Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

One of perspective approaches in treatment of hematological malignancies is activation of death receptors for TRAIL. However, leukemia cells studied to date have shown variable susceptibility to TRAIL. Our study demonstrates that cells of acute T-lymphoblastic leukemia MOLT-4 are resistant to TRAIL and that ionizing radiation in the therapeutically achievable dose of 1 Gy sensitizes TRAIL-resistant cells MOLT-4 to the TRAIL-induced apoptosis by increase in death receptors for TRAIL DR5. When TRAIL is applied after the irradiation in the time of increased DR5 positivity more efficient cell killing is achieved.
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PMID:Ionizing radiation sensitizes leukemic MOLT-4 cells to TRAIL-induced apoptosis. 1899 61

Resistance to imatinib is commonly associated with reactivation of Bcr-Abl signalling. However, Bcr-Abl-independent signalling pathways may be activated and contributed to imatinib resistance in some CML (chronic myelogenous leukaemia) patients. We had isolated three imatinib-resistant K562/R1, R2 and R3 variants with gradual loss of Bcr-Abl from K562 cells to develop effective therapeutic strategies for imatinib-resistant CML. Interestingly, we found that these cells became highly sensitive to TRAIL (tumour necrosis factor-related apoptosis-inducing factor) in comparison with K562 cells showing high resistance to TRAIL. Treatment of K562/R3 cells with TRAIL resulted in activation of TRAIL receptor pathway by including caspase 8 activation, Bid cleavage, cytochrome c release and caspase 3 activation. These results were accompanied by down-regulation of c-FLIP {cellular FLICE [FADD (Fas-associated death domain)-like interleukin 1beta-converting enzyme]-inhibitory protein} in imatinib-resistant K562 variants compared with K562 cells. Overexpression of c-FLIP in K562/R3 cells acquired TRAIL resistance and conversely, c-FLIP-silenced K562 cells became sensitive to TRAIL. Moreover, Bcr-Abl-silenced K562 cells showed down-regulation of c-FLIP and the subsequent overcome of TRAIL resistance. Taken together, our results demonstrated for the first time that the loss of Bcr-Abl in imatinib-resistant cells led to the down-regulation of c-FLIP and subsequent increase of TRAIL sensitivity, suggesting that TRAIL could be an effective strategy for the treatment of imatinib-resistant CML with loss of Bcr-Abl.
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PMID:Sensitization of imatinib-resistant CML cells to TRAIL-induced apoptosis is mediated through down-regulation of Bcr-Abl as well as c-FLIP. 1920 46

In the present study we demonstrated Jurkat leukemia cell lines of TIB152 and TIB153 with different sensitivities to recombinant soluble TRAIL cytotoxicity. TRAIL receptor death receptor 5 (DR5) was constitutively localized in the rafts in both cell lines. FADD, caspase-8, and PI3K-p85 subunit were recruited into DR5 lipid rafts of TIB152 but not in TIB153 cells. The expression and enzyme activity of acid sphingomyelinase, which digests sphingomyeline to produce ceramide and plays an essential role in lipid raft assembling, were higher in the rafts of TIB152 than in TIB153. These data provide evidences that DR5-recruited raft components contribute to the different sensitivity of Jurkat leukemia cell lines to TRAIL-induced cell death and may throw some light on the development of better therapeutic strategies for the cancer cells resistant to TRAIL treatment.
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PMID:Death receptor 5-recruited raft components contributes to the sensitivity of Jurkat leukemia cell lines to TRAIL-induced cell death. 1924 90

This study was aimed to investigate the mechanism of leukemia cell apoptosis induced by histone deacetylase inhibitor (HDACI). Flow cytometry was used to detect the apoptosis of leukemia cell lines NB4, U937 and Jurkat, and the changes of mRNA and protein expressions of TRAIL, DR4 and DR5 were detected by Western blot and RT-PCR respectively. The results showed that both TRAIL and DR5 protein and mRNA expressions in NB4, U937 and Jurkat cells increased after treated with sodium butyrate (SB) and in time-dependent manner. However, DR4 mRNA in leukemia cells was not significantly changed after treated with SB. It is concluded that the apoptosis mechanism of leukemic cell lines NB4, U937 and Jurkat induced by SB is closely related to the protein and mRNA expressions up-regulating TRAIL and DR5, but the DR4 may not participate in the apoptosis induced by SB.
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PMID:[Mechanism of leukemia cell apoptosis induced by sodium butyrate activating TRAIL pathway]. 1937 58

Conditionally replicating adenoviruses (CRAd) have been under extensive investigations as anticancer agents. Previously, we found that ZD55, an adenovirus serotype 5-based CRAd, infected and killed the leukemia cells expressing coxsackie adenovirus receptor (CAR). However, majority of leukemic cells lack CAR expression on their cell surface, resulting in resistance to CRAd infection. In this study, we showed that SG235, a novel fiber chimeric CRAd that has Ad35 tropism, permitted CAR-independent cell entry, and this in turn produced selective cytopathic effects in a variety of human leukemic cells in vitro and in vivo. Moreover, SG235 expressing exogenous tumor necrosis factor-related apoptosis-inducing ligand (SG235-TRAIL) effectively induced apoptosis of leukemic cells via the activation of extrinsic and intrinsic apoptotic pathway and elicited a superior antileukemia activity compared with SG235. In addition, normal hematopoietic progenitors were resistant to the inhibitory activity of SG235 and SG235-TRAIL. Our data suggest that these novel oncolytic agents may serve as useful tools for the treatment of leukemia.
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PMID:Effective gene-viral therapy of leukemia by a new fiber chimeric oncolytic adenovirus expressing TRAIL: in vitro and in vivo evaluation. 1941 52

p53 is expressed frequently, but is rarely mutated in anaplastic lymphoma kinase (ALK)-positive anaplastic large cell lymphoma (ALCL) tumours. Nutlin-3a is a recently developed small molecule that targets Mdm2, a critical negative regulator of p53, and disrupts the p53-Mdm2 interaction resulting in p53 stabilization and activation. We show that nutlin-3a activates p53 in ALK+ ALCL cells carrying a wild type (wt) or mutated but partially functional p53 gene resulting in p53-dependent cell-cycle arrest and apoptosis. Cell-cycle arrest was associated with upregulation of the cyclin-dependent kinase inhibitor p21. Nutlin-3a-induced apoptotic cell death was accompanied by Bax and Puma upregulation, downregulation of Bcl-xl, survivin, and caspase-3 cleavage, and this was reduced when p53-dependent transactivation activity was inhibited by pifithrin-alpha, or when pifithrin-mu was used to inhibit direct p53 targeting of mitochondria. Nutlin-3a sensitized the activation of the extrinsic apoptotic pathway in wt-p53 ALK+ ALCL cells, in part, through upregulation of DR-5 and downregulation of c-Flip(S/L), and was synergistic with TRAIL in cell death induction. In addition, nutlin-3a treatment enhanced doxorubicin cytotoxicity against ALK+ ALCL cells harbouring mt p53, and this was associated with p73 upregulation. These data suggest that disruption of the p53-mdm2 interaction by nutlin-3a offers a novel therapeutic approach for ALK+ ALCL patients.
Leukemia 2009 Dec
PMID:The therapeutic potential of p53 reactivation by nutlin-3a in ALK+ anaplastic large cell lymphoma with wild-type or mutated p53. 1974 26

Histone deacetylase inhibitors (HDACi) have demonstrated promising therapeutic potential in clinical trials for hematological malignancies. HDACi, such as SAHA/Vorinostat, Trichostatin A, and MS-275 were found to induce apoptosis of leukemic blasts through activation of the death receptor pathway and transcriptional induction of the Tumor Necrosis Factor (TNF)-related pro-apoptotic family members, TRAIL and FasL. The impact of HDACi on TNF-related costimulatory molecules such as 4-1BB ligand (4-1BBL/TNFSF9) is however not known. Following exposure to SAHA/Vorinostat, Trichostatin A, and MS-275, transcript levels were determined by real time PCR in Jurkat, Raji and U937 cells. Treatment with HDACi up-regulated TNFSF9 gene expression in the three leukemia cell lines, yet to different extend and with distinct kinetics, which did not require de novo protein synthesis and was not associated with DNAse I hypersensitive chromatin remodeling. Transcriptional activity of TNFSF9 promoter-luciferase constructs was induced up to 12 fold by HDACi, and implication of Sp1/Sp3 transcription factors binding to functional GC-box elements was evidenced by reporter gene assays, site-directed mutagenesis, and electrophoretic mobility shift assays. Functionality of modulated target genes was assessed in allogeneic mixed leukocyte reaction experiments. MS-275- and to a lesser extent Trichostatin A- and SAHA-treated Raji cells significantly up regulated T lymphocytes proliferation which was reduced by about 50% by a 4-1BB blocking recombinant protein, while MS-275- but neither Trichostatin A- nor SAHA-treated cells up-regulated IFNgamma secretion by T lymphocytes. Our results identify 4-1BBL/4-1BB as a downstream target of HDACi, especially of MS-275 anti-leukemia action in vitro. Thus, HDACi such as MS-275 displaying dual TNF-dependent proapoptotic and costimulatory activities might be favored for inclusion in HDACi-based anti-cancer therapeutic strategies.
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PMID:Anti-leukemia activity of MS-275 histone deacetylase inhibitor implicates 4-1BBL/4-1BB immunomodulatory functions. 1975 1

Although anti-cancer effects of cyclooxygenase 2 (COX2) inhibitors have been reported, most studies focused on the direct effects of COX2 inhibiters on colon cancer cells. On the other hand, several types of cancers express Fas ligand (FasL) and/or TRAIL and mediate apoptosis of T cells in vitro. The "counter-attack" machinery may account for the mechanisms by which tumors evade host immune surveillance. In this study we determined if COX2 inhibitor could modulate effector molecules of cell death on colon cancer cells changing their effects on cytotoxic T lymphocytes. Colon adenocarcinoma cells, HCA7 and HCT116, the former COX2-positive and the latter COX2-negative, were pre-incubated with/without a COX2 inhibitor, NS398. Subsequently, the cells were co-cultured with Jurkat T cell leukemia cells and damage to Jurkat cells was determined. Treatment with NS398 resulted in reduction of expression of FasL and TRAIL in HCA7 cells, whereas NS398 did not affect the expression of FasL and TRAIL in HCT116 cells. The number of viable Jurkat cells was diminished when cells were co-cultured with naive, non-pretreated HCA7 or HCA116 cells. Preincubation of HCA7 cells with NS398 before co-culture blunted the HCA7 cell-induced cell toxicity on Jurkat cells. In contrast, pretreatment with NS398 failed to inhibit the HCT116-induced Jurkat cell killing. Our results suggest that COX2 regulates the expression of FasL and TRAIL on COX2-positive colon cancer cells thereby evoking a counter-attack against cytotoxic T cells, which may lead to compromised host immune responses.
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PMID:Cyclooxygenase 2 modulates killing of cytotoxic T lymphocytes by colon cancer cells. 1979 24

Whether celastrol, a triterpene from traditional Chinese medicine, can modulate the anticancer effects of TRAIL, the cytokine that is currently in clinical trial, was investigated. As indicated by assays that measure plasma membrane integrity, phosphatidylserine exposure, mitochondrial activity, and activation of caspase-8, caspase-9, and caspase-3, celastrol potentiated the TRAIL-induced apoptosis in human breast cancer cells, and converted TRAIL-resistant cells to TRAIL-sensitive cells. When examined for its mechanism, we found that the triterpene down-regulated the expression of cell survival proteins including cFLIP, IAP-1, Bcl-2, Bcl-xL, survivin, and XIAP and up-regulated Bax expression. In addition, we found that celastrol induced the cell surface expression of both the TRAIL receptors DR4 and DR5. This increase in receptors was noted in a wide variety of cancer cells including breast, lung, colorectal, prostate, esophageal, and pancreatic cancer cells, and myeloid and leukemia cells. Gene silencing of the death receptor abolished the effect of celastrol on TRAIL-induced apoptosis. Induction of the death receptor by the triterpenoid was found to be p53-independent but required the induction of CAAT/enhancer-binding protein homologous protein (CHOP), inasmuch as gene silencing of CHOP abolished the induction of DR5 expression by celastrol and associated enhancement of TRAIL-induced apoptosis. We found that celastrol also induced reactive oxygen species (ROS) generation, and ROS sequestration inhibited celastrol-induced expression of CHOP and DR5, and consequent sensitization to TRAIL. Overall, our results demonstrate that celastrol can potentiate the apoptotic effects of TRAIL through down-regulation of cell survival proteins and up-regulation of death receptors via the ROS-mediated up-regulation of CHOP pathway.
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PMID:Celastrol, a triterpene, enhances TRAIL-induced apoptosis through the down-regulation of cell survival proteins and up-regulation of death receptors. 2749 61

Imatinib mesylate (imatinib), a competitive inhibitor of the BCR-ABL tyrosine kinase, is highly effective against chronic myelogenous leukemia (CML) cells. However, because 20-30% of patients affected by CML display either primary or secondary resistance to imatinib, intentional activation of Vgamma9Vdelta2 T cells by phosphoantigens or by agents that cause their accumulation within cells, such as zoledronate, may represent a promising strategy for the design of a novel and highly innovative immunotherapy capable to overcome imatinib resistance. In this study, we show that Vgamma9Vdelta2 T lymphocytes recognize, trogocytose, and efficiently kill imatinib-sensitive and -resistant CML cell lines pretreated with zoledronate. Vgamma9Vdelta2 T cell cytotoxicity was largely dependent on the granule exocytosis- and partly on TRAIL-mediated pathways, was TCR-mediated, and required isoprenoid biosynthesis by zoledronate-treated CML cells. Importantly, Vgamma9Vdelta2 T cells from patients with CML can be induced by zoledronate to develop antitumor activity against autologous and allogeneic zoledronate-treated leukemia cells, both in vitro and when transferred into immunodeficient mice in vivo. We conclude that intentional activation of Vgamma9Vdelta2 T cells by zoledronate may substantially increase their antileukemia activities and represent a novel strategy for CML immunotherapy.
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PMID:V gamma 9V delta 2 T lymphocytes efficiently recognize and kill zoledronate-sensitized, imatinib-sensitive, and imatinib-resistant chronic myelogenous leukemia cells. 2015 4


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