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)

We investigated the in vitro efficacy of all-trans retinoic acid (ATRA) and alpha-tocopherol succinate (alpha-TS) alone and in combination on the induction of cell death in freshly isolated leukemic cells obtained from chronic myeloid leukemia (CML) patients. In vitro cytotoxicity and induction of lipid peroxidation by ATRA (10 microM) and alpha-TS (25 or 50 microM) were evaluated in primary leukemic cells by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay and malondialdehyde formation respectively. Treatment of leukemic cells with alpha-TS alone or in combination with ATRA significantly (P < 0.05) decreased the cell viability in a concentration and time dependent manner as compared to peripheral blood mononuclear cells obtained from normal healthy controls. Lipid peroxidation was enhanced by 98% (P < 0.05) on combined treatment of cells with ATRA (10 microM) and alpha-TS (50 microM). ATRA alone did not enhance the externalization of phosphatidyl serine as studied by annexin-V binding using fluorescence activated cell sorter analysis, whereas in combination with alpha-TS it increased to 400% at 12 h. The treatment of leukemic cells to combination of ATRA with alpha-TS significantly decreased (P < 0.05) mitochondrial membrane potential and enhanced lysosomal destabilization. The combination of these drugs also increased mitochondrial and cytosolic reactive oxygen species (ROS) production, nitric oxide levels, and caspase-3 activity significantly and caused DNA fragmentation at 24 h in a concentration dependent manner in the leukemic cells. Our data suggest that ATRA in combination with alpha-TS efficiently induces apoptosis in leukemic cells, which may be a useful therapeutic modality in CML patients.
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PMID:ATRA promotes alpha tocopherol succinate-induced apoptosis in freshly isolated leukemic cells from chronic myeloid leukemic patients. 1787 76

This study was aimed to investigate the effect of STI571, an inhibitor of tyrosine kinase, on the proliferation and apoptosis of chronic myelogenous leukemia (CML) cells as well as expression of anti-apoptotic protein Mcl-1, and to explore the possible role of Mcl-1 in apoptosis-inducing mechanism. K562 cell line was used to observe the effect of STI571 on CML cells. Proliferation and cytotoxicity were analyzed by MTT assay. The apoptotic cells were labelled with Annexin V-FITC and PI and then analyzed by flow cytometry. The expression of apoptotic-related proteins in K562 cells was determined by Western blot with specific antibodies. The results showed that STI571 significantly inhibited the proliferation and induced apoptosis of K562 cells in a dose-and time-dependent manner. Coincidently, the protein phosphorylation on tyrosine residues was reduced and the expressions of anti-apoptotic protein Mcl-1 and Bcl-xl were down-regulated after exposure to STI571. It is concluded that STI571 induces the apoptosis of CML cells by down-regulating the expressions of Mcl-1 and Bcl-xl, which suggests that Mcl-1 and Bcl-xl may play an important role in anti-apoptotic process of CML cells.
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PMID:[STI571 induces apoptosis of K562 cells through down-regulation of anti-apoptotic protein Mcl-1 and Bcl-xl expression]. 1808 62

Natural phytoestrogens such as the isoflavones genistein and daidzein, and the flavones quercetin exhibit anti-cancer properties. This study was purpose to investigate the anti-proliferative effect of phytoestrogens on acute myeloid leukemia (AML) and chronic myeloid leukemia (CML) cells, and their synergistic antileukemic effect in combination with chemotherapeutic drugs. Optimal dosage of genistein, quercetin and in combination with chemicals for leukemia cells were determined by experiments. Cell viability, apoptosis induction and cell cycle arrest were detected by trypan blue staining, MTT assay, optical microscopy, flow cytometry (FCM). The schedule treatment of combination of genistein and chemicals was determined. The results showed that genistein exhibited a dose- and time-dependent inhibitory effect on cell proliferation in NB4 and HL-60 cells, induced apoptosis and cell cycle arrest in G2/M phase. Quercetin had evident inhibitory effect on the proliferation of K562 and K562/A cells. The combination of genistein and chemicals exerted a synergistic effect on cell growth inhibition. In conclusion, this study demonstrated the synergistic antileukemic effect of genistein with chemotherapeutic drugs on leukemic cells. This combination appears to be a new idea for the clinical novel treatment of leukemia.
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PMID:[Synergistic antileukemic effect of phytoestrogens and chemotherapeutic drugs on leukemic cell lines in vitro]. 1842 48

In order to investigate the effect of shRNA targeted to beta-catenin on the growth of K562 cells, plasmid containing beta-catenin specific shRNA sequence was transfected into K562 cells by lipofectamine 2000, and G418 was added to screen the positive cells. Real-time PCR and Western blot were used to detect the expression of beta-catenin. Cell growth curve, MTT and colony forming cell assays were used to evaluate the proliferation potential of cells. The results showed that the mRNA level of beta-catenin was reduced significantly in K562 cells transfected into interfering plasmid as compared with control plasmid, while the protein level failed to demonstrate difference by the time of 72 hours after transfection. After long-term culture with G418, the count of positive cells enhanced in control group while no positive cells survived in the interfering group. Colony-forming cell assays revealed that the K562 cells in interfering group formed colonies with very small size and low forming rate, compared with the control group, though the growth curve and MTT failed to illustrate differences. It is concluded that the beta-catenin-specific shRNA mediated by plasmid can effectively knockdown the expression of beta-catenin gene and inhibit the colony-forming ability in K562 cells, it is a potential target for the therapy of CML, even in blast crisis.
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PMID:[Effect of shRNA targeted to beta-catenin on K562 cell growth]. 1871 47

This study was aimed to investigate the possible influence of a novel E3 ubiquitin ligase CHIP (carboxyl terminus of Hsc70/Hsp70-interacting protein) on biological characteristics of cancer cells. Stable overexpression models in CML K562 cells were established via lipofectamine-mediated wild type CHIP and its TPR or U-box deletion mutants gene transfection. Followed G418 pressure selection, K562-CHIP stable transfected cell clones were obtained by limited dilution. The proliferation status and cell cycle were observed by MTT assay and FACS. The expression of related proteins and morphological changes were detected by Western blot and Wright-Giemsa staining. The results showed that overexpression of wild type CHIP did not inhibit cell proliferation, but slightly increased cell ratio of G(2)/M phase. CHIP gene had no effect on the stability of BCR-ABL kinase protein. HDAC inhibitor FK228-induced BCR-ABL degradation did not enhanced by CHIP. Notably the enlarged cells and abnormal mitotic cells remarkably increased in K562 WT-CHIP cells, indicating that CHIP may involve in the regulation of mitotic process. It is concluded that wild type CHIP induces mitotic abnormity in K562 cells.
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PMID:[Overexpression of CHIP in chronic myeloid leukemia K562 cells induces mitotic abnormality]. 1871 56

To study the structure activity relationship (SAR) on the cytotoxic activity and probe the structural requirement for the potent antitumor activity, a series of novel diazaspiro bicyclo hydantoin derivatives were designed and synthesized. Their structures were confirmed by (1)H NMR, LCMS and IR analyses. The antiproliferative effect of these compounds were determined against human leukemia, K562 (chronic myelogenous leukemia) and CEM (T-cell leukemia) cells using trypan blue and MTT assay, and the SAR associated with the position of N-terminal substituents in diazaspiro bicyclo hydantoin have also been discussed. It has been observed that these compounds displayed strong, moderate and weak cytotoxic activities. Interestingly, compounds having electron withdrawing groups at third and fourth position of the phenyl ring displayed selectively cytotoxic activities to both the cell lines tested with IC(50) value lower than 50 muM. In addition, the cytotoxic activities of the compounds 7(a-o) bearing the substituents at N-3 position of diazaspiro bicyclo hydantoin increases in the order alkene > ester > ether and plays an important role in determining their antitumor activities. The position and number of substituents in benzyl group attached to N-8 of diazaspiro bicyclo hydantoin nucleus interacted selectively with specific targets leading to the difference of biochemical and pharmacological effects.
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PMID:Synthesis and in vitro cytotoxic evaluation of novel diazaspiro bicyclo hydantoin derivatives in human leukemia cells: a SAR study. 1883 66

This study was aimed to investigate the effect of tyrosine kinase inhibitor (STI571) on growth and proliferation of K562 cells by using microarray method, the changes of gene expression in the process of K562 cell apoptosis induced by STI571 and the mechanism of K562 cell apoptosis. The gene microarray probes were prepared by RD-PCR technique, then the microarray of gene expression map was constructed; the morphologic changes of K562 cells were observed under phase-contrast microscopy before and after treatment with STI571; the apoptosis of K562 cells treated with STI571 was assayed by MTT method; the expression level of genes was analyzed by self-made microarray. The results indicated that after the treatment of STI571 for 24 hours, in K562 cells appeared major morphological changes, which included nuclear shrinkage, membrane bleb and scattered apoptotic bodies. DNA gel electrophoresis also showed that the typical "DNA ladder" phenomena existed in the treated group. After hybridization, detection and analysis with microarray method, expression of 9 genes significantly down-regulated and expression of 4 genes up-regulated. These differentially expressed genes included cell cycle related genes, cell metabolizing pathway related genes, signal transduction and transcription regulation related genes and antiapoptosis genes. It is concluded that STI571 can effectively inhibit the K562 cell growth and induce K562 cell apoptosis. The genes screened from this microarray offer new information for exploration of pathogenesis of K562 cell malignant transformation and shows abundant potential targets for the treatment of CML.
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PMID:[Signal pathway in apoptosis of K562 cells induced by STI571]. 1892 85

This study was aimed to compare HHGV678 with imatinib (IM) in growth inhibition of Bcr-Abl wild type and IM-resistant cell lines, investigate the possibility of replacing IM with HHGV678 in treatment of chronic myeloid leukemia (CML) and IM-resistant CML patients. Viability of two Bcr-Abl wild type cell lines (K562 and 32Dp210) and 16 IM-resistant cell lines (K562R and 15 Bcr-Abl point mutant cell lines) treated with HHGV678 and IM was analyzed by MTT. The apoptosis of those cells was identified by flow cytometry with Annexin V staining and DNA ladder analysis. Western blot was applied for detecting the expression of Bcr-Abl and phosphotyrosine protein levels. The results indicated that HHGV678 significantly inhibited the growth of two Bcr-Abl wild types and IM-resistant cell lines in dose-dependent manner except cell line of T315I point mutant. IC(50) results showed that the growth inhibition of HHGV678 was 15.5 and 28-fold higher than that of IM in K562, 32Dp210 and 1.4 to 124.3-fold higher than that of IM in 15 IM-resistant cell lines respectively. Compared with IM, HHGV678 more significantly inhibited phosphotyrosine kinase protein of the cells mentioned above at different concentrations. With most importance, HHGV678 of 10.0 micromol/L induced cell apoptosis of 40.06% and 33.32% in K562R and 32Dp210(T315I) cell lines, which were much higher than that of IM (19.77% and 10.68%). It is concluded that HHGV678 is more effective than IM in the growth inhibition of Bcr-Abl wild type cell lines and IM-resistant cell lines, especially in strongest IM-resistant cell lines. Further studies are needed to show whether HHGV678 may be a novel targeting drug in treatment of CML and IM-resistant CML patients.
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PMID:[Effect of a novel tyrosine kinase inhibitor HHGV678 on growth inhibition of Bcr-Abl wild type and IM-resistant cell lines in vitro]. 1892 91

Programmed death-1 ligand-1(PD-L1) is a recently identified member of the B7 family molecules and is shown to mediate the inhibition of immune responses. This study was purposed to enhance the weak immunological function of dendritic cells (DCs) derived from the patients with chronic myelocytic leukemia (CML) by blockade of the expression of PD-L1. Bone marrow mononuclear cells (BMMNCs) of CML patients were induced into DCs in the presence of cytokine cocktail of rhGM-CSF, rhIL-4 and TNF-alpha. The phenotypes of DCs were detected by flow cytometry, mixed lymphocyte reaction was analyzed by MTT assay and IFN-gamma, IL-2 and IL-10 in the cell culture supernatant were detected by ELISA. The results showed that the expression of PD-L1 on CML-DCs was upregulated with the maturation of CML-DCs. PD-L1-blockaded DCs could enhance T lymphocyte proliferation, increase the secretion of IL-2 and IFN-gamma, and inhibit the production of IL-10. Taken together, PD-L1-blockaded DCs originated from CML cells had more potent immunostimulatory capability. It is concluded that PD-L1 blockaded can enhance the function of CML-DCs. This approach presents new possibilities for achieving anti-tumor immunity by DC-based vaccination.
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PMID:[Effect of PD-L1 blockade on function of dendritic cells derived from chronic myelocytic leukemia]. 1892 14

Bmi-1 is a transcriptional repressor, which belongs to the polycomb group family. It has been demon- started that over-expression of Bmi-1 occurs in a variety of cancers, including several types of leukemia. Bmi-1 gene plays a key role in regulation of self-renewal in normal and leukemic stem cells. Acute myeloid leukemic cells lacking Bmi-1 undergo proliferation arrest and show signs of differentiation and apoptosis, which leads to the proposal of Bmi-1 as a potential target for therapeutic intervention in leukemia. The purpose of this study was to investigate the effect of short hairpin RNA (shRNA) targeting Bmi-1 on functions of K562 cell line. The shRNA eukaryotic expression vector targeting Bmi-1 was constructed and transfected into K562 cells through lipofectamine 2000. The mRNA and protein levels of Bmi-1 were detected by PCR and Western blot respectively. The proliferation of K562 after Bmi-1 silencing was measured by using MTT assay and clone formation assay. The cell cycle was detected by flow cytometry. The results indicated that among the four shRNA designed, there was a shRNA which efficiently interfered with the expression of Bmi-1. The results of PCR and Western blot validated that the Bmi-1 gene of K562 cells transfected with such a Bmi-1 shRNA was suppressed successfully. Although levels of Bmi-1 mRNA and protein were significantly reduced, delivery of this siRNAs had no effect on cell viability or growth. Flow cytometry analysis suggested that Bmi-1 inhibition did not affect the cell cycle. It is concluded that the suppression of Bmi-1 expression is not able to reduce proliferation of K562 cells, suggesting existence of some other parallel signaling pathways, which are fundamental for leukemic transformation and are independent of Bmi-1 over-expression. Bmi-1 over-expression may play a secondary role in chronic myeloid leukemia transformation.
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PMID:[Effect of silencing bmi-1 by RNA interference on function of K562 cell line]. 1937 48


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