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NEOPLASIA
From the Division of Clinical and Translational
Research, Sylvester Comprehensive Cancer Center, and Department of
Medicine, University of Miami School of Medicine, Miami, FL.
In present studies, treatment with tumor necrosis factor
(TNF)-related apoptosis inducing ligand (TRAIL, also known as Apo-2 ligand [Apo-2L]) is shown to induce apoptosis of the human acute leukemia HL-60, U937, and Jurkat cells in a dose-dependent manner, with
the maximum effect seen following treatment of Jurkat cells with 0.25 µg/mL of Apo-2L (95.0% ± 3.5% of apoptotic cells).
Susceptibility of these acute leukemia cell types, which are known to
lack p53wt function, did not appear to correlate with the
levels of the apoptosis-signaling death receptors (DRs) of Apo-2L, ie,
DR4 and DR5; decoy receptors (DcR1 and 2); FLAME-1
(cFLIP); or proteins in the inhibitors of apoptosis proteins
(IAP) family. Apo-2L-induced apoptosis was associated with the
processing of caspase-8, Bid, and the cytosolic accumulation of
cytochrome c as well as the processing of caspase-9 and
caspase-3. Apo-2L-induced apoptosis was significantly inhibited in
HL-60 cells that overexpressed Bcl-2 or Bcl-xL.
Cotreatment with either a caspase-8 or a caspase-9 inhibitor suppressed
Apo-2L-induced apoptosis. Treatment of human leukemic cells with
etoposide, Ara-C, or doxorubicin increased DR5 but not DR4, Fas, DcR1,
DcR2, Fas ligand, or Apo-2L levels. Importantly, sequential treatment
of HL-60 cells with etoposide, Ara-C, or doxorubicin followed by Apo-2L
induced significantly more apoptosis than treatment with Apo-2L,
etoposide, doxorubicin, or Ara-C alone, or cotreatment with Apo-2L and
the antileukemic drugs, or treatment with the reverse sequence of
Apo-2L followed by one of the antileukemic drugs. These findings
indicate that treatment with etoposide, Ara-C, or doxorubicin
up-regulates DR5 levels in a p53-independent manner and sensitizes
human acute leukemia cells to Apo-2L-induced apoptosis.
(Blood. 2000;96:3900-3906) Tumor necrosis factor (TNF)-related
apoptosis-inducing ligand (TRAIL), also called Apo-2 ligand (Apo-2L),
is a member of the TNF family, which has been shown to induce apoptosis
of a variety of tumor cell lines more efficiently than normal
cells.1-3 While in a recent report, TRAIL was demonstrated
to induce apoptosis of human hepatocytes, it has also been shown to
actively suppress human mammary adenocarcinoma growth in mice without
any significant toxic effects, which are seen with the in vivo use of
TNF and Fas ligand (CD95L).3,4 Apo-2L can bind to several
members of the TNF receptor family, ie, death receptors (DRs) 4 and 5, decoy receptors (DcRs) 1 and 2, and osteoprotegerin.1 DR4
and DR5 contain a cytoplasmic region consisting of a stretch of 80 amino acids, designated the death domain (DD), responsible for transducing the death signal.1 Ligation by Apo-2L recruits the adaptor molecule FADD to the DD of DR4 and
DR5.5 Through its death effector domain, FADD interacts
with caspase-8 and caspase-10.5,6 Although
FADD There are several known determinants of Apo-2L-induced apoptotic
signaling. Treatment with DNA-damaging anticancer agents can induce p53
and/or NFkB, which, in turn, can up-regulate DR5 and/or DR4
expression, thereby enhancing Apo-2L-induced apoptotic signaling.17,18 In contrast, DcR1, which is bound to the
cell membrane through a glycolipid anchor and lacks DD, and the levels of DcR2, which has an incomplete and inactive DD, bind and titrate down
Apo-2L and can act as inhibitors of Apo-2L-induced
apoptosis.1 Additionally, an endogenous
intracellular protein, FLAME-1 (also known as cFLIP, CASH,
CLARP, MRIT, I-FLICE, and Usurpin), which has an N-terminus FADD
homology and C-terminus caspase homology domains without caspase
activity, has a dominant-negative effect against caspase-8 and
caspase-10 and can potentially inhibit Apo-2L-induced death
signaling.19 Finally, the levels of inhibitors of
apoptosis proteins (IAP) family members, which include cIAP1, cIAP2,
XIAP, and survivin, may also inhibit Apo-2L-induced apoptosis by
specifically binding to and inhibiting the activities of caspase-3,
caspase-9, and caspase-7.20-22 Although the ability of
Apo-2L to induce apoptosis has been examined in a variety of human
tumor cell types, the molecular steps of Apo-2L-induced apoptosis and
its determinants have not been comprehensively evaluated in the human
acute leukemia cells.
Etoposide, Ara-C, and doxorubicin are highly active antileukemic
drugs.23 Intracellularly, following their interaction with DNA, these drugs ultimately cause DNA damage and cell-cycle
arrest.24 By, as yet, undefined signal(s), this
drug-induced DNA-damage and/or cell-cycle perturbation triggers the
mitochondrial Reagents
Cell culture
Preparation of S-100 fraction and Western analysis of cytosolic cytochrome c Untreated and drug-treated cells were harvested by centrifugation at 1000g for 10 minutes at 4°C. The cell pellets were washed once with ice-cold phosphate-buffered saline (PBS) and resuspended with 5 vol buffer (20 mmol/L Hepes-KOH, pH 7.5, 10 mmol/L KCl, 1.5 mmol/L MgCl2, 1 mmol/L sodium EDTA, 1 mmol/L sodium EGTA [ethylene glycol-bis {B-amino ethyl ether} N,N,N',N-tetra acetic acid], 1 mmol/L dithiothreitol, and 0.1 mmol/L phenylmethylsulfonyl fluoride), containing 250 mmol/L sucrose. The cells were homogenized with a 22-gauge needle, and the homogenates were centrifuged at 100 000g for 30 minutes at 4°C (S-100 fraction).12,30 The supernatants were collected, and the protein concentrations of S-100 were determined by the Bradford method (Bio-Rad, Hercules, CA). We used 20 to 30 µg of the S-100 fraction for Western blot analysis of cyt c, as described previously.31,32Western analyses of proteins Western analyses of DR4, DR5, Apo-2L, caspase-8, caspase-9, caspase-3, Fas R, Fas L, Bid, PARP, XIAP, cIAP, survivin, and -actin
were performed with the use of specific antiserums or monoclonal
antibodies according to previously reported
protocols.31,32 Horizontal scanning densitometry was
performed on Western blots by acquisition into Adobe PhotoShop (Apple,
Cupertino, CA) and analysis by the NIH Image Program (US National
Institutes of Health, Bethesda, MD). The expression of -actin was
used as a control.
Apoptosis assessment by Annexin-V staining After drug treatments, cells were resuspended in 100 µL staining solution (containing Annexin-V fluorescein and propidium iodide Annexin-V-FLUOS Staining Kit buffer, Boehringer Mannheim). Following incubation at room temperature for 15 minutes, cells were analyzed by flow cytometry.29 Annexin V binds to cells that express phosphotidylserine on the outer layer of the cell membrane, and propidium iodide stains the cellular DNA of cells with a compromised cell membrane. This allows for the discrimination of live cells (unstained with either fluorochrome) from apoptotic cells (stained only with Annexin V) and necrotic cells (stained with both Annexin V and propidium iodide).33Morphology of apoptotic cells After drug treatment, 50 × 103 cells were washed with PBS (pH 7.3) and resuspended in the same buffer. Cytospin preparations of the cell suspensions were fixed and stained with Wright stain. Cell morphology was determined by light microscopy. In all, 5 different fields were randomly selected for counting of at least 500 cells. The percentage of apoptotic cells was calculated for each experiment, as described previously.34Statistical analysis Significant differences between values obtained in a population of leukemic cells treated with different experimental conditions were determined by paired t-test analyses. A one-way analysis of variance was also applied to the results of the various treatment groups, and post hoc analysis was performed by means of the Bonferroni correction method.
Apo-2L induces apoptosis of human acute leukemia, HL-60, U937, and Jurkat cells Although Apo-2L has been reported to induce apoptosis of a variety of tumor cell types,3,4 the sensitivity of human acute leukemia cells to Apo-2L-induced apoptosis and its molecular determinants had not been comprehensively determined. The results of present studies (Figure 1A) demonstrate that exposure to Apo-2L for 24 hours induced a dose-dependent increase in apoptosis of the cultured acute leukemia HL-60, U937, and Jurkat cells, as determined by Annexin V staining followed by flow cytometry. This was confirmed by light-microscopic morphologic examination of the Wright-stained, cytospun, Apo-2L-treated cells (data not shown). Jurkat cells demonstrated the highest sensitivity: exposure to 250 ng/mL of Apo-2L induced apoptosis of 95.0% ± 3.5% of the cells. Treatment with 100 ng/mL of Apo-2L also produced significantly more apoptosis of Jurkat, followed by HL-60 and U937 cells (P < .01). As shown in Figure 1B, treatment of Jurkat cells with Apo-2L was associated with the processing of caspase-8 and Bid, as well as the cytosolic accumulation of cyt c. Exposure to Apo-2L also resulted in the processing of caspase-9 and caspase-3 and down-regulation of XIAP. In these immunoblots, with the commercially available antibodies, we have not been able to uniformly detect the cleaved fragments of the processed pro-forms of caspase-8, caspase-9, and caspase-3. With processing, the levels of the pro-forms decline, as shown in the immunoblots. These effects were more pronounced after treatment of Jurkat cells with 100 ng/mL Apo-2L, as compared with 10 ng/mL (Figure 1B). Exposure to Apo-2L also induced similar molecular events in HL-60 and U937 cells (data not shown). Thus, in the acute leukemia cells, Apo-2L also triggered the intrinsic pathway of apoptosis. Some but not all previous reports had shown a positive correlation of the sensitivity to Apo-2L with the expression of DR4 and DR5, or with the intracellular levels of FLAME-1.3,4,27,28 In contrast, as also previously reported for other cell types,3,18,27 data presented in Figure 1C do not show such a correlation in the leukemic cells. As compared with other cell types, Jurkat cells, which demonstrated the highest sensitivity to Apo-2L, expressed higher levels of DR5, but lacked the expression of DR4 (Figure 1C). Inconsistent with their increased sensitivity to Apo-2L, Jurkat cells expressed more DcR2 and FLAME-1 (I-FLICE) although their survivin levels were the lowest of the 3 cell types (Figure 1C). All cell types expressed barely detectable levels of DcR1 (data not shown).
Apo-2L-induced apoptosis of leukemic cells was inhibited by overexpression of Bcl-2 or Bcl-xL We examined the effect of Bcl-2 or Bcl-xL overexpression on Apo-2L-induced apoptosis of HL-60 cells. As compared with HL-60/neo cells, HL-60/Bcl-2 and HL-60/Bcl-xL cells possess approximately 3-fold higher levels of Bcl-2 and 5-fold higher levels of Bcl-xL, respectively (Figure 2B).35 Exposure to 100 ng/mL of Apo-2L induced apoptosis of 37.0% ± 2.0% of HL-60/neo cells. However, Apo-2L-induced apoptosis was suppressed in HL-60/Bcl-2 and HL-60/Bcl-xL cells (Figure 2A). This supported the observation that, in HL-60 cells, Apo-2L triggered the intrinsic pathway of apoptosis. This conclusion was further supported by the finding that cotreatment with the relatively specific caspase-9 inhibitor z-LEHD-fmk was as effective as the caspase-8 inhibitor z-IETD-fmk in suppressing Apo-2L-induced apoptosis of HL-60 cells (Figure 2C).
Etoposide-, Ara-C-, or doxorubicin-induced apoptosis is associated with up-regulation of DR5 but not DR4, Fas, or DcR1 and DcR2 Etoposide, Ara-C, and doxorubicin are commonly used antileukemic drugs. With the goal of preclinically investigating the antileukemic activity of novel combinations of Apo-2L with relatively high but clinically deliverable doses of etoposide, Ara-C, or doxorubicin, we first determined the sensitivity and molecular cascade of apoptosis triggered by these drugs in HL-60, U937, and Jurkat cells. Figure 3A clearly demonstrates that high but clinically achievable and relevant doses of etoposide, Ara-C, and doxorubicin induced apoptosis of approximately 30% to 75% of the leukemic cells. As also previously reported by us,35,36 these drugs triggered the intrinsic pathway of apoptosis by inducing the cytosolic accumulation of cyt c as well as the processing of caspase-9 and caspase-3 (Figure 3B). Treatment with etoposide, Ara-C, and doxorubicin (not shown) was also associated with down-regulation of XIAP and survivin levels (Figure 3C). XIAP has been previously reported to be processed during Fas-mediated apoptosis,37 while survivin expression is cell-cycle phase-dependent and is down-regulated during the nonmitotic phases.38 Importantly, treatment with etoposide, Ara-C, or doxorubicin induced DR5 levels in HL-60 and Jurkat cells (Figure 4A). This was also observed to a lesser extent in U937 cells (data not shown). In contrast, DcR2, Apo-2L, FasL, and Fas levels remained unaffected (Figure 4A). In all cell lines, DcR1 levels were barely detectable (data not shown). Figure 4B-C shows that exposure of HL-60 cells to 1.0 µmol/L or higher Ara-C for 6 hours or longer was necessary to produce an increase in DR5 levels. Lower levels and shorter exposure intervals to Ara-C did not increase DR5 levels in any cell type (data not shown). Although not shown, treatment with Ara-C, while markedly increasing DR5, reduced DR4 levels in HL-60 cells. This was not observed in the other cell types, which express very low levels of DR4 (data not shown).
Although treatment with the antileukemic drugs did not increase Apo-2L expression, to confirm that etoposide- or Ara-C-induced apoptosis was not mediated by even a transient induction of Apo-2L and that triggering of DR5-mediated apoptosis, we compared the effect of cotreatment with Apo-2L-R2(DR5):Fc on apoptosis induced by the antileukemic drugs or by Apo-2L. If treatment with the antileukemic drug produced any Apo-2L in the culture medium of the cells, apoptosis triggered by this, through induced DR5, would be blocked by Apo-2L-R2. As shown in Figure 4D, cotreatment with Apo-2L-R2:Fc (20 ng/mL) inhibited Apo-2L- but not etoposide- or Ara-C-induced apoptosis of HL-60 cells. Pretreatment with the antileukemic drugs increases Apo-2L-induced apoptosis To determine the functional significance of DR5 induction by the antileukemic drugs, we compared the apoptotic effects of the sequential treatment with Ara-C, etoposide, or doxorubicin followed by Apo-2L (6 hours of the drug followed by drug washout and 18 hours of Apo-2L treatment) with those of the drug administered alone or together with Apo-2L. Figure 5 demonstrates that significantly more apoptosis was observed following a sequential treatment of HL-60 cells with etoposide or Ara-C followed by Apo-2L, as compared with treatment with Apo-2L or either of the drugs alone. Sequential treatment with the drug followed by Apo-2L also yielded more apoptosis than cotreatment with Apo-2L plus Ara-C or etoposide (P < .01). To adequately assess the potentiating effects of pretreatment with the antileukemic drugs on Apo-2L-induced apoptosis, relatively lower concentrations of etoposide or Ara-C were used for these studies. Although not shown, a sequential treatment with Ara-C or etoposide followed by Apo-2L was also more effective than treatment with the reverse sequence of Apo-2L followed by either of the 2 drugs. For example, exposure to the reverse sequence of Apo-2L (100 ng/mL) for 18 hours followed by Ara-C (10 µmol/L for 6 hours) produced apoptosis of only 47% ± 6% of cells, as compared with apoptosis of 88% ± 9% cells observed with treatment with Ara-C followed by Apo-2L. Similar observations were made when doxorubicin was administered with Apo-2L, and Jurkat cells were used to investigate these treatment schedules (data not shown).
Several reports have demonstrated the sensitivity and molecular correlates of Apo-2L-induced apoptosis of cancer cells.3,4,25-28 Some of these reports have also shown that chemotherapeutic agents increase Apo-2L-induced apoptosis of epithelial cancer cells.25-28 In the present studies, however, we demonstrate for the first time that Apo-2L signals apoptosis of acute leukemia HL-60, U937, and Jurkat cells mainly through the intrinsic mitochondrial pathway of apoptosis. Since these cells lack a functional p53wt, our data also indicate that Apo-2L-induced apoptosis is independent of p53 status. This has also been demonstrated for other tumor cell types.27 Although the Apo-2L-sensitive acute leukemia cell types studied here expressed DR5 and, in HL-60, also DR4, the level of expression of these death-signaling receptors did not correlate with the sensitivity to Apo-2L. This correlation has been demonstrated by some but not all previously reported studies.3,25,27 DcR1 and DcR2 do not transduce Apo-2L-induced death signal.1,2 DcR2 has also been shown to inhibit apoptotic signaling by inducing NFkB activity.39 Ectopic overexpression of DcR1 and DcR2 has been shown to inhibit Apo-2L-induced apoptosis.1,40 However, in the present studies, the level of expression of the decoy receptors did not correlate with resistance to Apo-2L-induced apoptosis of the leukemic cells. These findings are similar to other previously reported observations about melanoma and breast cancer cells.3,25,41 We also did not find any correlation between intracellular FLAME-1 (cFLIP or I-FLICE) levels and the sensitivity of the leukemic cells to Apo-2L-induced apoptosis. The spliced variants of cFLIP are the long form (cFLIPL) and short form (cFLIPS). cFLIPL, which was the variant detected in our immunoblots by the antibody used, has the inhibitory effect on Fas L- and TRAIL-induced DISC activity.41 Although, similarly to our findings, increased levels of cFLIP have been shown to inhibit apoptosis owing to death receptor signals and have been correlated with resistance to Apo-2L-induced apoptosis,27,42-45 this has not been observed in all cell types.3 Since FLAME-1 exerts its inhibitory effect by binding to FADD and caspase-8, this dominant-negative effect on the activity of the DISC may depend on the levels and role of FADD in mediating Apo-2L-induced apoptosis.5 Treatment of the acute leukemia cells with Apo-2L clearly resulted in
the processing of caspase-8, Bid, caspase-9, and caspase-3, as well as
the cytosolic accumulation of cyt c. This indicates that
Apo-2L-induced processing and activation of caspase-8 triggered caspase-3 activity through the intrinsic (mitochondrial) pathway of
apoptosis. Bcl-2 and Bcl-xL overexpression have been
previously shown to exert their inhibitory effect on apoptosis by
blocking the release of cyt c and mitochondrial Previous studies and data presented here demonstrate that antileukemic drugs that cause DNA damage, eg, etoposide, Ara-C, and doxorubicin, also trigger the mitochondrial or intrinsic pathway of apoptosis.16,34-36 The resulting cytosolic accumulation of cyt c produces Apaf-1-, dATP-, and caspase-9-mediated activation of caspase-3,34-36 all of which can be inhibited by overexpression of Bcl-2 or Bcl-xL.34-36 In the present studies, we have extended these observations and demonstrated that etoposide- and Ara-C-induced caspase activity and apoptosis are also associated with down-regulation of the levels of XIAP and survivin. Although survivin has not been shown to be processed by caspases, its levels are low in nonmitotic phases of the cell cycle and increase markedly during mitosis.38 Since treatment with relatively high but clinically achievable and relevant doses of Ara-C, etoposide, or doxorubicin, as employed in the present studies, is known to arrest and increase the percentage of acute leukemia cells in the premitotic phases (G1, S, or G2) of the cell cycle, this may lower survivin expression in the drug-treated cells. Recent studies have suggested that chemotherapeutic agents might trigger apoptosis by inducing Fas or Fas L and activating the Fas-dependent pathway to apoptosis.48-50 However, other reports have shown that chemotherapeutic agents induce apoptosis through a Fas-independent pathway of apoptosis.51,52 Data from present studies also support this by demonstrating that etoposide, Ara-C, and doxorubicin did not induce Fas or Fas L. Treatment with these drugs also did not increase the expression of Apo-2L. Furthermore, cotreatment with a fusion protein containing the extracellular domains of DR4 or DR5 fused to the immunoglobin Fc region, ie, Apo-2L R1, or R2:Fc, did not inhibit etoposide- or Ara-C-induced, but blocked Apo-2L-induced, apoptosis. These data make it unlikely that FasL or Apo-2L expression is induced by etoposide or Ara-C or that the ligation of DR5 in the acute leukemic cells plays any significant role in apoptosis induced by these antileukemic drugs. Although Apo-2L expression was not enhanced, treatment with etoposide, Ara-C, and doxorubicin increased DR5 but not DR4 levels in the 3 acute leukemia cell types. This was observed after treatment with a threshold concentration and an exposure interval of each of the drugs. As noted above, these concentrations of the drugs are clinically achievable during the administration of induction therapy in relapsed leukemias with relatively high doses of these drugs. Previous reports have implicated p53 and NFkB as the transactivating factors in DR5 and DR4 up-regulation by DNA-damaging drugs such as etoposide or doxorubicin.18,53 Although the role of p53wt function in mediating DR5 up-regulation by the antileukemic drugs in the acute leukemia cells studied here can be excluded, NFkB may have been involved in mediating this effect. Regardless of the transcriptional activator involved in DR5 induction, the results presented here indicate that the increased DR5 levels due to treatment with antileukemic drugs should preferentially potentiate Apo-2L-induced apoptosis when exposure to Apo-2L follows treatment with the antileukemic drug. This was corroborated by our findings, which show that pretreatment of the leukemic cells with each of the 3 antileukemic drugs yielded more Apo-2L-induced apoptosis than treatment with Apo-2L, the drugs alone, or even cotreatment with Apo-2L plus each of the antileukemic drugs, or by the reverse sequence of exposure to Apo-2L followed by the antileukemic drugs. In summary, although Apo-2L and each of the antileukemic drugs studied here are shown to engage the intrinsic pathway of apoptosis by up-regulating DR5 levels, pretreatment with the drugs increases the responsiveness to Apo-2L-induced apoptosis. These data suggest a strategy to rationally combine Apo-2L and conventional antileukemic drugs in a regimen that would optimize the antileukemic activity and induce apoptosis of acute leukemia cells, which lack a functional p53wt.
Submitted April 17, 2000; accepted July 28, 2000.
The publication costs of this article were defrayed in part by page charge payment. Therefore, and solely to indicate this fact, this article is hereby marked "advertisement" in accordance with 18 U.S.C. section 1734.
Reprints: Kapil Bhalla, Moffitt Cancer Center and Research Institute, 12902 Magnolia Dr, MRC 3 East, Rm 3056, Tampa, FL 33612; e-mail: bhallakn{at}moffitt.usf.edu.
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  C.-C. Yeh, Y.-T. Deng, D.-Y. Sha, M. Hsiao, and M. Y.-P. Kuo Suberoylanilide hydroxamic acid sensitizes human oral cancer cells to TRAIL-induced apoptosis through increase DR5 expression Mol. Cancer Ther., September 1, 2009; 8(9): 2718 - 2725. [Abstract] [Full Text] [PDF]
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 K. Shenoy, Y. Wu, and S. Pervaiz LY303511 Enhances TRAIL Sensitivity of SHEP-1 Neuroblastoma Cells via Hydrogen Peroxide-Mediated Mitogen-Activated Protein Kinase Activation and Up-regulation of Death Receptors Cancer Res., March 1, 2009; 69(5): 1941 - 1950. [Abstract] [Full Text] [PDF]
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 P. G. Oliver, A. F. LoBuglio, K. R. Zinn, H. Kim, L. Nan, T. Zhou, W. Wang, and D. J. Buchsbaum Treatment of Human Colon Cancer Xenografts with TRA-8 Anti-death Receptor 5 Antibody Alone or in Combination with CPT-11 Clin. Cancer Res., April 1, 2008; 14(7): 2180 - 2189. [Abstract] [Full Text] [PDF]
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R. M. Locklin, E. Federici, B. Espina, P. A. Hulley, R. G. G. Russell, and C. M. Edwards Selective targeting of death receptor 5 circumvents resistance of MG-63 osteosarcoma cells to TRAIL-induced apoptosis Mol. Cancer Ther., December 1, 2007; 6(12): 3219 - 3228. [Abstract] [Full Text] [PDF]
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H. Hasegawa, Y. Yamada, K. Komiyama, M. Hayashi, M. Ishibashi, T. Yoshida, T. Sakai, T. Koyano, T.-S. Kam, K. Murata, et al. Dihydroflavonol BB-1, an extract of natural plant Blumea balsamifera, abrogates TRAIL resistance in leukemia cells Blood, January 15, 2006; 107(2): 679 - 688. [Abstract] [Full Text] [PDF]
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S. Bergeron, M. Beauchemin, and R. Bertrand Camptothecin- and etoposide-induced apoptosis in human leukemia cells is independent of cell death receptor-3 and -4 aggregation but accelerates tumor necrosis factor-related apoptosis-inducing ligand-mediated cell death Mol. Cancer Ther., December 1, 2004; 3(12): 1659 - 1669. [Abstract] [Full Text] [PDF]
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L. Tourneur, S. Delluc, V. Levy, F. Valensi, I. Radford-Weiss, O. Legrand, J. Vargaftig, C. Boix, E. A. Macintyre, B. Varet, et al. Absence or Low Expression of Fas-Associated Protein with Death Domain in Acute Myeloid Leukemia Cells Predicts Resistance to Chemotherapy and Poor Outcome Cancer Res., November 1, 2004; 64(21): 8101 - 8108. [Abstract] [Full Text] [PDF]
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 D. Chandra, G. Choy, X. Deng, B. Bhatia, P. Daniel, and D. G. Tang Association of Active Caspase 8 with the Mitochondrial Membrane during Apoptosis: Potential Roles in Cleaving BAP31 and Caspase 3 and Mediating Mitochondrion-Endoplasmic Reticulum Cross Talk in Etoposide-Induced Cell Death Mol. Cell. Biol., August 1, 2004; 24(15): 6592 - 6607. [Abstract] [Full Text] [PDF]
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M. Taniai, A. Grambihler, H. Higuchi, N. Werneburg, S. F. Bronk, D. J. Farrugia, S. H. Kaufmann, and G. J. Gores Mcl-1 Mediates Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand Resistance in Human Cholangiocarcinoma Cells Cancer Res., May 15, 2004; 64(10): 3517 - 3524. [Abstract] [Full Text] [PDF]
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F. Guo, C. Sigua, J. Tao, P. Bali, P. George, Y. Li, S. Wittmann, L. Moscinski, P. Atadja, and K. Bhalla Cotreatment with Histone Deacetylase Inhibitor LAQ824 Enhances Apo-2L/Tumor Necrosis Factor-Related Apoptosis Inducing Ligand-Induced Death Inducing Signaling Complex Activity and Apoptosis of Human Acute Leukemia Cells Cancer Res., April 1, 2004; 64(7): 2580 - 2589. [Abstract] [Full Text] [PDF]
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 K. R. Kalli, K. E. Devine, M. C. Cabot, C. R. Arnt, M. P. Heldebrant, P. A. Svingen, C. Erlichman, L. C. Hartmann, C. A. Conover, and S. H. Kaufmann Heterogeneous Role of Caspase-8 in Fenretinide-Induced Apoptosis in Epithelial Ovarian Carcinoma Cell Lines Mol. Pharmacol., December 1, 2003; 64(6): 1434 - 1443. [Abstract] [Full Text] [PDF]
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R. R. Rosato, J. A. Almenara, Y. Dai, and S. Grant Simultaneous activation of the intrinsic and extrinsic pathways by histone deacetylase (HDAC) inhibitors and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) synergistically induces mitochondrial damage and apoptosis in human leukemia cells Mol. Cancer Ther., December 1, 2003; 2(12): 1273 - 1284. [Abstract] [Full Text] [PDF]
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 A. Younes and M. E. Kadin Emerging Applications of the Tumor Necrosis Factor Family of Ligands and Receptors in Cancer Therapy J. Clin. Oncol., September 15, 2003; 21(18): 3526 - 3534. [Abstract] [Full Text] [PDF]
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T. R. Singh, S. Shankar, X. Chen, M. Asim, and R. K. Srivastava Synergistic Interactions of Chemotherapeutic Drugs and Tumor Necrosis Factor-related Apoptosis-inducing Ligand/Apo-2 Ligand on Apoptosis and on Regression of Breast Carcinoma in Vivo Cancer Res., September 1, 2003; 63(17): 5390 - 5400. [Abstract] [Full Text] [PDF]
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D. J. Buchsbaum, T. Zhou, W. E. Grizzle, P. G. Oliver, C. J. Hammond, S. Zhang, M. Carpenter, and A. F. LoBuglio Antitumor Efficacy of TRA-8 Anti-DR5 Monoclonal Antibody Alone or in Combination with Chemotherapy and/or Radiation Therapy in a Human Breast Cancer Model Clin. Cancer Res., September 1, 2003; 9(10): 3731 - 3741. [Abstract] [Full Text] [PDF]
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J. H. Kim, M. Ajaz, A. Lokshin, and Y. J. Lee Role of Antiapoptotic Proteins in Tumor Necrosis Factor-related Apoptosis-inducing Ligand and Cisplatin-augmented Apoptosis Clin. Cancer Res., August 1, 2003; 9(8): 3134 - 3141. [Abstract] [Full Text] [PDF]
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K. Uno, T. Inukai, N. Kayagaki, K. Goi, H. Sato, A. Nemoto, K. Takahashi, K. Kagami, N. Yamaguchi, H. Yagita, et al. TNF-related apoptosis-inducing ligand (TRAIL) frequently induces apoptosis in Philadelphia chromosome-positive leukemia cells Blood, May 1, 2003; 101(9): 3658 - 3667. [Abstract] [Full Text] [PDF]
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I. Muller, S. M. Pfister, U. Grohs, J. Zweigner, R. Handgretinger, D. Niethammer, and G. Bruchelt Receptor Activator of Nuclear Factor {kappa}B Ligand Plays a Nonredundant Role in Doxorubicin-induced Apoptosis Cancer Res., April 15, 2003; 63(8): 1772 - 1775. [Abstract] [Full Text] [PDF]
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I. Tegeder, S. Grosch, A. Schmidtko, A. Haussler, H. Schmidt, E. Niederberger, K. Scholich, and G. Geisslinger G Protein-independent G1 Cell Cycle Block and Apoptosis with Morphine in Adenocarcinoma Cells: Involvement of p53 Phosphorylation Cancer Res., April 15, 2003; 63(8): 1846 - 1852. [Abstract] [Full Text] [PDF]
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 Y. Kashio, K. Nakamura, M. J. Abedin, M. Seki, N. Nishi, N. Yoshida, T. Nakamura, and M. Hirashima Galectin-9 Induces Apoptosis Through the Calcium-Calpain-Caspase-1 Pathway J. Immunol., April 1, 2003; 170(7): 3631 - 3636. [Abstract] [Full Text] [PDF]
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X. Yang, M. S. Merchant, M. E. Romero, M. Tsokos, L. H. Wexler, U. Kontny, C. L. Mackall, and C. J. Thiele Induction of Caspase 8 by Interferon {gamma} Renders Some Neuroblastoma (NB) Cells Sensitive to Tumor Necrosis Factor-related Apoptosis-inducing Ligand (TRAIL) but Reveals That a Lack of Membrane TR1/TR2 Also Contributes to TRAIL Resistance in NB Cancer Res., March 1, 2003; 63(5): 1122 - 1129. [Abstract] [Full Text] [PDF]
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R. Nimmanapalli, E. O'Bryan, M. Huang, P. Bali, P. K. Burnette, T. Loughran, J. Tepperberg, R. Jove, and K. Bhalla Molecular Characterization and Sensitivity of STI-571 (Imatinib Mesylate, Gleevec)-resistant, Bcr-Abl-positive, Human Acute Leukemia Cells to SRC Kinase Inhibitor PD180970 and 17-Allylamino-17-demethoxygeldanamycin Cancer Res., October 15, 2002; 62(20): 5761 - 5769. [Abstract] [Full Text] [PDF]
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T. Naka, K. Sugamura, B. L. Hylander, M. B. Widmer, Y. M. Rustum, and E. A. Repasky Effects of Tumor Necrosis Factor-related Apoptosis-inducing Ligand Alone and in Combination with Chemotherapeutic Agents on Patients' Colon Tumors Grown in SCID Mice Cancer Res., October 15, 2002; 62(20): 5800 - 5806. [Abstract] [Full Text] [PDF]
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F. Guo, R. Nimmanapalli, S. Paranawithana, S. Wittman, D. Griffin, P. Bali, E. O'Bryan, C. Fumero, H. G. Wang, and K. Bhalla Ectopic overexpression of second mitochondria-derived activator of caspases (Smac/DIABLO) or cotreatment with N-terminus of Smac/DIABLO peptide potentiates epothilone B derivative-(BMS 247550) and Apo-2L/TRAIL-induced apoptosis Blood, May 1, 2002; 99(9): 3419 - 3426. [Abstract] [Full Text] [PDF]
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P. Secchiero, A. Gonelli, C. Celeghini, P. Mirandola, L. Guidotti, G. Visani, S. Capitani, and G. Zauli Activation of the nitric oxide synthase pathway represents a key component of tumor necrosis factor-related apoptosis-inducing ligand-mediated cytotoxicity on hematologic malignancies Blood, October 1, 2001; 98(7): 2220 - 2228. [Abstract] [Full Text] [PDF]
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G. Laurent and J.-P. Jaffrezou Signaling pathways activated by daunorubicin Blood, August 15, 2001; 98(4): 913 - 924. [Abstract] [Full Text] [PDF]
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Top
Abstract
Introduction
/
, Rb, and
DNA-PK, resulting in the morphologic features and DNA
fragmentation of apoptosis.
, they are relatively resistant to
Apo-2L-induced apoptotic signaling.
m and release of cyt c, which ultimately
results in the activities of caspase-9 and caspase-3. Recently,
etoposide, CPT-11, doxorubicin, 5-FU, and, to a lesser extent, taxol
were shown to augment Apo-2L-induced apoptosis of epithelial cancer
cells.
