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)

All-trans retinoic acid (tRA) and arsenic trioxide (As(2)O(3)) induce non-cross-resistant complete clinical remission in patients with acute promyelocytic leukemia with t(15;17) translocation and target PML-RARalpha, the leukemogenic protein, by different pathways suggesting a possible therapeutic synergism. To evaluate this possibility, this study examined the effect of As(2)O(3) on tRA-induced differentiation and, conversely, the effect of tRA on As(2)O(3)-induced apoptosis. As(2)O(3) at subapoptotic concentrations (0.5 microM) decreased tRA-induced differentiation in NB4 cells but synergized with atRA to induce differentiation in tRA-resistant NB4 subclones MR-2 and R4 cells as measured by nitroblue tetrazolium reduction and tRA-inducible genes (TTGII, RARbeta, RIG-E). tRA cleaved PML-RARalpha into distinct fragments in NB4 but not in tRA-resistant MR-2 or R4 cells, whereas As(2)O(3) completely degraded PML-RARalpha in all 3 cell lines. As(2)O(3)-induced apoptosis was decreased by tRA pretreatment of NB4 cells but not of R4 cells and was associated with a strong induction of Bfl-1/A1 expression, a Bcl-2 protein family member. Severe combined immunodeficient mice bearing NB4 cells showed an additive survival effect after sequential treatment, but a toxic effect was observed after simultaneous treatment with tRA and As(2)O(3). These data suggest that combined As(2)O(3) and tRA treatment may be more effective than single agents in tRA-resistant patients. Although in vitro data do not always translate to in vivo response, toxicity and potential drug antagonism may be diminished by decreasing the concentration of As(2)O(3) when given at the same time with therapeutic levels of tRA.
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PMID:Combined effect of all-trans retinoic acid and arsenic trioxide in acute promyelocytic leukemia cells in vitro and in vivo. 1113 70

Esculetin, a coumarin compound, has been shown to exhibit antioxidant and anti-inflammatory effects. In the present study, esculetin was found to inhibit the survival of human promyelocytic leukemia HL-60 cells in a concentration-dependent and time-dependent manner. HL-60 cells underwent internucleosomal DNA fragmentation and morphological changes characteristic of apoptosis after a 24-h treatment with esculetin (100 microM). Flow cytometric analysis showed that the hypodiploid nuclei of HL-60 cells were increased to 40.93% after a 36-h treatment with esculetin (100 microM). Further investigation showed that esculetin induced the release of cytochrome c from mitochondria into cytosol in a time-dependent and concentration-dependent manner. Moreover, esculetin application reduced Bcl-2 protein expression to 58% after 9 h as compared with that time at 0. Cysteine protease 32 kDa proenzyme (CPP32), a caspase 3, was activated and its substrate, poly (adenosine diphosphate-ribose) polymerase, was cleaved after a 24-h treatment of HL-60 cells with esculetin. These data suggest that esculetin induces apoptosis in human leukemia cells by increasing cytosolic translocation of cytochrome c and activation of CPP32.
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PMID:Induction of apoptosis by esculetin in human leukemia cells. 1128 9

Interactions between the cyclin-dependent kinase inhibitor (CDKI) flavopiridol (FP) and phorbol 12-myristate 13-acetate (PMA) were examined in U937 human leukemia cells in relation to differentiation and apoptosis. Simultaneous, but not sequential, exposure of U937 cells to 100 nM FP and 10 nM PMA significantly increased apoptosis manifested by characteristic morphological features, mitochondrial dysfunction, caspase activation, and poly(ADP-ribose) polymerase cleavage while markedly inhibiting cellular differentiation, as reflected by diminished plastic adherence and CD11b expression. Enhanced apoptosis in U937 cells was associated with an early caspase-independent increase in cytochrome c release and accompanied by a substantial decline in leukemic cell clonogenicity. Moreover, PMA/FP cotreatment significantly increased apoptosis in HL-60 promyelocytic leukemia cells and in U937 cells ectopically expressing the Bcl-2 protein. In U937 cells, coadministration of FP blocked PMA-induced expression and reporter activity of the CDKI p21WAF/CIP1 and triggered caspase-mediated cleavage of the CDKI p27KIP1. Coexposure to FP also resulted in a more pronounced and sustained activation of the mitogen-activated protein kinase kinase/extracellular signal-regulated protein kinase cascade after PMA treatment, although disruption of this pathway by the mitogen-activated protein kinase kinase 1 inhibitor U0126 did not prevent potentiation of apoptosis. FP accelerated PMA-mediated dephosphorylation of the retinoblastoma protein (pRb), an event followed by pRb cleavage culminating in the complete loss of underphosphorylated pRb (approximately Mr 110,000) by 24 h. Finally, gel shift analysis revealed that coadministration of FP with PMA for 8 h led to diminished E2F/pRb binding compared to the effects of PMA alone. Collectively, these findings indicate that FP modulates the expression/activity of multiple signaling and cell cycle regulatory proteins in PMA-treated leukemia cells and that such alterations are associated with mitochondrial damage and apoptosis rather than maturation. These observations also raise the possibility that combining CDKIs and differentiation-inducing agents may represent a novel antileukemic strategy.
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PMID:The cyclin-dependent kinase inhibitor (CDKI) flavopiridol disrupts phorbol 12-myristate 13-acetate-induced differentiation and CDKI expression while enhancing apoptosis in human myeloid leukemia cells. 1128 35

Multiple myeloma (MM) is a clonal B-cell malignancy characterized by slow-growing plasma cells in the bone marrow (BM). Patients with MM typically respond to initial chemotherapies; however, essentially all progress to a chemoresistant state. Factors that contribute to the chemorefractory phenotype include modulation of free radical scavenging, increased expression of drug efflux pumps, and changes in gene expression that allow escape from apoptotic signaling. Recent data indicate that arsenic trioxide (As(2)O(3)) induces remission of refractory acute promyelocytic leukemia and apoptosis of cell lines overexpressing Bcl-2 family members; therefore, it was hypothesized that chemorefractory MM cells would be sensitive to As(2)O(3). As(2)O(3) induced apoptosis in 4 human MM cell lines: 8226/S, 8226/Dox40, U266, and U266/Bcl-x(L). The addition of interleukin-6 had no effect on cell death. Glutathione (GSH) has been implicated as an inhibitor of As(2)O(3)-induced cell death either through conjugating As(2)O(3) or by sequestering reactive oxygen induced by As(2)O(3). Consistent with this possibility, increasing GSH levels with N-acetylcysteine attenuated As(2)O(3) cytotoxicity. Decreases in GSH have been associated with ascorbic acid (AA) metabolism. Clinically relevant doses of AA decreased GSH levels and potentiated As(2)O(3)-mediated cell death of all 4 MM cell lines. Similar results were obtained in freshly isolated human MM cells. In contrast, normal BM cells displayed little sensitivity to As(2)O(3) alone or in combination with AA. Together, these data suggest that As(2)O(3) and AA may be effective antineoplastic agents in refractory MM and that AA might be a useful adjuvant in GSH-sensitive therapies. (Blood. 2001;98:805-813)
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PMID:Ascorbic acid enhances arsenic trioxide-induced cytotoxicity in multiple myeloma cells. 1146 82

The biochemical properties and specificity of n-3 and n-6 polyunsaturated fatty acids (PUFAs) are not well known. Because PUFAs induce apoptosis of different cells, we studied the effect of various PUFAs, such as arachidonic acid (AA), eicosapentaenoic acid (EPA), and docosapentaenoic acid (DPA), on the fate of cultured human promyelocytic leukemia cells (HL-60) to elucidate the mechanism of apoptosis and the difference in action between n-3 and n-6 PUFAs. Fairly low concentrations of PUFAs inhibited the growth of HL-60 cells and induced their apoptosis by a mechanism that is sensitive to DMSO, an antioxidant, and z-Val-Ala-Asp(OMe)-fluoromethylketone (z-VAD-fmk), a pan-caspase inhibitor. PUFAs stimulated the generation of reactive oxygen species (ROS) and activated various types of caspase-like proteases, such as caspase-3, -6, -8, and -9, but not caspase-1. In addition, PUFAs triggered the reaction leading to the cleavage of Bid, a death agonist member of the Bcl-2 family, and also released cytochrome c from mitochondria into the cytosol. PUFAs also decreased the mitochondrial membrane potential of intact HL-60 cells. All of these actions of n-3 PUFAs were stronger than those of AA, an n-6 PUFA, although the mechanism is not known. PUFAs stimulate swelling and membrane depolarization of isolated mitochondria in a cyclosporin A-sensitive manner. The results indicated that PUFA-induced apoptosis of HL-60 cells may be caused, in part, by direct action on the cells and by activation of the caspase cascade through cytochrome c release coupled with mitochondrial membrane depolarization.
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PMID:Mechanism of apoptosis in HL-60 cells induced by n-3 and n-6 polyunsaturated fatty acids. 1154 18

Extracts of the whole herb of Artemisia asiatica Nakai (Asteraceae) have been used in traditional oriental medicine for the treatment of inflammation, cancer and other disorders. In the present work, we have evaluated the apoptosis-inducing capability of eupatilin (5,7-dihydroxy-3,4,6-trimethoxyflavone), a pharmacologically active ingredient of A. asiatica, in cultured human promyelocytic leukemia (HL-60) cells. Thus, eupatilin exhibited concentration-dependent inhibitory effects on viability and DNA synthesis capability of HL-60 cells. The anti-proliferative effect of eupatilin was attributable to its apoptosis-inducing activity as determined by characteristic nuclear condensation, in situ terminal end-labeling of fragmented DNA (TUNEL), release of mitochondrial cytochrome c into cytoplasm, proteolytic activation of caspases-9, -3, and -7, and cleavage of poly(ADP-ribose)polymerase. Eupatilin-induced HL-60 cell apoptosis does not appear to be mediated via alteration in Bcl-2/Bax-2. Taken together, the above findings suggest that eupatilin has chemopreventive and cytotoxic effects.
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PMID:Eupatilin, a pharmacologically active flavone derived from Artemisia plants, induces apoptosis in human promyelocytic leukemia cells. 1155 95

The irreversible destiny of apoptosis in its early stage might play a critical role in the apoptosis of human acute promyelocytic leukemia (APL) cell line induced by all-trans retinoic acid (ATRA). To characterize protein alterations during the apoptosis-initiation phase and to understand the metabolic status at that time, we investigated the protein profiles in the apoptosis-initiation phase of APL cell line HL-60 by proteomic analysis. ATRA-withdrawal was conducted to demonstrate that there was committed initiation phase of apoptosis triggered by 10(-6) M ATRA at day 3. Only after that time point, ATRA-treated cells irreversibly went to apoptosis. Also at that time point, the positive regulators of apoptosis such as STAT3 increased at protein level, whereas negative regulators (Bcl-2 and p-STAT3) decreased. In addition, caspase-3 also increased after that time. Furthermore, comparative proteomic analysis was utilized to examine the protein expression profiles during the initiation stage of apoptosis. Our results showed 12 upregulated and 7 downregulated proteins experiencing twofold alteration, including key regulators of signal transduction such as G-proteins and nucleic receptors, proteins related with metabolism, oxidation and reduction, proteins associated with the nucleus and cytoskeleton-related proteins. Some of them could be positive modulators to trigger apoptosis, whereas others could contribute to intracellular defense against apoptosis induced by exogenous triggers. The results above suggest that there is a subtle balance between apoptosis and the intracellular defense against apoptosis. Once the balance is disturbed, cells would irreversibly initiate to undergo the execution of apoptosis.
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PMID:Proteomic analysis of apoptosis initiation induced by all-trans retinoic acid in human acute promyelocytic leukemia cells. 1156 97

Cytotoxic effects of six isoflavonoids, tectorigenin, glycitein, tectoridin, glycitin, 6''-O-xylosyltectoridin, and 6''-O-xylosylglycitin isolated from the flower of Pueraria thunbergiana Benth. together with genistein, a known differentiation and apoptosis inducer, were examined. Among these isoflavonoids, tectorigenin and genistein exhibited cytotoxicity against various human cancer cells; glycitein showed only mild cytotoxicity. These results suggest that the isoflavone structure and 5-hydroxyl group are crucial for the cytotoxic properties and that glycosides are inactive. Moreover, tectorigenin induced differentiation of human promyelocytic leukemia HL-60 cells to granulocytes and monocytes/macrophages, and caused apoptotic changes of DNA in the cells, as did genistein. Tectorigenin also inhibited autophosphorylation of epidermal growth factor (EGF) receptor by EGF and decreased the expression of Bcl-2 protein, with less activity than genistein. From these results, tectorigenin may be a possible therapeutic agent for leukemia.
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PMID:Tectorigenin, an isoflavone of Pueraria thunbergiana Benth., induces differentiation and apoptosis in human promyelocytic leukemia HL-60 cells. 1164 14

We studied the effect of DW2282-,[(S)-(+)-4-phenyl-1-[N-(4-aminobenzoyl)-indoline-5-sulfonyl-4,5-dihydro-2-imidazolone].hydrochloride], a newly developed anti-cancer agent, on cell proliferation, cell cycle progression, and induction of apoptosis in human promyelocytic leukemia (HL-60) cells. DW2282, a diarylsulfonylurea compound, was cytotoxic to HL-60 cells, with an IC(50) of 1.0 microg/mL. Treatment with DW2282 fragmented DNA in a concentration- and time-dependent manner, suggesting that these cells underwent apoptosis. Flow cytometric analysis further confirmed that DW2282-treated HL-60 cells were hypodiploid, in terms of DNA content, and were arrested at the G(2)/M phase. The cell cycle arrest was reversible upon the removal of DW2282. HL-60 cells also underwent distinct morphological changes in response to DW2282 treatment, including the appearance of elongated cells with conical tails and other apoptotic characteristics. G(2)/M phase cell cycle arrest was accompanied by a decrease in the levels of cdc2, a protein that plays a critical role for progression through the G(2)/M phase. Treatment of HL-60 cells with DW2282 was also associated with decreased levels of the anti-apoptotic protein Bcl-2, activation of caspase-3, and proteolytic cleavage of poly(ADP-ribose) polymerase. Taken together, these results demonstrate that DW2282 dramatically suppressed HL-60 cell growth by inducing apoptosis after G(2)/M phase arrest. These findings are consistent with the possibility that G(2)/M phase arrest was mediated by the down-regulation of cdc2 levels in HL-60 cells. The data also suggest that DW2282 triggered apoptosis by decreasing Bcl-2 levels and activating caspase-3 protease. These results provide important new information towards understanding the mechanisms by which DW2282 and other diarylsulfonylureas mediate their therapeutic effects.
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PMID:Induction of G(2)/M phase arrest and apoptosis by a new synthetic anti-cancer agent, DW2282, in promyelocytic leukemia (HL-60) cells. 1172 80

Treatment of APL with ATRA or As2O3 alone or in combination with chemotherapy yields a complete remission as high as 85%-95%, but their mechanisms of action remain unclear. The mechanisms of action underlying ATRA treatment are (1) relocalization of the PML restoration of normal structure of nuclear bodies and degradation of PML-RAR alpha protein via caspase-mediated cleavage and proteosome-dependent degradation; (2) conversion of PML-RAR alpha from a transcription repressor (CoR) to a transcription activator (CoA) under therapeutic concentration of ATRA (3) coordinated genes expression induced by ATRA resulting in an elegant and intricate cellular program for the commitment to differentiation. 169 genes were modulated to express, with 100 genes up-regulated and 69 down-regulated. As2O3 exerts its action by dual dose-dependent manner. At higher concentration (1-2 microns/l), it induces apoptosis of the leukemic cells associated with disruption of mitochondrial membrane potential, elevation of caspase-3 and other caspases activity and decline of Bcl-2 expression. At lower concentration (0.1-0.5 micron/l), it triggers differentiation with elevation of CD11b expression accompanied by morphologically partial differentiation. At both concentrations, As2O3 causes degradation of PML-RAR alpha protein implicated probably in its mechanisms of action.
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PMID:Mechanism of action of all-trans retinoic acid and arsenic trioxide in the treatment of acute promyelocytic leukemia. 1189 Jan 9


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