-
[show abstract]
[hide abstract]
ABSTRACT: To investigate the effects of AML1B and AML1/ETO fusion gene on the transcription activity of TSC1 and TSC2 promotor and to explore its role in leukemogenesis.
The luciferase reporter plasmids of TSCs gene promoter containing a AML1 binding site were constructed, and cotransfected into CV-1 cells with AML1B or AML1/ETO expression plasmids separately. The transactivity of TSCs gene promoter was assayed by luminometer.
AML1B exhibited a transactivity to TSC2 gene promoter in a dosage-dependant manner, but showed no significant transactivity to TSC1's. The transactivity to TSC2 gene promoter showed 8.55 fold increase as companed with control group at 75 ng of pCMV5-AML/B. AML1/ETO showed a significant transactivity to TSC1, but no transactivity to TSC2's. However, AML1/ETO antagonized the effect of AMLlB to TSC2 gene promoter.
AML1B and AML1/ETO can regulate the transcription of TSC genes.
Zhonghua xue ye xue za zhi = Zhonghua xueyexue zazhi 12/2009; 30(12):804-7.
-
[show abstract]
[hide abstract]
ABSTRACT: Water temperature, pH, EC, TDS, ORP, Si and major anions (Cl- , NO3- and SO4(2-)) and major cations (Na+, K+, Ca2+ and Mg2+) in the Danjiangkou Reservoir, the water source area of the Middle Route of the South to North Water Transfer Project of China were monitored during the period of 2004-2006. Analysis of variance (ANOVA) and principal component analysis (PCA) were performed to explore their seasonal variations and origins. The results show that the water is slightly alkaline with an average pH ranging from 7.9 to 8.4. The water is HCO3- -Ca type with low mineralized degree, and its total dissolved solid ranges from 174.6-209.1 mg x L(-1). The major ions range are as follows: Cl-, from (4.0 +/- 0.5) mg x L(-1) to (6.9 +/- 1.8) mg x L(-1); NO3-, from (4.6 +/- 0.9) mg x L(-1) to (6.8 +/- 1.7) mg x L(-1); SO4(2-), from (24.3 +/- 2.7) mg x L(-1) to (35.4 +/- 6.9) mg x L(-1); HCO3-, from (133.0 +/- 11.7) mg x L(-1) to (153.5 +/- 29.6) mg x L(-1); Na+, from (2.0 +/- 0.3) mg x L(-1) to (5.3 +/- 1.0) mg x L(-1); K+, from (0.7 +/- 0.09) mg x L(-1) to (1.6 +/- 0.7) mg x L(-1); Ca2+, from (33.0 +/- 2.1) mg x L(-1) to (46.6 +/- 0.8) mg x L(-1); Mg2+, from (8.0 +/- 2.5) mg x L(-1) to (10.5 +/- 3.2) mg x L(-1). Statistical analyses indicate that the water quality variables display significant seasonal differences except HCO3 and Si. In general, major ion concentrations in flood season are relatively lower due to the dilution of precipitation. HCO3- accounts for 75%-88% of the total major anions, while Ca2+ and alkali-earth metals (Ca2+ + Mg2+) account for 60%-80% and 87%-96% of the total major cations respectively, reflecting that carbonic acid weathering is the main proton producer in the water. The major ions have no adverse effects on human according to water drinking quality guidelines of China and WHO.
Huan jing ke xue= Huanjing kexue / [bian ji, Zhongguo ke xue yuan huan jing ke xue wei yuan hui "Huan jing ke xue" bian ji wei yuan hui.] 01/2009; 29(12):3353-9.
-
[show abstract]
[hide abstract]
ABSTRACT: To investigate the expression of cell surface E-cadherin in leukemia cell and the correlation of cell membrane localization of beta-catenin with E-cadherin expression.
Bone marrow samples from 46 patients with acute leukemia and 17 normal donors were analyzed. Cell surface expression of E-cadherin and membrane localization of beta-catenin were labeled by immunofluorescence and analyzed with a laser scanning confocal fluorescence microscope in 14 specimens.
Cell surface E-cadherin expression level was significantly lower in leukemia cells (with the median fluorescent intensity of 16.78) than in normal hematopoietic progenitors (26.03). Correlation analysis showed that cell membrane localization of beta-catenin was correlated with E-cadherin expression (r = 0.74, P = 0.002). After E-cadherin was induced to express in leukemic cell by 5-Aza-CdR, membranous expression of beta-catenin was elevated while the nuclear expression reduced, indicating that E-cadherin-mediated adhesions could recruit beta-catenin to cell membrane.
The loss of E-cadherin in leukemia cells may result in beta-catenin translocating to the nuclear and transcriptional activation of its target genes.
Zhonghua xue ye xue za zhi = Zhonghua xueyexue zazhi 10/2008; 29(9):592-4.
-
[show abstract]
[hide abstract]
ABSTRACT: To explore the mechanism of PTEN gene expression silence in leukemia cells, and the effect of induced PTEN gene expression in leukemia cells.
Methylation status of PTEN in leukemic cell lines, including HL-60, Nalm-6, NB4, U937, Raji, K562 and KG-1a was assessed by methylation specific PCR (MSP). The cell lines were then treated with different concentrations of methyltransferase inhibitor 5-Aza-2'-deoxycytidine (5-Aza-CdR). After that the changes in PTEN methylation status were detected by MSP, and PTEN mRNA expression level by reverse transcription PCR (RT-PCR). Growth inhibition and apoptosis of HL-60 and Nalm-6 cells induced by 5-Aza-CdR were observed by MTT assay, and Wright and Annexin V staining, respectively.
Hypermethylation of PTEN promoter was detected in HL-60, U937, Nalm-6, Raji and KG-1a, while hypomethylation was found in NB4 and K562 by MSP. After 5-Aza-CdR treatment, the hypermethylation status of PTEN promoter in HL-60 and Nalm-6 cells was reversed and their PTEN mRNA expression levels were up regulated in dose dependent manner with the 5-Aza-CdR concentrations, and the cell apoptosis was induced.
Hypermethylation in the promoter region is one of major mechanisms responsible for transcriptional suppression of PTEN. Methyltransferase inhibitor could induce the expression of PTEN gene and lead to the leukemia cells apoptosis.
Zhonghua xue ye xue za zhi = Zhonghua xueyexue zazhi 06/2008; 29(5):289-92.
-
[show abstract]
[hide abstract]
ABSTRACT: To explore the signal transduction pathway in the differentiation and apoptosis of leukemia cells induced by heat shock protein 90 (HSP90) inhibitor 17-Allyl amide-17-demethoxygeldanamycin (17AAG).
Kasumi-1 cells were treated with increasing concentrations or exposure time of 17AAG. The total kit protein (CD117), phosphorylated kit protein and its downstream signaling molecules were measured by Western blot analysis. Mutated kit protein from control and 17AAG-treated Kasumi-1 cells was immunoprecipitated and immunoblotted for associated chaperones.
Total kit protein and kit activity were decreased in 17AAG treated cells, but c-kit mRNA level was not. Total AKT protein and phospho-AKT, as well as phospho-STAT3 were rapidly down-regulated in Kasumi-1 cell after treatment with 17AAG. There was no change in total STAT3 protein. Immunoprecipitation showed that 1 microM 17AAG treatment for 1 hour caused kit associated HSP90 decrease and HSP70 increase.
17AAG-induced apoptosis of Kasumi-1 cells is associated with a decline in Asn822Lys mutated kit protein level and phosphorylated kit, and with a downregulation in its downstream activated signaling molecules involved in proliferation. AKT is a client protein of HSP90. The changes of kit associated HSP90 and HSP70 satisfy the circulation mode of molecular chaperone complex.
Zhonghua xue ye xue za zhi = Zhonghua xueyexue zazhi 11/2007; 28(10):677-80.
-
[show abstract]
[hide abstract]
ABSTRACT: To investigate pig7 expression level in acute leukemia (AL) and its clinical significance and explore the possible mechanisms for pig7 silence in terms of methylation control.
Expression levels of pig7 mRNA in bone marrow samples from 138 patients with de novo AL and 21 normal controls and in 6 leukemic cell lines were detected by quantitative real-time reverse transcription PCR (RT-PCR). Differentiation induction effect by all-trans retinoic acid (ATRA) and concomitant change in pig7 expression were also monitored in NB4 cells. Endonuclease analysis was employed to determined the identity of pig7 transcript present in AL samples. Methylation specific PCR (MSP) was used to elucidate if hypermethylation was responsible for pig7 silence in AL.
Compared with that in normal control, pig7 expression was markedly decreased (0.62 vs 18.30, median, P < 0.01) in AL patients on progression (at diagnosis, relapse or refractory). No significant difference was observed between acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL). AL at diagnosis had a higher pig7 level than those with relapsed or refractory disease (1.43 vs 0.16, median, P < 0.05). The complete remission (CR) rate after chemotherapy was found to be significantly correlated with pig7 expression levels (P < 0.05). Differentiated NB4 cells showed an increased level of pig7 expression (from 1.61 +/- 0.72 to 44.75 +/- 3.93, P < 0.01). Only one form of pig7 transcripts i.e., Small integral membrane protein of late endosome (SIMPLE), was detected in AL patients. Hypermethylation of pig7 promoter was identified in K562 and HL-60 cells, in contrast to non-methylation predominant in U937 cells.
Aberrant down-regulation of pig7 provides novel insights into leukemogenesis and therapy response prediction in AL.
Zhonghua xue ye xue za zhi = Zhonghua xueyexue zazhi 09/2007; 28(8):532-6.
-
[show abstract]
[hide abstract]
ABSTRACT: To explore the relationship between CCAAT/enhancer binding protein alpha (C/EBPalpha) gene mutations and the development of acute myeloid leukemia (AML).
The whole coding region of C/EBPalpha gene were screened in 48 cases of AML and 11 normal subjects by PCR-single strand conformation polymorphism (PCR-SSCP) and sequencing.
C/EBPalpha mutations were detected in 5 of 48 AML patients. Four duplications and 1 deletion were confirmed by DNA sequencing. All of those are newly identified mutations.
Different mutation types of C/EBPalpha gene exist in a small number of patients with AML and might be related to the pathogenesis of some leukemias.
Zhonghua xue ye xue za zhi = Zhonghua xueyexue zazhi 06/2005; 26(5):299-302.
-
[show abstract]
[hide abstract]
ABSTRACT: Annonaceous acetogenins (ACG) are natural products found in the plant family Annonaceae and which strongly inhibited mitochondrial complex I. The inhibition of NADH oxidase of chicken liver mitochondria by three different structural ACG was studied here, and ACG was shown to have potent inhibitory activities similar to rotenone for NADH oxidase. The IC(50) values indicated that bis-adjacent tetrahydrofuran (THF) type squamocin C was more potent than non-adjacent bis-THF type squamostatin B, and the latter was more potent than non-THF type compound 1 in the assay. The roles of structural factors of ACG such as the terminal gamma-lactone, the features of other ring moieties and hydroxyl groups, as well as the alkyl chain were simply discussed in this study.
Biological & Pharmaceutical Bulletin 06/2003; 26(5):729-32. · 1.66 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: To study the inhibition of oxygen consumption by annonaceous acetogenins (ACG) and their structure-activity relationship (SAR).
The inhibition of oxygen consumption in chicken liver cell respiration by different structural ACG was studied by using oxygen electrode technique.
Six ACG showed potent inhibitory effects like rotenone which was a classical inhibitor of mitochondrial complex I, and was more potent than complex IV inhibitor KCN. The IC50 values of six ACG for inhibiting oxygen consumption suggested that bistetrahydrofuran (THF) ACG was 7-11 times more active than non-THF ACG, and A1-type ACG was more potent than A2-type ACG.
The terminal gamma-lactone was crucial for the inhibition of oxygen consumption. The distance between THF and gamma-lactone, the hydroxyl groups in the alkyl chain, were the important factors of SAR, but the 4-OH group possibly played some negative role in the exhibit of potent activity.
Yao xue xue bao = Acta pharmaceutica Sinica 11/2002; 37(10):818-20.
