Biomedical subjects

Qing-Hua Zhang

Publications and source records attributed to Qing-Hua Zhang.

10 recordsLinked to original sources

PubMed2006

Aberrant transcriptional regulation of the MLL fusion partner EEN by AML1-ETO and its implication in leukemogenesis.

The EEN (extra eleven nineteen) gene, located on chromosome 19p13, was cloned as a fusion with MLL from a patient with acute myeloid leukemia (AML) with translocation t(11;19)(q23;p13). In this study, we characterized the genomic structure of the EEN gene, including its 5' regulatory region and transcription start site (TSS). We found that Sp1 could bind to the guanine-cytosine (GC)-stretch of the EEN promoter and was critical for the normal EEN expression, whereas the leukemia-associated fusion protein AML1-ETO could aberrantly transactivate the EEN gene through an AML1 binding site. Of note, overexpressed EEN showed oncogenic properties, such as transforming potential in NIH3T3 cells, stimulating cell proliferation, and increasing the activity of transcriptional factor AP-1. Retroviral transduction of EEN increased self-renewal and proliferation of murine hematopoietic progenitor cells. Moreover, Kasumi-1 and HL60-cell growth was inhibited with down-regulation of EEN by RNAi. These findings demonstrate that EEN might be a common target in 2 major types of AML associated with MLL or AML1 translocations, and overexpression of EEN may play an essential role in leukemogenesis.

Acute Disease↗

PubMed2006

Correlation between genomic DNA copy number alterations and transcriptional expression in hepatitis B virus-associated hepatocellular carcinoma.

Human hepatocellular carcinoma (HCC) is one of the most common tumors worldwide, in which the genetic mechanisms of oncogenesis are still unclear. To investigate whether the genomic DNA copy number alterations may contribute to primary HCC, the cDNA microarray-based comparative genomic hybridization (CGH) analysis was here performed in 41 primary HCC infected by hepatitis B virus and 12 HCC cell lines. The resulting data showed that, on average, 7.25% of genome-wide DNA copy numbers was significantly altered in those samples (4.61+/-2.49% gained and 2.64+/-1.78% lost). Gains involving 1q, 6p, 8q and 9p were frequently observed in these cases; and whilst, losses involving Ip, 16q and 19p occurred in most patients. To address the correlation between the alteration of genomic DNA copy numbers and transcriptional expression, the same cDNA microarray was further applied in 20 HCC specimens and all available cell lines to figure out the gene expression profiles of those samples. Interestingly, the genomic DNA copy number alterations of most genes appeared not to be in generally parallel with the corresponding transcriptional expression. However, the transcriptional deregulation of a few genes, such as osteopontin (SPP1), transgelin 2 (TAGLN2) and PEG10, could be ascribed partially to their genomic aberrations, although the many alternative mechanisms could be involved in the deregulation of these genes. In general, this work would provide new insights into the genetic mechanisms in hepatocarcinogenesis associated with hepatitis B virus through the comprehensive survey on correlation between genomic DNA copy number alterations and transcriptional expression.

Adult↗

PubMed2006

Effect of short-term and long-term fasting on transcriptional regulation of metabolic genes in rat tissues.

Ninety-eight genes/ESTs with differential expressions in epididymal adipose tissue of fed and 3-day fasting (F3) rats were identified by microarray analysis. Genes for lipogenesis, glycolysis, and glucose aerobic oxidation were decreased in response to starvation. Further study was performed to investigate the expression patterns of these genes in rat tissues after short- and long-term starvations. The results of the increased expression of the pyruvate dehydrogenase kinase 4 (PDK4) gene and decreased pyruvate dehydrogenase (PDH) in rat muscle together with decreased fatty acid synthase (FAS) in rat adipose tissue after 1 day of fasting (F1) suggested from transcriptional level that glucose aerobic oxidation was down-regulated in rat muscle and synthesis of saturated fatty acids was inhibited in rat adipose tissue after short-term fasting. It was noted that the transcriptions of genes involved in the fatty acid oxidation, such as very-long-chain Acyl-CoA dehydrogenase (LCAH), Acyl-CoA oxidase (ACO), carnitine palmitoyltransferase-I (CPT-I), and carnitine-acylcarnitine translocase (CAT)L, were greatly increased in F1 rat liver, then began to decrease in F3 and 5-day fasting (F5) rat liver, combined with significantly increased serum non-esterified fatty acids (NEFA) in F1 rats and increased urea in F5 rats, suggesting that inhibition of the oxidation of lipid and not the decreased availability of these fuels may play an important role in the phase II-phase III of fasting transition in the long-term fasting rats.

Adaptation, Physiological↗

PubMed2006

Effects of withdrawal of Xuezhikang, an extract of cholestin, on lipid profile and C-reactive protein: a short-term time course study in patients with coronary artery disease.

OBJECTIVE: C-reactive protein (CRP) is considered a risk factor for coronary artery disease. In addition to its lipid-lowering properties, statin decreases the level of CRP. Abrupt cessation of statin therapy during treatment could increase CRP level independently of the elevation of serum lipids and the incidence of cardiac events in patients with atherosclerotic heart disease. Xuezhikang (XZK), an extract of cholestin, has a marked modulating effect on lipid and CRP concentrations in different study time course. However, no attention has been paid to the changes of lipid profile and CRP concentrations after withdrawal of XZK treatment. This study was designed to explore short-term time course effects on lipid profile and CRP concentrations after withdrawal of XZK treatment in coronary heart disease patients. MATERIALS AND METHODS: Seventy-five consecutive patients with documented coronary heart disease were randomly divided into three groups: 1. Pretreatment with XZK 1,200 mg daily for 6 weeks and then replaced by placebo (XZK discontinued group; n = 25); 2. Treatment with XZK 1,200 mg daily throughout the study (XZK continued group; n = 25); or 3. Placebo (no XZK group; n = 25). Lipid levels (total cholesterol, HDL-C, LDL-C and triglycerides) and CRP were assessed before receiving the XZK therapy, 1 day before discontinuation of XZK, and on days 1, 2, 3, 7 and 14 after discontinuation of XZK, respectively. RESULTS: After 6-week XZK treatment, the fasting total cholesterol, LDL-C, triglyceride and median hs-CRP concentrations decreased, whereas HDL-C concentration increased significantly (p < 0.001, respectively). At day 14 after discontinuation of XZK therapy, total cholesterol (15%), LDL-C (17%) and triglyceride (20%) significantly increased (p < 0.001, respectively), whereas HDL-C level (15%) significantly decreased (p < 0.05). The median level of CRP increased by 11, 65, 128, 103 and 101% on the first, second, third, seventh, and fourteenth day after withdrawal of XZK therapy (p > 0.05, <0.05, <0.001, <0.001, <0.001, compared with 1 day before withdrawal of XZK therapy, respectively). There was a prominent rebound of CRP concentration 3 days after discontinuation of XZK therapy. At this time point, hs-CRP concentration was higher than in the placebo group (p < 0.05). Seven to 14 days after discontinuation of XZK therapy, the hs-CRP concentration declined to a similar level as in the placebo group. No significant correlation was seen between the changes in hs-CRP and lipid profile at all time points. CONCLUSIONS: The level of hs-CRP increases on the second day after withdrawal of XZK and there is a prominent rebound 3 days after discontinuation of XZK therapy. The increase of CRP ends within 7 days, where lipids increase at 14 days after discontinuation of XZK therapy. The results may be clinically important for patients with coronary artery disease.

Anticholesteremic Agents↗

PubMed2005

Identification and characterization of a novel human histone H3 lysine 36-specific methyltransferase.

Histone methylation plays an important role in eukaryotic transcriptional regulation. A number of histone methyltransferases (HMTases) with distinct functions have been identified. The HSPC069/HYPB gene was originally isolated from the human hematopoietic stem/progenitor cells (HSPCs), and it was also identified as a huntingtin interacting protein, implicated in the pathogenesis of Huntington disease (HD). However, its biochemical function is poorly understood. Here we report the structural and functional characterization of the huntingtin interacting protein B (HYPB). 1) The triplicate AWS-SET-PostSET domains mediate a histone H3 lysine 36 specific HMTase activity. 2) A low charged region that is rich in glutamine and proline has been characterized as a novel transcriptional activation domain. The structural features of this region are evolutionarily conserved in vertebrates. 3) Coimmunoprecipitation assays indicate that HYPB protein associates with hyperphosphorylated RNA polymerase II (RNAPII) but not the unphosphorylated form. Furthermore, the RNAPII-association region of HYPB protein has been identified to encompass the C-terminal 142 amino acids. Thus, our results suggest that HYPB HMTase may coordinate histone methylation and transcriptional regulation in mammals and open perspective for the further study of the potential roles of HYPB protein in hematopoiesis and pathogenesis of HD.

Amino Acid Sequence↗

PubMed2005

Systems analysis of transcriptome and proteome in retinoic acid/arsenic trioxide-induced cell differentiation/apoptosis of promyelocytic leukemia.

Understanding the complexity and dynamics of cancer cells in response to effective therapy requires hypothesis-driven, quantitative, and high-throughput measurement of genes and proteins at both spatial and temporal levels. This study was designed to gain insights into molecular networks underlying the clinical synergy between retinoic acid (RA) and arsenic trioxide (ATO) in acute promyelocytic leukemia (APL), which results in a high-quality disease-free survival in most patients after consolidation with conventional chemotherapy. We have applied an approach integrating cDNA microarray, 2D gel electrophoresis with MS, and methods of computational biology to study the effects on APL cell line NB4 treated with RA, ATO, and the combination of the two agents and collected in a time series. Numerous features were revealed that indicated the coordinated regulation of molecular networks from various aspects of granulocytic differentiation and apoptosis at the transcriptome and proteome levels. These features include an array of transcription factors and cofactors, activation of calcium signaling, stimulation of the IFN pathway, activation of the proteasome system, degradation of the PML-RARalpha oncoprotein, restoration of the nuclear body, cell-cycle arrest, and gain of apoptotic potential. Hence, this investigation has provided not only a detailed understanding of the combined therapeutic effects of RA/ATO in APL but also a road map to approach hematopoietic malignancies at the systems level.

Antineoplastic Agents↗

PubMed2005

Detection of hepatitis B virus DNA by real-time PCR using TaqMan-MGB probe technology.

AIM: To develop a real-time PCR for detecting hepatitis B virus (HBV) DNA based on TaqMan technology using a new MGB probe. METHODS: Plasmid containing the sequence of X gene (1414-1744 nt) was constructed as HBV-DNA standard for quantitative analysis. A TaqMan-MGB probe between primers for amplification was designed to detect PCR products. The interested sequence contained in the plasmid and in clinical specimens was quantitatively measured. RESULTS: The detection limit of the assay for HBV DNA was 1 genome equivalent per reaction. A linear standard curve was obtained between 10(0) and 10(9) DNA copies/reaction (r>0.990). None of the negative control samples showed false-positive reactions in duplicate. HBV DNA was detected in 100% (50/50) of HBV patients with HbeAg, and in 72.0% (36/50) with HBsAg, HBeAb and HBcAb. The coefficient of variation for both intra- and inter-experimental variability demonstrated high reproducibility and accuracy. CONCLUSION: Real-time PCR based on TaqMan-MGB probe technology is an excellent method for detection of HBV DNA.

Base Sequence↗

PubMed2004

Functional contribution of EEN to leukemogenic transformation by MLL-EEN fusion protein.

The EEN (extra eleven nineteen) gene was originally cloned from a case of acute myeloid leukemia M5 subtype with translocation t (11; 19)(q23; p13), in which EEN was fused with MLL. To explore the involvement of EEN in leukemogenesis caused by MLL-EEN, we studied the transformation potential of the MLL-EEN fusion protein. MLL-EEN had oncogenic features, while, as a control, MLLDelta, the truncated form of MLL lacking the EEN moiety, did not show any oncogenic potential. MLL-EEN exerted a dominant-negative effect over wild-type EEN in terms of subcellular localization. Normally, EEN was found in the cytoplasm, but the MLL-EEN fusion protein was located in the nucleus, and EEN could be delocalized by MLL-EEN. This interaction is via a coiled-coil dimerization domain of EEN, which is reserved in the fusion protein. In addition, MLL-EEN might act as a potential transcriptional factor with the MLL part providing the DNA-binding domain and the EEN part providing the transcription activation domain, though EEN seems to have no direct role in transcriptional regulation. As an aberrant transcriptional factor, MLL-EEN could transactivate the promoter of HoxA7, a potential target gene of MLL.

Amino Acid Sequence↗

PubMed2004

A universal microarray for detection of SARS coronavirus.

Severe acute respiratory syndrome (SARS) is caused by the SARS coronavirus (SARS-CoV). There are many point mutations among SARS-CoV genome sequences. Previous studies suggested that the mutations are correlated closely with the SARS epidemic. It was found that the bases of six nucleotide positions (nt9404, nt9479, nt19838, nt21721, nt22222 and nt27827) with high-mutation rate have an important relationship with the SARS epidemic. For viral detection as well as genotyping, a universal microarray system was developed that combines RT-PCR and ligase detection reaction (LDR). The Zip Codes attached covalently to a slide remain constant and their complementary Zip Codes (cZip Codes) can be used for tagging target sequence, making the microarrays universal. The discriminating oligonucleotides contain on the 5' end "cZip Codes" that are used to direct LDR product to specific Zip Codes attached covalently to a slide. Since Zip Codes have no homology to either the target sequence or to other sequences in the genomes of both human host and SARS-CoV, there was no false signal due to mismatch hybridizations. 20 samples assayed with the universal microarray were confirmed by DNA sequencing, demonstrating that this microarray system is a promising diagnostic tool for detection and genotyping of the SARS-CoV.

Amino Acid Substitution↗

PubMed2003

[Preliminary analysis of gene expression profiles in oral cancer with microarray technique].

OBJECTIVE: To study the difference in gene expression between oral squamous cell carcinoma tissue and their surrounding normal tissue by microarray so as to investigate the preliminary mechanism of pathogenesis of oral cancer. METHODS: The tissues from 5 patients with oral squamous cell carcinoma tissue and their surrounding normal tissue from the same patients were analyzed by cDNA microarray technology(including 4124 genes). Total RNAs were isolated from two tissues, and then were reversely transcribed to cDNAs with the incorporations of fluorescent dUTP,for preparing the hybridization probes. The mixed probes were then hybridized to the cDNA microarray. After high-stringent washing, the cDNA microarray was scanned for the fluorescent signals and showed the differences between the two tissues. Bioinformatical analysis of those genes had been performed. RESULTS: Among the 4124 target genes, there were 37(0.89%)genes whose expression levels differed between the carcinoma and their surrounding normal tissues in all 5 cases. Bioinformatical analysis of those genes suggested that they may be related to the multistep process of carcinogenesis. CONCLUSION: cDNA microarray technique can simultaneously screen the different expressions of genes from 2 different kinds of tissue. Further analysis of the obtained genes will help to understand the molecular mechanism of malignant carcinoma.

Aged↗