OBJECTIVE: To develop an HPLC method for simultaneous determination five eatechins, including (+)-catechin, epicatechin, (-)-epigallocatechin, (-)-epicatechin gallate and (-)-epigallocatechin-3-gallate, as well as caffeine in Oolong tea. METHODS: The HPLC analysis was carried out on a Grace Allitima C18 column (4.6 mm × 250 mm, 5 μm), with a gradient elution acetonitrile-0.2% acetic acid at the flow rate 1.0 mL · min-1. The detective wave length was set at 280 nm, and the column temperature was set at 35℃. RESULTS: The calibration curve was linear within the range 5.95-952 μg · mL-1 for catechin, 6.36-1018 μg · mL-1 for epicatechin, 6.55-1048 μg · mL-1 for epigallocatechin, 7.80-1248) μg · mL-1 for epigallocatechin gallate, 10.83-1732 μg · mL-1 for epigallocatechin-3-gallate, and 13.38-2 140 μg · mL-1 for caffeine, respectively. The average recoveries for six determined marker compounds were 99.12%-102.12%. CONCLUSION: This method is simple, accurate, and practical for quality control Oolong tea. There are some differences in the contents the six marker compounds in the samples from different producing areas and different collection periods.

OBJECTIVETo study the potential effects of exogenous WT1 gene isoform on the differentiation of leukemia cell line NB4 and its possible molecular mechanisms.

METHODSThe recombinant eukaryotic expression vector (pCB6 + /WTA) containing full-length human WT1 isoform (WTA: -17AA/ -KTS) cDNA and the blank pCB6 + vector were transfected into leukemia cell line NB4 by electroporation. The WTA mRNA and protein in cells were detected by RT-PCR and Western blot. Cell morphology, NBT reduction and CD11b antigen expression in NB4 cells were assayed to evaluate cell differentiation. Expression of PML/RARalpha, p21 and c-myc genes was determined by semi-quantitative RT-PCR after transfection.

RESULTSCompared with NB4/WTA cells, NB4 and NB4/CMV (NB4 cells transfected with pCB6 + vector) cells had higher morphological differentiation rates and higher CD11b expression levels after exposure to ATRA for 48 hours. The percentage of NBT reduction in NB4/WTA cells was lower than that in control groups. The difference in NBT reduction rate between NB4/WTA and control cells was gradually increased after treated with ATRA for three days. The expression levels of PML/RARalpha, p21 and c-myc genes in NB4/WTA cells were notably increased.

CONCLUSIONOverexpression of exogenous WTA gene could partially inhibit the differentiation of NB4 cells by up-regulating the expression of PML/RARalpha, p21 and c-myc genes.

Cell Cycle ; Cell Differentiation ; genetics ; Cell Line, Tumor ; Cyclin-Dependent Kinase Inhibitor p21 ; metabolism ; Gene Expression Regulation, Neoplastic ; Genetic Vectors ; Humans ; Leukemia, Promyelocytic, Acute ; genetics ; metabolism ; pathology ; Proto-Oncogene Proteins c-myc ; metabolism ; RNA, Messenger ; genetics ; Transfection ; WT1 Proteins ; genetics ; metabolism

OBJECTIVETo study the DNA methylation status of WT1 gene promoter region in hematologic malignancy cell lines and its correlation with WT1 gene expression.

METHODS1. RT-PCR and methylation-specific PCR were performed for detecting WT1 gene expression and DNA methylation status in its promoter region in 8226, HL-60, Jurkat, K562, KG-1, NB4, Raji, SHI-1, U266 and U937 cell lines. 2. Treatment of U937 cells with 5-aza-CdR, a demethylation inducing agent and the changes in WT1 gene expression level and its promoter region methylation status were determined.

RESULTS1. HL-60, K562, KG-1, NB4 and SHI-1 cells showed higher levels while 8226, Jurkat, Raji, U266 and U937 cells showed extremely low levels of WT1 expression. DNA hypermethylation in WT1 gene promoter region was identified in 8226, Jurkat, Raji, U266 and U937 cells. 2. The WT1 gene expression in U937 was enhanced after treatment with 5-aza-CdR accompanied with the decrease of methylated and the increase of unmethylated levels in its promoter region.

CONCLUSIONModulation of the DNA methylation status in WT1 promoter region is one of the epigenetic mechanisms for regulating its expression.

Cell Line, Tumor ; DNA Methylation ; Gene Expression Regulation, Neoplastic ; Hematologic Neoplasms ; genetics ; Humans ; Promoter Regions, Genetic ; genetics ; WT1 Proteins ; genetics

OBJECTIVETo investigate retinoblastoma (Rb) associated protein 46 (RbAp46) gene expression levels in bone marrow (BM) cells of leukemia patients.

METHODSReal-time quantitative reverse polymerase chain reaction (QRT-PCR) method was used for detecting RbAp46 expression levels in BM cells of 140 patients with acute leukemia (AL), 13 with chronic myelogenous leukemia in chronic phase (CML-CP), 7 with CML in blast crisis (CML-BC) and 32 with non-leukemic disorders.

RESULTSThe M-Estimators of RbAp46 were higher in 98 newly diagnosed ALs and 5 relapsed ALs than in 28 ALs in complete remission (CR) and 32 non-leukemic controls (178.23 and 213.65 vs 85.89 and 88.08, respectively). No statistic difference was found between the CR group and control group, or between the newly diagnosed group and relapsed group. The M-Estimators of RbAp46 in patients with CML-CP was 58.27, similar to that in control, but much lower than that in CML-BC (173.24). Among 98 newly diagnosed ALs, the M-Estimators of RbAp46 in M(3) and M(4) were the lowest in all of the subtypes. Furthermore, the RbAp46 expression levels were not correlated with the expression of the fusion genes of bcr/abl, PML-RARalpha, and multidrug resistant gene (mdr1), but were positively correlated with Wilms' tumor gene (WT1) expression levels and negatively with AML1/ETO fusion gene expression.

CONCLUSIONRbAp46 expression levels in ALs and CML-BC were strikingly higher than that in non-leukemias and CML-CP, and might participate in leukemogenesis.

Adolescent ; Adult ; Aged ; Carrier Proteins ; genetics ; metabolism ; Child ; Female ; Gene Expression ; Humans ; Leukemia ; genetics ; metabolism ; Male ; Middle Aged ; Nuclear Proteins ; genetics ; metabolism ; Retinoblastoma-Binding Protein 7 ; Reverse Transcriptase Polymerase Chain Reaction ; methods

The aim of this study was to construct venus vector carrying the gene encoding insulin-like growth factor binding protein 7 (IGFBP7), which provides an effective platform for exploring the function of this gene in leukemia. After digestion by restriction endonuclease, the IGFBP7 gene was recombined with the transfer plasmid. The venus particles were packaged using 293T cells to transfect K562 cells, and identification was performed by means of flow cytometry, RT-PCR and Western blot. The results showed that the sequence of cloned IGFBP7 gene was the same as that in GenBank. The size of product restricted by BamHI was same as the predicted one. GFP expression was observed in 293T and K562 cells with the fluorescent microscopy and flow cytometry. The expression level of mRNA and protein of IGFBP7 was confirmed by RT-PCR and Western blotting in K562 cells. It is concluded that venus vector carrying IGFBP7 gene has been successfully constructed and provides basis for exploring function of IGFBP7 in K562 cells.
Cloning, Molecular ; Gene Expression ; Genetic Vectors ; Humans ; Insulin-Like Growth Factor Binding Proteins ; genetics ; K562 Cells ; Lentivirus ; genetics ; Plasmids ; Transfection

In order to study the potential of Venus, lentiviral vector, applied to acute myeloid leukemia, the recombinant vector Venus-C3aR was transfected into 293T packing cells by DNA-calcium phosphate coprecipitation. All virus stocks were collected and transfected into HL-60, the GFP expression in HL-60 cells was measured by flow cytometry. The expression level of C3aR1 in transfected HL-60 cells was identified by RT-PCR and flow cytometry. The lentiviral toxicity on HL-60 was measured by using CCK-8 method and the ability of cell differentiation was observed. The results indicated that the transfection efficacy of lentiviral vector on HL-60 cells was more than 95%, which meets the needs for further study. C3aR1 expression on HL-60 cells increased after being transfected with recombinant lentiviral vector. Before and after transfection, the proliferation and differentiation of cells were not changed much. It is concluded that the lentiviral vector showed a high efficacy to transfect AML cells and can be integrated in genome of HL-60 cells to realize the stable expression of interest gene. Meanwhile, lentiviral vector can not affect HL-60 cell ability to proliferate and differentiate.
Genetic Vectors ; HL-60 Cells ; Humans ; Lentivirus ; genetics ; Transfection

OBJECTIVETo evaluate the significance of quantitative detection of CCAAT/enhancer binding protein zeta (C/EBP zeta) transcripts in patients with chronic myeloid leukemia (CML).

METHODSReal-time quantitative polymerase chain reaction (RQ-PCR) assay was established and performed to measure the transcript level of C/EBP zeta in the bone marrow mononuclear cells from 76 patients with CML at different stages.

RESULTSC/EBP zeta transcripts were significantly decreased in CML patients in chronic phage, accelerated phage, and blastic crisis (median 2.5, 3.31, and 2.22, respectively), compared to that in normal controls (median 12.20). Further down-regulation of C/EBP zeta was observed in the patients resistant to interferon (median 1.56); however, its expression level returned to normal in the patients who obtained complete cytogenetic remission (median 15.43).

CONCLUSIONC/EBP zeta was down-regulated in CML patients, which might play a role in the leukemogenesis.

CCAAT-Enhancer-Binding Proteins ; genetics ; Humans ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive ; genetics ; Reverse Transcriptase Polymerase Chain Reaction ; methods ; Transcription, Genetic

Acute Disease ; Blast Crisis ; genetics ; Genes, Retinoblastoma ; Genes, Wilms Tumor ; Humans ; Leukemia ; genetics ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive ; pathology ; Polymerase Chain Reaction ; U937 Cells

OBJECTIVETo explore the hematopoietic pathophysiology of myelodysplastic syndrome (MDS) at stem/progenitor cell level by analyzing the gene expression profiles associated with hematopoiesis.

METHODSThe differentially expressed genes which were involved in the hematopoiesis were screened by microarray using CD34(+) cells from MDS patients firstly. RQ-PCR was then applied to validate the screened genes using CD34(+) cells from MDS-RA patients who had normal karyotype. The linkages with hematopoiesis among these validated genes were analyzed.

RESULTSAmong the differentially expressed genes in CD34(+) cells of MDS-RA patients, Rap1GAP was up-regulated significantly (P < 0.01). Cadherins, which can interplay with Rap1, including N-cadherin and E-cadherin, were down-regulated significantly (P < 0.01). β-catenin, a downstream effector of cadherins, was highly expressed in MDS-RA patients (P < 0.01). c-myc binding protein was down-regulated (P < 0.01), and c-myc promoter binding protein was up-regulated (P < 0.01). Rac1, Rac2 and Cdc42, which belong to RhoGTPases family and are associated with the cell morphology and hematopoiesis, were all expressed highly in MDS-RA patients (P < 0.01).

CONCLUSIONThe abnormal expression of cadherin, β-catenin and c-myc associated genes were closely related to the dysplastic hematopoiesis of MDS. The down regulation of cadherin was associated with the positive feedback mechanism between Rap1 and cadherin. The aberrant expression of Rac1, Rac2 and Cdc42 may contribute to the morphological dysplasia of MDS.

Cadherins ; genetics ; metabolism ; Gene Expression ; Gene Expression Profiling ; Genes, myc ; Humans ; Myelodysplastic Syndromes ; genetics ; metabolism ; beta Catenin ; genetics ; rap1 GTP-Binding Proteins ; genetics ; metabolism

OBJECTIVETo explore the effect of down-regulation of insulin-like growth factor binding protein 7 (IGFBP7) on the proliferation and invasiveness of leukemia cell line U937 cells.

METHODSThree pairs of double-strand siRNA targeting IGFBP7 gene were transfected into SMMC7721 cells to select the most efficient one for U937 cells. qRT-PCR and Western blot were used to detect the expression of IGFBP7 in U937 cells after transiently transfected with siRNA of IGFBP7. Cell proliferation, adhesion, trans-endothelial migration and invasion were performed in transfected cells and control groups.

RESULTSAfter transfected with siRNA of IGFBP7 in U937 cells, the ability of cell proliferation was significantly decreased at 24 h (0.580 ± 0.159) compared to that of parental cells and scramble negative control (1.049 ± 0.274, 0.946 ± 0.195, respectively) (P < 0.01). Adhesion of U937 cells transfected with IGFBP7 gene specific siRNA to ECV304 cells was significantly lower than that of the control groups (0.247 ± 0.031 vs 0.406 ± 0.023 and 0.395 ± 0.011) (P < 0.01). Transendothelial membrane of U937 cells into the bottom of the 24-well plate for experimental group were less than those in the control groups \[(0.387 ± 0.021)×10(5) vs (1.017 ± 0.031)×10(5) and (0.908 ± 0.027)×10(5)\]. Cells adherent to the matrigel for experimental group were less than those in the control groups \[(0.197 ± 0.098)×10(5) vs (0.493 ± 0.067)×10(5) and (0.469 ± 0.083)×10(5)\]. The difference was significant (P < 0.01).

CONCLUSIONIGFBP7 gene plays a contributing role in leukemogenesis involving in leukemic cells' proliferation and interaction with endothelial cells through adhesion, invasion and migration.

Cell Proliferation ; Down-Regulation ; Humans ; Insulin-Like Growth Factor Binding Proteins ; genetics ; metabolism ; Leukemia, Myeloid, Acute ; metabolism ; pathology ; Transfection ; U937 Cells