Oestrone-targeted liposomes for mitoxantrone delivery via oestrogen receptor - synthesis, physicochemical characterization and in-vitro evaluation.

OBJECTIVES: Targeted delivery of mitoxantrone (MTO, an anthraquinone drug with high antitumour effect) may be achieved using a novel nanoparticulate delivery system via binding the oestrogen receptor (ER, highly expressed in a variety of human tumours). METHODS: A novel liposomal nanoparticle (NP) was developed using a conjugate derived from 1, 2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[amino (polyethylene glycol)-2000] (DSPE-PEG2000 -NH2 ) and oestrone (ES, is known to bind the ER) to produce an ES-targeted PEGylated liposome (ES-SSL). The resulting targeted NP was loaded with MTO to produce a targeted liposome-MTO formulation (ES-SSL-MTO). KEY FINDINGS: The targeted formulation (~140 nm, 1.5 mV) achieved over 95% drug encapsulation efficiency and a favourable stability at 4, 25 and 37 °C up to 48 h. The flow cytometric data indicated that cellular uptake of ES-SSL into human leukaemia HL-60 cells was mediated via binding the oestrogen receptor. In addition, the ES-SSL-MTO significantly reduced the growth of HL-60 cells. CONCLUSIONS: Our results provide a proof of principle that ES-modified PEGylated liposomes can target the ER, thereby potentially improving the therapeutic benefits in ER-overexpressed tumours.

Screening and determination for potential α-glucosidase inhibitory constituents from Dalbergia odorifera T. Chen using ultrafiltration-LC/ESI-MS(n).

In the present study, it was demonstrated that ethyl acetate soluble fraction partitioned from heartwood of Dalbergia odorifera T. Chen (HEF) had a remarkable inhibitory effect on α-glucosidase. Therefore HEF was selected as a starting material for screening the potential α-glucosidase inhibitors using ultrafiltration liquid chromatography/mass spectrometry (UF-LC/MS). Twenty-six compounds were identified with analysis of LC/MS. UF assay indicated that 18 compositions might be α-glucosidase inhibitors in HEF; eight of them were estimated for their α-glucosidase inhibitory activity, and the results showed that (2S)-liquiritigenin, (2S)-4',6-dihydroxy- 7-methoxyflavanone and isoliquiritigenin displayed obvious inhibition of yeast α-glucosidase. In addition, in order to control the quality of HEF, the content of five compounds in HEF was simultaneously determined for the first time. These results provide an important theoretical base for the further application of HEF to treat type 2 diabetes in the clinic and development of natural α-glucosidase inhibitors with low toxicity.

Human catalytic antibody Se-scFv-B3 with high glutathione peroxidase activity.

In order to generate catalytic antibodies with glutathione peroxidase (GPX) activity, we prepared GSH-S-2,4-dinitrophenyl t-butyl ester (GSH-S-DNPBu) as target antigen. Three clones (A11, B3, and D5) that bound specifically to the antigen were selected from the phage display antibody library (human synthetic VH + VL single-chain Fv fragment (scFv) library). Analysis of PCR products using gel electrophoresis and sequencing showed that only clone B3 beared intact scFv-encoding gene, which was cloned into the expression vector pPELB and expressed as soluble form (scFv-B3) in Escherichia coli Rosetta. The scFv-B3 was purified by Ni(2+)-immobilized metal affinity chromatography (IMAC). The yield of purified proteins was about 2.0-3.0 mg of proteins from 1 L culture. After the active site serines of scFv-B3 were converted into selenocysteines (Secs) with the chemical modification method, we obtained the human catalytic antibody (Se-scFv-B3) with GPX activity of 1288 U/micromol.