Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019204 (hepatocellular carcinoma)
 71,386 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Heme oxygenase (HO) catalyzes the rate-controlling step of physiologic heme catabolism, namely, the oxidation of the alpha-methene bridge of the macrocycle with formation of CO, Fe, and biliverdin. HO-1, the first isoform of HO to be identified, is highly inducible by a large number of physical and chemical factors. Many of these factors cause oxidative or other stresses to cells. In this work, we have studied the regulation of the chick HO-1 gene, using selected promoter--reporter constructs of the gene transiently or stably transfected into primary cultures of chick embryo liver cells or into the LMH line of chicken hepatoma cells. By use of deletional and mutational analyses, DNase protection, and electromobility shift DNA-binding assays, we identified a heretofore undefined regulatory region in the 5'-UTR of the chick HO-1 gene which confers up-regulation of reporter gene (luciferase) expression in the presence of heme and other selected metalloporphyrins. This new metalloporphyrin-responsive element (MPRE) was localized to a 200-bp region 3.8 to 3.6 kb upstream of the transcription starting point of the chick HO-1 gene. It responded particularly to heme and cobalt protoporphyrin with maximal inductions at 10-15 microM concentrations and 15-18 h of exposure. In contrast, sodium arsenite, a prototypical stress-type inducer of HO-1, led to down-regulation of the reporter gene down stream of MPRE. DNase analysis identified an 18-mer oligonucleotide that was required for the metalloporphyrin response (5'-(-3711)TATTGCAGCTGTGTGGGG-3'). Mutations at any of four sites within this oligonucleotide abrogated the metalloporphyrin-dependent up-regulation of reporter gene expression. Nuclear protein extracts of cells treated with heme or cobalt protoporphyrin showed specific enhanced binding to this 18-mer. We conclude that the chick HO-1 promoter region contains a unique sequence that subserves up-regulation of the gene by metalloporphyrins and propose the name "metalloporphyrin-responsive element" for this sequence.
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PMID:Mapping of the chick heme oxygenase-1 proximal promoter for responsiveness to metalloporphyrins. 1188 1

Insulin directly down-regulates the gene expression of the rat CYP2E1 by altering its mRNA stability (De Waziers, I., Garlatti, M., Bouguet, J., Beaune, P. H., and Barouki, R. (1995) Mol. Pharmacol. 47, 474-479). Because the regulation of CYP mRNA stability was poorly understood, the molecular mechanisms involved in this regulation in the rat hepatoma H4IIEC3 cell line were studied. By using RNase T1 protection methods, the formation of a major CYP2E1 RNA-protein complex was observed. By competition experiments, the binding site of this complex was located on a 16-nucleotide sequence in the 5'-proximal region of the CYP2E1-coding sequence. Insulin did not modify the binding pattern of proteins to this sequence. and transfections of expression vectors or antisense oligonucleotides were undertaken to demonstrate the actual functionality of the 16-mer sequence. The insertion of this sequence in a luciferase gene was sufficient to render the chimeric mRNA sensitive to insulin. Furthermore, transfection of H4IIEC3 cells with antisense oligonucleotide complementary to this sequence blocked the insulin effect on the CYP2E1 mRNA expression, i.e. its rapid degradation. All these results demonstrate that this 16-nucleotide sequence is implicated in the CYP2E1 post-transcriptional regulation by insulin.
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PMID:Identification of a 16-nucleotide sequence that mediates post-transcriptional regulation of rat CYP2E1 by insulin. 1227 Sep 35

Interleukin-6 (IL-6) is a helical cytokine exerting pleiotropic activities including the regulation of hematopoiesis, B cell activation and acute-phase reaction. The structure-function relationship of the molecule is the subject of intensive investigation using point and deletion mutants. Our objective was to analyse the role of the N-terminal 18-46 region in IL-6-mediated expression of junB protooncogene and fibrinogen production, reflecting the acute phase response, with synthetic overlapping peptides. mRNA expression of junB was monitored by competitive RT-PCR, while sandwich ELISA was used for the detection of fibrinogen in the supernatant of HepG2 human hepatoma cells. We found that even short synthetic octapeptides can be stimulatory (in the absence of IL-6) or inhibitory (in the presence of IL-6) in both assays. To establish the molecular mechanism by which synthetic peptides exert their biological effects electromobility shift assay was carried out using HepG2 nuclear extracts. Peptides inducing junB expression initiate gel shifts of STAT3/DNA complexes, which may indicate the involvement of this signal transduction pathway. Circular dicroism spectroscopy data suggest that 8-11-mer peptides representing different parts of the 18-46 region have a marked tendency to adopt ordered conformations in a water/trifluoroethanol (1:1 v/v) mixture. Competition studies with rhIL-6 and selected fluorophore-labelled peptides indicate the presence of more than one binding site on soluble IL-6 receptor. Considering the possible multiple etiologic role of IL-6 in the pathogenesis of various diseases, these peptides could be useful for dissection of IL-6 related biological effects.
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PMID:Interleukin-6 N-terminal peptides modulate the expression of junB protooncogene and the production of fibrinogen in HepG2 cells. 1271 92

DNA frayed wires are a novel, multistranded form of DNA that arises from interactions between single-stranded oligodeoxyribonucleotides with the general sequence d(N(x)G(y)) or d(G(y)N(x)), where y > 10 and x > 5. Frayed wires exhibit greater stability with respect to thermal and chemical denaturation than single- or double-stranded DNA molecules and, thus, may have potential usefulness for DNA drug delivery. However, the stability and uptake of frayed wires have not been investigated in biological systems. Our objective was to examine the cellular uptake and stability of frayed wires in cultured hepatic cells. In these studies, the parent oligonucleotide d(A(15)G(15)) was used to form DNA frayed wires (DNA(FW)) while a random 30-mer oligonucleotide was used as the control nonaggregated DNA (DNA(SS)). Uptake and metabolism studies of DNA(FW) were performed in cultured human hepatoma, HepG2 cells and compared to DNA(SS). Our results indicate that DNA(FW) are not cytotoxic and that their intracellular uptake in HepG2 cells is 2-3.5-fold greater than that of DNA(SS) within the first 2 h (p < 0.05). Similarly, nuclear localization of DNA(FW) is 10-13-fold higher than that of DNA(SS) (p < 0.05). As both internalized and extracellular DNA(FW) appear to be more stable in vitro than DNA(SS), the enhanced uptake may be due to either increased stability or enhanced intracellular transport. These studies also indicate that uptake of DNA(FW) likely occurs via active processes such as receptor-mediated endocytosis similar to mechanisms which have been proposed for DNA(SS). The internalization pathways of DNA(FW) may differ somewhat from that of DNA(SS) insofar as chloroquine does not appear to alter DNA(FW) uptake and degradation, as is the case with DNA(SS).
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PMID:Cellular uptake and metabolism of DNA frayed wires. 1451 93

Previously, we reported that a 7-mer HLA-A11-restricted peptide (YVNTNMG) of hepatitis B virus (HBV) core Ag (HBcAg(88-94)) was associated with heat shock protein (HSP) gp96 in liver tissues of patients with HBV-induced hepatocellular carcinoma (HCC). This peptide is highly homologous to a human HLA-A11-restricted 9-mer peptide (YVNVNMGLK) and to a mouse H-2-K(d)-restricted 9-mer peptide (SYVNTNMGL). To further characterize its immunogenicity, BALB/c mice were vaccinated with the HBV 7-mer peptide. It was found that a specific CTL response was induced by the 7-mer peptide, although the response was approximately 50% of that induced by the mouse H-2-K(d)-restricted 9-mer peptide, as detected by ELISPOT, tetramer, and (51)Cr release assays. To evaluate the adjuvant effect of HSP gp96, mice were coimmunized with gp96 and the 9-mer peptide, and a significant adjuvant effect was observed with gp96. To further determine whether the immune effect of gp96 was dependent on peptide binding, the N- and C-terminal fragments of gp96, which are believed to contain the putative peptide-binding domain, were cloned and expressed in Escherichia coli. CTL assays indicated that only the N-terminal fragment, but not the C-terminal fragment, was able to produce the adjuvant effect. These results clearly demonstrated the potential of using gp96 or its N-terminal fragment as a possible adjuvant to augment CTL response against HBV infection and HCC.
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PMID:Generation of murine CTL by a hepatitis B virus-specific peptide and evaluation of the adjuvant effect of heat shock protein glycoprotein 96 and its terminal fragments. 1561 Dec 41

Diabetes has been reported to increase CYP2E1 (cytochrome P450) and CYP2B1 expression at both the mRNA and protein levels in rat livers. This increase has been attributed to mRNA stabilization and can be reversed by daily insulin treatment. In a previous study, we showed that this hormone directly down-regulates CYP2E1 and 2B1 expression through a post-transcriptional mechanism in rat hepatoma cell lines. We then aimed to identify the molecular mechanisms involved in this regulation. We first identified a 16-mer sequence that we later showed to be the actual functional target of insulin on the rat CYP2E1 mRNA. Similar work was performed with CYP2B1. We first investigated the presence of mRNA-protein interactions. Using cytoplasmic proteins of Fao cells treated or not with insulin (0.1 microM) and the full-length CYP2B1 mRNA as a probe, a major CYP2B1 RNA-protein complex was observed with RNase T1 protection experiments. With the use of different CYP2B1 mRNA probes and by means of competition experiments with antisense oligonucleotides, a protein fixation site was located on a 16-nt sequence in the 5' part of the coding region. This sequence has a hairpin loop structure, shows 80% sequence identity with a structure previously identified on CYP2E1 and is also responsible for the post-transcriptional effects of insulin on this mRNA. Protein(s) bound to both CYP2B1 and CYP2E1 sequences are cytosolic and have an apparent molecular mass of 60 kDa. The protein(s) that bind(s) to both these sequences and the insulin transduction signal involved in this regulation remain(s) to identified.
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PMID:Regulatory sequence responsible for insulin destabilization of cytochrome P450 2B1 (CYP2B1) mRNA. 1561 13

HCV is an ideal target for siRNA as its genome, a single-stranded RNA, is translated into a single viral polyprotein and replicated into negative-stranded RNA. In the present study, we monitored the effects of 36 different small interfering RNAs (siRNAs) transcribed from a plasmid-derived expression system on the luciferase activities expressed from a full-length HCV replicon, to identify potent siRNA target sites. Delivery of nine selected siRNA expression vectors into human hepatoma cells (Huh7) carrying a genomic HCV replicon resulted in a significant reduction in viral protein and RNA levels. Moreover, synthetic siRNAs directed to target sites (core, NS3, NS4A and NS4B coding regions) in the HCV genome efficiently suppressed viral replication in a dose-dependent manner. A transient mouse model system expressing viral structural proteins in the liver was constructed using the hydrodynamic transfection method to confirm in vivo anti-HCV activity of the selected siRNAs. A 21-nucleotide siRNA, which can hybridize to the HCV core coding region with a single G-U base pair, suppressed weakly transgene expression in mice. However, this anti-viral effect was enhanced upon substitution with a 27-mer duplex RNA. Our results will provide useful information about designing potent siRNAs against variable target sites.
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PMID:Inhibition of hepatitis C virus gene expression by small interfering RNAs using a tri-cistronic full-length viral replicon and a transient mouse model. 1697 54

The purpose of this study was to screen peptides that can specifically bind to human hepatocellular carcinoma (hHCC) cells using phage display of random peptide library in order to develop a peptide-based carrier for the diagnosis or therapy of hHCC. A peptide 12-mer phage display library was employed and 4 rounds of subtractive panning were performed using the hHCC cell line HepG2 as the target. After panning, the phages that specifically bound to and internalized in hHCC cells were selected. The selected phages demonstrated highly specific affinity to HepG2 cells analyzed by ELISA and immunofluorescence analysis. 57.3% of the selected phage clones displayed repeated sequence FLLEPHLMDTSM, and 4 amino acid residues, FLEP were extremely conservative. Based on the sequencing results, a 16-mer peptide (WH-16) was synthesized. The competitive ELISA showed that the binding of the phage clones displayed sequence FLLEPHLMDTSM to HepG2 cells was efficiently inhibited by WH-16. Our findings indicate that cellular binding of phage is mediated via its displayed peptide and the synthesized 16-mer peptide may have the potential to be a delivery carrier in target diagnosis or therapy for hHCC.
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PMID:Screening and identification of a novel hepatocellular carcinoma cell binding peptide by using a phage display library. 1856 28

The hepatitis C virus (HCV) is a single-stranded (ss) RNA virus that is responsible for chronic liver diseases, such as cirrhosis, end-stage liver disease, and hepatocellular carcinoma. Driven by the need to detect the presence of the HCV viral sequence, herein it is demonstrated for the first time that the nonlinear optical (NLO) properties of gold nanoparticles can be used for screening and quantifying HCV RNA without any modification, with excellent detection limit (80 pM) and selectivity (single base-pair mismatch). The hyper-Rayleigh scattering (HRS) intensity increases 25 times when label-free, 145-mer, HCV ss-RNA is hybridized with 400 pM target RNA. The mechanism of HRS intensity change is discussed with experimental evidence for a higher multipolar contribution to the NLO response of gold nanoparticles.
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PMID:Sequence-specific HCV RNA quantification using the size-dependent nonlinear optical properties of gold nanoparticles. 1921 36

Our previous study of gene alterations in 29 hepatocellular carcinoma (HCC) using AP-PCR amplified with 59 different 10-mer arbitrary primers and gene cloning, indicated DNA alterations by DNA fingerprints from 34 primers. Among these, the altered DNA fragment from primer U-8 predominated (62%). The aim of this report is to identify the gene alterations on chromosomal banding and gene expression in these patients, including the association of these alterations with patient demographic data. Seven different sequences, mapped to chromosomes 5q33.3, 7q31.33, 7q34, 9p24.3, 10q25.3, 13q31.3, and 16p11.2, were identified by gene cloning and nucleotide sequencing. Novel PNLIPRP3 gene over-expression and DOCK8 gene under-expression were observed in 41% and 44% of these patients, respectively, which point to an association of these genes and the development of HCC. Likewise, allelic loss on chromosome 10q25.3 was associated with shorter survival among HCC patients (P=0.03); this indicated that allelic loss on chromosome 10q25.3 may serve as a prognostic marker in patients with HCC.
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PMID:Novel PNLIPRP3 and DOCK8 gene expression and prognostic implications of DNA loss on chromosome 10q25.3 in hepatocellular carcinoma. 1964 Jan 99


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