scholarly journals Esculetin induces apoptosis of SMMC-7721 cells through IGF-1/PI3K/Akt-mediated mitochondrial pathways

2017 ◽  
Vol 95 (7) ◽  
pp. 787-794 ◽  
Author(s):  
Juan Li ◽  
Shuang Li ◽  
Xiuli Wang ◽  
Hongxin Wang
Keyword(s):  
Mitochondrial Membrane ◽  
Caspase 3 ◽  
Annexin V ◽  
Coumarin Derivative ◽  
Caspase 9 ◽  
Cytochrome C Release ◽  
Dapi Staining ◽  
Cancer Cell Growth ◽  
Induced Apoptosis ◽  
Apoptotic Effects

Esculetin (6,7-dihydroxycoumarin) is a coumarin derivative extracted from natural plants and has been reported to have anticancer activity. However, the mechanism by which esculetin prevents human hepatic cancer cell growth is still largely unknown. In this study, we investigated the effect of esculetin on human hepatocellular carcinoma (HCC) SMMC-7721 cells and explored the cell signal mechanism. Our data indicated that esculetin induced apoptosis in SMMC-7721 cells, which were supported by DAPI staining and Annexin V/PI staining. Meanwhile, esculetin increased the activities of caspase-3 and caspase-9, promoted bax expression, decreased bcl-2 expression, and triggered collapse of mitochondrial membrane potential, and increased cytochrome c release from mitochondria. In addition, the inactivation of IGF-1, PI3K, and Akt was observed after esculetin administration. Furthermore, pretreatment with IGF-1 before esculetin administration abrogated the pro-apoptotic effects of esculetin, while PI3K inhibitor increased the pro-apoptotic effects of esculetin. These results indicated that esculetin induced the apoptosis of SMMC-7721 cells through IGF-1/PI3K/Akt-regulated mitochondrial dysfunction.

scholarly journals Polyamine depletion prevents camptothecin-induced apoptosis by inhibiting the release of cytochromec

2002 ◽  
Vol 282 (6) ◽  
pp. C1290-C1297 ◽  
Author(s):  
Qing Yuan ◽  
Ramesh M. Ray ◽  
Leonard R. Johnson
Keyword(s):  
Cytochrome C ◽  
Mammalian Cells ◽  
Caspase 3 ◽  
Intestinal Epithelial ◽  
Caspase 9 ◽  
Cytochrome C Release ◽  
Polyamine Synthesis ◽  
Antiapoptotic Proteins ◽  
Induced Apoptosis ◽  
Rate Limiting

C1297, 2002; 10.1152/ajpcell.00351.2001.We have shown previously that depletion of polyamines delays apoptosis induced by camptothecin in rat intestinal epithelial cells (IEC-6). Mitochondria play an important role in the regulation of apoptosis in mammalian cells because apoptotic signals induce mitochondria to release cytochrome c. The latter interacts with Apaf-1 to activate caspase-9, which in turn activates downstream caspase-3. Bcl-2 family proteins are involved in the regulation of cytochrome c release from mitochondria. In this study, we examined the effects of polyamine depletion on the activation of the caspase cascade, release of cytochrome cfrom mitochondria, and expression and translocation of Bcl-2 family proteins. We inhibited ornithine decarboxylase, the first rate-limiting enzyme in polyamine synthesis, with α-difluoromethylornithine (DFMO) to deplete cells of polyamines. Depletion of polyamines prevented camptothecin-induced release of cytochrome c from mitochondria and decreased the activity of caspase-9 and caspase-3. The mitochondrial membrane potential was not disrupted when cytochrome c was released. Depletion of polyamines decreased translocation of Bax to mitochondria during apoptosis. The expression of antiapoptotic proteins Bcl-xL and Bcl-2 was increased in DFMO-treated cells. Caspase-8 activity and cleavage of Bid were decreased in cells depleted of polyamines. These results suggest that polyamine depletion prevents IEC-6 cells from apoptosis by preventing the translocation of Bax to mitochondria, thus preventing the release of cytochrome c.

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.

scholarly journals Rhein ElicitsIn VitroCytotoxicity in Primary Human Liver HL-7702 Cells by Inducing Apoptosis through Mitochondria-Mediated Pathway

2015 ◽  
Vol 2015 ◽  
pp. 1-19 ◽  
Author(s):  
Guy-Armel Bounda ◽  
Wang Zhou ◽  
Dan-dan Wang ◽  
Feng Yu
Keyword(s):  
Cytochrome C ◽  
Molecular Mechanisms ◽  
Caspase 3 ◽  
Morphological Changes ◽  
Fatty Degeneration ◽  
Apoptotic Cells ◽  
Dependent Manner ◽  
Caspase 9 ◽  
Cytochrome C Release ◽  
Induced Apoptosis

Objective. To study rhein-induced apoptosis signaling pathway and to investigate its molecular mechanisms in primary human hepatic cells.Results. Cell viability of HL-7702 cells treated with rhein showed significant decrease in dose-dependent manner. Following rhein treatment (25 μM, 50 μM, and 100 μM) for 12 h, the detection of apoptotic cells was significantly analyzed by flow cytometry and nuclear morphological changes by Hoechst 33258, respectively. Fatty degeneration studies showed upregulation level of the relevant hepatic markers (P< 0.01). Caspase activities expressed significant upregulation of caspase-3, caspase-9, and caspase-8. Moreover, apoptotic cells by rhein were significantly inhibited by Z-LEHD-FMK and Z-DEVD-FMK, caspase-9 inhibitor, and caspase-3 inhibitor, respectively. Overproduction of reactive oxygen species, lipid peroxidation, and loss of mitochondrial membrane potential were detected by fluorometry. Additionally, NAC, a ROS scavenger, significantly attenuated rhein-induced oxidative damage in HL-7702 cells. Furthermore, real-time qPCR results showed significant upregulation of p53, PUMA, Apaf-1, and Casp-9 and Casp-3 mRNA, with no significant changes of Fas and Cytochrome-c. Immunoblotting revealed significant Cytochrome-c release from mitochondria into cytosol and no change in Fas expression.Conclusion. Taken together, these observations suggested that rhein could induce apoptosis in HL-7702 cells via mitochondria-mediated signal pathway with involvement of oxidative stress mechanism.

scholarly journals Loss of Caspase-9 Reveals Its Essential Role for Caspase-2 Activation and Mitochondrial Membrane Depolarization

2007 ◽  
Vol 18 (1) ◽  
pp. 84-93 ◽  
Author(s):  
Ajoy K. Samraj ◽  
Dennis Sohn ◽  
Klaus Schulze-Osthoff ◽  
Ingo Schmitz
Keyword(s):  
Cytochrome C ◽  
Anticancer Drugs ◽  
Mitochondrial Membrane ◽  
Genotoxic Stress ◽  
Caspase 9 ◽  
Cytochrome C Release ◽  
Mitochondrial Outer Membrane Permeabilization ◽  
Mitochondrial Membrane Depolarization ◽  
Caspase 2 ◽  
Induced Apoptosis

Caspase-9 plays an important role in apoptosis induced by genotoxic stress. Irradiation and anticancer drugs trigger mitochondrial outer membrane permeabilization, resulting in cytochrome c release and caspase-9 activation. Two highly contentious issues, however, remain: It is unclear whether the loss of the mitochondrial membrane potential ΔΨMcontributes to cytochrome c release and whether caspases are involved. Moreover, an unresolved question is whether caspase-2 functions as an initiator in genotoxic stress-induced apoptosis. In the present study, we have identified a mutant Jurkat T-cell line that is deficient in caspase-9 and resistant to apoptosis. Anticancer drugs, however, could activate proapoptotic Bcl-2 proteins and cytochrome c release, similarly as in caspase-9–proficient cells. Interestingly, despite these alterations, the cells retained ΔΨM. Furthermore, processing and enzyme activity of caspase-2 were not observed in the absence of caspase-9. Reconstitution of caspase-9 expression restored not only apoptosis but also the loss of ΔΨMand caspase-2 activity. Thus, we provide genetic evidence that caspase-9 is indispensable for drug-induced apoptosis in cancer cells. Moreover, loss of ΔΨMcan be functionally separated from cytochrome c release. Caspase-9 is not only required for ΔΨMloss but also for caspase-2 activation, suggesting that these two events are downstream of the apoptosome.

Inhibition of hypoxia/reoxygenation-induced apoptosis in metallothionein-overexpressing cardiomyocytes

2001 ◽  
Vol 280 (5) ◽  
pp. H2292-H2299 ◽  
Author(s):  
Guang-Wu Wang ◽  
Zhanxiang Zhou ◽  
Jon B. Klein ◽  
Y. James Kang
Keyword(s):  
Cytochrome C ◽  
Caspase 3 ◽  
Ischemia Reperfusion ◽  
Annexin V ◽  
Terminal Deoxynucleotidyl Transferase ◽  
Cytochrome C Release ◽  
Apoptotic Pathway ◽  
Fetal Bovine ◽  
Induced Apoptosis ◽  
Hypoxia Reoxygenation

To study possible mechanisms for metallothionein (MT) inhibition of ischemia-reperfusion-induced myocardial injury, cardiomyocytes isolated from MT-overexpressing transgenic neonatal mouse hearts and nontransgenic controls were subjected to 4 h of hypoxia (5% CO2-95% N2, glucose-free modified Tyrode's solution) followed by 1 h of reoxygenation in MEM + 20% fetal bovine serum (FBS) (5% CO2-95% air), and cytochrome c-mediated caspase-3 activation apoptotic pathway was determined. Hypoxia/reoxygenation-induced apoptosis was significantly suppressed in MT-overexpressing cardiomyocytes, as measured by both terminal deoxynucleotidyl transferase-mediated deoxyuridine 5-triphosphate nick-end labeling and annexin V-FITC binding. In association with apoptosis, mitochondrial cytochrome c release, as determined by Western blot, was observed to occur in nontransgenic cardiomyocytes. Correspondingly, caspase-3 was activated as determined by laser confocal microscopic examination with the use of FITC-conjugated antibody against active caspase-3 and by enzymatic assay. The activation of this apoptotic pathway was significantly inhibited in MT-overexpressing cells, as evidenced by both suppression of cytochrome c release and inhibition of caspase-3 activation. The results demonstrate that MT suppresses hypoxia/reoxygenation-induced cardiomyocyte apoptosis through, at least in part, inhibition of cytochrome c-mediated caspase-3 activation.

Involvement of the Mitochondria-Caspase Pathway in HeLa Cell Death Induced by 2-Ethanolamino-2-Demethoxy-17-Ethanolimino-Hypocrellin B (EAHB)-Mediated Photodynamic Therapy

2012 ◽  
Vol 31 (5) ◽  
pp. 483-492 ◽  
Author(s):  
Zhixiang Zhou ◽  
Chen Zhao ◽  
Wei Liu ◽  
Qianqian Li ◽  
Lina Zhang ◽  
...  
Keyword(s):  
Photodynamic Therapy ◽  
Hela Cells ◽  
Caspase 3 ◽  
Caspase 9 ◽  
Cytochrome C Release ◽  
Hypocrellin B ◽  
Confocal Fluorescence ◽  
Cellular Apoptosis ◽  
Induced Apoptosis ◽  
Dependent Mechanism

In order to elucidate the mechanism of cytotoxicity photoinduced by 2-ethanolamino-2-demethoxy-17-ethanolimino-hypocrellin B (EAHB), a derivative of hypocrellin B (HB), cellular uptake, subcellular localization as well as photodynamic therapy (PDT) efficiency of EAHB, and cell apoptosis photoinduced by EAHB were investigated in HeLa cells by laser confocal fluorescence microscopy, 3-(4,5-Dimethylthiazol-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assay, flow cytometry, DNA fragmentation on agarose gel, and Western blot. The results showed EAHB was distributed throughout the cytoplasm of the cell, with no detectable penetration into the nucleus. The proportion of dead cells increased with increases in both the dosage of light and the concentration of EAHB. Its phototoxicity to HeLa cells proceeded via apoptosis. The EAHB-PDT treatment induced a cytochrome c release from the mitochondria into the cytosol followed by the activation of both caspase 3 and caspase 9 in HeLa cells. The results suggested that EAHB-PDT treatment induced apoptosis in HeLa cells, and the cellular apoptosis involved a mitochondria-/caspase-dependent mechanism.

scholarly journals Ligands of the Mitochondrial 18 kDa Translocator Protein Attenuate Apoptosis of Human Glioblastoma Cells Exposed to Erucylphosphohomocholine

2008 ◽  
Vol 30 (5) ◽  
pp. 435-450
Author(s):  
Wilfried Kugler ◽  
Leo Veenman ◽  
Yulia Shandalov ◽  
Svetlana Leschiner ◽  
Ilana Spanier ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Cytochrome C ◽  
Cyclosporin A ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Membrane ◽  
Translocator Protein ◽  
Glioblastoma Cells ◽  
Caspase 9 ◽  
Cytochrome C Release ◽  
Induced Apoptosis

Background: We have previously shown that the anti-neoplastic agent erucylphosphohomocholine (ErPC3) requires the mitochondrial 18 kDa Translocator protein (TSPO), formerly known as the peripheral-type benzodiazepine receptor (PBR), to induce cell death via the mitochondrial apoptosis pathway.Methods: With the aid of the dye JC-1 and cyclosporin A, applied to glioblastoma cells, we now investigated the significance of opening of the mitochondrial permeability transition pore (MPTP) for ErPC3-induced apoptosis in interaction with the TSPO ligands, PK 11195 and Ro5 4864. Furthermore, we measured cytochrome c release, and caspase-9 and -3 activation in this paradigm.Results: The human glioblastoma cell lines, U87MG, A172 and U118MG express the MPTP-associated TSPO, voltage-dependent anion channel and adenine nucleotide transporter. Indeed, ErPC3-induced apoptosis was inhibited by the MPTP blocker cyclosporin A and by PK 11195 and Ro5 4864 in a concentration-dependent manner. Furthermore, PK 11195 and Ro5 4864 inhibited collapse of the mitochondrial membrane potential, cytochrome c release, and caspase-9 and -3 activation caused by ErPC3 treatment.Conclusions: This study shows that PK 11195 and Ro5 4864 inhibit the pro-apoptotic function of ErPC3 by blocking its capacity to cause a collapse of the mitochondrial membrane potential. Thus, the TSPO may serve to open the MPTP in response to anti-cancer drugs such as ErPC3.

Taurine inhibits apoptosis by preventing formation of the Apaf-1/caspase-9 apoptosome

2004 ◽  
Vol 287 (4) ◽  
pp. C949-C953 ◽  
Author(s):  
Tomoka Takatani ◽  
Kyoko Takahashi ◽  
Yoriko Uozumi ◽  
Eriko Shikata ◽  
Yasuhiro Yamamoto ◽  
...  
Keyword(s):  
Cytochrome C ◽  
Mitochondrial Membrane ◽  
Mitochondrial Depolarization ◽  
Caspase 9 ◽  
Cytochrome C Release ◽  
Neonatal Cardiomyocytes ◽  
Simulated Ischemia ◽  
Taurine Treatment ◽  
Induced Apoptosis ◽  
Apoptotic Cascade

Cardiomyocyte apoptosis contributes to cell death during myocardial infarction. One of the factors that regulate the degree of apoptosis during ischemia is the amino acid taurine. To study the mechanism underlying the beneficial effect of taurine, we examined the interaction between taurine and mitochondria-mediated apoptosis using a simulated ischemia model with cultured rat neonatal cardiomyocytes sealed in closed flasks. Exposure to medium containing 20 mM taurine reduced the degree of apoptosis following periods of ischemia varying from 24 to 72 h. In the untreated group, simulated ischemia for 24 h led to mitochondrial depolarization accompanied by cytochrome c release. The apoptotic cascade was also activated, as evidenced by the activation of caspase-9 and -3. Taurine treatment had no effect on mitochondrial membrane potential and cytochrome c release; however, it inhibited ischemia-induced cleavage of caspase-9 and -3. Taurine loading also suppressed the formation of the Apaf-1/caspase-9 apoptosome and the interaction of caspase-9 with Apaf-1. These findings demonstrate that taurine effectively prevents myocardial ischemia-induced apoptosis by inhibiting the assembly of the Apaf-1/caspase-9 apoptosome.

scholarly journals Activation of the intrinsic and extrinsic pathways in high pressure-induced apoptosis of murine erythroleukemia cells

2008 ◽  
Vol 13 (1) ◽  
Author(s):  
Takeo Yamaguchi ◽  
Kenji Hashiguchi ◽  
Satoshi Katsuki ◽  
Wakako Iwamoto ◽  
Shoichiro Tsuruhara ◽  
...  
Keyword(s):  
High Pressure ◽  
Mitochondrial Membrane ◽  
Caspase 3 ◽  
Caspase Inhibitor ◽  
Cytochrome C Release ◽  
Peptide Substrates ◽  
Erythroleukemia Cells ◽  
Induced Apoptosis ◽  
Murine Erythroleukemia ◽  
Murine Erythroleukemia Cells

AbstractWe previously demonstrated that caspase-3, an executioner of apoptosis, is activated in the pressure-induced apoptosis of murine erythroleukemia (MEL) cells (at 100 MPa). Here, we examined the pathway of caspase-3 activation using peptide substrates and caspase inhibitors. Using the substrates of caspases-8 and -9, it was found that both are activated in cells under high pressure. The production of nuclei with sub-G1 DNA content in 100 MPa-treated MEL cells was suppressed by inhibitors of caspases-8 and -9, and pan-caspase. In 100 MPa-treated cells, pan-caspase inhibitor partially prevented the cytochrome c release from the mitochondria and the breakdown of mitochondrial membrane potential. These results suggest that the intrinsic and extrinsic pathways are activated in apoptotic signaling during the high pressure-induced death of MEL cells.

Overexpression of Pygopus2 protects HeLa cells from vinblastine-induced apoptosis

2009 ◽  
Vol 390 (2) ◽  
pp. 157-165 ◽  
Author(s):  
Degejing De ◽  
Apeng Chen ◽  
Zhiqiang Wu ◽  
Songya Lv ◽  
Guoqing He ◽  
...  
Keyword(s):  
Mitochondrial Membrane ◽  
Caspase 3 ◽  
Caspase 9 ◽  
Human Carcinoma ◽  
Multiple Functions ◽  
Apoptotic Protein ◽  
Hela Cell Lines ◽  
Apoptotic Activity ◽  
Induced Apoptosis ◽  
Transcriptional Complex

Abstract Pygopus, a very important component of the Wnt signaling transcriptional complex, has multiple functions in both Wnt-dependent and -independent pathways. Human Pygopus2 (Pygo2) is expressed in many cancers and plays an important role in tumor growth. In the present study, we generated human carcinoma (HeLa) cell lines stably expressing Pygo2, which counteracts vinblastine-induced apoptosis. The anti-apoptotic function was determined by DNA fragmentation, sub-G1 appearance, loss of mitochondrial membrane potential (Δψm) and the activation of caspase-9 and caspase-3. In addition, we found that Pygo2 effectively blocks vinblastine-induced c-Jun and AP-1 activation, maintains the anti-apoptotic protein Bcl-2 in an unphosphorylated state, and thus can render cells resistant to apoptosis. However, Pygo2 does not alter the vinblastine-induced cell cycle changes. Here, we describe an anti-apoptotic activity exerted by Pygo2 through blocking activation of the JNK/AP-1 signaling pathway induced by vinblastine.

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