UMLS:C0023473 - FACTA Search

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Query: UMLS:C0023473 (chronic myeloid leukemia)
18,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Apicidin, a histone deacetylase inhibitor, is a novel cyclic tetrapeptide with potent antiproliferative activity against various cancer cells. We examined whether apicidin potentiates the imatinib-induced apoptosis of Bcr-Abl-positive human leukaemia cells. In K562 cells, the co-administration of minimally toxic concentrations of imatinib and apicidin (imatinib/apicidin) for 48 h produced a marked increase in mitochondrial damage, processing of caspase cascades and apoptosis. Similar results were observed in leukaemic blasts obtained from patients with chronic myeloid leukaemia in blast crisis. Imatinib/apicidin co-treatment for 48 h resulted in a near complete loss of the full-length XIAP (X-linked inhibitor of apoptosis) protein, with a corresponding increase in the 29-kDa XIAP cleavage product. Both the degradation of XIAP and increased release of second mitochondria-derived activator of caspase/direct IAP-binding protein with low pI (Smac/DIABLO) into the cytosol were abrogated by pretreatment with the caspase-3 inhibitor DEVD-CHO. Imatinib/apicidin co-treatment for 48 h produced a prominent decrease in Bcr-Abl protein levels in a caspase-dependent manner. In summary, these data indicate that apicidin potentiates the imatinib-induced apoptosis of Bcr-Abl-positive leukaemia cells through the enhanced activation of the mitochondria-dependent caspase cascades, accompanied by caspase-dependent downregulation of Bcr-Abl and XIAP. These findings generate a rationale for further investigation of apicidin and imatinib as a potential therapeutic strategy in Bcr-Abl-positive leukaemias.
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PMID:Apicidin potentiates the imatinib-induced apoptosis of Bcr-Abl-positive human leukaemia cells by enhancing the activation of mitochondria-dependent caspase cascades. 1468 26

A tyrosine kinase inhibitor, STI571, has been demonstrated to be effective for the treatment of chronic myelogenous leukemia (CML). STI571 inhibits tyrosine kinase activity of ABL and induces apoptosis of CML cells. However, drug resistance develops commonly in patients with blast phase CML, and has become a significant therapeutic problem. We examined the effects of aminopeptidase inhibitors on CML cell line (K562) and a STI571-resistant subline of K562. Ubenimex and the more potent aminopeptidase inhibitor, actinonin, inhibited proliferation of both K562 cells and STI571-resistant K562 cells and also induced their apoptosis in dose- and time-dependent manners. Ubenimex and actinonin induced the activation of caspase-3, and the induction of apoptosis was inhibited by pan-caspase inhibitor, indicating this apoptosis is caspase-dependent. We found that serine phosphorylation of both MAPK and glycogen synthase kinase-3beta were suppressed by aminopeptidase inhibitors in parent K562 and STI571-resistant K562 cells. The expression level of cyclin D1 protein was also reduced by ubenimex and actinonin in both cell lines. These results indicated STI571-resistance does not confer the cross-resistance to aminopeptidase inhibitors in K562 cells and revealed the new findings of aminopeptidase inhibitor-induced intracellular signaling pathways.
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PMID:Aminopeptidase inhibitors inhibit proliferation and induce apoptosis of K562 and STI571-resistant K562 cell lines through the MAPK and GSK-3beta pathways. 1473 54

The reputation of garlic (Allium sativum) as an effective remedy for tumours extends back to the Egyptian Codex Ebers of 1550 b.c. Several garlic compounds including allicin and its corresponding sulfide inhibit the proliferation and induce apoptosis of several human non-leukaemia malignant cells including breast, bladder, colorectal, hepatic, prostate cancer, lymphoma and skin tumour cell lines. Ajoene (4,5,9-trithiadodeca-1,6,11-triene-9-oxide) is a garlic-derived compound produced most efficiently from pure allicin and has the advantage of a greater chemical stability than allicin. Several clinical trials and in vitro studies of ajoene have demonstrated its best-known anti-thrombosis, anti-microbial and cholesterol lowering activities. Recently, topic application of ajoene has produced significant clinical response in patients with skin basal cell carcinoma. Ajoene was shown to inhibit proliferation and induce apoptosis of several human leukaemia CD34-negative cells including HL-60, U937, HEL and OCIM-1. Also, ajoene induces 30% apoptosis in myeloblasts from chronic myeloid leukaemia patient in blast crisis. More significantly, ajoene profoundly enhanced the apoptotic effect of the two chemotherapeutic drugs: cytarabine and fludarabine in human CD34-positive resistant myeloid leukaemia cells through enhancing their bcl-2 inhibitory and caspase-3 activation activities. The two key anti-leukaemia biological actions of ajoene were the inhibition of proliferation and the induction of apoptosis. Studies have shown the anti-proliferation activity of ajoene to be associated with a block in the G2/M phase of cell cycle in human myeloid leukaemia cells. The apoptosis inducing activity of ajoene is via the mitochondria-dependent caspase cascade through a significant reduction of the anti-apoptotic bcl-2 that results in release of cytochrome c and the activation of caspase-3. Since acute myeloid leukaemia (AML) is a heterogeneous malignant disease in which disease progression at the level of CD34-positive cells has a major impact on resistance to chemotherapy and relapse and the inability to undergo apoptosis is a crucial mechanism of multi-drug resistance in AML patients. The recent findings of the potent enhancing activity of ajoene on chemotherapy-induced apoptosis in CD34-positive resistant human myeloid leukaemia cells suggest a novel promising role for the treatment of refractory and/or relapsed AML patients as well as elderly AML patients. Further studies are warranted to evaluate similar enhancing effect for ajoene in blast cells from AML patients in primary cultures before its introduction in pilot clinical study.
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PMID:Ajoene (natural garlic compound): a new anti-leukaemia agent for AML therapy. 1515 86

Imatinib (STI571, Gleevec) is a tailored drug for chronic myelogenous leukemia (CML), whereas arsenic compounds were used as ancient remedies for CML with certain efficacy. The aim of this study was to investigate the potential benefit of combination therapy with imatinib and arsenic sulfide (As(4)S(4)). Analysis of cell proliferation and clonogenic ability showed that As(4)S(4) and imatinib exerted synergistic effects on both K562 cells and fresh CML cells. The effective concentrations on fresh CML cells were pharmacokinetically available in vivo but had much less inhibitory effect on CD34(+) cells from the nonleukemic donors. Examination of cell cycles showed that As(4)S(4) induced G(2)/M arrest whereas imatinib induced G(1) arrest. Using a number of parameters such as morphology, annexin V/propidium iodide (PI), mitochondrial transmembrane potential, caspase-3 activity, and Fas/Fas-L, the synergistic effects were revealed on induction of cell apoptosis, largely through the mitochondrial pathway. The 2 drugs also exhibited a synergistic effect in targeting BCR-ABL protein. While As(4)S(4) triggered its degradation and imatinib inhibited its tyrosine kinase activity, combined use of the 2 led to lower protein/enzymatic activity levels of BCR-ABL. Our in vitro data thus strongly suggest a potential clinical application of imatinib and As(4)S(4) combination on CML.
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PMID:Combined effects of As4S4 and imatinib on chronic myeloid leukemia cells and BCR-ABL oncoprotein. 1533 52

Bcr-Abl-expressing primary or cultured leukemia cells display high levels of the antiapoptotic heat shock protein (hsp) 70 and are resistant to cytarabine (Ara-C), etoposide, or Apo-2L/TRAIL (TNF-related apoptosis-inducing ligand)-induced apoptosis. Conversely, a stable expression of the cDNA of hsp70 in the reverse orientation attenuated not only hsp70 but also signal transducers and activators of transcription 5 (STAT5) and Bcl-x(L) levels. This increased apoptosis induced by cytarabine, etoposide, or Apo-2L/TRAIL. Ectopic expression of hsp70 in HL-60 cells (HL-60/hsp70) inhibited Ara-C and etoposide-induced Bax conformation change and translocation to the mitochondria; attenuated the accumulation of cytochrome c, Smac, and Omi/HtrA2 in the cytosol; and inhibited the processing and activity of caspase-9 and caspase-3. Hsp70 was bound to death receptors 4 and 5 (DR4 and DR5) and inhibited Apo-2L/TRAIL-induced assembly and activity of the death-inducing signaling complex (DISC). HL-60/hsp70 cells exhibited increased levels and DNA binding activity of STAT5, which was associated with high levels of Pim-2 and Bcl-x(L) and resistance to apoptosis. Expression of the dominant negative (DN) STAT5 resensitized HL-60/hsp70 cells to cytarabine, etoposide, and Apo-2L/TRAIL-induced apoptosis. Collectively, these findings suggest that hsp70 inhibits apoptosis upstream and downstream of the mitochondria and is a promising therapeutic target for reversing drug-resistance in chronic myeloid leukemia-blast crisis and acute myeloid leukemia cells.
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PMID:Mechanistic role of heat shock protein 70 in Bcr-Abl-mediated resistance to apoptosis in human acute leukemia cells. 1538 81

Both aging and diabetes are characterized by the formation of advanced glycation end products (AGEs). Both exhibit other similarities including deficits in wound healing that are associated with higher rates of fibroblast apoptosis. In order to investigate a potential mechanism for enhanced fibroblast apoptosis in diabetes and aged individuals, experiments were carried out to determine whether the predominant advanced glycation end product in skin, N-epsilon-(carboxymethyl) lysine (CML)-collagen, could induce fibroblast apoptosis. In vivo experiments established that CML-collagen but not unmodified collagen induced fibroblast apoptosis and that apoptosis was dependent upon caspase-3, -8, and -9 activity. In vitro experiments demonstrated that CML-collagen but not control collagen induced a time- and dose-dependent increase in fibroblast apoptosis. By use of blocking antibodies, apoptosis was shown to be mediated through receptor for AGE signaling. AGE-induced apoptosis was largely dependent on the effector caspase, caspase-3, which was activated through both cytoplasmic (caspase-8-dependent) and mitochondrial (caspase-9) pathways. CML-collagen had a global effect of enhancing mRNA levels of pro-apoptotic genes that included several classes of molecules including ligands, receptors, adaptor molecules, mitochondrial proteins, and others. However, the pattern of expression was not identical to the pattern of apoptotic genes induced by tumor necrosis factor alpha.
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PMID:Advanced glycation end products enhance expression of pro-apoptotic genes and stimulate fibroblast apoptosis through cytoplasmic and mitochondrial pathways. 1559 Jun 48

The DNA methylation inhibitor 5-Aza-2'-deoxycytidine (5-Aza-CdR) has significant therapeutic value for the treatment of patients with myelodysplastic syndrome (MDS), acute myeloid leukemia (AML) and chronic myeloid leukemia (CML). The demethylating effect of 5-Aza-CdR has been well characterized. In contrast, less is known about the molecular events downstream of the methylation inhibition. Here, 5-Aza-CdR induced apoptosis in AML cells (both p53 mutant and wild-type) but not in epithelial or normal PBMCs. Cell death was accompanied by activation of the mitochondrial apoptosis pathway, as shown by release of cytochrome c and AIF and loss of mitochondrial membrane potential (DeltaPsim). Activation of caspase-3 (but not -6 and -8) was detectable using Western blot analysis and measurement of caspase enzymatic activity. 5-Aza-CdR treatment resulted in the induction of p21, which correlated with the arrest of AML cells in the G1 cell cycle phase. Induction of p21 expression was independent of its promoter methylation status but mediated by 5-Aza-CdR-induced reexpression of the tumor-suppressor p73, a known upstream regulator of p21. The p73 promoter was hypermethylated in AML cell lines and in primary AML cells but not in epithelial cells, which were resistant toward 5-Aza-CdR. Therefore, 5-Aza-CdR-mediated specific killing of myeloid cells might be dependent on its ability to revert p73 promoter methylation and to reexpress p73 mRNA. In addition, exogenous expression of p73 rendered epithelial cells sensitive to apoptosis induced by 5-Aza-CdR or other cytostatic drugs. We therefore conclude that p73 is a relevant target for methylation-dependent efficacy of 5-Aza-CdR in AML cells.
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PMID:5-Aza-2'-deoxycytidine induces p21WAF expression by demethylation of p73 leading to p53-independent apoptosis in myeloid leukemia. 1560 9

Interactions between the histone deacetylase (HDAC) inhibitors suberanoylanilide hydroxamic acid (SAHA) and sodium butyrate (SB) and the heat shock protein (Hsp) 90 antagonist 17-allylamino 17-demethoxygeldanamycin (17-AAG) have been examined in Bcr-Abl(+) human leukemia cells (K562 and LAMA84), including those sensitive and resistant to STI571 (imatinib mesylate). Cotreatment with 17-AAG and SAHA or SB synergistically induced mitochondrial dysfunction (cytochrome c and apoptosis-inducing factor release), caspase-3 and -8 activation, apoptosis, and growth inhibition. Similar effects were observed in LAMA84 cells and K562 cells resistant to STI571, as well as in CD34(+) cells isolated from the bone marrows of three patients with chronic myelogenous leukemia. These events were associated with increased binding of Bcr-Abl, Raf-1, and Akt to Hsp70, and inactivation of extracellular signal-regulated kinase 1/2 and Akt. In addition, 17-AAG/SAHA abrogated the DNA binding and the transcriptional activities of signal transducer and activator of transcription (STAT) 5 in K562 cells, including those ectopically expressing a constitutively active STAT5A construct. Cotreatment with 17-AAG and SAHA also induced down-regulation of Mcl-1, Bcl-xL, and B-Raf; up-regulation of Bak; cleavage of 14-3-3 proteins; and a profound conformational change in Bax accompanied by translocation to the membrane fraction. Moreover, ectopic expression of Bcl-2 attenuated cell death induced by this regimen, implicating mitochondrial injury in the lethality observed. Together, these findings raise the possibility that combining HDAC inhibitors with the Hsp90 antagonist 17-AAG may represent a novel strategy against Bcr-Abl(+) leukemias, including those resistant to STI571.
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PMID:Cotreatment with suberanoylanilide hydroxamic acid and 17-allylamino 17-demethoxygeldanamycin synergistically induces apoptosis in Bcr-Abl+ Cells sensitive and resistant to STI571 (imatinib mesylate) in association with down-regulation of Bcr-Abl, abrogation of signal transducer and activator of transcription 5 activity, and Bax conformational change. 1562 78

We compare the effects of Imatinib mesylate (Glivec) on chronic myeloid leukemia derived cell lines K562 and JURL-MK1. In both cell lines, the cell cycle arrests in G(1)/G(0) phase within 24 h after the addition of 1 microM Imatinib. This is followed by a decrease of Ki-67 expression and the induction of apoptosis. In JURL-MK1 cells, the apoptosis is faster in comparison with K562 cells: the caspase-3 activity reaches the peak value (20 to 30 fold of the control) after about 40 h and the apoptosis proceeds to its culmination point, the DNA fragmentation, within 48 h following 1 microM Imatinib addition. Unlike K562 cells, JURL-MK1 cells possess a probably functional p53 protein inducible by TPA (tetradecanoyl phorbol acetate) or UV-B irradiation. However, no increase in p53 expression was observed in Imatinib-treated JURL-MK1 cells indicating that the difference in the apoptosis rate between the two cell lines is not due to the lack of p53 in K562 cells. Imatinib also triggers erythroid differentiation both in JURL-MK1 and K562 cells. Glycophorin A expression occurred simultaneously with the apoptosis, even at the single cell level. In K562 cells, but not in JURL-MK1 cells, the differentiation process involved increased hemoglobin synthesis. However, during spontaneous evolution of JURL-MK1 cells in culture, the effects produced by Imatinib progressively changed from the fast apoptosis to the more complete erythroid differentiation. We suggest that the apoptosis and the erythroid differentiation are parallel effects of Imatinib and their relative contributions, kinetics and completeness are related to the differentiation stage of the treated cells.
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PMID:Fast apoptosis and erythroid differentiation induced by imatinib mesylate in JURL-MK1 cells. 1577 Jun 64

Mitochondria play a key role in the regulation of apoptosis induced by numerous antitumor chemotherapeutic and other toxic agents. Photodynamic therapy (PDT) exerts significant cellular killing efficacy through either an apoptotic or necrotic cell death pathway. This study investigated the mechanism underlying the killing effects of a novel amphipathic photosensitizer [di-sulfonated di-phthalimidomethyl phthalocyanine zinc (ZnPcS2P2)]-mediated photodynamic therapy (ZnPcS2P2-PDT) on K562 cells. Apoptosis was evident in the post-PDT cells through the TdT-mediated dUTP nick end labeling (TUNEL) method and DNA fragmentation assay. After ZnPcS2P2-PDT, K562 cells underwent mitochondria-dependent apoptosis as evidenced by the release of cytochrome c from mitochondria into cytosol, accompanied by mitochondrial membrane potential (deltapsim) reduction, indicating the opening of the mitochondrial permeability transition pore (PTP). The activities of protease from the caspase family and caspase-3 were also significantly elevated. Furthermore, ZnPcS2P2-PDT down-regulated the expression of chimaeric Bcr-Abl oncoprotein, which is the molecular hallmark of chronic myelogenous leukemia (CML).
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PMID:ZnPcS2P2-based photodynamic therapy induces mitochondria-dependent apoptosis in K562 cells. 1599 10

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