Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0017638 (glioma)
 30,880 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Ultrafine fibers containing water-soluble drugs were successfully electrospun from water-in-oil (W/O) emulsions, in which the aqueous phase contained the water-soluble drugs and the oily phase was a chloroform solution of amphiphilic poly (ethylene glycol)-poly (L-lactic acid) (PEG-PLLA) diblock copolymer. The diameter of the electrospun fibers was in the range of 300 nm-1 microm. A water-soluble anticancer agent, doxorubicin hydrochloride (Dox), was used as the model drug. Its content in the fibers was 1-5 wt.% and it was entirely encapsulated inside the electrospun fibers. Its release from the fibers was controlled by the combined diffusion mechanism and enzymatic degradation mechanism. At the early stage, the diffusion mechanism was predominant and a certain time later, the enzymatic degradation mechanism became predominant. The antitumor activity of the Dox incorporated in the PEG-PLLA fibers against mice glioma cells (C6 cell lines) was evaluated by MTT method. The results showed that the Dox could be released from the fibers without losing cytotoxicity.
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PMID:Ultrafine medicated fibers electrospun from W/O emulsions. 1616 43

A new prototype of nanoconjugate, Polycefin, was synthesized for targeted delivery of antisense oligonucleotides and monoclonal antibodies to brain tumors. The macromolecular carrier contains: 1. biodegradable, nonimmunogenic, nontoxic beta-poly(L-malic acid) of microbial origin; 2. Morpholino antisense oligonucleotides targeting laminin alpha4 and beta1 chains of laminin-8, which is specifically overexpressed in glial brain tumors; 3. monoclonal anti-transferrin receptor antibody for specific tissue targeting; 4. oligonucleotide releasing disulfide units; 5. L-valine containing, pH-sensitive membrane disrupting unit(s), 6. protective poly(ethylene glycol); 7. a fluorescent dye (optional). Highly purified modules were conjugated directly with N-hydroxysuccinimidyl ester-activated beta-poly(L-malic acid) at pendant carboxyl groups or at thiol containing spacers via thioether and disulfide bonds. Products were chemically validated by physical, chemical, and functional tests. In vitro experiments using two human glioma cell lines U87MG and T98G demonstrated that Polycefin was delivered into the tumor cells by a receptor-mediated endocytosis mechanism and was able to inhibit the synthesis of laminin-8 alpha4 and beta1 chains at the same time. Inhibition of laminin-8 expression was in agreement with the designed endosomal membrane disruption and drug releasing activity. In vivo imaging showed the accumulation of intravenously injected Polycefin in brain tumor tissue via the antibody-targeted transferrin receptor-mediated endosomal pathway in addition to a less efficient mechanism known for high molecular mass biopolymers as enhanced permeability and retention effect. Polycefin was nontoxic to normal and tumor astrocytes in a wide range of concentrations, accumulated in brain tumor, and could be used for specific targeting of several biomarkers simultaneously.
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PMID:Polycefin, a new prototype of a multifunctional nanoconjugate based on poly(beta-L-malic acid) for drug delivery. 1653 61

The purpose of the present study was to develop implantable BCNU-loaded poly(ethylene glycol)-poly(L-lactic acid) (PEG-PLLA) diblock copolymer fibers for the controlled release of 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU). BCNU was well incorporated and dispersed uniformly in biodegradable PEG-PLLA fibers by using electrospinning method. Environmental Scanning Electron Microscope (ESEM) images indicated that the BCNU-loaded PEG-PLLA fibers looked uniform and their surfaces were reasonably smooth. Their average diameters were below 1500 nm. The release rate of BCNU from the fiber mats increased with the increase of BCNU loading amount. In vitro cytotoxicity assay showed that the PEG-PLLA fibers themselves did not affect the growth of rat Glioma C6 cells. Antitumor activity of the BCNU-loaded fibers against the cells was kept over the whole experiment process, while that of pristine BCNU disappeared within 48 h. These results strongly suggest that the BCNU/PEG-PLLA fibers have an effect of controlled release of BCNU and are suitable for postoperative chemotherapy of cancers.
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PMID:BCNU-loaded PEG-PLLA ultrafine fibers and their in vitro antitumor activity against Glioma C6 cells. 1689 Oct 29

We described here a liposomal carrier system in which the targeting ligand was sulfatide, a glycosphingolipid known to bind several extracellular matrix (ECM) glycoproteins whose expression was highly up-regulated in many tumors. In vitro experiments with human glioma cell lines demonstrated that robust intracellular uptake of the liposomes depended specifically on the presence of sulfatide as the key liposomal component. Significant amount of the liposomes remained largely intact in the cytoplasm for hours following their internalization. When anticancer drug doxorubicin (DOX) was encapsulated in such liposomes, most of the drug was preferably delivered into the cell nuclei to exert its cytotoxicity. Use of this drug delivery system to deliver DOX for treatment of tumor-bearing nude mice displayed much improved therapeutic effects over the free drug or the drug carried by polyethylene glycol (PEG)-grafted liposomes. Our results demonstrate a close link between effective intracellular uptake of the drug delivery system and its therapeutic outcome. Moreover, the sulfatide-containing liposomes (SCL) may represent an interesting ligand-targeted drug carrier for a wide spectrum of cancers in which sulfatide-binding ECM glycoproteins are expressed.
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PMID:Intracellular drug delivery by sulfatide-mediated liposomes to gliomas. 1696 44

A novel amphiphilic polymer-paclitaxel conjugate P(LGG-paclitaxel)-PEG-P(LGG-paclitaxel) has been prepared. It was derived from its parent polymer P(LGG)-PEG-P(LGG), poly{(lactic acid)-co-[(glycolic acid)-alt-(l-glutamic acid)]}-block-poly(ethylene glycol)-block-poly{(lactic acid)-co-[(glycolic acid)-alt-(l-glutamic acid)]}, which was prepared by ring-opening copolymerization of l-lactide (LLA) with (3s)-benzoxylcarbonylethyl-morpholine-2,5-dione (BEMD) in the presence of dihydroxyl PEG with molecular weight of 4600 as a macroinitiator using stannous octoate (Sn(Oct)(2)) as catalyst, and by subsequent catalytic hydrogenation. It could self-assemble into micelles in an aqueous system with P(LGG-paclitaxel) block in the core and PEG in the shell. ESEM and DLS analysis of the micelles revealed a homogeneous spherical morphology and a unimodal size distribution. In vitro release of paclitaxel from the conjugate micelles showed that its release rate depended on pH value and was higher at lower pH than in neutral condition. In vitro antitumor activity of the paclitaxel conjugate against rat brain glioma C6 cells was evaluated by MTT method. The results showed that the paclitaxel can be released from the conjugate without losing cytotoxicity.
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PMID:A novel polymer-paclitaxel conjugate based on amphiphilic triblock copolymer. 1718 76

We report the development of a biostable methotrexate-immobilized iron oxide nanoparticle drug carrier that may potentially be used for real-time monitoring of drug delivery through magnetic resonance imaging. Methotrexate (MTX) was immobilized on the nanoparticle surface via a poly(ethylene glycol) self-assembled monolayer (PEG SAM). The cytotoxicity of the nanoparticle-drug conjugate (NP-PEG-MTX) to target cells was studied with 9L glioma cells. Cellular uptake experiments showed that the uptake of NP-PEG-MTX conjugates by glioma cells was considerably higher than that of control nanoparticles. Magnetic resonance imaging in 9L cells cultured with NP-PEG-MTX of various concentrations showed significant contrast enhancement. NP-PEG-MTX demonstrated higher cytotoxicity in 9L cells to free MTX in vitro. Leucovorin, an MTX antidote, was used to rescue the cells that had been exposed to NP-PEG-MTX or free MTX, and the experiment verified the biocompatibility of NP-PEG-MTX conjugates and the MTX on NP-PEG-MTX conjugates to be the true source of the cytotoxicity to the target cells. TEM results showed that NP-PEG-MTX conjugates were internalized into the 9L cellular cytoplasm and retained its crystal structure therein for up to 144 h, as identified by electron diffraction. This prolonged particle retention may allow physicians to image tumor cells exposed to the NP-PEG-MTX conjugate over an extended therapeutic time course.
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PMID:Methotrexate-immobilized poly(ethylene glycol) magnetic nanoparticles for MR imaging and drug delivery. 1719 23

A novel method for synthesis of anti-EGFR immunoliposomes using folate-folate binding protein (FBP) affinity is described. An anti-EGFR antibody (cetuximab or C225) was covalently linked to FBP via a thioether bond. Liposomes incorporating a lipophilic folate derivative (folate-PEG-cholesterol) were prepared by polycarbonate membrane extrusion. Anti-EGFR immunoliposomes were then obtained by combining FBP-C225 and folate-liposomes and evaluated for uptake and cytotoxicity in EGFR-overexpressing U87 human glioblastoma cells. Anti-EGFR immunoliposomes constructed via folate-FBP affinity exhibited excellent stability under physiological pH, and quickly released the bound FBP-C225 upon low pH (pH 3.5) treatment. Flow cytometry and fluorescence microscopy showed similar receptor-specific binding and internalization for both folate-FBP affinity-coupled and covalently coupled C225-immunoliposomes, but not for the non-targeted IgG-immunoliposomes. C225-immunoliposomes loaded with anticancer drug doxorubicin were more cytotoxic than non-targeted immunoliposomes in EGFR-overexpressing U87 glioma cells. Folate-FBP affinity is a potential method for construction of immunoliposomes and may have applications in synthesis of targeted drug carriers in general.
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PMID:Construction of anti-EGFR immunoliposomes via folate-folate binding protein affinity. 1721 81

The objective of the present study was to construct epidermal growth factor receptor (EGFR) targeting cetuximab-immunoliposomes (ILs) for targeted delivery of boron compounds to EGFR(+) glioma cells for neutron capture therapy. The ILs were synthesized by using a novel cholesterol-based membrane anchor, maleimido-PEG-cholesterol (Mal-PEG-Chol), to incorporate cetuximab into liposomes by either surface conjugation or a post-insertion method. For post-insertion, the transfer efficiency of MAb conjugates from micelles to liposome was examined at varying temperatures, mPEG2000-DSPE ratios, and micelle-to-liposome lipid ratios. Following this, the cetuximab-ILs were evaluated for targeted delivery of the encapsulated boron anion, dodecahydro-closo-dodecaborate (2-) (B12H122-), to human EGFR gene transfected F98EGFR glioma cells as potential delivery agents for boron neutron capture therapy (BNCT). In addition, cellular uptake of cetuximab-ILs, encapsulating a fluorescence dye, was analyzed by confocal fluorescence microscopy and flow cytometry, and boron content was quantified by ICP-MS. Much greater ( approximately 8-fold) cellular uptake of boron was obtained using cetuximab-ILs in EGFR(+) F98EGFR compared with nontargeted human IgG-ILs. On the basis of these observations, we have concluded that cholesterol can serve as an effective anchor for MAb in liposomes, and cetuximab-ILs are potentially useful delivery vehicles for BNCT of gliomas.
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PMID:Synthesis of cetuximab-immunoliposomes via a cholesterol-based membrane anchor for targeting of EGFR. 1722 62

Effective targeting of drugs to cells requires that the drug reach the target cell and interact specifically with it. In this study, we synthesized a biomacromolecular, multivalent construct intended to target glioblastoma tumors. The construct was created by linking three dodecapeptides, reported to bind the alpha 6beta1 integrin, with poly(ethylene glycol) linkers. The construct is intended to be delivered locally, and it demonstrates a more homogeneous and more rapid perfusion profile in comparison with quantum dots. The binding specificity of the construct was investigated by using glioblastoma cells and normal human astrocyte cells. The results reveal qualitative differences in binding between glioma and normal human astrocyte cells, with a moderate increase in binding avidity due to multivalency (0.79 microM for the trivalent construct versus 4.28 microM for the dodecapeptide). Overall, biomacromolecular constructs appear to be a promising approach for targeting with high biocompatibility, good perfusion abilities, and specificity.
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PMID:Specificity and mobility of biomacromolecular, multivalent constructs for cellular targeting. 1803 7

A great challenge for gene therapy is to develop a high efficient gene delivery system with low toxicity. Nonviral vectors are still attractive although the current agents displayed some disadvantages (i.e., low transfection efficiency, high toxicity). To overcome the high toxicity of poly(ethylene imine) (PEI) and low transfection efficiency of PEGylated PEI (PEG-PEI), we linked a cell specific target molecule folate (FA) on poly(ethylene glycol) (PEG) and then grafted the FA-PEG onto hyperbranched PEI 25kDa. The FA-PEG- grafted-hyperbranched-PEI (FA-PEG-PEI) effectively condensed plasmid DNA (pDNA) into nanoparticles with positive surface charge under a suitable N/P ratio. Tested in deferent cell lines (i.e., HEK 293T, glioma C6 and hepatoma HepG2 cells), no significant cytotoxicity of FA-PEG-PEI was added to PEG-PEI. More importantly, significant transfection efficiency was exhibited in FA-targeted cells. Reporter assay showed that FA-PEG-PEI/pDNA complexes had significantly higher transgene activity than that of PEI/pDNA in folate-receptor (FR) positive (HEK 293T and C6) cells but not FR-negative (HepG2) cells. These results indicated that FA-PEG-PEI might be a promising candidate for gene delivery with the characteristics of good biocompatibility, potential biodegradability, and relatively high gene transfection efficiency.
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PMID:Synthesis and characterization of folate-PEG-grafted-hyperbranched-PEI for tumor-targeted gene delivery. 1820 60


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