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Mitochondrial Cytochrome C (mitochondrial + cytochrome_c)

Distribution by Scientific Domains
Medical Sciences75%

Terms modified by Mitochondrial Cytochrome C

  • mitochondrial cytochrome c oxidase
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  • mitochondrial cytochrome c oxidase subunit i
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  • mitochondrial cytochrome c release
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    Selected Abstracts

    Involvement of p38 mitogen-activated protein kinase pathway in honokiol-induced apoptosis in a human hepatoma cell line (hepG2)

    LIVER INTERNATIONAL, Issue 10 2008
    Junfang Deng
    Abstract Background: Honokiol has been known to have antitumour activity. This study was conducted to evaluate the antiproliferative potential of honokiol against the hepG2 heptocellular cell line and its mechanism of action. Methods: hepG2 cells were treated with honokiol of 0,40 ,g/ml concentration. The cytotoxic effect of honokiol was determined by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The apoptosis was evaluated by flow cytometry. Western blots were used to analyse the expression of various proteins (procaspase-9, procaspase-3, cleaved caspase-3, cytochrome c, Bcl-2, Bax, Bad, Bcl-XL and p38). Results: Honokiol induced apoptosis with a decreased expression of procaspase-3 and -9 and an increased expression of active caspase-3. Exposure of hepG2 cells to honokiol resulted in the downregulation of Bcl-XL and Bcl-2 expression and the release of mitochondrial cytochrome c to the cytosol. In addition, honokiol activated the p38 mitogen-activated protein kinase (MAPK) pathway, and the inhibition of this pathway by SB203580 reduced honokiol-induced apoptosis and activation of caspase-3. Conclusion: Honokiol induces apoptosis of hepG2 human hepatocellular carcinoma cells through activation of the p38 MAPK pathway, and, in turn, activation of caspase-3. [source]

    Betulin induces mitochondrial cytochrome c release associated apoptosis in human cancer cells

    MOLECULAR CARCINOGENESIS, Issue 7 2010
    Yang Li
    Abstract We examined whether betulin, a naturally abundant compound, has anticancer functions in human cancer cells. The results showed that betulin significantly inhibited cell viability in cervix carcinoma HeLa cells, hepatoma HepG2 cells, lung adenocarcinoma A549 cells, and breast cancer MCF-7 cells with IC50 values ranging from 10 to 15,µg/mL. While betulin exhibited only moderate anticancer activity in other human cancer cells such as hepatoma SK-HEP-1 cells, prostate carcinoma PC-3, and lung carcinoma NCI-H460, with IC50 values ranging from 20 to 60,µg/mL, it showed minor growth inhibition in human erythroleukemia K562 cells (IC50,>,100,µg/mL). We further investigated the mechanism of anticancer activity by betulin, using HeLa cells as an experimental model. Betulin (10,µg/mL) induces apoptotic cell death, as evidenced by morphological characteristics such as membrane phosphatidylserine translocation, nuclear condensation/fragmentation, and apoptotic body formation. A kinetics analysis showed that the depolarization of mitochondrial membrane potential and the release of mitochondrial cytochrome c occurred as early as 30,min after treatment with betulin. Betulin, unlike its chemical derivative betulinic acid, did not directly trigger mitochondrial cytochrome c release in isolated mitochondria. Importantly, Bax and Bak were rapidly translocated to the mitochondria 30,min after betulin treatment. The sequential activation of caspase-9 and caspase-3/-7 and the cleavage of poly(ADP-ribose) polymerase (PARP) were observed behind those mitochondrial events. Furthermore, specific downregulation of either caspase-9, Bax, or Bak by siRNA effectively reduced PARP cleavage and caspase-3 activation. Taken together, the lines of evidence demonstrate that betulin triggers apoptosis of human cancer cells through the intrinsic apoptotic pathway. © 2010 Wiley-Liss, Inc. [source]

    Plumbagin induces reactive oxygen species, which mediate apoptosis in human cervical cancer cells

    MOLECULAR CARCINOGENESIS, Issue 4 2004
    Priya Srinivas
    There is an emerging evidence that plumbagin (5-hydroxy-2-methyl-1, 4-naphthoquinone) may have potential as a chemotherapeutic agent. However, the growth inhibitory mechanisms of plumbagin have remained unexplored. The aim of the study was to determine whether plumbagin-induced cell death in human cervical cancer cell line, ME-180, exhibited biochemical characteristics of apoptosis and to check whether N -acetyl- l -cysteine (NAC), which is a free radical scavenger, can reverse the cytotoxic effects of plumbagin. It can be concluded from the results that plumbagin inhibits the growth of ME-180 cells in a concentration and time-dependent manner. The cytotoxic effect of plumbagin induced cell death is through the generation of reactive oxygen species (ROS) and subsequent induction of apoptosis as demonstrated by the present data. Treatment of cells with plumbagin caused loss of mitochondrial membrane potential (,,m), and morphological changes characteristic of apoptosis, such as the translocation of phosphatidyl serine, nuclear condensation, and DNA fragmentation. Moreover, plumbagin-induced apoptosis involved release of mitochondrial cytochrome c and apoptosis inducing factor (AIF), thus activation of caspase-dependent and -independent pathways, as shown by the plumbagin-mediated activation of caspase-3 and -9. Our results also show that pretreatment of ME-180 cells with NAC blocks plumbagin-induced loss of ,,m and subsequent release of cytochrome c, AIF, and caspase-9 and -3 activation, thus inhibiting the apoptotic ability of plumbagin. © 2004 Wiley-Liss, Inc. [source]

    The Effects of Ligand Exchange and Mobility on the Peroxidase Activity of a Bacterial Cytochrome c upon Unfolding

    CHEMBIOCHEM, Issue 4 2005
    Jonathan A. R. Worrall Dr.
    Abstract The effect on the heme environment upon unfolding Paracoccus versutus ferricytochrome c-550 and two site-directed variants, K99E and H118Q, has been assessed through a combination of peroxidase activity increase and one-dimensional NMR spectroscopy. At pH 4.5, the data are consistent with a low- to high-spin heme transition, with the K99E mutation resulting in a protein with increased peroxidase activity in the absence of or at low concentrations of denaturant. Furthermore, the mobility of the polypeptide chain at pH 4.5 for the wild-type protein has been monitored in the absence and presence of denaturant through heteronuclear NMR experiments. The results are discussed in terms of local stability differences between bacterial and mitochondrial cytochromes c that are inferred from peroxidase activity assays. At pH 7.0, a mixture of misligated heme states arising from protein-based ligands assigned to lysine and histidine is detected. At low denaturant concentrations, these partially unfolded misligated heme forms inhibit the peroxidase activity. Data from the K99E mutation at pH 7.0 indicate that K99 is not involved in heme misligation, whereas histidine coordination is proven by the data from the H118Q variant. [source]