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)

Nonviral gene transfer vectors have been actively studied in the past years in order to obtain structural entities with minimum size and defined shape. The final size of a gene transfer vector, which is compacted into unimolecular complexes, is directly proportional to the mass of the nucleic acid to be compacted. Thus, the purpose of this study was to assess the possibility of producing ssDNA vectors and their biophysical and biological characterization. We have obtained ssDNA/poly-L-lysine complexes that are significantly smaller than their double-stranded counterparts. We have also identified a lesser aggregative behavior of compacted single-stranded vs. double-stranded DNA vectors in the presence of physiological NaCl concentrations. Expression of compacted ssDNA is observed in hepatoma cell lines. Moreover, we have successfully delivered galactosylated ssDNA complexes into cells that express the asialoglycoprotein receptor via receptor-mediated endocytosis. The reduced size and biophysical behavior of ssDNA vectors may provide an advantage for transfection of eukaryotic cells.
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PMID:Single-stranded DNA condensed with poly-L-lysine results in nanometric particles that are significantly smaller, more stable in physiological ionic strength fluids and afford higher efficiency of gene delivery than their double-stranded counterparts. 1220 31

The hepatic asialoglycoprotein receptor (ASGP-R) is an endocytic recycling receptor that mediates the endocytosis of desialylated glycoproteins. The human ASGP-R is composed of two homologous subunits, H1 and H2, and the cytoplasmic Cys residues in both subunits are palmitoylated. To study the effects of palmitoylation on ASGP-R activity and function, we generated four types of stably transfected cell lines in SK-Hep-1 hepatoma cells, expressing wild-type, or partially or completely palmitoylation-defective ASGP-Rs containing Cys-to-Ser mutations in either one or both subunits. Scatchard analysis showed that all four stable cell lines expressed a similar number of binding sites for asialo-orosomucoid, with comparable dissociation constants of approximately 1-3nM. Immunofluorescence confocal microscopy indicated a normal distribution of the palmitoylation-defective H1 and H2 subunits compared to the wild-type. However, cell lines expressing palmitoylation-defective ASGP-Rs had markedly reduced rates of ligand uptake and degradation compared to cells expressing wild-type ASGP-Rs. We conclude that failure to palmitoylate Cys residues in either or both subunits of human ASGP-Rs results in very inefficient uptake and degradation of ligands.
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PMID:Palmitoylation-defective asialoglycoprotein receptors are normal in their cellular distribution and ability to bind ligand, but are defective in ligand uptake and degradation. 1235 51

Specific gene delivery into hepatoma cells by liposomes and specific gene expression under the control of the cyclin A promoter were examined in HepG2 cells, a hepatoblastoma cell line that overexpresses cyclin A. A plasmid carrying the luciferase gene under the cyclin A promoter sequence was condensed with poly-L-lysine and encapsulated into anionic asialofetuin-labeled liposomes (AF-liposomes), which were preferentially taken up by hepatocytes through the action of the asialoglycoprotein receptor (AgpR). AF-liposomes delivered plasmids to the hepatoma cells by receptor-mediated endocytosis through the AgpR, and transgene expression could be achieved under the control of the cyclin A promoter. Furthermore, a fusogenic lipid, DOPE, as a liposomal component was required for the enhancement of transfection efficiency of AF-liposomes.
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PMID:Efficient gene transfer to hepatoblastoma cells through asialoglycoprotein receptor and expression under the control of the cyclin A promoter. 1261 47

1. The metabolic pathway(s) of OGT 719, a novel nucleoside analogue in which galactose is covalently attached to the N1 of 5-fluorouracil (FU), have been investigated with (19)F-NMR spectroscopy in (1) the isolated perfused rat liver (IPRL) model, (2) normal rats, (3) rats bearing the HSN LV10 sarcoma, (4) nude mice xenografted with the human hepatoma HepG2 and (5) urine from patients. 2. The administration of OGT 719 results in the formation of small amounts of FU. IPRL experiments with OGT 719 in combination with asialofetuin, a natural asialoglycoprotein receptor (ASGP-r), suggest competitive binding of OGT 719 to the ASGP-r. 3. The data obtained in non-tumour rats also demonstrated an extremely low metabolization of OGT 719 into FU and alpha-fluoro-beta-alanine, the well-known major metabolite of FU. 4. A comparison of tumour extracts from rats bearing the HSN LV10 sarcoma treated with FU or OGT 719 showed the incorporation of FU into RNA in rats treated with FU but not in rats treated with OGT 719; nevertheless, the incorporation of FU into RNA was observed in the liver from rats treated with OGT 719. 5. In a human hepatoma xenografted to nude mice, both the OGT 719 and FU contents of the tumour were markedly higher than in the corresponding liver, suggesting a tumour-specific trapping of OGT 719 in hepatoma. 6. The metabolism of OGT 719 was also extremely low in patients. 7. In conclusion, the present study shows the value of (19)F-NMR for demonstrating for the first time that OGT 719 is a prodrug of FU although very poorly metabolized.
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PMID:Metabolism of a novel nucleoside analogue, OGT 719, in the isolated perfused rat liver model, in rats, in tumour models and in patients. 1263 46

Success of human gene therapy depends upon the development of delivery vehicles or vectors, which can selectively deliver therapeutic genes to target cells with efficiency and safety. Previous studies have shown an efficient, systemic trans-gene expression in many cell lines (in vitro) by using an anionic liposomal vector, based on the composition of retroviral envelopes (artificial viral envelopes, AVEs). The AVE-liposomes and their complexes with plasmid (DNA) were characterized according to zeta potential measurements and transmission electron microscopy (TEM). We successfully demonstrated that AVE liposomes, dispersed in 10% serum-containing growth medium, efficiently delivered plasmid DNA to HuH-7 (human hepatoma cell line) cells. We assessed the utility of liver-targeted vesicles as a drug/gene delivery system for the treatment of liver diseases. We found that small unilamellar AVE vesicles containing 15 mol% digalactosyl diglyceride (DGDG) are efficiently targeted to the liver via the hepatic asialoglycoprotein receptor.
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PMID:Efficient gene delivery with serum into human cancer cells using targeted anionic liposomes. 1520 7

A major goal for gene therapy is to obtain targeted vectors that transfer genes efficiently to specific cell types. The liver possesses a variety of characteristics that make this organ very attractive for gene therapy. In the present study, four cholesterylated thiogalactosides 1a approximately d with different spacer length were synthesized to formulate novel lipid-polycation-DNA (LPD) complexes, which were composed of galactosylated cationic liposomes, protamine sulfate and plasmid DNA. The galactosylated LPD1c significantly improved the levels of gene expression in cultured hepatoma cells HepG2 and SMMC-7721, while LPD1a and LPD1b did not significantly improve the levels compared with non-galactosylated LPD. Meanwhile, increased transfection activity was not observed in mouse fibroblasts L929 for galactosylated LPDs. Cytotoxicity of galactosylated LPDs assay showed they had no obvious toxicities to L929 cells and HepG2 cells. In summary, the length of the spacer between the anchor and galactose residues was important for the recognition of asialoglycoprotein receptor. The LPD1c described here, combining the condensing effect of protamine and the targeting capability of cholesterylated thiogalactosides, are potentially useful gene carriers to liver parenchymal cells.
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PMID:Targeted gene delivery to hepatoma cells using galactosylated liposome-polycation-DNA complexes (LPD). 1582 63

The asialoglycoprotein receptor (ASGP-R) on the hepatocyte membrane is a specific targeting marker for gene and drug delivery. Polyethylenimine (PEI) is a polycationic nonviral vector that is used for gene transfer. We have synthesized galactosylated polyethylenimine-graft-poly(ethylene glycol) (GPP) for performing gene delivery to the hepatocytes. The present study reports on the in vitro and in vivo data that was achieved in hepatoma bearing transgenic mice. The cytotoxicity was decreased with the increasing PEG content. The particle size of the complex was increased with the increasing PEG at an N/P ratio of 3.0, while the zeta potentials were decreased. The (99m)Tc labeled complexes were transfected into HepG2 and HeLa cells, while the GFP reporter genes were mainly expressed in the HepG2 cells. The in vivo data was achieved in ALB/c-Ha-ras transgenic mice. (99m)Tc labeled GPP(50)/DNA was injected into the mice via the tail vein, and the gamma images were acquired at 5, 15 and 30 min. The (99m)Tc labeled complexes were mainly localized in the heart and liver, and they were excreted through the kidneys. The GFP gene was mainly expressed in the proliferating cells at the tumor periphery. This result was confirmed by PCNA staining. The GPP(50)/DNA complexes were bound to ASGP-R of the proliferating hepatocytes in vitro and in vivo. The present results demonstrate the feasibility of nonviral gene transfer using galactosylated PEI-PEG in vivo.
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PMID:Asialoglycoprotein receptor targeted gene delivery using galactosylated polyethylenimine-graft-poly(ethylene glycol): in vitro and in vivo studies. 1625 76

To obtain scFv (single-chain variable fragment) against human ASGPR (asialoglycoprotein receptor), a human non-immune phage antibody library was screened with the recombinant CRD (carbohydrate recognition domain) of rCRDH1 (the H1 subunit of human ASGPR). Anti-rCRDH1 phage clones were obtained after four rounds of screening with rCRDH1-coated immunotubes and single positive colonies were further selected with the expressed thioredoxin-His-S tag of the wild-type pET32c. Two specific anti-rCRDH1 phage clones (named C1 and C2) were transfected into Escherichia coli HB2151 and induced for secreted expression of scFv antibody. The purified anti-rCRDH1 C1 and C2 single-chain antibodies were characterized by immunoblotting and immunohistochemistry. Both antibodies were found to specifically recognize denatured and native forms of the ASGPR and thus could potentially be used as targeting molecules for gene therapy of hepatocellular carcinoma or other liver diseases.
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PMID:Characterization of a single-chain variable fragment (scFv) antibody directed against the human asialoglycoprotein receptor. 1639 34

In order to obtain an HCC-selective drug delivery system, a novel functional lipid, which is cleaved by the protease activity of matrix metalloproteinase-2 (MMP-2), was developed. The amino group of dioleoylphosphatidylethanolamine (DOPE) was conjugated with PEGylated MMP-2 substrate peptide (Gly-Pro-Leu-Gly-Ile-Ala-Gly-Gln), and MMP-2-cleavable PEG-Peptide-DOPE (PEG-PD) was synthesized. When PEG-PD was incorporated in galactosylated liposomes (Gal-PEG-PD-liposomes), we expected that Gal-PEG-PD-liposomes would not be taken up by normal hepatocytes due to the steric hindrance effect, but would be activated around HCC cells by secreted MMPs. In the pretreatment by hMMP2 (1, 5, and 10mug/ml), an hMMP2 concentration-dependent higher uptake of Gal-PEG-PD-liposomes was observed in HepG2 cells, suggesting PEG-PD cleavage. In the presence of an excess of galactose, the uptake of Gal-PEG-PD-liposomes with hMMP2 was significantly inhibited, suggesting asialoglycoprotein receptor-mediated uptake of Gal-PEG-PD-liposomes following the PEG-PD cleavage. Pretreatment of Gal-PEG-PD-liposomes with the conditioned medium of B16BL6, which contained secreted MMPs, enhanced the binding to HepG2 cells, as in the case of hMMP-2 treatment. Moreover, the cytotoxicity of N(4)-octadecyl-1-beta-d-arabinofuranosylcytosine (NOAC) incorporated Gal-PEG-PD-liposomes was enhanced by hMMPs (5mug/ml) and its cytotoxicity was significantly reduced by the presence of an excess of galactose in HepG2 cells. In conclusion, Gal-PEG-PD-liposomes were successfully developed for novel HCC-selective targeting.
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PMID:Novel PEG-matrix metalloproteinase-2 cleavable peptide-lipid containing galactosylated liposomes for hepatocellular carcinoma-selective targeting. 1648 46

Two retinoids, ATRA and 13cisRA, were incorporated into liposomes of different composition and charge and added to two hepatoma cell lines with different degree of transformation to measure cytotoxicity by MTT assay. Retinoid-free cationic liposomes were more toxic than the other kinds (anionic and made only of PC) but were also the best delivery system for retinoic acid to induce specific cytotoxic effects on these tumor hepatoma cell lines. Galactosyl-sphingosine containing cationic liposomes increased the cytotoxic effect induced by ATRA on Hep3B cells when compared to glucosyl-sphingosine cationic liposomes, but did not improve the effect induced by free retinoid or ATRA loaded into liposomes without glycolipids. This suggests that in this cell line, ATRA is being incorporated by a mechanism mediated by the asialoglycoprotein receptor, but at the same time, non-specific sugar-independent capture is also taking place as well as free diffusion of ATRA directly through the membrane. Galactose-specific effect was not observed in HepG2 cells treated with ATRA or both cell lines treated with 13cisRA. In fact, treatment of HepG2 cells with retinoids entrapped into liposomes likely induces proliferation instead of cytotoxicity, a result that interferes with the measurement of cell death by MTT. Compared to the specific effect of ATRA entrapped into cationic liposomes, vesicles made only by PC, did not mediate a specific mechanism, since differences between ATRA in galactosyl- and glucosyl-shpingosine PC-liposomes were not statistically significant. The specific mechanism was not present in the myoblastic cell line C2C12, where ATRA incorporated into galactosyl- and glucosyl-sphingosine containing cationic and PC-liposomes, was able to induce cytotoxicity at the same extent. Micelles containing ATRA and galactosyl-sphingosine had a significantly more toxic effect than the retinoid administered together with glucosyl-sphingosine, in Hep3B cells. Also, micelles containing ATRA were more toxic than glycolipid-containing liposomes with ATRA, for both kinds of sphingosines. The same effect was not observed in C2C12 cells, where glycolipid-containing liposomes worked better than micelles, and a sugar-specific mechanism was not seen. This suggests that, even though galactose-containing cationic liposomes could be a promising approach, a galactose-specific emulsion system could be the best strategy to specifically deliver retinoic acid to liver tumor cells, since it shows tissue specificity (perhaps induced by ASGPR-mediated internalization) and a stronger cytotoxic effect than the retinoid incorporated into liposomes.
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PMID:Cytotoxic effect induced by retinoic acid loaded into galactosyl-sphingosine containing liposomes on human hepatoma cell lines. 1687 Mar 66


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