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1.
Article in English | MEDLINE | ID: mdl-38634257

ABSTRACT

BACKGROUND: The indication of laparoscopic liver resection (LLR) for treating large hepatocellular carcinoma (HCC) is controversial. In this study, we compared the short-term and long-term outcomes of LLR and open liver resection (OLR) for large HCC. MATERIAL AND METHODS: We searched eligible articles about LLR versus OLR for large HCC in PubMed, Cochrane Library, and EMBASE and performed a meta-analysis. RESULTS: Eight publications involving 1,338 patients were included. Among them, 495 underwent LLR and 843 underwent OLR. The operation time was longer in the LLR group (MD: 22.23, 95% CI: 4.14-40.33, p = 0.02). but the postoperative hospital stay time was significantly shorter (MD : -4.88, CI: -5.55 to -4.23, p < 0.00001), and the incidence of total postoperative complications and major complications were significantly fewer (OR: 0.49, 95% CI:0.37-0.66, p < 0.00001; OR: 0.54, 95% CI:0.36 - 0.82, p = 0.003, respectively). Patients in the laparoscopic group had no significant difference in intraoperative blood loss, intraoperative transfusion rate, resection margin size, R0 resection rate, three-year overall survival (OS) and three-year disease-free survival (DFS). CONCLUSION: LLR for large HCC is safe and feasible. This surgical strategy will not affect the long-term outcomes of patients.

2.
ACS Nano ; 18(13): 9486-9499, 2024 Apr 02.
Article in English | MEDLINE | ID: mdl-38497998

ABSTRACT

Agrichemical losses are a severe threat to the ecological environment. Additionally, some agrichemical compounds contain abundant salt, which increases the instability of formulations, leading to a lower agrichemical utilization and soil hardening. Fortunately, the biological amphiphilic emulsifier sodium deoxycholate alleviates these problems by forming stable Janus core-shell emulsions through salinity-driven interfacial self-assembly. According to the interfacial behavior, dilational rheology, and molecular dynamics simulations, Janus-emulsion molecules are more closely arranged than traditional-emulsion molecules and generate an oil-water interfacial film that transforms into a gel film. In addition, at the same spray volume, the deposition area of the Janus emulsion increased by 37.70% compared with that of the traditional emulsion. Owing to the topology effect and deformation, the Janus emulsion adheres to rice micropapillae, achieving better flush resistance. Meanwhile, based on response of the Janus emulsion to stimulation by carbon dioxide (CO2), the emulsion lost to the soil can form a rigid shell for inhibiting the release of pesticides and metal ions from harming the soil. The pyraclostrobin release rate decreased by 50.89% at 4 h after the Janus emulsion was exposed to CO2. The Chao1 index of the Janus emulsion was increased by 12.49% as compared to coconut oil delivery in soil microbial community. The Janus emulsion ingested by harmful organisms can be effectively absorbed in the intestine to achieve better control effects. This study provides a simple and effective strategy, which turns waste into treasure, by combining metal ions in agrichemicals with natural amphiphilic molecules to prepare stable emulsions for enhancing agrichemical rainfastness and weakening environmental risk.


Subject(s)
Agrochemicals , Salinity , Emulsions/chemistry , Carbon Dioxide , Ions , Soil
3.
Mol Ther Oncolytics ; 24: 788-798, 2022 Mar 17.
Article in English | MEDLINE | ID: mdl-35317514

ABSTRACT

Bispecific antibodies (BsAbs) are a class of promising anticancer immunotherapies. Among them, the US Food and Drug Administration (FDA)-approved blinatumomab (BLI) is very effective in eliminating the minimum residual disease (MRD) of acute lymphoblastic leukemia (ALL), resulting in long-term remission in many individuals. However, the need for months-long intravenous delivery and high cost limit its clinical acceptance. Here we demonstrate that these problems can be solved by a BsAb expressed by one intramuscular (i.m.) dose of a minicircle DNA vector (MC). In a human B lymphoma xenograft mouse model, when microcancers became detectable in bone marrow, the mice received an i.m. dose of the MC encoding the BsAb anti-CD3/CD20 (BsAb.CD20), followed by 8 subsequent intravenous (i.v.) doses, one every other day (q2d), of human T cells to serve as effectors. The treatment resulted in persistent expression of a therapeutic level of serum BsAb.CD20 and complete regression or growth retardation of the cancers in the mice. These results suggest that the i.m. MC technology can eliminate the physical and financial burdens of i.v. delivered BLI without compromising anticancer efficacy and that cancer can be treated as easily as injecting a vaccine. This, together with other superior MC features, such as safety and affordability, suggests that the i.m. MC BsAb technology has great clinical application potential.

4.
Zootaxa ; 4821(3): zootaxa.4821.3.8, 2020 Aug 03.
Article in English | MEDLINE | ID: mdl-33056316

ABSTRACT

The intra-specific variation of two species of Helorus Latreille (Hymenoptera, Heloridae) from NW China is studied and for the first time the sexual variation in Chinese Helorus species is described. Both sexes of Helorus antefurcalis He Xu, 2015 (new for Shaanxi) and H. caii He Xu, 2015 (up to now only known from one male), are described and illustrated. Helorus xinjiangensis He Xu, [June] 2015, is a new junior synonym of H. alborzicus Izadizadeh, van Achterberg Talebi, [April] 2015 and H. elgoni Risbec, 1950, is re-instated as valid species. A revised key to the Old World species of Helorus Latreille (except Australian region) is included.


Subject(s)
Hymenoptera , Animals , China , Female , Male
5.
Biomaterials ; 250: 120072, 2020 08.
Article in English | MEDLINE | ID: mdl-32361307

ABSTRACT

Ovarian cancer has become one of the most common gynecological cancers with a high mortality. However, conventional surgery together with combination chemotherapy is difficult to achieve ideal therapeutic effect. Although genetic immunotherapy is applied to active immune responses against cancer, the absence of efficient in vivo gene delivery technique is still an obstacle in clinical application. To overcome these problems, a minicircle DNA vector encoding humanized anti-EpCAM/CD3 bispecific antibody (BsAbEPH) has been constructed. Moreover, different shapes of calcium phosphate (CaPO) biomaterials were prepared. Specifically, the CaPO-nanoneedle-mediated "cell perforation" transfection technology achieves high levels of gene expression in peritoneal cavity. In an intraperitoneal xenograft model with human ovarian cancer cell line SKOV3, the CaPO-nanoneedle/minicircle DNA system expressed BsAbEPH resulted in significant retardation of cancer growth and extension of mouse life-span with limited toxicity. And this system can be made as off-the-shelf and easy-to-use products. Therefore, CaPO-nanoneedle based non-viral gene delivery technology will have great potential in clinical application.


Subject(s)
Immunotherapy , Ovarian Neoplasms , Animals , Calcium Phosphates , Female , Gene Transfer Techniques , Humans , Mice , Ovarian Neoplasms/genetics , Ovarian Neoplasms/therapy , Transfection
6.
Biomater Sci ; 6(3): 633-641, 2018 Feb 27.
Article in English | MEDLINE | ID: mdl-29411792

ABSTRACT

Bispecific T-cell engagers (BiTEs) are single chain variable fragments with specific structures, which could connect the surface antigen on cancer cells and CD3 ligands on T cells, and then engage the T cells for cancer immunotherapy. In this report, a novel organic-inorganic hybrid gene delivery system composed of stearic acid modified polyethyleneimine (stPEI) and calcium phosphate (CaP) was used to deliver MC.DNA into cells to express BiTE antibodies. This gene delivery system exhibits high transfection efficiency, long-term effects and low cytotoxicity in vitro. Furthermore, the gene production, anti-IGF1R/CD3 bispecific T-cell engager, exhibited a rapid redirection activity in T cells to induce cancer cell apoptosis. In summary, the results confirmed that stPEI-CaP could be an efficient gene delivery system for BiTE encoding MC.DNA based gene immunotherapy.


Subject(s)
Calcium Phosphates/chemistry , Polyethyleneimine/chemistry , Single-Chain Antibodies/administration & dosage , Surface-Active Agents/chemistry , T-Lymphocytes/drug effects , Transfection/methods , CD3 Complex/immunology , Calcium Phosphates/adverse effects , Cells, Cultured , Genetic Therapy/methods , HEK293 Cells , Hep G2 Cells , Humans , Immunotherapy/methods , Polyethyleneimine/adverse effects , Receptor, IGF Type 1/immunology , Single-Chain Antibodies/genetics , Single-Chain Antibodies/immunology , Surface-Active Agents/adverse effects , T-Lymphocytes/metabolism
7.
Cancer Med ; 6(1): 207-219, 2017 01.
Article in English | MEDLINE | ID: mdl-27998038

ABSTRACT

Emerging evidence suggest that the heterogeneity of cancer limits the efficacy of immunotherapy. To search for optimal therapeutic targets for enhancing the efficacy, we used whole-exome sequencing data of 23 early cervical tumors from Chinese women to investigate the hierarchical structure of the somatic mutations and the neo-epitopes. The putative neo-epitopes were predicted based on the mutant peptides' strong binding with major histocompatibility complex class I molecules. We found that each tumor carried an average of 117 mutations and 61 putative neo-epitopes. Each patient displayed a unique phylogenetic tree in which almost all subclones harbored neo-epitopes, highlighting the importance of individual neo-epitope tree in determination of immunotherapeutic targets. The alterations in FBXW7 and PIK3CA, or other members of the significantly altered ubiquitin-mediated proteolysis and extracellular matrix receptor interaction related pathways, were proposed as the earliest changes triggering the malignant progression. The neo-epitopes involved in these pathways, and located at the top of the hierarchy tree, might become the optimal candidates for therapeutic targets, possessing the potential to mediate T-cell killing of the descendant cells. These findings expanded our understanding in early stage of cervical carcinogenesis and offered an important approach to assist optimizing the immunotherapeutic target selection.


Subject(s)
Epitopes/metabolism , Mutation , Papillomavirus Infections/immunology , Sequence Analysis, DNA/methods , Uterine Cervical Neoplasms/genetics , Uterine Cervical Neoplasms/immunology , Adult , Asian People/genetics , Cell Cycle Proteins/genetics , China , Class I Phosphatidylinositol 3-Kinases/genetics , Early Detection of Cancer , Exome , F-Box Proteins/genetics , F-Box-WD Repeat-Containing Protein 7 , Female , Humans , Immunotherapy , Middle Aged , Papillomavirus Infections/genetics , Phylogeny , Ubiquitin-Protein Ligases/genetics , Uterine Cervical Neoplasms/virology
8.
Hum Gene Ther ; 28(2): 216-225, 2017 02.
Article in English | MEDLINE | ID: mdl-27802782

ABSTRACT

Bispecific antibodies (BsAbs), capable of directing T cells to kill specific cancer cells by transiently binding the two cell types, have emerged as one class of promising cancer immunotherapies. However, their wide clinical application might be hampered by two deficiencies: high cost and inconvenience in drug administration. This study presents concept-proving data that these problems could be bypassed by using an enhanced nonviral DNA vector minicircle (MC) to produce BsAb in vivo. It was found that the anti-CD3/CD20 produced from the minicircle (MC.CD20) could effectively mediate the T-cell killing of multiple CD20-positive human B-cell lymphoma cell lines in vitro. More importantly, it was demonstrated that delivery of 5 µg of MC.CD20 to mouse liver via hydrodynamic injection resulted in both the expression of a therapeutic level of anti-CD3/CD20 throughout the 32-day experiment and effective anticancer activity in a B-cell lymphoma xenograft mouse model. The data suggest that MC encoding the BsAbs may become an attractive cancer immunotherapy modality based on its excellent features of safety, efficacy, and convenience in both preparation and use, and its affordability once the delivery technology matures.


Subject(s)
Antibodies, Bispecific/therapeutic use , Antigens, CD20/immunology , CD3 Complex/immunology , DNA, Circular/genetics , Genetic Vectors/administration & dosage , Immunotherapy , Lymphoma, B-Cell/therapy , Animals , Antibodies, Monoclonal/therapeutic use , Disease Models, Animal , Genetic Engineering , Humans , Lymphoma, B-Cell/genetics , Lymphoma, B-Cell/immunology , Mice
9.
Biomater Sci ; 5(1): 120-127, 2016 Dec 20.
Article in English | MEDLINE | ID: mdl-27892545

ABSTRACT

Gene therapy has great promise for the treatment of obtained and inherited serious diseases. However, the lack of safe and efficient gene delivery systems remains a barrier for their clinical application. Here, we reported a potential gene delivery vehicle composed of the erythrocyte membrane and cationic polymers, for example the XtremeGENE from Roche and the ε-caprolactone modified polyethylenimine. In addition to high efficiency, this system showed negligible cytotoxicity compared to the two cationic polymers alone in various cell lines, including human embryonic kidney cells (293T), human liver cancer cells (Huh7 and HepG2), murine dendritic cells (DC2.4) and human umbilical cord mesenchymal stem cells (Hu-MSCs). Moreover, the results of confocal laser scanning microscopy and flow cytometry suggested that the cell uptake of this gene vector was improved and might be introduced by the fusion interaction between the erythrocyte membrane and targeted cells.Thus, all the results revealed that the erythrocyte membrane based gene delivery system might be able to serve as an excellent gene delivery system.


Subject(s)
Caproates/chemistry , Erythrocyte Membrane/chemistry , Gene Transfer Techniques , Lactones/chemistry , Polyethyleneimine/chemistry , Polymers/chemistry , Animals , Cell Line , DNA/chemistry , Humans , Mice
10.
ACS Appl Mater Interfaces ; 8(30): 19284-90, 2016 Aug 03.
Article in English | MEDLINE | ID: mdl-27267084

ABSTRACT

Minicircle DNA (mcDNA) is a kind of enhanced nonviral DNA vector with excellent profiles in biosafety and transgene expression. Herein, we reported a novel amphiphilic polymer comprising polyethylenimine(PEI) modified Poly(ß-amino ester) PEI-PBAE(C16) for efficient mcDNA delivery in vivo. The synthesized polymer could condense mcDNA into nanoscaled structure and exhibited efficient gene transfection ability without detectable cytotoxicity. Importantly, when injected into mouse intraperitoneally, these PEI-PBAE(C16) nanocomplexes were able to result in high level of trangene expression which lasted at least 72 h. Overall, these results demonstrated the PEI-PBAE(C16) can mediate effective and safe gene delivery in vivo with clinical application potential.


Subject(s)
DNA/administration & dosage , Polymers/chemical synthesis , Transfection/methods , Animals , Cell Survival/drug effects , Gene Expression , Mice , Polyethyleneimine/chemistry , Polymers/chemistry , Polymers/toxicity , Transfection/standards
11.
Sci Rep ; 6: 25552, 2016 05 13.
Article in English | MEDLINE | ID: mdl-27174254

ABSTRACT

HBV covalently closed circular DNA (cccDNA) is drug-resistant and responsible for viral persistence. To facilitate the development of anti-cccDNA drugs, we developed a minicircle DNA vector (MC)-based technology to produce large quantity of recombined cccDNA (rcccDNA) resembling closely to its wild-type counterpart both in structure and function. The rcccDNA differed to the wild-type cccDNA (wtcccDNA) only in that it carried an extra 36-bp DNA recombinant product attR upstream of the preC/C gene. Using a procedure similar to standard plasmid production, milligrams of rcccDNA can be generated in common laboratories conveniently. The rcccDNA demonstrated many essential biological features of wtcccDNA, including: (1) undergoing nucleation upon nucleus entry; (2) serving as template for production of all HBV RNAs and proteins; (3) deriving virions capable of infecting tree shrew, and subsequently producing viral mRNAs, proteins, rcccDNA and infectious virions. As an example to develop anti-cccDNA drugs, we used the Crispr/Cas9 system to provide clear-cut evidence that rcccDNA was cleaved by this DNA editing tool in vitro. In summary, we have developed a convenient technology to produce large quantity of rcccDNA as a surrogate of wtcccDNA for investigating HBV biology and developing treatment to eradicate this most wide-spreading virus.


Subject(s)
DNA, Circular/genetics , DNA, Recombinant/genetics , DNA, Viral/genetics , Hepatitis B virus/genetics , Animals , CRISPR-Cas Systems , Cell Line, Tumor , Hepatitis B/virology , Hepatitis B virus/metabolism , Hepatitis B virus/physiology , Host-Pathogen Interactions , Humans , RNA, Viral/genetics , Tupaiidae/virology , Viral Proteins/genetics , Viral Proteins/metabolism , Virion/genetics , Virion/metabolism , Virus Replication/genetics
12.
J Colloid Interface Sci ; 463: 93-8, 2016 Feb 01.
Article in English | MEDLINE | ID: mdl-26520815

ABSTRACT

Gene therapy has held great promise for treating specific acquired and inherited diseases. However, the lack of safe and efficient gene delivery systems remains as the major challenge. Poly(ß-amino ester)s (PBAEs) have attracted much attention due to their outstanding properties in biosafety, DNA delivery efficiency and convenience in synthesis. In this paper, we reported the further enhancement of the PBAE functions by increasing its positive charge through conjugating with low molecular weight polyethylenimine (LPEI). The resulted LPEI-PBAE polymer was able to condense minicircle DNA (mcDNA) forming nanoparticles with a diameter of 50-200nm. Furthermore, as compared to parental PBAE and a commercial transfection reagent very common in laboratory application, the LPEI-PBAE demonstrated significantly higher transfection efficiency with little cytotoxicity. These results suggested LPEI-PBAEs are worthy of further optimization for gene therapy applications.


Subject(s)
DNA, Circular/administration & dosage , DNA, Circular/chemistry , Gene Transfer Techniques , Polyethyleneimine/chemistry , Polymers/chemistry , Polymers/chemical synthesis , Animals , Cell Line , DNA, Circular/genetics , Humans , Molecular Weight , Nanoparticles/adverse effects , Nanoparticles/chemistry , Particle Size , Polyethyleneimine/adverse effects , Polymers/adverse effects , Surface Properties , Swine
13.
Mol Ther Methods Clin Dev ; 1: 14062, 2015.
Article in English | MEDLINE | ID: mdl-26052527

ABSTRACT

DNA vectors for human gene therapy have to meet the efficacy and safety requirements. Minicircles (MCs), a class of optimized DNA vectors free of plasmid backbone (PB) DNAs, have emerged as promising candidates because of their superior transgene expression profiles. However, the existence of impure DNAs, including the unrecombined MC producing plasmid (PP) and PB circle, in the MC products made using the current technologies exceed the safety limit. Here, we report the development of an enhanced triplex DNA (TriD) technology to eliminate almost all the impure DNAs from the MC products. To do this, a pair of optimized TriD forming sequences was placed to flank the kanamycin resistance gene in the PP. The MC products were incubated with a biotinylated TriD forming DNA oligonucleotide (olig), and the resulted TriDs were removed by binding to streptovidin-coated magnetic beads. Consequently, the residual impure DNAs were 0.03% or less in the final MC products. The reproducibility of this technique was confirmed with MCs of various transgene expression cassettes, sizes, and quantities, suggesting its great potential in making high quality MC for human gene therapy.

14.
Sci Rep ; 5: 11100, 2015 Jun 09.
Article in English | MEDLINE | ID: mdl-26057841

ABSTRACT

One of the major problems influencing the therapeutic efficacy of stem cell therapy is the poor cell survival following transplantation. This is partly attributed to insufficient resistance of transplanted stem cells to oxidative and inflammatory stresses at the injured sites. In the current study, we demonstrated the pivotal role of antioxidant levels in human umbilical cord mesenchymal stem cells (hUCMSCs) dynamic in vitro anti-stress abilities against lipopolysaccharide (LPS)/H2O2 intoxication and in vivo therapeutic efficacy in a murine acute liver failure model induced by D-galactosamine/LPS (Gal/LPS) by either reducing the antioxidant levels with diethyl maleate (DEM) or increasing antioxidant levels with edaravone. Both the anti- and pro-oxidant treatments dramatically influenced the survival, apoptosis, and reactive oxygen species (ROS) production of hUCMSCs through the MAPK-PKC-Nrf2 pathway in vitro. When compared with untreated and DEM-treated cells, edaravone-treated hUCMSCs rescued NOD/SCID mice from Gal/LPS-induced death, significantly improved hepatic functions and promoted host liver regeneration. These effects were probably from increased stem cell homing, promoted proliferation, decreased apoptosis and enhanced secretion of hepatocyte growth factor (HGF) under hepatic stress environment. In conclusion, elevating levels of antioxidants in hUCMSCs with edaravone can significantly influence their hepatic tissue repair capacity.


Subject(s)
Antioxidants/therapeutic use , Liver Failure, Acute/drug therapy , Mesenchymal Stem Cells/drug effects , Stress, Physiological , Antioxidants/pharmacology , Humans , Mesenchymal Stem Cells/cytology , Models, Biological
15.
PLoS One ; 9(8): e104392, 2014.
Article in English | MEDLINE | ID: mdl-25101638

ABSTRACT

Mesenchymal stem cells (MSCs) have exhibited therapeutic effects in multiple animal models so that are promising liver substitute for transplantation treatment of end-stage liver diseases. However, it has been shown that over-manipulation of these cells increased their tumorigenic potential, and that reducing the in vitro culture time could minimize the risk. In this study, we used a D-galactosamine plus lipopolysaccharide (Gal/LPS)-induced acute liver failure mouse model, which caused death of about 50% of the mice with necrosis of more than 50% hepatocytes, to compare the therapeutic effects of human umbilical cord MSCs (hUCMSCs) before and after induction of differentiation into hepatocyte (i-Heps). Induction of hUCMSCs to become i-Heps was achieved by treatment of the cells with a group of growth factors within 4 weeks. The resulted i-Heps exhibited a panel of human hepatocyte biomarkers including cytokeratin (hCK-18), α-fetoprotein (hAFP), albumin (hALB), and hepatocyte-specific functions glycogen storage and urea metabolism. We demonstrated that transplantation of both cell types through tail vein injection rescued almost all of the Gal/LPS-intoxicated mice. Although both cell types exhibited similar ability in homing at the mouse livers, the populations of the hUCMSCs-derived cells, as judged by expressing hAFP, hCK-18 and human hepatocyte growth factor (hHGF), were small. These observations let us to conclude that the hUCMSCs was as effective as the i-Heps in treatment of the mouse acute liver failure, and that the therapeutic effects of hUCMSCs were mediated largely via stimulation of host hepatocyte regeneration, and that delivery of the cells through intravenous injection was effective.


Subject(s)
Fetal Blood , Hepatocytes/metabolism , Liver Failure, Acute/metabolism , Liver Failure, Acute/therapy , Mesenchymal Stem Cell Transplantation , Mesenchymal Stem Cells/metabolism , Animals , Cell Differentiation , Disease Models, Animal , Heterografts , Humans , Mice , Mice, Inbred NOD , Mice, SCID
16.
Biomaterials ; 34(14): 3688-96, 2013 May.
Article in English | MEDLINE | ID: mdl-23419644

ABSTRACT

Gene therapy is a very promising technology for treatment of liver diseases. Minicircle DNA (MCDNA) is a versatile gene vector, which possesses excellent features in bio-safety and duration of transgene expression. However, its application has been hampered by the lack of an efficient gene delivery system. In this study, we developed a magnetic resonance imaging (MRI) visible nanoparticle to monitor MCDNA gene delivery and explore the potential of gene therapy in vivo. The nanoparticle was constructed via self-assembly of stearic acid modified low molecular polyethyleneimine (stPEI) and superparamagnetic iron oxide (SPIO) nanocrystals. The multiple SPIO nanocrystals with a controlled clustering structure in the nanoparticles were designed to achieve high MRI sensitivity. Furthermore, the MCDNA was combined with the nanoparticles via electronic interaction. Through intrabiliary infusion, the stPEI-SPIO/MCDNA nanoparticles were efficiently delivered to liver that was visualized by MRI in vivo and confirmed by histology. Moreover, the MCDNA nanoparticles exhibited non-cytotoxicity with no obvious inflammation in the transfection sites. These results indicate that stPEI-SPIO nanoparticle is able to serve as both an efficient DNA vector delivery system and a sensitive agent for MRI visualization.


Subject(s)
Biliary Tract/metabolism , DNA/administration & dosage , DNA/chemistry , Ferric Compounds/chemistry , Liver/metabolism , Magnetic Resonance Imaging/methods , Nanoparticles/administration & dosage , Nanoparticles/chemistry , Animals , Female , Genetic Therapy , Immunohistochemistry , Mice , Mice, Inbred BALB C
17.
Nanoscale ; 5(2): 744-52, 2013 Jan 21.
Article in English | MEDLINE | ID: mdl-23224057

ABSTRACT

As a versatile gene vector, minicircle DNA (mcDNA) has a great potential for gene therapy. However, some serious challenges remain, such as to effectively deliver mcDNA into targeted cells/tissues and to non-invasively monitor the delivery of the mcDNA. Superparamagnetic iron oxide (SPIO) nanoparticles have been extensively used for both drug/gene delivery and diagnosis. In this study, an MRI visible gene delivery system was developed with a core of SPIO nanocrystals and a shell of biodegradable stearic acid-modified low molecular weight polyethyleneimine (Stearic-LWPEI) via self-assembly. The Stearic-LWPEI-SPIO nanoparticles possess a controlled clustering structure, narrow size distribution and ultrasensitive imaging capacity. Furthermore, the nanoparticle can effectively bind with mcDNA and protect it from enzymatic degradation. In conclusion, the nanoparticle shows synergistic advantages in the effective transfection of mcDNA and non-invasive MRI of gene delivery.


Subject(s)
DNA/metabolism , Drug Delivery Systems , Magnetic Resonance Imaging/methods , Nanoparticles/chemistry , Nanotechnology/methods , Cell Line, Tumor , Cell Survival , DNA/chemistry , Ferric Compounds/chemistry , Genetic Therapy/methods , Genetic Vectors , Heparin/chemistry , Humans , Magnetics , Molecular Weight , Plasmids/metabolism , Polyethyleneimine/chemistry , Stearic Acids/chemistry , Transfection
18.
Nat Biotechnol ; 28(12): 1287-9, 2010 Dec.
Article in English | MEDLINE | ID: mdl-21102455

ABSTRACT

Minicircle DNA vectors allow sustained transgene expression in quiescent cells and tissues. To improve minicircle production, we genetically modified Escherichia coli to construct a producer strain that stably expresses a set of inducible minicircle-assembly enzymes, ΦC31 integrase and I-SceI homing endonuclease. This bacterial strain produces purified minicircles in a time frame and quantity similar to those of routine plasmid DNA preparation, making it feasible to use minicircles in place of plasmids in mammalian transgene expression studies.


Subject(s)
Biotechnology/methods , Cloning, Molecular/methods , DNA, Circular , Genetic Vectors , Plasmids , Escherichia coli/genetics
19.
Int J Pharm ; 308(1-2): 160-7, 2006 Feb 03.
Article in English | MEDLINE | ID: mdl-16359836

ABSTRACT

Combination of adsorption by porous CaCO(3) microparticles and encapsulation by polyelectrolyte multilayers via the layer-by-layer (LbL) self-assembly was proposed for sustained drug release. Firstly, porous calcium carbonate microparticles with an average diameter of 5 microm were prepared for loading a model drug, ibuprofen (IBU). Adsorption of IBU into the pores was characterized by ultraviolet (UV), infrared (IR), thermogravimetric analysis (TGA), Brunauer-Emmett-Teller (BET) experiment and X-ray diffraction (XRD). The adsorbed IBU amount Gamma was 45.1mg/g for one-time adsorption and increased with increasing adsorption times. Finally, multilayer films of protamine sulfate (PRO) and sodium poly(styrene sulfonate) (PSS) were formed on the IBU-loaded CaCO(3) microparticles by the layer-by-layer self-assembly. Amorphous IBU loaded in the pores of the CaCO(3) microparticles had a rapider release in the gastric fluid and a slower release in the intestinal fluid, compared with the bare IBU crystals. Polyelectrolyte multilayers assembled on the drug-loaded particles by the LbL reduced the release rate in both fluids. In this work, polymer/inorganic hybrid core-shell microcapsules were fabricated for controlled release of poorly water-soluble drugs. The porous inorganic particles are useful to load drugs in amorphous state and the polyelectrolyte multilayer films coated on the particle assuage the initial burst release.


Subject(s)
Anti-Inflammatory Agents, Non-Steroidal/chemistry , Calcium Carbonate/chemistry , Drug Compounding/methods , Ibuprofen/chemistry , Polymers/chemistry , Adsorption , Body Fluids/chemistry , Delayed-Action Preparations , Hydrogen-Ion Concentration , Microscopy, Electron, Scanning , Particle Size , Porosity , Solubility , Solvents , Spectrophotometry, Infrared , Temperature
20.
Hum Gene Ther ; 16(1): 126-31, 2005 Jan.
Article in English | MEDLINE | ID: mdl-15703495

ABSTRACT

We have shown previously that minicircle DNA vectors free of plasmid bacterial DNA sequences are capable of persistent high level of transgene expression in vivo. The minicircle is generated in bacteria from a parental plasmid containing an inducible phage oC31 integrase gene and a therapeutic expression cassette flanked with attB and attP sites. The oC31-mediated intramolecular recombination between attB and attP results in the formation of two circular DNA molecules, one containing the eukaryotic expression cassette (minicircle), and the other the plasmid bacterial DNA backbone (BB). Previously, the minicircle was purified away from the plasmid BB by a restriction enzyme digestion step and ultracentrifugation in cesium chloride. We have now included the endonuclease I-SceI gene together with its recognition site in the minicircle-producing plasmid to allow the linearization and degradation of the plasmid BB in bacteria. The minicircle can then be isolated by routine plasmid purification procedures such as a one-step affinity column. With additional modifications to our previous strategy, we can prepare a minicircle encoding a 4-kb human factor IX expression cassette, up to 1.8 mg of minicircle with 97% purity was prepared from a 1 liter bacterial culture. The high yield, simple purification, and robust and persistent transgene expression make these vectors viable for gene therapy applications.


Subject(s)
DNA, Bacterial/physiology , DNA, Circular/isolation & purification , Gene Transfer Techniques , Genetic Vectors/isolation & purification , Plasmids , Transgenes/physiology , Bacteria/genetics , Factor IX/genetics , Factor IX/isolation & purification , Factor IX/metabolism , Humans
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