Generation of reactive oxygen species by a novel berberine-bile acid analog mediates apoptosis in hepatocarcinoma SMMC-7721 cells.

2,3-Methenedioxy-9-O-(3'α,7'α-dihydroxy-5'ß-cholan-24'-propy-lester)berberine (B4) is a novel berberine-bile acid analog synthesized in our laboratory. Previously, we showed that B4 exerted greater cytotoxicity than berberine in several human cancer cell lines. Therefore, we further evaluated the mechanism governing its anticancer actions in hepatocellular carcinoma SMMC-7721 cells. B4 inhibited the proliferation of SMMC-7721 cells, and stimulated reactive oxygen species (ROS) production and mitochondrial membrane depolarization; anti-oxidant capacity was reduced. B4 also induced the release of cytochrome c from the mitochondria to the cytosol and an increase in poly ADP-ribose polymerase (PARP) cleavage products, reflective of caspase-3 activation. Moreover, B4 induced the nuclear translocation of apoptosis-inducing factor (AIF) and a rise in DNA fragmentation. Pretreatment with the anti-oxidant N-acetylcysteine (NAC) inhibited B4-mediated effects, including cytotoxicity, ROS production, mitochondrial membrane depolarization increase in intracellular Ca2+, cytochrome c release, PARP cleavage, and AIF translocation. Our data suggest that B4 induces ROS-triggered caspase-dependent and caspase-independent apoptosis pathways in SMMC-7721 cells and that ROS production may be a specific potential strategy for treating hepatic carcinoma.

Preparation and physicochemical properties of 10-hydroxycamptothecin (HCPT) nanoparticles by supercritical antisolvent (SAS) process.

The goal of the present work was to study the feasibility of 10-hydroxycamptothecin (HCPT) nanoparticle preparation using supercritical antisolvent (SAS) precipitation. The influences of various experimental factors on the mean particle size (MPS) of HCPT nanoparticles were investigated. The optimum micronization conditions are determined as follows: HCPT solution concentration 0.5 mg/mL, the flow rate ratio of CO(2) and HCPT solution 19.55, precipitation temperature 35 °C and precipitation pressure 20 MPa. Under the optimum conditions, HCPT nanoparticles with a MPS of 180 ± 20.3 nm were obtained. Moreover, the HCPT nanoparticles obtained were characterized by Scanning electron microscopy, Dynamic light scattering, Fourier-transform infrared spectroscopy, High performance liquid chromatography-mass spectrometry, X-ray diffraction and Differential scanning calorimetry analyses. The physicochemical characterization results showed that the SAS process had not induced degradation of HCPT. Finally, the dissolution rates of HCPT nanoparticles were investigated and the results proved that there is a significant increase in dissolution rate compared to unprocessed HCPT.

SFE-CO2 extract from Typhonium giganteum Engl. tubers, induces apoptosis in human hepatoma SMMC-7721 cells involvement of a ROS-mediated mitochondrial pathway.

Typhonium giganteum Engl. (BaiFuzi) is one of the herbs commonly used in traditional Chinese medicine against cancer. In our previous studies, 37 compounds were identified the SFE-CO(2) (supercritical fluid extraction with CO(2)) extract by GC-MS, including the four major components [ß-sitosterol (40.22%), campesterol (18.45%), n-hexadecanoic acid (9.52%) and (Z,Z)-9,12-octadecadienoic acid (8.15%)]. The anti-cancer mechanisms of the SFE-CO(2 )extract from T. giganteum Engl. tubers have not been reported as yet. In this paper, the molecular mechanisms of the SFE-CO(2) extract-mediated apoptosis in SMMC-7721 cells were further examined. SFE-CO(2) extract inhibited the growth of SMMC-7721 cells in a time- and dose-dependent manner, arrested the cell cycle in the S phase and G2/M phase, and induced apoptosis. In addition, reactive oxygen species (ROS) increase, reduction of mitochondrial membrane potential, a rise in intracellular calcium levels were found in SMMC-7721 cells after treated with the extract. Western blot analysis showed that the extract caused down-regulation of Bcl-2 expression, and up-regulation of Bax expression. Moreover, caspase-3 and caspase-9 protease activity significantly increased in a dose-dependent manner. Collectively, our results showed that the SFE-CO(2) extract from T. giganteum Engl. tubers induces apoptosis in SMMC-7721 cells involving a ROS-mediated mitochondrial signalling pathway.

Environmentally friendly aqueous solution synthesis of hierarchical CaWO4 microspheres at room temperature.

An environmentally friendly route for the synthesis of hierarchical CaWO4 microspheres with novel morphology at room temperature has been successfully developed. CaCl2 and Na2WO4 were used as reaction regents, and distilled water was used as an environmentally friendly solvent. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and photoluminescence spectroscopy. This green wet-chemical route provides a simple, one-step, low-cost approach for the large-scale synthesis of hierarchical CaWO4 microspheres with relatively uniform diameters of 3-6 microm. The hierarchical microspheres are built up with numerous nanorods with an average diameter of 50 nm, which are radially oriented to the microsphere center. SEM observations of different intermediates indicate the possible growth process, in which the hierarchical structure growth is from nuclei through kayak-like, rod-like, peanut-like, dumbbell-like, and peach-like structures to final microspheres, via "self-assembled preferential end growth" of kayak-like particles in aqueous solution. The hierarchical CaWO4 microspheres exhibit a strong, broad blue emission peak of 412 nm.

Ca(II) doped ß-In2S3 hierarchical structures for photocatalytic hydrogen generation and organic dye degradation under visible light irradiation.

Hierarchical structures assembled by two-dimensional (2D) nanosheets could inherit the characteristics of nanosheets and acquire additional advantages from the unique secondary architectures, which would have important influences on the photocatalytic properties of semiconductor nanomaterials. In this work, we successfully synthesized Ca(II) doped ß-In2S3 hierarchical structures stacked by thin nanosheets by a simple solution chemical process. The effects of reaction temperature and Ca2+ concentration on the size and morphology of the products were systematically investigated. The photocatalytic applications of the ß-In2S3 hierarchical structures were evaluated for hydrogen production and degradation of Rhodamine B (RhB) under visible light irradiation (λ>420nm). The ß-In2S3 hierarchical structures showed promising activity towards photocatalytic hydrogen production (145.0µmolg-1h-1) and RhB solution (1×10-5M) was completely degraded within 100min under visible light irradiation.

Room temperature synthesis of hollow CdMoO(4) microspheres by a surfactant-free aqueous solution route.

Hollow cadmium molybdate microspheres have been successfully prepared via a template-free aqueous solution method with the assistance of NaCl at room temperature. The structure and morphology of the CdMoO(4) hollow microspheres were characterized by X-ray diffraction, field-emission scanning electron microscopy, and transmission electron microscopy. The microspheres have diameters of 3-6 microm and hollow interiors of 2-3 microm. The shell is composed of numerous single-crystalline nanorods with diameters of 30-120 nm and lengths of 1-2 microm which are radially oriented to the center. A certain concentration of NaCl plays a key important role in the formation process of hollow microspheres, which might provide a suitable chemical environment to favor the formation of hollow CdMoO(4) microspheres. A possible NaCl-induced Ostwald ripening process is proposed for the formation of hollow CdMoO(4) microspheres on the basis of scanning electron microscopy observation of intermediate products at different precipitation stages.

Binding interactions of water-soluble camptothecin derivatives with bovine serum albumin.

In this study, the binding interactions of the water-soluble camptothecin derivatives hydroxycamptothecin (10-HCPT), topotecan (TPT), and camptothecin quaternary salt (CPT8), to bovine serum albumin (BSA) were determined using fluorescence spectra and UV-vis spectra. The results revealed that the fluorescence of BSA was strongly quenched by the binding of camptothecin derivatives to BSA. The quenching mechanism of the camptothecin derivatives was found to be static according to the Stern-Volmer equation. The binding constant and binding sites were confirmed by fluorescence quenching spectra. The thermodynamic parameters Gibbs free energy change (ΔG<0), enthalpy change (ΔH>0), and entropy change (ΔS>0) implied that the interaction process was spontaneous and endothermic, and the interaction forces between camptothecin compounds and BSA were found to be hydrophobic. According to Föster non-radioactive energy transfer, the binding distances between 10-HCPT, TPT, and CPT8, and BSA were determined to be 1.73nm, 1.63nm, and 1.61nm, respectively. The synchronous fluorescence spectra confirmed that the camptothecin compounds cannot cause conformational changes in BSA. A rapid and sensitive method for determining the binding interaction between water-soluble camptothecin derivatives and BSA was established based on these principles of fluorescence quenching.

Preparation, characterization and targeting of micronized 10-hydroxycamptothecin-loaded folate-conjugated human serum albumin nanoparticles to cancer cells.

BACKGROUND: The purpose of this study was to develop a method for targeted delivery of 10-hydroxycamptothecin (HCPT)-loaded nanoparticles (NPs) to cancer cells. METHODS: We first used a supercritical antisolvent process to prepare micronized HCPT (nHCPT), and then folate-conjugated human serum albumin (HSA) nHCPT-loaded NPs (FA-HSA-nHCPT-NPs) were prepared using a NP-coated method combined with a desolvation technique. The amount of folate conjugation was 16 µg · mg(-1) HSA. RESULTS: The particle size of the spherical nHCPT microparticles obtained was 118.5 ± 6.6 nm. The particle size and zeta potential of the FA-HSA-nHCPT-NPs were 233.9 ± 1.2 nm and -25.23 ± 2.98 mV, respectively. The FA-HSA-nHCPT-NPs exhibited a smooth surface and a distinct spherical shape, and the results of differential scanning calorimetry and X-ray diffraction indicated that the FA-HSA-nHCPT-NPs presented in a nanostructured amorphous state. The FA-HSA-nHCPT-NPs showed sustained-release characteristics for 120 hours in vitro, with a drug-loading content of 7.3% and an encapsulating efficiency of 79.1%. CONCLUSION: The FA-NPs were effective delivery systems for uptake by SGC7901 cells compared with folate-free NPs. These results suggest that a NP-coated method combined with a desolvation technique is effective for preparing NPs with drugs having poor solubility in water and most organic solvents, using albumin as the wall material. FA-HSA-NPs are a stable delivery system and have the potential for targeted delivery of anticancer drugs.