ROS mediated apoptotic pathways in primary effusion lymphoma: Comment on induction of apoptosis by Shikonin through ROS-mediated intrinsic and extrinsic pathways in primary effusion lymphoma

A family of baculovirus inhibitor-of-apoptosis (IAP) genes is present in mammals, insects, and baculoviruses, but the mechanism by which they block apoptosis is unknown. We have identified a protein encoded by the Drosophila mod(mdg4) gene which bound to the baculovirus IAPs. This protein induced rapid apoptosis in insect cells, and consequently we have named it Doom. Baculovirus IAPs and P35, an inhibitor of aspartate-specific cysteine proteases, blocked Doom-induced apoptosis. The carboxyl terminus encoded by the 3' exon of the doom cDNA, which distinguishes it from other mod(mdg4) cDNAs, was responsible for induction of apoptosis and engagement of the IAPs. Doom localized to the nucleus, while the IAPs localized to the cytoplasm, but when expressed together, Doom and the IAPs both localized in the nucleus. Thus, IAPs might block apoptosis by interacting with and modifying the behavior of Doom-like proteins that reside in cellular apoptotic pathways.

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Targeting xIAP Is More Important Than Bcl-Xl in Lymphomas with Constitutive Activation of NF-kB.

Blood ◽

10.1182/blood.v108.11.2390.2390 ◽

2006 ◽

Vol 108 (11) ◽

pp. 2390-2390

Author(s):

Yanjuan He ◽

Joan Cain ◽

Lee Ratner ◽

Leon Bernal-Mizrachi

Keyword(s):

Cell Lines ◽

Annexin V ◽

Fold Increase ◽

Daudi Cell ◽

Xiap Expression ◽

Apoptotic Effect ◽

Effective Doses ◽

Induction Of Apoptosis ◽

Apoptotic Pathways

Abstract Pathways resulting in resistance to apoptosis are essential to the process of lymphomagenesis. One such pathway, the nuclear factor-kB (NFkB), has been shown to be a key element in coordinating the anti-apoptotic effect of these malignancies. However the mechanisms used by which NFkB prevents apoptosis are not well understood. It has been suggested that NFkB inhibits activation of the intrinsic, extrinsic and common apoptotic pathways. Previous work in our lab using two different virally mediated lymphoma models (Tax/HTLV1 and LMP1/EBV driven tumors) has identified two candidates that could explain these results: X chromosome-linked inhibitor of apoptosis (xIAP) and BCL-xL. Although the current literature extensively demonstrates the role of BCL-xL in lymphomas, little is known about the importance of xIAP in these malignancies. To answer this question we tested the apoptotic effect of etoposide or tumor necrosis factor (TNF) after knocking down bcl-xL and xIAP expression in our lymphoma models (SC and Daudi cell lines) using a lentivirus expressing siRNAs. After 24 hours of treatment with etoposide and TNF, we measured apoptosis by flow cytometry using double staining with Annexin V-Alexa Fluorescense and propidium iodide. Interestingly, xIAP siRNA-expressing cell lines demonstrated 2–4 fold increase in the induction of apoptosis after treatment with etoposide as compared to a nearly 2 fold increase in those expressing Bcl-xL siRNA (see Table below). No synergism was seen after treatment with TNF. Based on this finding, we then tested a novel small molecule, homolog smac, (SHC, kindly provided by Dr. PG Harren) to determine the possible therapeutic effect of xIAP inhibitors. After titration, the two most effective doses were selected (25 μM and 50 μM) to treat Daudi cell lines for 24hrs, with either etoposide or TNF. At doses of 25 μM , we observed a 2 fold increase in the induction of apoptosis produced by etoposide compared to that seen in control (DMSO + etoposide) or SHC alone and no synergism with TNF confirming the siRNA data. More importantly, at doses of 50 μM, SHC alone demonstrated activity with a 5 fold increase in apoptosis and a nearly 10 fold increase as compared to control (DMSO) when etoposide was added. Overall, we have demonstrated that xIAP and bcl-xL are important in mediating NFkB-resistance to apoptosis. However, our findings suggested that xIAP is a more potent anti-apoptotic signal and opens the door for further drug development aimed at testing xIAP-inhibitors in lymphomas. Induction of Apoptosis in xIAP or Bcl-xL siRNA expressing cell lines siRNA/Compound Etoposide TNF Untreated xIAP 43.1 ± 17.6 17.04 ± 1.4 14.3 ± 2 SC Bcl-xL 18.39± 3.7 9.4 ± 0.22 12.5 ± 2.7 Luc/DMSO 14.9 ± 1.8 14.4 ± 5.6 14.03 ± 1.25 xIAP 9.2 ± 3.2 4.7 ± 0.48 4.6 ± 0.44 Bcl-xL 8.9 ± 0.5 5.3 ± 1.7 4.16 ± 0.4 Daudi Luc/DMSO 5.49 ± 1.71 4.28 ± 0.5 6.2 ± 0.9 SHC 25 μM 20.07 ± 4.8 12.8 ± 3.9 12.1 ± 3.2 SHC 50 μM 47.7 ± 14.55 38.3 ± 0.99 32.7 ± 8.99

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Interleukin-12 p40- and Fas Ligand-Dependent Apoptotic Pathways Involving STAT-1 Phosphorylation Are Triggered during Infection with a Virulent Strain of Toxoplasma gondii

Infection and Immunity ◽

10.1128/iai.71.5.2577-2583.2003 ◽

2003 ◽

Vol 71 (5) ◽

pp. 2577-2583 ◽

Cited By ~ 25

Author(s):

L. Cristina Gavrilescu ◽

Eric Y. Denkers

Keyword(s):

Toxoplasma Gondii ◽

Fas Ligand ◽

Virulent Strain ◽

Fluorescein Isothiocyanate ◽

Interleukin 12 ◽

Caspase Inhibitor ◽

Apoptosis Induction ◽

High Virulence ◽

Induction Of Apoptosis ◽

Apoptotic Pathways

ABSTRACT Toxoplasma gondii is an opportunistic intracellular parasite. Infection with the high-virulence T. gondii strain RH induces inflammatory cytokine overproduction and uncontrolled apoptosis in lymphoid organs. Here, we show by fluorescent terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL) assay and binding of fluorescein isothiocyanate-conjugated VAD-FMK, an irreversible pan-caspase inhibitor, that parasite-triggered apoptosis occurs among CD4+, CD8+, B220+, Gr-1+, and NK1.1+ splenic populations. Caspases 8 and 9 were activated during infection, implicating cell surface death receptors and mitochondria in apoptosis. Induction of apoptosis was absent among all cell populations in both interleukin-12 (IL-12) p40- and Fas ligand (FasL)-negative mice. STAT-1 phosphorylation correlated with onset of apoptosis during infection, but in the absence of IL-12 p40 and functional FasL, activation of this transcription factor failed to occur. The results demonstrate T. gondii-induced activation of multiple apoptotic pathways, dependent upon both IL-12 p40 and FasL, that may play a role in the lethal pathology of infection.

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Highly selective fusion and accumulation of hybrid liposomes into primary effusion lymphoma cells along with induction of apoptosis

Biochemical and Biophysical Research Communications ◽

10.1016/j.bbrc.2010.02.016 ◽

2010 ◽

Vol 393 (3) ◽

pp. 445-448 ◽

Cited By ~ 6

Author(s):

Tomomi Towata ◽

Yuji Komizu ◽

Shinya Suzu ◽

Ryuichi Ueoka ◽

Seiji Okada

Keyword(s):

Primary Effusion Lymphoma ◽

Lymphoma Cells ◽

Selective Fusion ◽

Induction Of Apoptosis

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The Extracts of Artemisia absinthium L. Suppress the Growth of Hepatocellular Carcinoma Cells through Induction of Apoptosis via Endoplasmic Reticulum Stress and Mitochondrial-Dependent Pathway

Molecules ◽

10.3390/molecules24050913 ◽

2019 ◽

Vol 24 (5) ◽

pp. 913 ◽

Cited By ~ 3

Author(s):

Xianxian Wei ◽

Lijie Xia ◽

Dilinigeer Ziyayiding ◽

Qiuyan Chen ◽

Runqing Liu ◽

...

Keyword(s):

Cell Cycle ◽

Endoplasmic Reticulum ◽

Endoplasmic Reticulum Stress ◽

Antioxidant Activities ◽

Ethanol Extract ◽

Hepatoma Cells ◽

Artemisia Absinthium ◽

Induction Of Apoptosis ◽

Apoptotic Pathways ◽

Dependent Pathway

Artemisia absinthium L. has pharmaceutical and medicinal effects such as antimicrobial, antiparasitic, hepatoprotective, and antioxidant activities. Here, we prepared A. absinthium ethanol extract (AAEE) and its subfractions including petroleum ether (AAEE-Pe) and ethyl acetate (AAEE-Ea) and investigated their antitumor effect on human hepatoma BEL-7404 cells and mouse hepatoma H22 cells. The cell viability of hepatoma cells was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The apoptosis, cell cycle, mitochondrial membrane potential (Δψm), and reactive oxygen species (ROS) were analyzed by flow cytometry. The levels of proteins in the cell cycle and apoptotic pathways were detected by Western blot. AAEE, AAEE-Pe, and AAEE-Ea exhibited potent cytotoxicity for both BEL-7404 cells and H22 cells through the induction of cell apoptosis and cell cycle arrest. Moreover, AAEE, AAEE-Pe, and AAEE-Ea significantly reduced Δψm, increased the release of cytochrome c, and promoted the cleavage of caspase-3, caspase-9, and poly(ADP-ribose) polymerase (PARP) in BEL-7404 and H22 cells. AAEE, AAEE-Pe, and AAEE-Ea significantly upregulated the levels of ROS and C/EBP-homologous protein (CHOP). Further, AAEE, AAEE-Pe, and AAEE-Ea significantly inhibited tumor growth in the H22 tumor mouse model and improved the survival of tumor mice without side effects. These results suggest that AAEE, AAEE-Pe, and AAEE-Ea inhibited the growth of hepatoma cells through induction of apoptosis, which might be mediated by the endoplasmic reticulum stress and mitochondrial-dependent pathway.

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