👤 Caiyan Liang

To find out the mechanisms of HBx gene inducing oval cell malignant transformation into hepatoma carcinoma cell. The changes of morphology, cell cycle, differentiated markers, c-myc and TGF-alpha in pEGFP-HBx oval cells strain, which stably expressed HBx gene, were studied by inversion phase contrast microscope and transmission electron microscopy, flow cytometry, periodic acid-schiff (PAS) staining, soft agar growth assay, real-time PCR, immunocytochemistry. pEGFP-oval cells and LE/6 oval cells were used as control groups. (1) The pEGFP-HBx oval cells showed bigger in size with malformed nucleus as compared with control groups. (2) Flow cytometry showed that, in contrast with the control groups, the proportion of pEGFP-HBx oval cells arrested in G0/G1 phase decreased but in S or G2/M phase rose. Moreover, the population of aneuploid cells increased obviously. (3) PAS staining showed that there were many glycogen granules in the cytoplasm of pEGFP-HBx oval cell. (4) The pEGFP-HBx oval cell formed colonies in the soft agar. (5) Compared with the control groups, the expression of HNF-4 alpha, AFP, c-myc and TGF-alpha rose obviously, whereas the expression of CK-7 and CK-19 decreased. And the expression of cps1 mRNA was not in the extent of detection. The HBx gene can provoke abnormal differentiation of oval cell and induce oval cell malignant transformation. Show less

Androgen deprivation is commonly used in the treatment of metastatic prostate cancer. The (-)-gossypol enantiomer has been demonstrated as an effective inhibitor of Bcl-2 in the treatment of prostate cancer. However, the mechanism of gossypol as an inhibitor of androgen biosynthesis is not clear. The present study compared (+)- and (-)-gossypols in the inhibition of 3beta-hydroxysteroid dehydrogenase (3beta-HSD) and 17beta-HSD isoform 3 (17beta-HSD3) in human and rat testes. Gossypol enantiomers were more potent inhibitors of rat 3beta-HSD with IC(50)s of approximately 0.2microM compared to 3-5microM in human testes. However, human 17beta-HSD3 was more sensitive to inhibition by gossypol enantiomers, with IC(50)s of 0.36+/-0.09 and 1.13+/-0.12 for (-)- and (+)-gossypols, respectively, compared to 3.43+/-0.46 and 10.93+/-2.27 in rat testes. There were species- and enantiomer-specific differences in the sensitivity of the inhibition of 17beta-HSD3. Gossypol enantiomers competitively inhibited both 3beta-HSD and 17beta-HSD3 by competing for the cofactor binding sites of these enzymes. Gossypol enantiomers, fed orally to rats (20mg/kg), inhibited 3beta-HSD but not 17beta-HSD3. This finding was consistent with the in vitro data, in which rat 3beta-HSD was more sensitive to gossypol inhibition than rat 17beta-HSD3. As the reverse was true for the human enzymes, gossypol might be useful for treating metastatic prostate cancer. Show less

The apolipoprotein (apo) AI/CIII/AIV/AV cluster genes are expressed at different levels in the liver and intestine. The apoCIII enhancer, a common regulatory element, regulates the tissue-specific expression of apoAI, apoCIII, and apoAIV but not apoAV. To study this regulation at the chromatin level, the histone modifications and intergenic transcription in the human apoAI/CIII/AIV/AV cluster were investigated in HepG2 and Caco-2 cells and in the livers of transgenic mice carrying the human gene cluster constructs with or without the apoCIII enhancer. We found that both the promoters and the intergenic regions of the apoAI/CIII/AIV genes were hyperacetylated and formed an open subdomain that did not include the apoAV gene. Hepatic and intestinal intergenic transcripts were identified to transcribe bidirectionally with strand preferences along the cluster. The deletion of the apoCIII enhancer influenced both histone modification and intergenic transcription in the apoAI/CIII/AIV gene region. These results demonstrate that the apoCIII enhancer contributes to the maintenance of an active chromatin subdomain of the apoAI/CIII/AIV genes, but not apoAV. Show less

Epstein-Barr virus (EBV) infection plays a key role in the pathogenesis of nasopharyngeal carcinoma (NPC). This study was to explore the effects of the recurrent infection by EBV reactivation on the genomic expression profile of NPC. The microarray expression data from different cell lines subjected to primary infection of EBV+ vs. EBV- targets in NPC and recurrent EBV reactivation were collected from public data depository. Cross comparison, t-test analysis as well as filtering by flag, expression level and fold change were used to analyze the data and identify differential genes. Moreover, a set of web-based applications, such as DAVID (database for annotation, visualization and integrated discovery), pSTIING (protein, signaling, transcriptional interactions and inflammation networks gateway), GATHER (gene annotation tool to help explain relationships) and TELiS (transcription element listening system), were used to analyze and predict the probable expression profile of the differential genes. As compared with the genes expressed during primary infection of EBV, 25 genes, including DUSP1, TOP1, HOXA9, DEK, PABPC1 and IMPDH2, were differentially expressed during EBV reactivation. Many of them were oncogenic. The differential genes together with related transcriptional factors were interacted mainly through 2 mechanisms: one mainly included TOP1, DUSP1, DUSP6, and RPS28; the other one was a circuit of PITX1, CD9, HOXA9 and IMPDH2. The differential genes might participate in EBV reactivation by changing their expression level through two mechanisms, which contributes to the final development of NPC. Show less

The current study examined the effects of operant ethanol (EtOH) self-administration on gene expression kin the nucleus accumbens (ACB) and amygdala (AMYG) of inbred alcohol-preferring (iP) rats. Rats self-trained on a standard two-lever operant paradigm to administer either water-water, EtOH (15% v/v)-water, or saccharin (SAC; 0.0125% g/v)-water. Animals were killed 24 h after the last operant session, and the ACB and AMYG dissected; RNA was extracted and purified for microarray analysis. For the ACB, there were 513 significant differences at the p<0.01 level in named genes: 55 between SAC and water; 215 between EtOH and water, and 243 between EtOH and SAC. In the case of the AMYG (p<0.01), there were 48 between SAC and water, 23 between EtOH and water, and 63 between EtOH and SAC group. Gene Ontology (GO) analysis indicated that differences in the ACB between the EtOH and SAC groups could be grouped into 15 significant (p<0.05) categories, which included major categories such as synaptic transmission, cell and ion homeostasis, and neurogenesis, whereas differences between the EtOH and water groups had only 4 categories, which also included homeostasis and synaptic transmission. Several genes were in common between the EtOH and both the SAC and water groups in the synaptic transmission (e.g., Cav2, Nrxn3, Gabrb2, Gad1, Homer1) and homeostasis (S100b, Prkca, Ftl1) categories. Overall, the results suggest that changes in gene expression in the ACB of iP rats are associated with the reinforcing effects of EtOH. Show less

To study the gene mutation in a patient with multiple exostoses, identify the disease-causing gene mutation. Polymerase chain reaction and DNA sequencing were used to screen the EXT1 or EXT2 gene mutation, while mismatch primer amplification and restriction endonuclease digestion were performed to confirm the mutation. By DNA sequencing, a mutation in the seventh intron was detected and located at 26 bp of 3' splice site upstream in EXT1 gene, which was unreported before. Mismatch primer amplification and restriction fragment length polymorphism analysis suggested that this mutation was not detected in the normal control. The mutation 1633-26(C-->A) may be the disease-causing mutation in this patient with multiple exostoses. Show less

Although oligonucleotide chips, cDNA microarrays, differential display reverse transcription-PCR, and other approaches have been used to screen implantation-related molecules, the mechanism by which embryo implantation occurs is still unknown. The aim of this study was to profile the differential gene expression between interimplantation site and implantation site in mouse uterus on day 5 of pregnancy by serial analysis of gene expression (SAGE). In our two SAGE libraries of 11-bp tags, the total numbers of tags sequenced were 48,121 for the interimplantation site and 50,227 for the implantation site. There were 1,039 tags specifically expressed at interimplantation site, and 1,252 tags specifically expressed at the implantation site. Based on the p value, there were 195 tags significantly up-regulated at the interimplantation site and 261 tags significantly up-regulated at the implantation site, of which 100 genes were single matched at the interimplantation site and 127 genes were single matched at the implantation site, respectively. By reverse transcription-PCR, the tag ratio between the implantation site and interimplantation site was verified on 14 significantly changed genes. Using in situ hybridization, 1810014L12Rik, Psmb5, Cd63, Npm1, Fads3, and Tagln2 were shown to be highly expressed at the implantation site compared with the interimplantation site. Compared with the interimplantation site, Ddx39 was strongly expressed in the subluminal stromal cells at the implantation site on day 5 of pregnancy. Ddx39 expression at the implantation site was specifically induced by active blastocysts. Additionally, Ddx39 expression was significantly up-regulated by estrogen in the ovariectomized mice. In our SAGE data, many implantation-related genes were identified in mouse uterus. Our data could be a valuable source for future study on embryo implantation. Show less

The apoAI/CIII/AIV gene cluster is involved in lipid metabolism and has a complex pattern of gene expression modulated by a common regulatory element, the apoCIII enhancer. A new member of this cluster, apolipoprotein (apo) AV, has recently been discovered as a novel modifier in triglyceride metabolism. To determine the expression of all four apo genes in combination and, most importantly, whether the transcription of apoAV is coregulated by the apoCIII enhancer in the cluster, we generated an intact transgenic line carrying the 116-kb human apoAI/CIII/AIV/AV gene cluster and a mutant transgenic line in which the apoCIII enhancer was deleted from the 116-kb structure. We demonstrated that the apoCIII enhancer regulated hepatic and intestinal apoAI, apoCIII, and apoAIV expression; however, it did not direct the newly identified apoAV in the cluster. Furthermore, human apo genes displayed integrated position-independent expression and a closer approximation of copy number-dependent expression in the intact transgenic mice. Because apoCIII and apoAV play opposite roles in triglyceride homeostasis, we analyzed the lipid profiles in our transgenic mice to assess the effects of human apoAI gene cluster expression on lipid metabolism. The triglyceride level was elevated in intact transgenic mice but decreased in mutant ones compared with nontransgenic mice. In addition, the expression of human apoAI and apoAIV elevated high density lipoprotein cholesterol in transgenic mice fed an atherogenic diet. In conclusion, our studies with human apoAI/CIII/AIV/AV gene cluster transgenic models showed that the apoCIII enhancer regulated expression of apoAI, apo-CIII, and apoAIV but not apoAV in vivo and showed the influences of expression of the entire cluster on lipid metabolism. Show less

Liver X receptors (LXRs) regulate target genes that are critical in lipoprotein metabolism and atherosclerosis. Apolipoprotein AIV (ApoAIV) is an apolipoprotein that is associated with chylomicrons and high-density lipoproteins. Plasma ApoAIV level in humans is inversely correlated with coronary artery events and overexpression of ApoAIV in mice results in significant reduction in atherosclerosis. We report here that LXRs directly regulate apoAIV at the transcriptional level. Treatment of C57B6 mice with a synthetic LXR agonist, T0901317, resulted in significant increases in plasma apoAIV that was associated with high-density lipoprotein. Examination of both intestinal and liver apoAIV mRNA revealed specific increases in liver mRNA only. In a human heptoma HepG2 cell model, apoAIV mRNA was up-regulated upon the treatment with either native or synthetic LXR agonists. Nuclear run-on study revealed a significant increase in the ApoAIV transcriptional rate upon LXR activation. Examination of the human apoAIV proximal promoter revealed a potential LXR response element that demonstrated binding with HepG2 nuclear extracts. Cotransfection studies in HepG2 cells indicated that this responsive element was functional in mediating the human ApoAIV gene response to LXR agonists. In addition, we identified a functional LXR-responsive element at 3' end enhancer region of mouse ApoAIV gene. We conclude that ApoAIV is a direct target gene of LXRs that may contribute to the antiatherogenic effect of LXR activation. Show less

The liver provides for long-term energy needs of the body by converting excess carbohydrate into fat for storage. Insulin is one factor that promotes hepatic lipogenesis, but there is increasing evidence that glucose also contributes to the coordinated regulation of carbohydrate and fat metabolism in liver by mechanisms that are independent of insulin. In this study, we show that the transcription factor, carbohydrate response element-binding protein (ChREBP), is required both for basal and carbohydrate-induced expression of several liver enzymes essential for coordinated control of glucose metabolism, fatty acid, and the synthesis of fatty acids and triglycerides in vivo. Show less

The MEK family of protein kinases plays key roles in regulating cellular responses to mitogens as well as environmental stress. Inappropriate activation of these kinases contributes to tumorigenesis. In contrast, anthrax lethal factor, the principal virulence factor of anthrax toxin, has been demonstrated to selectively inactivate MEKs. In this article we will discuss recent advances in our understanding of molecular aspects of the pathogenesis of anthrax, emphasizing the potential role of MEK signalling in this disease, and outline novel strategies to use anthrax lethal toxin in the treatment of cancer. Show less