Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P10415 (Bcl-2)
 33,771 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Gemtuzumab ozogamicin (Mylotarg) is an immunoconjugate composed of a recombinant humanized murine anti-CD33 antibody linked to calicheamicin, a potent cytotoxic agent. The aim of this review is to summarize ongoing trials with gemtuzumab ozogamicin in combination with chemotherapy in acute myeloid leukemia (AML) patients. The studies include determination of safety and efficacy of gemtuzumab ozogamicin in combination with chemotherapy in previously untreated as well as relapsed and refractory AML patients. These studies also determine gemtuzumab ozogamicin's activity in patients with other CD33+ neoplastic diseases such as myelodysplastic syndrome, acute promyelocytic leukemia, chronic myeloid leukemia, and certain subsets of acute lymphocytic leukemia. Moreover, trials are exploring the use of gemtuzumab ozogamicin with novel targeted agents such as Bcl-2 antisense molecules. Gemtuzumab ozogamicin is associated with an acceptable toxicity profile as a single agent; however, the incidence of veno-occlusive disease remains a concern with the use of gemtuzumab ozogamicin in combination with chemotherapy.
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PMID:Trials with gemtuzumab ozogamicin (Mylotarg) combined with chemotherapy regimens in acute myeloid leukemia. 1197 Jul 67

Arsenic trioxide (As2O3) can induce clinical remission in patients with acute promyelocytic leukemia (APL) through induction of apoptosis. To investigate the potential therapeutic usage of As2O3 in cervical cancer and its possible mechanisms, human cervical cancer cell line HeLa was employed. The cells underwent apoptosis in response to As2O3, accompanied by a decrease of mitochondrial membrane potential and caspase-3 activation. Overexpression of Bcl-2, however, prevented the dissipation of mitochondrial membrane potential, subsequently protecting the cells from As2O3-induced apoptosis. As2O3 increased cellular content of reactive oxygen species (ROS), especially hydrogen peroxide (H2O2), and the antioxidant N-acetyl-L-cysteine completely suppressed As2O3-induced apoptosis. Furthermore, incubation of the cells with catalase resulted in significant suppression of As2O3-induced apoptosis. The above results indicate that the induction of HeLa cell apoptosis by As2O3 involved an early decrease in cellular mitochondrial membrane potential and increase in ROS content, predominantly H2O2, followed by caspase-3 activation and DNA fragmentation.
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PMID:Arsenic trioxide induces apoptosis through a reactive oxygen species-dependent pathway and loss of mitochondrial membrane potential in HeLa cells. 1206 50

Arsenic trioxide has recently been shown to inhibit growth and induce apoptosis in acute promyelocytic leukemia (APL), but little is known about the molecular mechanisms mediating these effects. In the present study, we determined the molecular pathways that lead to apoptosis after treatment of cells with arsenic trioxide. Arsenic trioxide treatment of U937 cells leads to apoptosis, which is accompanied by activation of caspase 3 (as measured by decreased levels of the 32 kDa inactive form and increased proteolytic cleavage of PLC-gamma1). The broad-range caspase inhibitor z-VAD-fmk inhibits this induction of apoptosis, supporting a direct link between caspase activation and arsenic trioxide induction of apoptosis. This activation of apoptosis is accompanied by release of cytochrome c, down-regulation of cIAP1, and inactivation of Akt. Bcl-2 overexpression attenuates arsenic trioxide-induced apoptosis in U937 cells by inhibition of caspase 3 activity, but not inhibition of Akt. In addition, arsenic trioxide-induced apoptosis was caused by the generation of reactive oxygen species, which was prevented by antioxidant NAC (N-acetyl-cysteine). Co-treatment with NAC markedly prevented dephosphorylation of Akt, activation of caspase 3, and down-regulation of cIAP1. These data indicate that arsenic trioxide can cause cell damage by inactivating the Akt-related cell survival pathway and generating the reactive oxygen species, providing a new mechanism for arsenic trioxide-induced apoptosis.
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PMID:Arsenic trioxide-induced apoptosis in U937 cells involve generation of reactive oxygen species and inhibition of Akt. 1216 6

We studied the effect of momordin I, a compound purified from a plant, Ampelopsis japonica, on cell proliferation and induction of apoptosis in human promyelocytic leukemia (HL-60) cells. Momordin I was cytotoxic to HL-60 cells with an IC50 of 19.0 microg/ml. The antiproliferative effects of momordin I appear to be attributable to its induction of apoptotic cell death, as momordin I induced nuclear morphology changes and internucleosomal DNA fragmentation and it increased the proportion of hypodiploid cells. Momordin I treatment also gradually decreased the expression of.the anti-apoptotic protein Bcl-2, but increased the expression of the pro-apoptotic protein Bax. In addition, momordin I treatment increased the activation of caspase-3 and cleavage of poly (ADP-ribose) polymerase. In this study we showed that momordin I induced apoptosis of HL-60 cells by reduction of the Bcl-2:Bax ratio and by activation of caspase-3. These results provide important information towards understanding the mechanism by which momordin I induces apoptosis.
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PMID:Induction of apoptosis by momordin I in promyelocytic leukemia (HL-60) cells. 1216 88

Arsenic trioxide (As(2)O(3)) has been found to induce apoptosis in leukemia cell lines and clinical remissions in patients with acute promyelocytic leukemia. In this study, we investigated the cytotoxic effect and mechanisms of action of As(2)O(3) in human tumor cell lines. As(2)O(3) caused inhibition of cell growth (IC(50) range, 3-14 microM) in a variety of human solid tumor cell lines, including four human non-small-cell lung cancer cell lines (H460, H322, H520, H661), two ovarian cancer cell lines (SK-OV-03, A2780), cervical cancer HeLa, and breast carcinoma MCF-7, as assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Flow cytometry analysis showed that As(2)O(3) treatment resulted in a time-dependent accumulation of cells in the G(2)/M phase. We observed, using Wright-Giemsa and 4',6-diamidine-2-phenylindole-dihydrochloride staining, that As(2)O(3) blocked the cell cycle in mitosis. In vitro examination revealed that As(2)O(3) markedly promoted tubulin polymerization without affecting GTP binding to beta-tubulin. Immunocytochemical and EM studies of treated MCF-7 cells showed that As(2)O(3) treatment caused changes in the cellular microtubule network and formation of polymerized microtubules. Similar to most anti-tubulin agents, As(2)O(3) treatment induced up-regulation of the cyclin B1 levels and activation of p34(cdc2)/cyclinB1 kinase, as well as Bcl-2 phosphorylation. Furthermore, activation of caspase-3 and -7 and cleavage of poly(ADP-ribose) polymerase and beta-catenin occurred only in As(2)O(3)-induced mitotic cells, not in interphase cells, suggesting that As(2)O(3)-induced mitotic arrest may be a requirement for the activation of apoptotic pathways. In addition, As(2)O(3) exhibited similar inhibitory effects against parental MCF-7, P-glycoprotein-overexpressing MCF-7/doxorubicin cells, and multidrug resistance protein (MRP)-expressing MCF-7/etoposide cells (resistance indices, 2.3 and 1.9, respectively). Similarly, As(2)O(3) had similar inhibitory effect against parental ovarian carcinoma A2780 cells and tubulin mutation paclitaxel-resistant cell lines PTx10 and PTx22 (resistance indices, 0.86 and 0.93, respectively), suggesting that its effect on tubulin polymerization and G(2)/M phase arrest is distinct from that of paclitaxel. Taken together, our data demonstrate that As(2)O(3) has a paclitaxel-like effect, markedly promotes tubulin polymerization, arrests cell cycle at mitosis, and induces apoptosis. In addition, As(2)O(3) is a poor substrate for transport by P-glycoprotein and MRP, and non-cross-resistant with paclitaxel resistant cell lines due to tubulin mutation, suggesting that As(2)O(3) may be useful for treatment of human solid tumors, particularly in patients with paclitaxel resistance.
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PMID:Arsenic trioxide produces polymerization of microtubules and mitotic arrest before apoptosis in human tumor cell lines. 1218 29

The effects of the PKC activator and down-regulator bryostatin 1 and the PKC and Chk1 inhibitor 7-hydroxystaurosporine (UCN-01) were compared with respect to potentiation of 1-beta-D-arabinofuranosylcytosine (ara-C)-induced apoptosis in human myelomonocytic leukemia cells (U937). Whereas bryostatin 1 and UCN-01 both markedly enhanced ara-C-induced mitochondrial injury (e.g., cytochrome c and Smac/DIABLO release, loss of mitochondrial membrane potential), caspase activation, and apoptosis, ectopic expression of an N-terminal loop-deleted Bcl-2 mutant protein protected cells from ara-C/UCN-01- but not ara-C/bryostatin 1-mediated lethality. Conversely, ectopic expression of CrmA or dominant-negative caspase-8 abrogated potentiation of ara-C-mediated apoptosis by bryostatin 1 but not by UCN-01. Exposure of cells to ara-C and bryostatin 1 (but not UCN-01) resulted in sustained release of tumor necrosis factor (TNF) alpha; moreover, potentiation of ara-C lethality by bryostatin 1 (but not by UCN-01) was reversed by coadministration of TNF soluble receptors or the selective PKC inhibitor bisindolylmaleimide (1 microM). Finally, similar events were observed in the human promyelocytic leukemia cell line HL-60. Together, these findings suggest that potentiation of ara-C lethality in human myeloid leukemia cells by bryostatin 1 but not UCN-01 involves activation of the extrinsic, receptor-mediated apoptotic pathway, and represents a consequence of bryostatin 1-mediated release of TNF-alpha. They also argue that the mechanism by which bryostatin 1 promotes ara-C-induced mitochondrial injury, caspase activation, and apoptosis involves factors other than or in addition to PKC down-regulation or modulation of Bcl-2 phosphorylation status.
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PMID:Bryostatin 1 and UCN-01 potentiate 1-beta-D-arabinofuranosylcytosine-induced apoptosis in human myeloid leukemia cells through disparate mechanisms. 1248 56

We studied the mechanism of the cytotoxic effects of 5-aminolevulinic acid-based photodynamic therapy (ALA-PDT; induction with 1 mM ALA for 4 h followed by a blue light dose of 18 J/cm(2)) on the human promyelocytic leukemia cell line HL60 using biochemical and electron microscopy methods. The disruption of mitochondrial membrane potential, deltapsi(m), was paralleled by a decrease in ATP level, unmasking of the mitochondrial antigen 7A6, release of cytochrome c into the cytoplasm, activation of caspases 9 and 3 and cleavage of poly(ADP-ribose) polymerase (PARP). This was followed by DNA fragmentation. These data suggest that ALA-PDT activates the mitochondrial apoptotic pathway. The level of endoplasmic reticulum Ca(2+)-binding chaperones ERp57 and ERp72 and of anti-apoptotic proteins Bcl-2 and Bcl-x(L) was decreased whereas that of Ca(2+)-binding protein calmodulin and the stress protein HSP60 was elevated following ALA-PDT. Inhibition of the initiator caspase 9, execution caspase 3 and Ca(2+)-dependent protease m-calpain, did not prevent DNA fragmentation. We conclude that, in our in vitro model, ALA-based photodynamic treatment initiates several signaling processes in HL60 cells that lead to rapidly progressing apoptosis, which is followed by slow necrosis. Two apoptotic processes proceed in parallel, one representing the mitochondrial pathway, the other involving disruption of calcium homeostasis and activation of the endoplasmic reticulum stress-mediated pathway.
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PMID:Mitochondrial and endoplasmic reticulum stress-induced apoptotic pathways are activated by 5-aminolevulinic acid-based photodynamic therapy in HL60 leukemia cells. 1263 80

Recently, it was suggested the potential role of gamma-tocopheryl quinone (gamma-TQ), an oxidative metabolite of gamma-tocopherol, as a powerful chemotherapeutic agent, since it was shown that this molecule exerts powerful cytotoxic effects, induces apoptosis and escapes drug resistance in human acute lymphoblastic leukemia and promyelocytic leukemia cells. We have studied the apoptogenic potential of gamma-TQ in cultured human leukemia HL-60 and colon adenocarcinoma WiDr cells, and in murine thymoma cells growing in vivo in ascites form. The cells were treated with gamma-TQ and apoptosis was evaluated morphologically by acridine-orange staining and cytofluorimetrically by Annexin V binding assay. gamma-TQ-induced apoptosis in a dose- and time-dependent manner in all the cell types tested, although HL-60 and thymoma cells were much more sensitive than WiDr cells. In HL-60 cells apoptosis was mediated by the activation of the caspase-3 cascade. In particular, we observed a time- and dose-dependent increase in the activities of the upstream caspase-9 and caspase-8 and of the downstream caspase-3. The activation of caspase-9 preceded that of caspase-8 and its specific inhibition completely prevented apoptosis. These findings and data showing the precocious release of cytochrome c from mitochondria, a decrease in Bcl-2, and a change in mitochondrial transmembrane potential (Delta psi(m)), all suggest that the intrinsic mitochondrial pathway is primarily involved in the development of gamma-TQ-induced apoptosis. The late activation of caspase-8 and data showing the partial cleavage of pro-apoptotic protein BID suggest that the initial activation of caspase-9 may be potentiated by a feedback amplification loop involving the caspase-8/BID pathway.
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PMID:gamma-Tocopheryl quinone induces apoptosis in cancer cells via caspase-9 activation and cytochrome c release. 1266 1

Mitochondria plays a central role in apoptotic cell death. The intermembrane space of mitochondria contains a number of soluble molecules whose release from the organelle to the cytosol or the nucleus induces cell death. Thus, molecules that directly trigger mitochondria membrane permeabilisation are efficient cytotoxic drugs. Mitochondria is one of the cellular targets for commonly used epipodophyllotoxins, adenine deoxynucleoside analogs and taxanes as well as recently developped agents such as the pentacyclic triterpene betulinic acid and the lymphotoxic agent FTY720. Most informations on anthracyclines point to the mitochondrial membrane as the main target of cardiotoxicity. Mitochondria is also a target for arsenite trioxide, an old cytotoxic agent recently used for treating acute promyelocytic leukemia, lonidamine, a dichlorinated derivative of indazole-3-carboxylic acid developped as a chemosensitizer, the retinoic acid receptor gamma activator CD437 and nitric oxide (NO). Recently, cytotoxic drugs have been specifically designed to directly affect the mitochondrial function. These include the positively charged alpha-helical peptides, which are attracted to and disrupt the negatively charged mitochondrial membrane, thus inducing mammalian cell apoptosis when targeted intracellularly. Various strategies have been proposed also to directly inhibit Bcl-2 and related anti-apoptotic proteins, including antisense oligonucleotides (e.g. Genasense, currently tested in phase III trials), small molecules that mimic the BH3 dimerization domain of these proteins and kinase inhibitors. Ligands of the mitochondrial benzodiazepine receptor such as the isoquinolone carboxamide derivative PK11195 also overcome the membrane-stabilizing effect of Bcl-2, whereas the adenosine nucleotide translocator (ANT) and the mitochondrial DNA are two other potential cellular targets for cytotoxic agents. Potentially, new compounds directly targeting the mitochondria may be useful in treating hematological malignancies. The challenge is now to selectively target these mitochondria permeabilizing agents to malignant cells. This review briefly summarizes the role of the mitochondria in cell death and describes these various strategies for targeting the mitochondria to induce apoptosis.
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PMID:Mitochondria as a target for inducing death of malignant hematopoietic cells. 1276 32

Arsenic trioxide (As(2)O(3)) has been used successfully in the treatment of acute promyelocytic leukemia. However, effects of As(2)O(3) in normal peripheral blood T cells have not been studied in detail. The purpose of this study was to investigate whether As(2)O(3) would induce apoptosis in normal T cells and therefore may have immunosuppressive side effects. Apoptosis was measured by terminal deoxynucleotidyl transferase-mediated nick end labeling assay, caspase activation by flow cytometry and colorimetric assay, mitochondrial transmembrane potential (deltapsi(m)), intracellular reactive oxygen species (ROS), and intracellular reduced glutathione (GSH) by flow cytometry. The release of cytochrome c and apoptosis-inducing factor (AIF) from the mitochondria was measured by confocal microscopy, and the expression of molecules regulating apoptosis was measured by Western blotting. As(2)O(3), at clinically achievable therapeutic concentrations, induces apoptosis in peripheral blood T cells. As(2)O(3)-induced apoptosis was associated with reduced deltapsi(m), enhanced generation of intracellular ROS, decreased levels of intracellular GSH, release of cytochrome c and AIF from the mitochondria, activation of caspases, down-regulation of Bcl-2 and Bcl-x(L), and up-regulation of Bax expression. In addition, exogenous GSH protected lymphocytes from As(2)O(3)-induced apoptosis. Furthermore, overexpression of Bcl-2 inhibited As(2)O(3)-induced apoptosis and blocked depolarization of deltapsi(m), generation of ROS, and release of both cytochrome c and AIF. These data indicate that As(2)O(3) induces apoptosis in T cells by enhancing oxidative stress and that Bcl-2 appears to play a major role in As(2)O(3)-induced apoptosis.
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PMID:Arsenic trioxide induces apoptosis in peripheral blood T lymphocyte subsets by inducing oxidative stress: a role of Bcl-2. 1293 60


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