Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0023473 (chronic myeloid leukemia)
 18,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Kaempferol (3,4',5,7-tetrahydroxyflavone) is a flavonoid with anti- and pro-oxidant activity present in various natural sources. Kaempferol has been shown to posses anticancer properties through the induction of the apoptotic program. Here we report that treatment of the chronic myelogenous leukemia cell line K562 and promyelocitic human leukemia U937 with 50 microM kaempferol resulted in an increase of the antioxidant enzymes Mn and Cu/Zn superoxide dismutase (SOD). Kaempferol treatment induced apoptosis by decreasing the expression of Bcl-2 and increasing the expressions of Bax. There were also induction of mitochondrial release of cytochrome c into cytosol and significant activation of caspase-3, and -9 with PARP cleavage. Kaempferol treatment increased the expression and the mitochondria localization of the NAD-dependent deacetylase SIRT3. K562 cells stably overexpressing SIRT3 were more sensitive to kaempferol, whereas SIRT3 silencing did not increase the resistance of K562 cells to kaempferol. Inhibition of PI3K and de-phosphorylation of Akt at Ser473 and Thr308 was also observed after treating both K562 and U937 cells with kaempferol. In conclusion our study shows that the oxidative stress induced by kaempferol in K562 and U937 cell lines causes the inactivation of Akt and the activation of the mitochondrial phase of the apoptotic program with an increase of Bax and SIRT3, decrease of Bcl-2, release of cytochrome c, caspase-3 activation, and cell death.
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PMID:Kaempferol induces apoptosis in two different cell lines via Akt inactivation, Bax and SIRT3 activation, and mitochondrial dysfunction. 1916 Apr 23

TNF-related apoptosis-inducing ligand (TRAIL) is a pro-apoptotic cytokine that is capable of inducing apoptosis in a wide variety of cancer cells but not in normal cells. Although many cancer cells are sensitive to TRAIL-induced apoptosis, chronic myeloid leukemia (CML) develops resistance to TRAIL. In this study, we investigated whether apicidin, a novel histone deacetylase inhibitor, could overcome the TRAIL resistance in CML-derived K562 cells. Compared to treatment with apicidin or TRAIL alone, cotreatment with apicidin and TRAIL-induced apoptosis synergistically in K562 cells. This combination led to activation of caspase-8 and Bcl-2 interacting domain (Bid), resulting in the cytosolic accumulation of cytochrome c from mitochondria as well as an activation of caspase-3. Treatment with apicidin resulted in down-regulation of Bcr-Abl and inhibition of its downstream target, PI3K/AKT-NF-kappaB pathway. In addition, apicidin decreased the level of NF-kappaB-dependent Bcl-x(L), leading to caspase activation and Bid cleavage. These results suggest that apicidin may sensitize K562 cells to TRAIL-induced apoptosis through caspase-dependent mitochondrial pathway by regulating expression of Bcr-Abl and its related anti-apoptotic proteins. Therefore, the present study suggests that combination of apicidin and TRAIL may be an effective strategy for treating TRAIL-resistant Bcr-Abl expressing CML cells.
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PMID:Cotreatment with apicidin overcomes TRAIL resistance via inhibition of Bcr-Abl signaling pathway in K562 leukemia cells. 1926 63

Imatinib mesylate (IM), a potent inhibitor of the BCR/ABL tyrosine kinase, has become standard first-line therapy for patients with chronic myeloid leukemia (CML), but the frequency of resistance increases in advancing stages of disease. Elimination of BCR/ABL-dependent intracellular signals triggers apoptosis, but it is unclear whether this activates additional cell survival and/or death pathways. We have shown here that IM induces autophagy in CML blast crisis cell lines, CML primary cells, and p210BCR/ABL-expressing myeloid precursor cells. IM-induced autophagy did not involve c-Abl or Bcl-2 activity but was associated with ER stress and was suppressed by depletion of intracellular Ca2+, suggesting it is mechanistically nonoverlapping with IM-induced apoptosis. We further demonstrated that suppression of autophagy using either pharmacological inhibitors or RNA interference of essential autophagy genes enhanced cell death induced by IM in cell lines and primary CML cells. Critically, the combination of a tyrosine kinase inhibitor (TKI), i.e., IM, nilotinib, or dasatinib, with inhibitors of autophagy resulted in near complete elimination of phenotypically and functionally defined CML stem cells. Together, these findings suggest that autophagy inhibitors may enhance the therapeutic effects of TKIs in the treatment of CML.
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PMID:Targeting autophagy potentiates tyrosine kinase inhibitor-induced cell death in Philadelphia chromosome-positive cells, including primary CML stem cells. 1936 92

ZD6474 is an orally available, small-molecule tyrosine kinase inhibitor. This study explores the effect of ZD6474 on imatinib-resistant K562 cell lines, which show markedly increased SRC family kinases (SFKs) activity. ZD6474 induces growth arrest and apoptosis of imatinib-resistant and parental K562 cells, as well as inhibition of Src activity and its downstream effectors, the anti-apoptotic Bcl-2 family. ZD6474 treatment also inhibits the activity of STAT3 and reactivation of its activity results in suppression of the anti-tumor effects of SFKs inhibitors. A single oral administration of ZD6474 produced dose-dependent inhibition of imatinib-resistant K562 cells xenograft tumors. These results suggest that clinical assessment of ZD6474 against imatinib-resistant CML is warranted.
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PMID:ZD6474 inhibits Src kinase leading to apoptosis of imatinib-resistant K562 cells. 1939 92

Gambogic acid (GA), a major active component of gamboge, exhibits potent anticancer activity in many kinds of cancer cells. However, the anticancer mechanism of GA is not clearly understood. Here we showed that GA could cause growth inhibition, induce the G0/G1 phase cell cycle arrest and apoptosis in human chronic myelogenous leukemia cell line K562 cells. Since steroid receptor coactivator-3 (SRC-3), overexpressed in many human malignancies including leukemia, is a central target for cancer therapy, we also explored the effects of GA on SRC-3 and SRC-3-regulated gene products in K562. GA treatment downregulated the expression of SRC-3 and then inhibited the activity of Akt kinase and its downstream targets p70 S6 kinase 1 (S6K1) and glycogen synthase kinase 3beta (GSK3beta) without changes in total protein levels of these three proteins, which thus influenced the expression of the apoptosis related gene Bcl-2 in K562 cells. These results suggest that GA might exhibit its strong antitumor effects via the interruption of SRC-3.
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PMID:Gambogic acid induces G0/G1 arrest and apoptosis involving inhibition of SRC-3 and inactivation of Akt pathway in K562 leukemia cells. 1943 30

Patients who develop chronic myeloid leukemia (CML) are currently treated with tyrosine kinase inhibitors (TKIs), which inhibit the function of the oncogene BCR/Abl. Most CML cells undergo apoptosis when BCR/Abl tyrosine kinase activity is suppressed by TKIs. Cells surviving drug treatment are either stem cells (CML in early phase) or cells with BCR/Abl-dependent or -independent mechanisms of drug resistance (CML in advanced phase). Since survival of these cells is thought to be responsible for disease recurrence, it is critical to find ways to fully eradicate CML stem cells. We have recently shown that when CML cells, including stem cells, are exposed to TKI they activate an autophagic program, which relies on intracellular calcium and is not inhibited by Bcl-2. Pharmacological or RNAi-mediated inhibition of autophagy potentiates the effect of TKI in inducing death of CML cells, including the stem cells. These data strongly suggest that inhibition of autophagy may improve the therapeutic effects of TKIs in the treatment of CML. In addition, they give credence to the idea that in cancer cells autophagy is part of a stereotypic response to stress and specifically to abrogation of their main oncogenic signal(s).
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PMID:Targeted therapies and autophagy: new insights from chronic myeloid leukemia. 1971 59

Imatinib is a targeted selective inhibitor of chimaeric Bcr-Abl tyrosine kinase developed for effective therapy of chronic myelogenous leukemia (CML) and acute lymphocytic leukemia (ALL) patients. Unfortunately, evidence now exists to indicate that a portion of such patients treated with imatinib acquire resistance and subsequently relapse. To understand the heterogeneous basis of imatinib resistance, we have investigated the possible mechanism(s) via which hemin, a key regulator of hematopoiesis that is converted to heme intracellularly, renders CML cells less susceptible to imatinib. Hemin at 30-90 aM protected a substantial proportion (>40%) of human Bcr-Abl(+) CML cells (K-562 and KU-812) from imatinib-induced cell killing by increasing the imatinib IC50 value, reducing DNA damage, and promoting erythroid differentiation. RT-PCR assessment of RNA transcripts encoded by human GAPDH, Ggamma-globin, Bcr-Abl, HO-2, Hpr-6, CEBPa, Bcl-2a, Bcl-2b, and Nrf2 genes revealed that hemin selectively counteracted the repression of antiapoptotic Bcl-2a, Bcl-2b, and Nrf2 genes in imatinib-treated cells. These genes are markedly repressed by imatinib alone in human K-562 CML cells. Hemin, however, had no detectable effect on the expression of the Bcr-Abl gene. Moreover, inhibition of de novo heme biosynthesis by succinyl-acetone enhanced the killing effect of imatinib. These data clearly indicate that: (a) cellular heme resulted from de novo biosynthesis and hemin uptake alters the developmental stage of human Bcr-Abl(+) CML cells and their susceptibility to imatinib; (b) cellular heme counteracts the ability of imatinib to repress Bcl-2 and Nrf2 gene expression; and (c) inhibitors of de novo biosynthesis can be developed and combined with imatinib to enhance its antileukemic activity.
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PMID:Hemin counteracts the repression of Bcl-2 and NrF2 genes and the cell killing induced by imatinib in human Bcr-Abl(+) CML cells. 1980 84

Emodin (1,3,8-trihydroxy-6-methyl-anthraquinone), a natural anthraquinone derivative isolated from Rheum palmatum L, has been reported to exhibit anti-cancer effect on several human cancers such as liver cancers and lung cancers. However, the molecular mechanisms of emodin-mediated tumor regression have not been fully defined. Our preliminary study showed that emodin had highly cytotoxic effect on human chronic myeloid leukemia K562 cell lines. This study was performed to investigate the anti-tumor effect of emodin in human K562 cell line in vitro and in vivo. The MTT data showed the inhibition on growth of K562 cells following emodin treatment. Flow cytometry showed that the cell cycle of K562 cells was arrested in G(0)/G(1) phase. Through Western blot analysis, we found that the apoptosis-related protein Bcl-2 was decreased in a dose-dependent manner and the Bax was increased after emodin treatment. Moreover, activations of caspase-3, -8 and -9 were demonstrated in vitro and in vivo. The increased Bax concurrent with the decreased of Bcl-2 indicated that emodin treatment might result in apoptosis of K562 cells. The cell apoptosis was also directly demonstrated by Annexin V-FITC, and DNA fragmentation assay. Additionally, the tumoricidal effect of emodin was measured using a xenograft nude mice model. We found that, after inoculated with the K562 cells, the nude mice treated with emodin showed a significant decrease of tumor volume and tumor weight in comparison to the control. Emodin could cause the regression of tumor. Both in vitro and in vivo studies suggest that emodin can be developed as a promising anti-chronic myeloid leukemia drug.
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PMID:Anti-tumor activity of emodin against human chronic myelocytic leukemia K562 cell lines in vitro and in vivo. 1985 84

Curcumin (1), a natural polyphenolic compound, has shown strong antioxidant and anticancer activities. Several molecular mechanisms have been attributed to its inhibitory effects on a wide range of tumor cells. In this study, the response of the chronic myeloid leukemia cell line K562 cells to 1 is investigated. Curcumin inhibited the viability of K562 cells in a dose- and time-dependent manner. Furthermore, curcumin-induced cell death was associated with the formation of the apoptosome complex, the collapse of the mitochondrial membrane potential, and caspase-3 activation. Curcumin treatment also induced Bid cleavage and downregulated the expression of Bcl-2 protein. Surprisingly, even with these molecular features of apoptosis, we showed that 1 stimulated autophagy, which was evidenced by microtubule-associated protein light chain 3 (LC3) immunoreactivty. Curcumin also increased the protein levels of beclin 1 and membrane form LC3 (LC3-II). Autophagy inhibitor bafilomycin A1 and the pan-caspase inhibitor Z-VAD-fmk suppressed curcumin-induced K562 cell death. Overall, these results suggest that curcumin induces autophagic and apoptotic death of K562 cells. These findings suggest that both apoptotic and autophagic mechanisms contribute to the curcumin-induced K562 cell death.
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PMID:Autophagic and apoptotic mechanisms of curcumin-induced death in K562 cells. 2018 54

Meisoindigo, a derivative of Indigo naturalis, has been used in China for chronic myeloid leukemia. In vitro cell line studies have shown that this agent might induce apoptosis and myeloid differentiation of acute myeloid leukemia (AML). In this study, we explored its mechanisms and potential in AML. NB4, HL-60, and U937 cells and primary AML cells were used to examine its effects and the NOD/SCID animal model was used to evaluate its in vivo activity. Meisoindigo inhibited the growth of leukemic cells by inducing marked apoptosis and moderate cell-cycle arrest at the G(0)/G(1) phase. It down-regulated anti-apoptotic Bcl-2, and up-regulated pro-apoptotic Bak and Bax and cell-cycle related proteins, p21and p27. Furthermore, it induced myeloid differentiation, as demonstrated by morphologic changes, up-regulation of CD11b, and increased nitroblue tetrazolium reduction activity in all cell lines tested. In addition, meisoindigo down-regulated the expression of human telomerase reverse transcriptase and enhanced the cytotoxicity of conventional chemotherapeutic agents, cytarabine and idarubicin. As with the results from cell lines, meisoindigo also induced apoptosis, up-regulated p21 and p27, and down-regulated Bcl-2 in primary AML cells. The in vivo anti-leukemic activity of meisoindigo was also demonstrated by decreased spleen size in a dose-dependent manner. Taking these results together, meisoindigo is a potential agent for AML.
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PMID:Meisoindigo is a promising agent with in vitro and in vivo activity against human acute myeloid leukemia. 2023 51


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