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)

In previous reports several receptors for either natural hepatitis B virus (HBV) particles or genetically engineered virus have been described, whereby endocytosis represents a putative uptake mechanism for HBV particles. We have found that HBV-particles from viremic carriers could bind to the human asialoglycoprotein receptor (ASGPR), which mediates glycoprotein uptake into liver cells. The HBV-ASGPR interaction was studied in a cell culture system using hepatoma HepG2 and HuH7 cells compared to COS cells as controls. About 50% of HBsAg-secretion into the cell culture supernatant after HBV-inoculation as a function of HBV-uptake could be inhibited by the specific ASGPR-ligand asialofetuin. COS-cells did not show HBsAg-secretion. If the cells were grown as clones, 15% of HepG2-cells demonstrated HBsAg-secretion but only 5% in the presence of asialofetuin. HBV-particle uptake was further confirmed by HBV-DNA analysis using PCR. HBV-ASGPR interaction was studied with purified, biotin-conjugated human ASGPR. Quantitative inhibition with asialofetuin indicated a high-affinity binding of HBV-particles to purified ASGPR. After denaturing polyacrylamid gel electrophoresis and transblotting of isolated HBV-particles a receptor-blotting system was established which identified distinct binding sites for biotinylated receptors. These results suggest that the ASGPR is capable of specifically binding HBV-particles and, moreover, to mediate their hepatic endocytosis which ultimately could be responsible for the HBV-infection of liver cells.
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PMID:Receptor-mediated entry of hepatitis B virus particles into liver cells. 934 95

Galectin-3 and asialoglycoprotein receptor are lectins belonging to the classes of soluble lectins and of membrane C type lectins respectively. Conflicting results have been reported concerning their transcription level in the time course development of tumours. In the present study we investigated the abnormalities and the transcription levels of galectin-3 and asialoglycoprotein receptor genes in liver-targeted SV40 large T transgenic mice related to normal mice. In the strain expressing the highest level of large T, 100% of the male mice reproducibly developed an hepatocarcinoma. We provide evidence that the galectin-3 and asialoglycoprotein receptor genes are stable in such mice. The galectin-3 gene is weakly transcribed and its level is identical and constant in normal and transgenic mice, suggesting a lack of involvement in the development of large T-induced hepatocarcinoma. The asialoglycoprotein receptor gene is actively transcribed and its level remains high all along the development of the tumour; therefore, in such an hepatocarcinoma the asialoglycoprotein receptor could be used to take up drugs, genes or oligonucleotides associated with glycosylated carriers bearing galactose residues in a terminal non-reducing position.
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PMID:Lack of modulation of the galectin-3 and asialoglycoprotein receptor transcription in hepatocarcinoma of transgenic mice. 956 25

Mixed infection of cells with both Moloney murine leukemia virus (MoMLV) and related or heterologous viruses produces progeny pseudotype virions bearing the MoMLV genome encapsulated by the envelope of the other virus. In this study, pseudotype formation between MoMLV and the prototype parainfluenza virus Sendai virus (SV) was investigated. We report for the first time that SV infection of MoMLV producer cells results in the formation of MoMLV(SV) pseudotypes, which display a largely extended host range compared to that of MoMLV particles. This could be associated with SV hemagglutinin-neuraminidase (SV-HN) glycoprotein incorporation into MoMLV envelopes. In contrast, solitary incorporation of the other SV glycoprotein, SV fusion protein (SV-F), resulted in a distinct and narrow extension of the MoMLV host range to asialoglycoprotein receptor (ASGP-R)-positive cells (e.g., cultured human hepatoma cells). Since stably ASGP-R cDNA-transfected MDCK cells, but not parental ASGP-R-negative MDCK cells, were found to be transduced by MoMLV(SV-F) pseudotypes and transduction of ASGP-R-expressing cells was found to be inhibited by ASGP-R antiserum, a direct proof for the ASGP-R-restricted tropism of MoMLV(SV-F) pseudotypes was provided. Cultivation of ASGP-R-positive HepG2 hepatoma cells on Transwell-COL membranes led to a significant enhancement of MoMLV(SV-F) titers in subsequent flowthrough transduction experiments, thereby suggesting the importance of ASGP-R accessibility at the basolateral domain for MoMLV(SV-F) pseudotype transduction. The availability of such ASGP-R-restricted MoMLV(SV-F)-pseudotyped vectors opens up new perspectives for future liver-restricted therapeutic gene transfer applications.
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PMID:Pseudotype formation of Moloney murine leukemia virus with Sendai virus glycoprotein F. 957 8

Different ratios of DNA phosphate to polyethylenimine amine were used for encapsulation and delivery to liver cells of chloramphenicol acetyl transferase (CAT) or luciferase expression plasmids in cationic, neutral and anionic liposomes. Positive liposomes consisted of dioleoyl phosphatidylcholine (DOPC): dioleoyl trimethylammonium propane (DOTAP) (6:1 molar ratio); neutral liposomes were composed of DOPC and dioleoyl phosphatidylethanolamine (DOPE) (1:1); and negative liposomes contained dioleoyl phosphatidylserine (DOPS) and DOPC (1:1). All formulations included 8 mol% galatocerebroside for targeting to the hepatocyte asialoglycoprotein receptor. Liposomes were prepared by film hydration followed by sequential extrusion through 0.8-0.2 mumol polycarbonate membranes. Transfection efficiency of HuH-7 human hepatoma cells and isolated rat hepatocytes was determined by CAT enzyme-linked immunosorbent assay (ELISA) or luciferase activity. Uptake of liposomal-encapsulated, fluorescently labeled 68-mer oligonucleotides was assessed by confocal microscopy. All three formulations demonstrated a twofold or greater increase in transfection efficiency and significantly lower toxicity compared to nonencapsulated polyethylenimine complexes. Negative liposomes were most effective, particularly in the rat hepatocytes. Only the cationic and anionic liposomal formulations exhibited significant thermodynamic stability. These formulations are readily characterized for size, phospholipid and DNA content, and they represent feasible systems for optimizing in vivo delivery systems to hepatocytes.
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PMID:Enhanced gene transfer into HuH-7 cells and primary rat hepatocytes using targeted liposomes and polyethylenimine. 971 89

Galactose was introduced to poly(L-lysine) (PLL) with an average molecular weight of 13,000 to develop a hepatocyte-specific carrier for gene drugs. The pharmacokinetic characteristics of a model plasmid, pCAT (plasmid DNA encoding chloramphenicol acetyltransferase reporter gene), complexed with galactosylated PLL (Gal-PLL) was studied in mice in relation to its physicochemical properties. pCAT/Gal-PLL complex at a ratio of 1:0.6 (w/w) has a zeta potential of -20 mV and a mean particle size of about 180 nm. After intravenous injection, [32P]pCAT/Gal-PLL was rapidly eliminated from the circulation and preferentially taken up by the liver's parenchymal cells. The hepatic uptake of [32P]pCAT/Gal-PLL was significantly inhibited by prior administration of Gal-bovine serum albumin, suggesting that the uptake was mediated by the asialoglycoprotein receptors on hepatocytes. In vitro transfection experiments using a hepatoma cell line expressing the asialoglycoprotein receptor revealed that pCAT/Gal-PLL gave a high CAT gene expression whereas pCAT complexed with unmodified PLL failed to transfect the cells.
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PMID:Targeted delivery of plasmid DNA complexed with galactosylated poly(L-lysine). 974 38

pH-sensitive liposomes composed of dioleoylphosphatidylethanolamine and cholesterol hemisuccinate (3:2 mol/mol) bearing the N-acetylglucosamine derivative of bovine serum albumin (N-Ac-BSA) were applied for receptor-mediated delivery in chicken hepatoma (LMH) cells expressing the N-Ac-BSA-binding asialoglycoprotein receptor. Fluorescently labeled dextran was entrapped in liposomes by a modified freeze-thawing method (encapsulation efficiency of 23%). A novel method of coupling proteins onto the surface of preformed liposomes yielded a coupling efficiency of 60-70%. The association of pH-sensitive and lecithin liposomes with LMH cells was monitored by fluorescence-activated cell sorting and confocal microscopy. Prerequisites for receptor-mediated delivery to LMH cells were both the pH sensitivity of liposomes and the presence of N-Ac-BSA on the liposomal surface.
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PMID:pH-sensitive liposomes for receptor-mediated delivery to chicken hepatoma (LMH) cells. 974 53

Galactose-targeted delivery of macromolecules and drug conjugates to asialoglycoprotein receptor (ASGPR) positive cells has been widely documented in animals, although targeting in humans has never been demonstrated. In this study we report the pharmacokinetics and imaging determined in the first patient enrolled in a phase I clinical study of the poly[N-(2-hydroxypropyl)methacrylamide] copolymer bearing doxorubicin and galactosamine, known as PK2. Gradient high performance liquid chromatography (HPLC) evaluation of plasma and urine has been combined with 123I-based imaging to show biphasic clearance of the drug from the plasma (half-lives of 78+/-1 and 990+/-15), and approximately 30% delivery of the drug to the hepatic region, as determined by planar whole body imaging at 24 h. This patient has a multifocal hepatoma, and single photon emission computed tomography (SPECT) analysis showed a ratio of tumour tissue to normal liver uptake of approximately 1:3, at 24 h. On the basis of this patient, effective hepatic targeting can be achieved following an intravenous dose of 20 mg/m2 doxorubicin as PK2, however the therapeutic usefulness of this targeted drug has yet to be established.
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PMID:Preliminary clinical study of the distribution of HPMA copolymers bearing doxorubicin and galactosamine. 989 15

The expression of asialoglycoprotein receptor (ASGP-R) on human hepatocarcinoma cells might be exploited to reduce the extrahepatic toxicity of DNA synthesis inhibitors by their conjugation with galactosyl- terminating peptides. We conjugated 2',2'-difluorodeoxycytidine (dFdC), an inhibitor of DNA synthesis active on solid tumors, with lactosaminated poly-L-lysine (L-poly(LYS)). In experiments in vitro, L-poly(LYS)-dFdC inhibited proliferation of Hep G2 cells, a human hepatocarcinoma cell line which maintains the ASGP-R. Inhibition was rescued by asialofetuin. To study the pharmacological action of the conjugate in vivo, we used rats 18-24 hr after 2/3 hepatectomy and observed that regenerating hepatocytes expressed ASGP-R on their surface and internalized L-poly(LYS)-dFdC. Conjugate uptake by bone marrow, spleen, and intestine was negligible. We also found that L-poly(LYS)-dFdC inhibited [3H]thymidine incorporation into DNA of regenerating liver. These results indicated that hepatectomized rats were a suitable animal model to study the pharmacological action, on DNA-synthesizing hepatocytes, of conjugates binding to ASGP-R and carrying inhibitors of DNA synthesis. L-poly(LYS)-dFdC also inhibited [3H]thymidine incorporation in bone marrow, spleen, and intestine. Evidence was obtained that inhibition of DNA synthesis in extrahepatic tissues was a consequence of drug release from hepatocytes into blood-stream after the bond with the carrier has been broken down within liver cells. Possible ways of reducing the exit of dFdC from liver cells, thereby obtaining an inhibition of DNA synthesis restricted to dividing hepatocytes, were discussed.
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PMID:Inhibition of [3H]thymidine incorporation into DNA of rat regenerating liver by 2',2'-difluorodeoxycytidine coupled to lactosaminated poly-L-lysine. 1007 85

OGT 719 is a novel p.o. bioavailable nucleoside analogue in which galactose is incorporated onto the fluoropyrimidine moiety of the cytotoxic agent 5-fluorouracil (5-FU). OGT 719 has been designed to reduce the systemic toxicity normally associated with 5-FU while retaining activity against disease localized in the liver, in which it may be preferentially localized through the asialoglycoprotein receptor (ASGP-R). We report studies confirming the activity of OGT 719 in inhibiting growth of metastatic human colorectal tumors in the liver of nude mice. The human colorectal cancer cell line C170HM2 readily forms liver metastases in vivo. Oral administration of 1500 mg/kg/day OGT 719 inhibited liver tumor burden by 95% compared with vehicle control, without any observable signs of toxicity. When the tumor burden was increased and the same OGT 719 treatment was compared with a standard clinical dose regimen of 25 mg/kg/day 5-FU/leucovorin given i.v., both treatments were equally efficacious, although 5-FU/leucovorin treatment started 7 days earlier. In contrast to 5-FU, OGT 719 is p.o. bioavailable and has a plasma half-life between 1.5 and 3 h. Several colorectal cancer cell lines express the asialoglycoprotein receptor, although no significant levels can be detected in C170HM2 cells, consistent with the observation that OGT 719 is approximately 3 log orders of magnitude less potent in vitro than 5-FU. Flux through thymidylate synthase, as measured by 3H release from [3H]dUrd, was inhibited by OGT 719 at 4 h. The notable difference in the potency of OGT 719 efficacy on C170HM2 cells in vitro and in vivo supports our model of liver-specific activation of OGT 719. As our data suggest, OGT 719 may significantly inhibit growth of metastatic colorectal tumors in the liver in vivo. This hypothesis is presently being explored in clinical trials for primary hepatocellular carcinoma and colorectal liver metastases.
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PMID:A novel, orally administered nucleoside analogue, OGT 719, inhibits the liver invasive growth of a human colorectal tumor, C170HM2. 1009 58

Receptor-mediated gene delivery is an attractive method for gene transfer in vitro and shows promise for in vivo gene therapy applications. In the current study, we have selected the cytokine interleukin-2 (IL-2) gene to explore the feasibility of receptor-mediated gene transfer into human hepatocellular carcinoma HepG2 cells, using Epstein-Barr virus (EBV)-based vectors. We have developed a targeted DNA delivery system for the treatment of liver cancer by gene therapy. This system utilizes the hepatocyte-specific asialoglycoprotein receptor, which is uniquely expressed on liver cell membranes but not present on other cell types. Galactosylated histone, a ligand to the asialoglycoprotein receptors, was synthesized, and a new EBV-based expression vector bearing the human IL-2 cDNA was constructed and conjugated to the ligand through ionic interactions. The ligand/IL-2 DNA complex was able to bind specifically to cell-surface receptors on the target cell and, when incubated with HepG2 cells, resulted in elevated levels of IL-2 gene expression. These results indicate that therapeutic genes like IL-2 in ligand/DNA complex can be transferred into hepatoma cells via the hepatocyte receptor. This study constitutes an encouraging first step in the assessment of receptor-mediated gene transfer as a technique for gene therapy in liver cancer.
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PMID:Receptor-mediated interleukin-2 gene transfer into human hepatoma cells. 1034 Dec 90


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