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)

The physicochemical properties and gene transfer ability of lactose-polyethylene glycol-grafted poly-L-lysine (Lac-PEG-PLL) were investigated. A dye displacement assay showed that plasmid DNA self-assembled with Lac-PEG-PLL, and condensation began at a <1:1 charge ratio of plasmid DNA to polymer. In atomic force microscopy, spontaneously assembled Lac-PEG-PLL/DNA complexes revealed a compact structure, with a size of about 100-200 nm. Circular dichroism spectra of Lac-PEG-PLL/DNA complexes revealed that the secondary structure of DNA was altered by complex formation and was similar to that of the poly-L-lysine/DNA complex. Lac-PEG-PLL was shown to protect DNA against nuclease action in a DNase I protection assay. The cytotoxicity test demonstrated that the complex composed of plasmid DNA and Lac-PEG-PLL had little influence on the viability of HepG2 cells, especially in comparison with that of poly-L-lysine/DNA complexes. In conclusion, our copolymer, Lac-PEG-PLI, formed complexes with plasmid DNA (on average, 150 nm), gave little cytotoxicity, and showed increased efficiency of gene transfer into hepatoma cells in vitro. Lactose-polyethylene glycol was grafted to poly-L-lysine to be used as a gene carrier for hepatoma cell targeting and to improve the solubility of the polyplexes. The average size of the carrier/DNA complexes was about 150 nm. The complexes also proved to have high resistance against nuclease attack and little cytotoxicity. The polymer also delivered plasmid DNA efficiently into a HepG2 cell line. Lac-PEG-PLL was more efficient than Lipofectin or galactose-PEG-PLL in transfection efficiency.
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PMID:Characterization of a targeted gene carrier, lactose-polyethylene glycol-grafted poly-L-lysine and its complex with plasmid DNA. 1056 93

A block copolymer composed of cationic polymer and poly(ethylene glycol) (PEG) was used as a DNA carrier. Poly(2-(dimethylamino)ethyl methacrylate (DMAEMA)-co-N-vinyl-2-pyrrolidone (NVP)) having a terminal carboxylic group was synthesized by free radical polymerization using an initiator, 4,4'-azobis(4-cyanovaleric acid). The terminal carboxylic acid was activated by N-hydroxysuccinimide (NHS) with dicyclohexylcarbodiimide (DCC) and then conjugated with PEG-bis(amine). For specific gene targeting to asialoglycoprotein receptor of hepatocytes, a galactose moiety was incorporated into the PEG terminal end of poly(DMAEMA-NVP)-b-PEG by reductive coupling using lactose and sodium cyanoborohydride. RSV luciferase plasmid was used as a reporter gene, and in vitro gene transfection efficiency was measured in HepG2 human hepatocarcinoma cells. Poly(DMAEMA-NVP)-b-PEG-galactose/DNA complexes formed at 0.5-2 polymer/plasmid weight ratio had compacted structures around 200 nm particle size and exhibited slightly negative surface charge. These complexes were coated with a cationic, pH sensitive, endosomolytic peptide, KALA, to generate positively charged poly(DMAEMA-NVP)-b-PEG-galactose/DNA/KALA complex particles. In the presence of serum proteins, both the PEG block and the galactose moiety of poly(DMAEMA-NVP)-b-PEG-galactose greatly enhanced the gene transfection efficiency, which was very close to that of Lipofectamine plus. Irrespective of the presence of serum proteins, as the KALA/DNA weight ratio increased, the transfection efficiency of poly(DMAEMA-NVP)-b-PEG-galactose was enhanced due to the pH dependent endosomal disruptive property of KALA. This study demonstrates that sufficient transfection efficiency as high as that of commercial agent could be attained by judicious formulation of molecular engineered poly(DMAEMA-NVP)-b-PEG-galactose in combination with an endosomolytic peptide, KALA.
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PMID:Poly(DMAEMA-NVP)-b-PEG-galactose as gene delivery vector for hepatocytes. 1099 13

Hepatitis C is a major public health problem because of the high incidence of its related hepatocellular carcinoma. With the progress in molecular biology, the mechanisms of persistent infection, chronic inflammation, and hepatocarcinogenesis have been described in terms of virus, host, and virus-cell interactions. On the other hand, clinically, some recent studies using a large number of subjects with long-term observation after interferon therapy showed that improving hepatic inflammation might be associated with regression or retardation of fibrosis. However, current therapy for hepatitis C, although effective in some patients, is problematic even though the efficacy of combination therapy, interferon plus ribavirin, or PEG-interferon has been reported. Here we review the progress and discuss the prospective view of hepatitis C virus research from a point of view of both basic and clinical aspects.
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PMID:[Recent progress and prospective view of chronic hepatitis C research]. 1149 31

Interferon(IFN) is an essential component of the treatment of chronic HCV infection and at present, it is the most important to improve its efficacy, not only for HCV chronic liver diseases, but also for the prevention of HCV-associated hepatocellular carcinoma. Two long-acting IFN preparations(PEG-IFN alpha 2a and 2b) have been used at present and clinical studies have shown that sustained virologic, biochemical and histological responder rates are significantly higher in PEG-IFN-treated patients with HCV associated chronic hepatitis and cirrhosis comparing with ones treated with conventional IFN. In addition, PEG-IFN treatment in combination with ribavirin seems to be the best for HCV-associated chronic liver diseases.
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PMID:[Present status of clinical trials on long-acting IFNs preparations (PEG-IFN alpha 2a, alpha 2b, IFN alpha-minipellet)]. 1149 53

Ricin has long been employed to construct immunotoxins, whose efficacy was often undermined by immunogenicity. Pegylation (modification of proteins with polyethylene glycol, PEG) was one of those recently developed approaches to circumvent immunogenicity of legions of drugs. Herein, pegylation of ricin was found to have barely changed the RNA N-glycosidase activity and protein synthesis inhibiting activity of ricin, but remarkably altered the cytotoxicity of ricin on hepatoma cell line (BEL7404) or the immunoreactivity with polyclonal anti-ricin antibodies. This result suggested that the attached PEG or monomethyloxyl polyethylene glycol (mPEG) groups did not hinder ricin from hydrolyzing ribosomal RNA, but indeed covered some areas on the surface of ricin molecule, including those involved in the interaction with cellular receptors and epitopes recognized by polyclonal antibodies. Pegylation, masking certain epitopes of ricin, might contribute to alleviate the immunogenicity of the toxin. Approach in this work, if applied to thereby constructed immunotoxins, would help improve the prospective efficacy of these toxins.
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PMID:Bioactivities of ricin retained and its immunoreactivity to anti-ricin polyclonal antibodies alleviated through pegylation. 1185 38

Polycation vehicles used for in vitro gene delivery require alteration for successful application in vivo. Modification of polycations by direct grafting of additional components, e.g., poly(ethylene glycol) (PEG), either before or after DNA complexation, tend to interfere with polymer/DNA binding interactions; this is a particular problem for short polycations such as linear, beta-cyclodextrin-containing polycations (betaCDPs). Here, a new method of betaCDP polyplex (polycation/DNA composite structures) modification is presented that exploits the ability to form inclusion complexes between cyclodextrins and adamantane. Surface-PEGylated betaCDP polyplexes are formed by self-assembly of the polyplexes with adamantane-PEG conjugates. While unmodified polyplexes rapidly aggregate and precipitate in salt solutions, the PEGylated betaCDP polyplexes are stable at conditions of physiological salt concentration. Addition of targeting ligands to the adamantane-PEG conjugates allows for receptor-mediated delivery; galactosylated betaCDP-based particles reveal selective targeting to hepatocytes via the asialoglycoprotein receptor. Galactosylated particles transfect hepatoma cells with 10-fold higher efficiency than glucosylated particles (control), but show no preferential transfection in a cell line lacking the asialoglycoprotein receptor. Thus, surface modification of betaCDP-based polyplexes through the use of cyclodextrin/adamantane host/guest interactions endows the particles with properties appropriate for systemic application.
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PMID:Development of a nonviral gene delivery vehicle for systemic application. 1200 55

Some murine melanomas and hepatocellular carcinomas (HCCs) have been shown to be auxotrophic for arginine. Arginine deiminase (ADI; EC 3.5.3.6.), an arginine-degrading enzyme isolated from Mycoplasma, can inhibit growth of these tumors. We found that ADI was specific for arginine and did not degrade other amino acids. Although arginine is not an essential amino acid for most cells, all human melanomas and HCCs tested were found to be inhibited by ADI in vitro. Arginine is synthesized from citrulline in two steps by argininosuccinate synthetase and argininosuccinate lyase. Melanomas and HCCs did not express argininosuccinate synthetase mRNA but did express argininosuccinate lyase mRNA, suggesting that the arginine auxotrophy of these cells was a result of an inability to produce argininosuccinate synthetase. Human melanomas and HCCs were transfected with an expression plasmid containing argininosuccinate synthetase cDNA. The transfected cells were much more resistant to ADI than the parental cells in vitro and in vivo. Initial attempts to use ADI in vivo indicated that this enzyme had little efficacy, consistent with its short circulation half-life. Formulation of ADI with polyethylene glycol to produce ADI-SS PEG(20,000 mw) resulted in an enzyme with a much longer circulation half-life that, and although equally effective in vitro, was more efficacious in the treatment of mice implanted with human melanomas and HCCs. These data indicate that sensitivity of melanoma and HCC is due to the absence of argininosuccinate synthetase in these cells and that an effective formulation of ADI, which causes a sustained decrease in arginine, may be a useful treatment for arginine auxotrophic tumors including melanoma and HCC.
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PMID:Pegylated arginine deiminase (ADI-SS PEG20,000 mw) inhibits human melanomas and hepatocellular carcinomas in vitro and in vivo. 1235 51

Both enhanced vascular permeability and angiogenesis of tumor sustain rapid growth of tumor involving many vascular mediators and high vascular density. On the contrary, however, they can be utilized for macromolecular drug delivery to tumor. Impaired reticuloendothelial/lymphatic clearance of macromolecules from the tumor, or lack of such clearance, is another unique characteristic of tumor tissue, which results intratumor retention of macromolecular drugs thus delivered (Figure 1). Consequently, enhanced permeability and retention (EPR) effect is the basis for the selective targeting of macromolecular drugs to tumor, and the EPR concept is now utilized for selective delivery of many macromolecular anticancer agents in aqueous formation for i.v. or i.a. as well as oily formation for i.a. dosing, which is not possible for low-molecular-weight drugs because of rapid washout by capillary vascular blood flow. This EPR concept has been validated in clinical settings with hepatoma and other solid tumors. In our laboratories, several promising macromolecular anticancer drugs after SMANCS, such as PEG-XO, PEG-DAO, PEG-ZnPP, were developed, warranting further investigation for clinical application. More efficient drug delivery to tumor, especially of macromolecular drugs, may be possible by enhancing the EPR effect with the use of various vascular permeability mediators or potentiators. Suppression of the EPR effect by the use of appropriate inhibitors or antidotes, such as the bradykinin antagonist HOE 140 and protease inhibitors or NOS inhibitors, may also be possible. Thus, one may be able to suppress or retard tumor growth and tumor metastasis. Also, by suppressing vascular permeability with antidotes such as the bradykinin antagonist HOE 140, pleural fluid in lung cancer and ascitic fluid in abdominal carcinomatosis may be controlled and the clinical course of cancer patients may be improved. In summary, tumor vasculature can be an excellent target for delivery of macromolecular anticancer drugs; the most beneficial class of drugs in view of tumor-selective targeting based on the EPR effect in solid tumor as well as compliance of patients and ultimate therapeutic efficacy.
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PMID:Factors and mechanism of "EPR" effect and the enhanced antitumor effects of macromolecular drugs including SMANCS. 1267 6

Of the large number of patients chronically infected with hepatitis C virus (HCV), only about one third have progressive liver disease, and will eventually develop cirrhosis and hepatocellular carcinoma. These are the patients for whom effective antiviral treatment is most needed. Therapy is currently recommended for patients with chronic hepatitis C who have abnormal alanine aminotransferase (ALT) levels, detectable hepatitis C virus ribonucleic acid (HCV RNA) in the blood, and significant necroinflammatory changes and/or fibrosis on liver biopsy. The current gold standard in terms of treatment efficacy is the combination of peginterferon (PEG-IFN) and ribavirin. The overall sustained virological response rate (SVR) with these regimens is 54 to 61% following 48 weeks of therapy. Patients with genotype 1 infection have a 42 to 51% likelihood of response to 48 weeks of therapy. Those with genotypes 2 or 3 infection will respond to 24 weeks of therapy in 78 to 82% of cases. These SVR rates are 5 to 10 percentage points higher in all patient groups than in those obtained with standard doses of interferon (IFN) and ribavirin. Retreatment of nonresponders to standard IFN monotherapy using PEG-IFN and ribavirin has achieved SVR rates of 34 to 40%. Retreatment of patients who relapsed after IFN monotherapy has resulted in an SVR rate of about 60%. A SVR after retreatment of relapsers and nonresponders with PEG-IFN and ribavirin is more likely in patients previously treated with IFN monotherapy, those with HCV genotypes 2 or 3, patients with low viral load (<2 million copies/mL), and individuals who had a significant decrease in HCV RNA levels during the initial treatment. The potential benefits of long-term anti-HCV suppressive therapy in nonresponders are currently under investigation.
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PMID:Clinical trial results of peginterferons in combination with ribavirin. 1293 67

Hepatitis C is a major cause of liver-related morbidity and mortality worldwide. In fact, chronic hepatitis C is considered as one of the primary causes of chronic liver disease, cirrhosis and hepatocellular carcinoma, and is the most common reason for liver transplantation. The primary objectives for the treatment of HCV-related chronic hepatitis is to eradicate infection and prevent progression of the disease. The treatment has evolved from the use of alpha-interferon (IFNalpha) alone to the combination of IFNalpha plus ribavirin, with a significant improvement in the overall efficacy, and to the newer PEG-IFNs which have further increased the virological response, used either alone or in combination with ribavirin. Despite these positive results, in terms of efficacy, concerns are related to the safety and adverse events. Many patients must reduce the dose of PEG-IFN or ribavirin, others must stop the treatment and a variable percentage of subjects are not suitable owing to intolerance toward drugs. IFNbeta represents a potential therapeutic alternative for the treatment of chronic viral hepatitis and in some countries it plays an important role in therapeutic protocols. Aim of the present paper was to review available data on the safety of IFNbeta treatment in HCV-related chronic hepatitis. The rates of treatment discontinuation and/or dose modification due to the appearance of severe side effects during IFNbeta are generally low and in several clinical studies no requirements for treatment discontinuation and/or dose modifications have been reported. The most frequent side effects experienced during IFNbeta treatment are flu-like syndromes, fever, fatigue and injection-site reactions. No differences in terms of side-effect frequency and severity between responders and non-responders have been reported. A more recent study, performed to compare IFNbeta alone or in combination with ribavirin, confirmed the good safety profile of both treatments. Similar trends of adverse event frequency have been observed in subpopulations such as patients with genotype-1b HCV hepatitis unresponsive to IFNalpha treatment or with HCV-related cirrhosis and patients with acute viral hepatitis. If further studies will confirm the efficacy of combined IFNbeta and ribavirin treatment, this regimen could represent a safe and alternative therapeutic option in selected patients.
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PMID:Safety of interferon beta treatment for chronic HCV hepatitis. 1469 60


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