some kinetochores that have attached microtubules in monastrol-treated cells, indicating that kinetochore microtubule attachment alone may not satisfy the spindle assembly checkpoint. Monastrol also inhibits bipolar spindle formation in Xenopus egg extracts. However, it does not prevent the targeting of Eg5 to the monoastral spindles that form. Imaging bipolar spindles disassembling in the presence of monastrol allowed direct observations of outward directed forces in the spindle, orthogonal to the pole-to-pole axis. Monastrol is thus a useful tool to study mitotic processes, detection and correction of chromosome malorientation, and contributions of Eg5 to spindle assembly and maintenance.

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