Zhenghong Xu

The performance of docetaxel-loaded solid lipid nanoparticles targeted to hepatocellular carcinoma

Human hepatocellular carcinoma (HCC) is one of the major causes of death worldwide. Targeted uptake of therapeutic agent in the cell-, tissue- or disease-specific manner represents a potential technology for the treatment of HCC. A new docetaxel-loaded hepatoma-targeted solid lipid nanoparticle (tSLN) was designed and prepared with galactosylated dioleoylphosphatidyl ethanolamine. The cellular cytotoxicity, cellular uptake, subcellular localization, in vivo toxicity, therapeutic effect, biodistribution and histology of tSLNs were investigated. The tSLNs showed the particle size about 120nm with encapsulation efficiency >90%, a low burst effect within the first day and a sustained release for the next 29 days in vitro. Cytotoxicity of tSLNs against hepatocellular carcinoma cell line BEL7402 was superior to Taxotere and non-targeted SLNs (nSLNs). The tSLNs also showed better tolerant and antitumor efficacy in murine model bearing hepatoma compared with Taxotere or nSLNs. The studies on cellular uptake and biodistribution indicated that the better antitumor efficacy of tSLNs was attributed to both the increased accumulation of drug in tumor and more cellular uptake by hepatoma cells. The histology demonstrated that tSLNs had no detrimental effect on both healthy liver and liver with fibrosis. These results implied that this targeted nanocarrier of docetaxel could enhance its antitumor effect in vivo with low systemic toxicity for the treatment of locally advanced and metastatic HCC.

Arginine-chitosan/DNA self-assemble nanoparticles for gene delivery: In vitro characteristics and transfection efficiency

Chitosan (Cs) is a natural cationic polysaccharide that has shown potential as non-viral vector for gene delivery because of its biocompatibility and low toxicity. However, chitosan used for gene delivery is limited due to its poor water solubility and low transfection efficiency. The purpose of this work was to prepare Arginine-chitosan (Arg-Cs)/DNA self-assemble nanoparticles (ACSNs), and determine their in vitro characteristics and transfection efficiency against HEK 293 and COS-7 cells. Our experimental results showed that the particle size and zeta potential of ACSNs prepared with different N/P ratios were 200-400nm and 0.23-12.25mV, respectively. The in vitro transfection efficiency of ACSNs showed dependence on pH of transfection medium, and the highest expression efficiency was obtained at pH 7.2. The transfection efficiency increased with the ratio of chitosan-amine/DNA phosphate (N/P ratio) from 1 to 5, and reached the highest level with the N/P ratio 5. Effect of plasmid dosage on the transfection efficiency showed the highest transfection efficiency was obtained at 4microg/well for HEK 293 cells and 6microg/well for COS-7 cells. The transfection efficiency of ACSNs was much higher than that of Cs/DNA self-assemble nanoparticles (CSNs). The average cell viability of ACSNs was over 90%. These results suggested that ACSNs could be a safe and effective non-viral vector for gene delivery.

The characteristics and performance of a multifunctional nanoassembly system for the co-delivery of docetaxel and iSur-pDNA in a mouse hepatocellular carcinoma model.

Human hepatocellular carcinoma (HCC) is one of the most causes of cancer-related death and is well known because of resistant to chemotherapeutic drug. Co-delivery of antitumor agent docetaxel and iSur-pDNA, a suppressor of metastatic and resistance-related protein survivin, was postulated to achieve synergistic/combined effect of antitumor drug and gene therapeutics. To valid this hypothesis, a folate-modified multifunctional nanoassembly (FNA) loading both docetaxel and iSur-pDNA was constructed and evaluated as a therapeutic approach for HCC. The FNAs were prepared with folate-modified lipid FA-PEG-DSPE as the target to tumor, protamine sulfate (PS) as the condenser to protect and enhance the nuclear transfer of iSur-pDNA, and DOPE-based lipid envelope as the carrier of doctaxel and PS/DNA complex to achieve their co-delivery and enhance internalization into hepatoma cells. FNAs showed the particle size about 200nm with encapsulation efficiency >90%. Blank nanoassemblies (BNAs) loading only reporter gene revealed higher transfection efficiency with neglectable cytotoxicity compared with Lipofectamine 2000, which could result from enhanced cellular uptake via ligand-receptor recognition and efficient nuclear delivery mediated by PS. Cytotoxicity of FNAs against hepatocellular carcinoma cell line BEL 7402 was much higher than either docetaxel or non-docetaxel FNAs (nFNAs) loading only iSur-pDNA, and was also superior to the combined treatment with free docetaxel and nFNAs. Better antitumor efficacy of FNAs with low systemic toxicity was also observed on mouse hepatocellular carcinoma xenograft model. These results suggested that co-delivery of docetaxel and iSur-pDNA with FNAs could be a safer and more efficient strategy for the treatment of locally advanced and metastatic HCC.

The role of daidzein-loaded sterically stabilized solid lipid nanoparticles in therapy for cardio-cerebrovascular diseases

Daidzein is a very good candidate for treating cardio-cerebrovascular diseases, but its poor oral absorption and bioavailability limit its curative efficacy. In this work, daidzein-loaded solid lipid nanoparticles (SLNs) with PEGylated phospholipid as stabilizer were successfully prepared by hot homogenization method. SLNs showed the mean particle size 126+/-14 nm with entrapment efficiency 82.5+/-3.7%. In vitro release of SLNs demonstrated a sustained release manner with cumulative release over 90% within 120 h in bovine serum albumin solution (4%, w/v). The pharmacokinetic behavior showed that SLNs loading daidzein could significantly increase circulation time compared with orally administrated daidzein suspension or intravenously delivered daidzein solution. SLNs showed the better effect on cardiovascular system of the anesthetic dogs by reducing the myocardial oxygen consumption (MOC) and the coronary resistance (CR) in heart compared with oral suspension or intravenous solution. The SLNs demonstrated the best effect on cerebrovascular system by increasing cerebral blood flow (CeBF) and reducing cerebrovascular resistance (CeR) in anesthetized dogs, and the protective effect on rats with ischemia-reperfusion injury model among three formulations. These results suggested that SLNs could be a potential candidate for the treatment of cardio-cerebrovascular diseases.

A Smart Nanoassembly Consisting of Acid-Labile Vinyl Ether PEG−DOPE and Protamine for Gene Delivery: Preparation and in Vitro Transfection

The conception of a modular designed and viruslike nonviral vector has been presented for gene delivery. Recently, we constructed a new smart nanoassembly (SNA) with multifunctional components that was composed of a condensed core of pDNA with protamine sulfate (PS) and a dioleoyl phosphatidylethanolamine (DOPE)-based lipid envelope containing poly(ethylene glycol)--vinyl ether--DOPE (PVD). SNAs with mPEG 2000 (SNAs1) or mPEG 5000 (SNAs2) loading PS/DNA were prepared by the lipid film hydration technique. The particle size was about 160 nm for SNAs1 and 240 nm for SNAs2 loading PS/DNA (10:1 w/w), and the zeta potential was about 4 mV for two SNAs. The in vitro release experiment indicated that PVD possessed a good ability for self-dePEGylation, which could result in the recovery of an excellent fusogenic capacity of DOPE at low pH. SNAs showed a higher transfection efficiency and much lower cytotoxicity than did Lipofectamine 2000 on HEK 293, HeLa, and COS-7 cells. The cellular uptake and subcellular localization demonstrated that the superior transfection efficiency of SNAs could result from the fact that the DOPE-based lipid envelope containing PVD increased PS/DNA in the cytoplasm, and protamine enhanced the nuclear delivery or overcame the nuclear membrane barrier. These results implied that the PVD-based nanoassembly loading PS/DNA could be a promising gene delivery system.

Poly(imidazole/DMAEA)phosphazene/DNA self-assembled nanoparticles for gene delivery: Synthesis and in vitro transfection

A new cationic derivate of polyphosphazene with imidazole and 2-dimethylaminoethylamino (DMAEA) as side groups, poly(imidazole/DMAEA)phosphazene (PIDP), was synthesized and investigated for gene delivery. The half-lives of PIDP degradation under neutral (pH 7.4) and acidic conditions (pH 5.0) were 22 and 3 days at 37 degrees C, respectively. The cytotoxicity of PIDP assayed by MTT was much lower than that of poly(2-dimethylaminoethylamino)phosphazene (PDAP) and PEI 25K. PIDP could condense DNA into nanoparticles with a size around 100 nm and zeta potential (+25 mV) at the ratio of 10:1 (PIDP/DNA, w/w). The transfection efficiency of PIDP/DNA complex nanoparticles (PICNs) against 293T, COS-7 and Hela cells was much higher than that of PDAP/DNA complexes nanoparticles (PDCNs) and PEI/DNA complexes nanoparticles (PECNs) at 10:1 (polymer/DNA, w/w). Therefore, PIDP could be a safe, efficient and promising cationic polymer for gene therapy.

Histidylated cationic polyorganophosphazene/DNA self-assembled nanoparticles for gene delivery

Cationic polyorganophosphazene has shown the ability to deliver gene. To obtain more efficient transfection, His(Boc)-OMe bearing histidine moiety was introduced to synthesize a new derivative of cationic polyphosphazenes with another side group of 2-dimethylaminoethylamine (DMAEA). The poly(DMAEA/His(Boc)-OMe)phosphazene (PDHP) and DNA could self-assemble into nanoparticles with a size around 110 nm and zeta potential of +15 mV at the PDHP/DNA ratio of 10:1 (w/w). The maximum transfection efficiency of PDHP/DNA self-assembled nanoparticles (PHSNs) against 293 T cells was much higher than that of poly(di-2-dimethylaminoethylamine) phosphazenes (PDAP)/DNA self-assembled nanoparticles (PASNs) and PEI 25/DNA self-assembled nanoparticles (PESNs) at the polymer/DNA ratio of 10:1, but the cytotoxicity of PDHP assayed by MTT was much lower than that of PDAP and PEI 25. These results suggested that PDHP could be a good candidate with high transfection efficiency and low cytotoxicity for gene delivery.