Biomacromolecules. 2009 Aug 10; 10(8): 2175-82Gao Y, Zhang Z, Chen L, Gu W, Li YThe selective introduction of a trimethylammonium cationic group into the C-6 position of chitosan (Cs) was successfully performed by "click chemistry" for the first time, and the 6-N,N,N-trimethyltriazole-Cs (TCs) showed good solubility in water. TCs showed strong DNA binding ability and high protection of DNA against nuclease degradation assessed by gel electrophoresis assay. TCNs showed lower degree of flocculation than Cs/DNA self-assembled nanoparticles (CsNs) in the presence of medium containing serum within 60 min. The introduction of trimethyltriazole group led to significantly increased cellular uptake compared with unmodified Cs, which resulted in higher transfection efficiency in HEK 293 and MDA-MB-468 cells. TCs were noncytotoxic, and viability of cells exposure to TCNs for 24 h was over 80% even at 50 microg/mL of polymer. These results suggested that TCs could be an efficient and safe material for gene delivery.

Biol Pharm Bull. 2009 Sep; 32(9): 1533-7Sun X, Zhang X, Hu H, Lu Y, Chen J, Yasuda K, Wang HProliferation of hepatic stellate cells (HSCs) is central for the development of fibrosis during liver injury. Our aim in this study was to determine whether berberine could inhibit HSC proliferation in vitro and prevent experimental liver fibrosis in vivo. Activated rat hepatic stellate cells (CFSCs) were incubated with various concentrations (0-20 microg/ml) of berberine. After 48 h incubation, berberine significantly inhibited CFSC proliferation and induced cell cycle arrest in G1 phase. Real-time and Western blotting revealed that both p21 and p27 expression was markedly reduced by berberine. Berberine also decreased Akt phosphorylation and FoxO1 phosphorylation, which led to FoxO1 nuclear translocation. Berberine effectively prevented CCl(4)-induced liver fibrosis in mice, which was accompanied by a decrease in the number of activated HSCs. Thus, berberine was able to prevent liver fibrosis by inhibition of hepatic stellate cell proliferation.

Acta Pharmacol Sin. 2009 Sep; 30(9): 1359-68Zhou YB, Feng X, Wang LN, Du JQ, Zhou YY, Yu HP, Zang Y, Li JY, Li JAIM: To discover novel cell division cycle 25 (CDC25) B inhibitors and elucidate the mechanisms of inhibition in cancer cells. METHODS: Cell growth inhibition was detected by MTT assay, the cell cycle was analyzed by flow cytometry, and protein expression and phosphorylation was examined by Western blot analysis. RESULTS: LGH00031 inhibited CDC25B irreversibly in vitro in a dose-dependent manner, and impaired the proliferation of tumor cell lines. In synchronized HeLa cells, LGH00031 delayed the cell cycle progression at the G(2)/M phase. LGH00031 increased cyclin-dependent kinase 1 (CDK1) tyrosine 15 phosphorylation and cyclin B1 protein level. The activity of LGH00031 against CDC25B in vitro relied on the existence of 1,4-dithiothreitol (DTT) or dihydrolipoic acid and oxygen. The oxygen free radical scavenger catalase and superoxide dismutase reduced the inactivation of CDC25 by LGH00031, confirming that reactive oxygen species (ROS) mediate the inactivation process in vitro. LGH00031 accelerated cellular ROS production in a dose-dependent manner, and N-acetyl cysteine (NAC) markedly decreased the ROS production induced by LGH00031. Correspondingly, the LGH00031-induced decrease in cell viability and cell cycle arrest, cyclin B1 protein level, and phosphorylation of CDK1 tyrosine 15 were also rescued by NAC that decreased ROS production. CONCLUSION: The activity of LGH00031 at the molecular and cellular level is mediated by ROS.

J Chromatogr B Analyt Technol Biomed Life Sci. 2009 Aug 21; Zhan Y, Chen X, Zhao X, Zhong DLeuprolide is a synthetic nonapeptide that has two basic amino acids, arginine and histidine, in its structure. By selection of an appropriate analytical column and optimizing the mobile phase composition, an improved analytical method has been developed and validated to determine leuprolide concentrations in human serum. After methanol-induced protein precipitation of serum samples and Oasis((R)) HLB cartridge solid-phase extraction, leuprolide and an internal standard (alarelin) were analyzed on a C(18) column interfaced with a triple quadrupole tandem mass spectrometer with positive electrospray ionization. The mobile phase consisted of acetonitrile-water-propionic acid (20:80:0.05). The analyte and internal standard were both detected in the selective reaction monitoring mode. The method exhibited a linear range of 0.018-45.2ng/mL for leuprolide. The intra- and inter-assay precisions were 11.5% or less relative standard deviation (R.S.D.), and accuracy was within +/-2.8% relative error (RE). The lower limit of quantification (LLOQ) was identifiable and reproducible at 0.018ng/mL, with acceptable precision and accuracy. The validated LC-MS/MS method was tested to a clinical pharmacokinetic study of leuprolide after a single subcutaneous injection of 1mg leuprolide acetate in healthy male Chinese volunteers.