scholarly journals Rapid Apoptosis Induced by Shiga Toxin in HeLa Cells

2003 ◽  
Vol 71 (5) ◽  
pp. 2724-2735 ◽  
Author(s):  
Jun Fujii ◽  
Takashi Matsui ◽  
Daniel P. Heatherly ◽  
Kailo H. Schlegel ◽  
Peter I. Lobo ◽  
...  
Keyword(s):  
Dna Fragmentation ◽  
Hela Cells ◽  
Shiga Toxin ◽  
Specific Inhibitor ◽  
Mitochondrial Pathway ◽  
Caspase 8 ◽  
Dependent Manner ◽  
Mitochondrial Membranes ◽  
Caspase 9 ◽  
Induced Apoptosis

ABSTRACT Apoptosis was induced rapidly in HeLa cells after exposure to bacterial Shiga toxin (Stx1 and Stx2; 10 ng/ml). Approximately 60% of HeLa cells became apoptotic within 4 h as detected by DNA fragmentation, terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL) assay, and electron microscopy. Stx1-induced apoptosis required enzymatic activity of the Stx1A subunit, and apoptosis was not induced by the Stx2B subunit alone or by the anti-globotriaosylceramide antibody. This activity was also inhibited by brefeldin A, indicating the need for toxin processing through the Golgi apparatus. The intracellular pathway leading to apoptosis was further defined. Exposure of HeLa cells to Stx1 activated caspases 3, 6, 8, and 9, as measured both by an enzymatic assay with synthetic substrates and by detection of proteolytically activated forms of these caspases by Western immunoblotting. Preincubation of HeLa cells with substrate inhibitors of caspases 3, 6, and 8 protected the cells against Stx1-dependent apoptosis. These results led to a more detailed examination of the mitochondrial pathway of apoptosis. Apoptosis induced by Stx1 was accompanied by damage to mitochondrial membranes, measured as a reduced mitochondrial membrane potential, and increased release of cytochrome c from mitochondria at 3 to 4 h. Bid, an endogenous protein known to permeabilize mitochondrial membranes, was activated in a Stx1-dependent manner. Caspase-8 is known to activate Bid, and a specific inhibitor of caspase-8 prevented the mitochondrial damage. Although these data suggested that caspase-8-mediated cleavage of Bid with release of cytochrome c from mitochondria and activation of caspase-9 were responsible for the apoptosis, preincubation of HeLa cells with a specific inhibitor of caspase-9 did not protect against apoptosis. These results were explained by the discovery of a simultaneous Stx1-dependent increase in endogenous XIAP, a direct inhibitor of caspase-9. We conclude that the primary pathway of Stx1-induced apoptosis and DNA fragmentation in HeLa cells is unique and includes caspases 8, 6, and 3 but is independent of events in the mitochondrial pathway.

Arsenic trioxide–induced apoptosis in myeloma cells: p53-dependent G1 or G2/M cell cycle arrest, activation of caspase-8 or caspase-9, and synergy with APO2/TRAIL

Blood ◽  
2003 ◽  
Vol 101 (10) ◽  
pp. 4078-4087 ◽  
Author(s):  
Qun Liu ◽  
Susan Hilsenbeck ◽  
Yair Gazitt
Keyword(s):  
Cell Cycle ◽  
Arsenic Trioxide ◽  
Cell Lines ◽  
Myeloma Cell ◽  
Caspase 8 ◽  
Dependent Manner ◽  
Caspase 9 ◽  
Myeloma Cells ◽  
Induced Apoptosis ◽  
In Cells

Abstract Arsenic trioxide (ATO) has been shown to induce differentiation and apoptosis in acute promyelocytic leukemia (APL) cells concomitant with down-regulation of the PML-RARα fusion protein, a product of the t(15:17) translocation characteristic of APL leukemic cells. However, ATO is also a potent inducer of apoptosis in a number of other cancer cells lacking the t(15:17) translocation. The exact mechanism of ATO-induced apoptosis in these cells is not yet clear. We tested the effect of ATO on 7 myeloma cell lines with varying p53 status and report that in cells with mutated p53, ATO induced rapid and extensive (more than 90%) apoptosis in a time- and dose-dependent manner concomitant with arrest of cells in G2/M phase of the cell cycle. Myeloma cells with wild-type (wt) p53 were relatively resistant to ATO with maximal apoptosis of about 40% concomitant with partial arrest of cells in G1 and up-regulation of p21. The use of caspase blocking peptides, fluorescence-tagged caspase-specific substrate peptides, and Western immunoblotting confirmed the involvement of primarily caspase-8 and -3 in ATO-induced apoptosis in myeloma cells with mutated p53 and primarily caspase-9 and -3 in cells expressing wt p53. We also observed up-regulation by ATO of R1 and R2 APO2/TRAIL (tumor necrosis factor–related apoptosis-inducing ligand) receptors. Most important, however, we observed a synergy between ATO and APO2/TRAIL in the induction of apoptosis in the partially resistant myeloma cell lines and in myeloma cells freshly isolated from myeloma patients. Our results justify the use of the combination of these 2 drugs in clinical setting in myeloma patients.

Role of mitochondria in aspirin-induced apoptosis in human gastric epithelial cells

2005 ◽  
Vol 289 (4) ◽  
pp. G731-G738 ◽  
Author(s):  
Maria J. Redlak ◽  
Jacinda J. Power ◽  
Thomas A. Miller
Keyword(s):  
Epithelial Cells ◽  
Complex Formation ◽  
Oxidative Phosphorylation ◽  
Caspase 8 ◽  
Mucosal Cell ◽  
Dependent Manner ◽  
Gastric Epithelial Cells ◽  
Caspase 9 ◽  
Mitochondrial Fractions ◽  
Induced Apoptosis

This study was undertaken to determine whether the Bcl-2 family proteins and Smac are regulators of aspirin-mediated apoptosis in a gastric mucosal cell line known as AGS cells. Cells were incubated with varying concentrations of acetylsalicylic acid (ASA; 2–40 mM), with or without preincubation of caspase inhibitors. Apoptosis was characterized by Hoechst staining and DNA-histone-associated complex formation. Antiapoptotic Bcl-2, proapoptotic Bax and Bid, Smac, and cytochrome- c oxidase (COX IV) were analyzed by Western blot analyses from cytosol and mitochondrial fractions. ASA downregulated Bcl-2 protein expression and induced Bax translocation into the mitochondria and cleavage of Bid. In contrast, expression of Smac was significantly decreased in mitochondrial fractions of ASA-treated cells. Bax and Bid involvement in apoptosis regulation was dependent on caspase activation, because caspase-8 inhibition suppressed Bax translocation and Bid processing. Caspase-9 inhibition prevented Smac release from mitochondria. Additionally, increased expression of the oxidative phosphorylation enzyme COX IV was observed in mitochondrial fractions exposed to ASA at concentrations >5 mM. Although caspase-8 inhibition had no effect on aspirin-induced apoptosis and DNA-histone complex formation, caspase-9 inhibition significantly decreased both of these events. We conclude that Bcl-2 protein family members and Smac regulate the apoptotic pathway in a caspase-dependent manner. Our results indicate also that mitochondrial integration and oxidative phosphorylation play a critical role in the pathogenesis of apoptosis in human gastric epithelial cells.

scholarly journals Bullatacin Triggered ABCB1-Overexpressing Cell Apoptosis via the Mitochondrial-Dependent Pathway

2009 ◽  
Vol 2009 ◽  
pp. 1-9 ◽  
Author(s):  
Yong-Ju Liang ◽  
Xu Zhang ◽  
Chun-Ling Dai ◽  
Jian-Ye Zhang ◽  
Yan-Yan Yan ◽  
...  
Keyword(s):  
Cell Apoptosis ◽  
Multidrug Resistant ◽  
Resistant Cell ◽  
Ros Generation ◽  
Caspase 8 ◽  
Dependent Manner ◽  
Caspase 9 ◽  
Concentration Dependent Manner ◽  
Induced Apoptosis ◽  
Dependent Pathway

This paper was to explore bullatacin-mediated multidrug-resistant cell apoptosis at extremely low concentration. To investigate its precise mechanisms, the pathway of cell apoptosis induced by bullatacin was examined. Bullatacin causes an upregulation of ROS and a downregulation ofΔΨmin a concentration-dependent manner in ABCB1-overexpressing KBv200 cells. In addition, cleavers of caspase-9, caspase-3, and PARP were observed following the release of cytochrome c from mitochondria after bullatacin treatment. However, neither cleavage of caspase-8 nor change of expression level of bcl-2, bax and Fas was observed by the same treatment. Pretreating KBv200 cells with N-acetylcysteine, an antioxidant modulator, resulted in a significant reduction of ROS generation and cell apoptosis induced by bullatacin. Bullatacin-induced apoptosis was antagonized by z-LEHD-fmk, a caspase-9 inhibitor, but not by z-IETD-fmk, a caspase-8 inhibitor. These implied that apoptosis of KBv200 cells induced by bullatacin was associated with the mitochondria-dependent pathway that was limited to activation of apical caspase-9.

scholarly journals Caspase 3 is Activated through Caspase 8 instead of Caspase 9 during H2O2-induced Apoptosis in HeLa Cells

2011 ◽  
Vol 27 (5) ◽  
pp. 539-546 ◽  
Author(s):  
Yinyuan Wu ◽  
Dianjun Wang ◽  
Xiaodong Wang ◽  
Yinyin Wang ◽  
Fangli Ren ◽  
...  
Keyword(s):  
Hela Cells ◽  
Caspase 3 ◽  
Caspase 8 ◽  
Caspase 9 ◽  
Induced Apoptosis

scholarly journals NeosedumosideIII induced Apoptosis of Human Hepatocellular Carcinoma HepG2 cells and SMMC-7721 Cells and Related Mechanism

2021 ◽  
Author(s):  
Xin-Yu Li ◽  
Xin Zhou ◽  
Yu- Liu ◽  
Feng Qiu ◽  
Qing-Qing Zhao
Keyword(s):  
Hepatocellular Carcinoma ◽  
Cell Cycle ◽  
Hepg2 Cells ◽  
Caspase 3 ◽  
Human Hepatocellular Carcinoma ◽  
Caspase 8 ◽  
Dependent Manner ◽  
Caspase 9 ◽  
Induced Apoptosis

Abstract Purpose: NeosedumosideIII (Neo) is a megastigmanes and belongs to monocyclic sesquiterpenoids compound with antioxidant, anti-inflammatory and other pharmacological activities. In order to explore the anti-cancer effect and possible mechanism of Neo, the study examined the anti-proliferation and apoptosis effect of Neo against human hepatocellular carcinoma HepG2 cells and SMMC-772 cells and related mechanism in vitro. Methods ：The anti-proliferation effect of Neo was detected on HepG2 cells and SMMC-772 cells by MTT assay and IC50 with increasing dose and time. Cell cycle and apoptosis were detected by flow cytometer. The changes of Bcl-2, Bax, Caspase-3, Caspase-8 and Caspase-9 proteins were detected by western blotting.Results ：The results indicated that Neo could inhibited proliferation of HepG2 cells and SMMC-772 cells in vitro and promoted apoptosis, it significantly induced apoptosis of HepG2 cells and SMMC-772 cells arrested cell cycle at G0/G1 phase in a dose-dependent manner, reduce the expression of Bcl-2 protein, and increase the expression of Bax and Caspase-3, Caspase-8 and Caspase-9 proteins. Conclusion：Neo could inhibit proliferation and induce apoptosis of HepG2 cells and SMMC-7721 cells in vivo which suggested that it might be served as a promising candidate for the treatment of liver cancer.

Antileukemic drugs increase death receptor 5 levels and enhance Apo-2L–induced apoptosis of human acute leukemia cells

Blood ◽  
2000 ◽  
Vol 96 (12) ◽  
pp. 3900-3906 ◽  
Author(s):  
Jinghai Wen ◽  
Nimmanapalli Ramadevi ◽  
Diep Nguyen ◽  
Charles Perkins ◽  
Elizabeth Worthington ◽  
...  
Keyword(s):  
Acute Leukemia ◽  
Fas Ligand ◽  
Leukemia Cell ◽  
Jurkat Cells ◽  
Leukemia Cells ◽  
Maximum Effect ◽  
Caspase 8 ◽  
Dependent Manner ◽  
Caspase 9 ◽  
Induced Apoptosis

Abstract In present studies, treatment with tumor necrosis factor (TNF)–related apoptosis inducing ligand (TRAIL, also known as Apo-2 ligand [Apo-2L]) is shown to induce apoptosis of the human acute leukemia HL-60, U937, and Jurkat cells in a dose-dependent manner, with the maximum effect seen following treatment of Jurkat cells with 0.25 μg/mL of Apo-2L (95.0% ± 3.5% of apoptotic cells). Susceptibility of these acute leukemia cell types, which are known to lack p53wt function, did not appear to correlate with the levels of the apoptosis-signaling death receptors (DRs) of Apo-2L, ie, DR4 and DR5; decoy receptors (DcR1 and 2); FLAME-1 (cFLIP); or proteins in the inhibitors of apoptosis proteins (IAP) family. Apo-2L–induced apoptosis was associated with the processing of caspase-8, Bid, and the cytosolic accumulation of cytochrome c as well as the processing of caspase-9 and caspase-3. Apo-2L–induced apoptosis was significantly inhibited in HL-60 cells that overexpressed Bcl-2 or Bcl-xL. Cotreatment with either a caspase-8 or a caspase-9 inhibitor suppressed Apo-2L–induced apoptosis. Treatment of human leukemic cells with etoposide, Ara-C, or doxorubicin increased DR5 but not DR4, Fas, DcR1, DcR2, Fas ligand, or Apo-2L levels. Importantly, sequential treatment of HL-60 cells with etoposide, Ara-C, or doxorubicin followed by Apo-2L induced significantly more apoptosis than treatment with Apo-2L, etoposide, doxorubicin, or Ara-C alone, or cotreatment with Apo-2L and the antileukemic drugs, or treatment with the reverse sequence of Apo-2L followed by one of the antileukemic drugs. These findings indicate that treatment with etoposide, Ara-C, or doxorubicin up-regulates DR5 levels in a p53-independent manner and sensitizes human acute leukemia cells to Apo-2L–induced apoptosis.

Polyamines are required for activation of c-Jun NH2-terminal kinase and apoptosis in response to TNF-α in IEC-6 cells

2003 ◽  
Vol 285 (5) ◽  
pp. G980-G991 ◽  
Author(s):  
Sujoy Bhattacharya ◽  
Ramesh M. Ray ◽  
Mary Jane Viar ◽  
Leonard R. Johnson
Keyword(s):  
Cytochrome C ◽  
Dna Fragmentation ◽  
Caspase 3 ◽  
Specific Inhibitor ◽  
Cell Types ◽  
Caspase 9 ◽  
Cytochrome C Release ◽  
Tnf Α ◽  
Induced Apoptosis ◽  
Jnk Activation

Intracellular polyamine homeostasis is important for the regulation of cell proliferation and apoptosis and is necessary for the balanced growth of cells and tissues. Polyamines have been shown to play a role in the regulation of apoptosis in many cell types, including IEC-6 cells, but the mechanism is not clear. In this study, we analyzed the mechanism by which polyamines regulate the process of apoptosis in response to tumor necrosis factor-α (TNF-α). TNF-α or cycloheximide (CHX) alone did not induce apoptosis in IEC-6 cells. Significant apoptosis was observed when CHX was given along with TNF-α, as indicated by a significant increase in the detachment of cells, caspase-3 activity, and DNA fragmentation. Polyamine depletion by treatment with α-difluoromethylornithine significantly reduced the level of apoptosis, as judged by DNA fragmentation and the caspase-3 activity of attached cells. Apoptosis in IEC-6 cells was accompanied by the activation of upstream caspases-6, -8, and -9 and NH2-terminal c-Jun kinase (JNK). Inhibition of JNK activation prevented caspase-9 activation. Polyamine depletion prevented the activation of JNK and of caspases-6, -8, -9, and -3. SP-600125, a specific inhibitor of JNK activation, prevented cytochrome c release from mitochondria, JNK activation, DNA fragmentation, and caspase-9 activation in response to TNF-α/CHX. In conclusion, we have shown that polyamine depletion delays and decreases TNF-α-induced apoptosis in IEC-6 cells and that apoptosis is accompanied by the release of cytochrome c, the activation of JNK, and of upstream caspases as well as caspase-3. Polyamine depletion prevented JNK activation, which may confer protection against apoptosis by modulation of upstream caspase-9 activation.

Antileukemic drugs increase death receptor 5 levels and enhance Apo-2L–induced apoptosis of human acute leukemia cells

Blood ◽  
2000 ◽  
Vol 96 (12) ◽  
pp. 3900-3906 ◽  
Author(s):  
Jinghai Wen ◽  
Nimmanapalli Ramadevi ◽  
Diep Nguyen ◽  
Charles Perkins ◽  
Elizabeth Worthington ◽  
...  
Keyword(s):  
Acute Leukemia ◽  
Fas Ligand ◽  
Leukemia Cell ◽  
Jurkat Cells ◽  
Leukemia Cells ◽  
Maximum Effect ◽  
Caspase 8 ◽  
Dependent Manner ◽  
Caspase 9 ◽  
Induced Apoptosis

In present studies, treatment with tumor necrosis factor (TNF)–related apoptosis inducing ligand (TRAIL, also known as Apo-2 ligand [Apo-2L]) is shown to induce apoptosis of the human acute leukemia HL-60, U937, and Jurkat cells in a dose-dependent manner, with the maximum effect seen following treatment of Jurkat cells with 0.25 μg/mL of Apo-2L (95.0% ± 3.5% of apoptotic cells). Susceptibility of these acute leukemia cell types, which are known to lack p53wt function, did not appear to correlate with the levels of the apoptosis-signaling death receptors (DRs) of Apo-2L, ie, DR4 and DR5; decoy receptors (DcR1 and 2); FLAME-1 (cFLIP); or proteins in the inhibitors of apoptosis proteins (IAP) family. Apo-2L–induced apoptosis was associated with the processing of caspase-8, Bid, and the cytosolic accumulation of cytochrome c as well as the processing of caspase-9 and caspase-3. Apo-2L–induced apoptosis was significantly inhibited in HL-60 cells that overexpressed Bcl-2 or Bcl-xL. Cotreatment with either a caspase-8 or a caspase-9 inhibitor suppressed Apo-2L–induced apoptosis. Treatment of human leukemic cells with etoposide, Ara-C, or doxorubicin increased DR5 but not DR4, Fas, DcR1, DcR2, Fas ligand, or Apo-2L levels. Importantly, sequential treatment of HL-60 cells with etoposide, Ara-C, or doxorubicin followed by Apo-2L induced significantly more apoptosis than treatment with Apo-2L, etoposide, doxorubicin, or Ara-C alone, or cotreatment with Apo-2L and the antileukemic drugs, or treatment with the reverse sequence of Apo-2L followed by one of the antileukemic drugs. These findings indicate that treatment with etoposide, Ara-C, or doxorubicin up-regulates DR5 levels in a p53-independent manner and sensitizes human acute leukemia cells to Apo-2L–induced apoptosis.

scholarly journals Polypeptide Fraction fromArca subcrenataInduces Apoptosis and G2/M Phase Arrest in HeLa Cells via ROS-Mediated MAPKs Pathways

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Xianjing Hu ◽  
Zhang Zhang ◽  
Ting Liu ◽  
Liyan Song ◽  
Jianhua Zhu ◽  
...  
Keyword(s):  
Cervical Cancer ◽  
Hela Cells ◽  
Underlying Mechanism ◽  
Cyclin B1 ◽  
Mitochondrial Pathway ◽  
Dependent Manner ◽  
Phase Arrest ◽  
M Phase ◽  
Induced Apoptosis ◽  
High Level

Arca subcrenatais documented in the literature of marine Traditional Chinese Medicine. Polypeptide fraction fromA. subcrenata, coded as P2, was demonstrated to possess significant antitumor activity in our previous study. However, the underlying mechanism remains undefined. The present study was carried out to investigate the underlying antitumor mechanism of P2 in human cervical cancer HeLa cells by MTT, FCM, LSCM, and western blot assays. The results revealed that P2 significantly induced apoptosis of HeLa cells in a concentration- and time-dependent manner. High level of ROS was provoked by P2, which was in turn responsible for induction of apoptosis through activation of intrinsic mitochondrial pathway and JNK1/2, p38 MAPK pathways, as well as inhibition of ERK1/2 pathway, as evidenced by the abrogation of P2’s effect on HeLa cells preincubated with the ROS scavenger NAC. P2 also was observed to display significant effect on G2/M phase arrest by downregulating the expression of cyclin B1/cdc2 complex and upregulating the expression of p21. These findings demonstrate that P2 induces apoptosis and G2/M phase arrest in HeLa cells through ROS-mediated MAPKs pathways, suggesting that P2 would be worth investigating as a promising agent within the scope of marine drugs for treatment of cervical cancer.

scholarly journals Japanese encephalitis virus infection activates caspase-8 and -9 in a FADD-independent and mitochondrion-dependent manner

2008 ◽  
Vol 89 (8) ◽  
pp. 1930-1941 ◽  
Author(s):  
Chang-Huei Tsao ◽  
Hong-Lin Su ◽  
Yi-Ling Lin ◽  
Han-Pang Yu ◽  
Shu-Ming Kuo ◽  
...  
Keyword(s):  
Japanese Encephalitis Virus ◽  
Japanese Encephalitis ◽  
Caspase 3 ◽  
Encephalitis Virus ◽  
Dominant Negative Mutant ◽  
Caspase 8 ◽  
Dependent Manner ◽  
Caspase 9 ◽  
Effector Caspase ◽  
Induced Apoptosis

Japanese encephalitis virus (JEV), a mosquito-borne flavivirus, replicates primarily at the endoplasmic reticulum and thereby triggers apoptosis of infected cells. This study investigated the hierarchical activation of the caspase network induced by JEV infection. It was found that JEV activated the initiators caspase-8 and -9, as well as effector caspase-3, in infected baby hamster kidney and mouse neuroblastoma (N18) cells. In neuronal N18 cells, JEV infection triggered cytochrome c release from mitochondria, which in turn activated caspase-9 and -3. Treatment of JEV-infected N18 cells with cyclosporin A or ruthenium red, which attenuate mitochondrial injuries, blocked activation of caspase-9 or -3, typifying that, in neuronal cells, this apoptosis involves the mitochondrial pathway. Alternatively, in caspase-3-deficient MCF-7 cells, JEV persisted and readily triggered a typical apoptotic response, including cytochrome c release and full activation of caspase-9 and -8 along with caspase-6, indicating that JEV did not require caspase-3 to manifest caspase-8 activation and apoptosis. Interestingly, a Fas-associated death-domain-containing protein (FADD) dominant-negative mutant, which interfered with transmission of the extracellular death signals into cells through the Fas/tumour necrosis factor (TNF) receptor, failed to block JEV-induced apoptosis and caspase-8 activation, implying that receptor oligomerization of the Fas/TNF pathway might not participate in JEV-induced apoptosis. Taken together, these results illustrate that JEV infection triggers caspase cascades involving the initiators caspase-8 and -9, probably through FADD-independent but mitochondrion-dependent pathways.

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