[Preparation of borneol loaded hollow mesoporous silica nanoparticles and effect on borneol volatility].

The hollow mesoporous silica nanoparticles (HMSNs) were prepared by hard template method, with a size of 300 nm and shell thickness of 25 nm. Borneol was loaded with solvent impregnation method in order to solve the stability problem of borneol in pharmaceutics, and the BET, TEM and FT-IR were used to characterize the HMSNs and the borneol-HMSNs drug delivery system. The optimal drug loading time, maximum drug loading capacity and the volatility of borneol were investigated. The results showed that HMSNs which were prepared at room temperature and neutral conditions had good sphericity, achieved high drug loading of borneol in a short time, and the drug loading was up to 74.04% within 6 hours; meanwhile, volatility of borneol in the system was greatly improved. This novel drug delivery system provides a new idea for wide application of borneol in the traditional Chinese medicine.

[Preparation and stability of ß-carotene loaded using mesoporous silica nanoparticles as carriers system].

1,3,5-Trimethylbenzene (1,3,5-TMB) was used as the pore-enlarging modifier to expand the pore size of MCM-41 (mobil company of matter) mesoporous silica nanoparticles. The solvent impregnation method was adopted to assemble non-water-soluble ß-carotene into the pore channel of MCM-41. The MCM-41 and drug assemblies were characterized by TEM, FT-IR, elemental analysis and N2 adsorption-desorption. The results showed that MCM-41 has good sphericity and regular pore structure. The research also investigated the optimal loading time, the drug loading and the vitro stability of the ß-carotene. As a drug carrier, the modified MCM-41 showing a shorter drug loading time, the drug loading as high as 85.58% and the stability of ß-carotene in drug assemblies has improved. The study of this new formulation provides a new way for ß-carotene application.

Generation of N-acylphosphatidylethanolamine by members of the phospholipase A/acyltransferase (PLA/AT) family.

Bioactive N-acylethanolamines (NAEs), including N-palmitoylethanolamine, N-oleoylethanolamine, and N-arachidonoylethanolamine (anandamide), are formed from membrane glycerophospholipids in animal tissues. The pathway is initiated by N-acylation of phosphatidylethanolamine to form N-acylphosphatidylethanolamine (NAPE). Despite the physiological importance of this reaction, the enzyme responsible, N-acyltransferase, remains molecularly uncharacterized. We recently demonstrated that all five members of the HRAS-like suppressor tumor family are phospholipid-metabolizing enzymes with N-acyltransferase activity and are renamed HRASLS1-5 as phospholipase A/acyltransferase (PLA/AT)-1-5. However, it was poorly understood whether these proteins were involved in the formation of NAPE in living cells. In the present studies, we first show that COS-7 cells transiently expressing recombinant PLA/AT-1, -2, -4, or -5, and HEK293 cells stably expressing PLA/AT-2 generated significant amounts of [(14)C]NAPE and [(14)C]NAE when cells were metabolically labeled with [(14)C]ethanolamine. Second, as analyzed by liquid chromatography-tandem mass spectrometry, the stable expression of PLA/AT-2 in cells remarkably increased endogenous levels of NAPEs and NAEs with various N-acyl species. Third, when NAPE-hydrolyzing phospholipase D was additionally expressed in PLA/AT-2-expressing cells, accumulating NAPE was efficiently converted to NAE. We also found that PLA/AT-2 was partly responsible for NAPE formation in HeLa cells that endogenously express PLA/AT-2. These results suggest that PLA/AT family proteins may produce NAPEs serving as precursors of bioactive NAEs in vivo.

Lipophilic amines as potent inhibitors of N-acylethanolamine-hydrolyzing acid amidase.

N-Acylethanolamines (NAEs) including N-arachidonoylethanolamine (anandamide) and N-palmitoylethanolamine are endogenous lipid mediators. These molecules are degraded to the corresponding fatty acids and ethanolamine by fatty acid amide hydrolase (FAAH) or NAE-hydrolyzing acid amidase (NAAA). Lipophilic amines, especially pentadecylamine (2c) and tridecyl 2-aminoacetate (11b), were found to exhibit potent NAAA inhibitory activities (IC(50)=5.7 and 11.8µM), with much weaker effects on FAAH. These simple structures would provide a scaffold for further improvement in NAAA inhibitory activity.

Regulation of peroxisomal lipid metabolism by catalytic activity of tumor suppressor H-rev107.

H-rev107 is a mammalian protein belonging to the HRAS-like suppressor family. Although the protein was originally found as a tumor suppressor, currently it is receiving considerable attention as a regulator of adipocyte lipolysis. We recently revealed that purified recombinant H-rev107 has phospholipase A(1/2) activity, releasing free fatty acids from glycerophospholipids with a preference for esterolysis at the sn-1 position. In the present study, we constitutively expressed H-rev107 in cloned HEK293 cells to examine its biological function in living cells. Initially, the cells accumulated free fatty acids. We also found a remarkable decrease in the levels of ether-type lipids, including plasmalogen and ether-type triglyceride, with a concomitant increase in fatty alcohols, substrates for the biosynthesis of ether-type lipids. Considering that peroxisomes are involved in the ether-type lipid biosynthesis, we next focused on peroxisomes and found that the peroxisomal markers 70-kDa peroxisomal membrane protein and catalase were abnormally distributed in the transfected cells. These biochemical and morphological abnormalities were not seen in HEK293 cells stably expressing a catalytically inactive mutant of H-rev107. When H-rev107 or its fusion protein with enhanced green fluorescence protein was transiently expressed in mammalian cells, both proteins were associated with peroxisomes in some of the observed cells. These results suggest that H-rev107 interferes with the biosynthesis of ether-type lipids and is responsible for the dysfunction of peroxisomes in H-rev107-expressing cells.

Enzymological analysis of the tumor suppressor A-C1 reveals a novel group of phospholipid-metabolizing enzymes.

A-C1 protein is the product of a tumor suppressor gene negatively regulating the oncogene Ras and belongs to the HRASLS (HRAS-like suppressor) subfamily. We recently found that four members of this subfamily expressed in human tissues function as phospholipid-metabolizing enzymes. Here we examined a possible enzyme activity of A-C1. The homogenates of COS-7 cells overexpressing recombinant A-C1s from human, mouse, and rat showed a phospholipase A½ (PLA½) activity toward phosphatidylcholine (PC). This finding was confirmed with the purified A-C1. The activity was Ca²âº independent, and dithiothreitol and Nonidet P-40 were indispensable for full activity. Phosphatidylethanolamine (PE) was also a substrate and the phospholipase A1 (PLA1) activity was dominant over the PLA2 activity. Furthermore, the protein exhibited acyltransferase activities transferring an acyl group of PCs to the amino group of PEs and the hydroxyl group of lyso PCs. As for tissue distribution in human, mouse, and rat, A-C1 mRNA was abundantly expressed in testis, skeletal muscle, brain, and heart. These results demonstrate that A-C1 is a novel phospholipid-metabolizing enzyme. Moreover, the fact that all five members of the HRASLS subfamily, including A-C1, show similar catalytic properties strongly suggests that these proteins constitute a new class of enzymes showing PLA½ and acyltransferase activities.

Characterization of the human tumor suppressors TIG3 and HRASLS2 as phospholipid-metabolizing enzymes.

Tazarotene-induced protein 3 (TIG3) and HRAS-like suppressor family 2 (HRASLS2) exhibit tumor-suppressing activities and belong to the lecithin retinol acyltransferase (LRAT) protein family. Since Ca(2+)-independent N-acyltransferase and H-rev107 (another tumor suppressor), both of which are members of the LRAT family, have been recently reported to possess catalytic activities related to phospholipid metabolism, we examined possible enzyme activities of human TIG3 and HRASLS2 together with human H-rev107. The purified recombinant proteins of TIG3, HRASLS2, and H-rev107 functioned as phospholipase (PL) A(1/2) in a Ca(2+)-independent manner with maximal activities of 0.53, 0.67, and 2.57 micromol/min/mg of protein, respectively. The proteins were active with various phosphatidylcholines (PCs) and phosphatidylethanolamines (PEs), and for most of substrates the PLA(1) activity was much higher than the PLA(2) activity. In addition, HRASLS2 catalyzed N-acylation of PE to form N-acyl-PE and O-acylation of lyso PC to form PC. TIG3 and H-rev107 catalyzed the N-acylation and O-acylation at relatively low rates. Moreover, these three proteins showed different expression profiles in human tissues. These results suggest that the tumor suppressors TIG3, HRASLS2 and H-rev107 are involved in the phospholipid metabolism with different physiological roles.

Induction of apoptosis in human renal cell carcinoma cells by vitamin E succinate in caspase-independent manner.

OBJECTIVES: Renal cell carcinoma (RCC) is one of the most drug-resistant malignancies, and an effective therapy is lacking for metastatic RCC. Vitamin E (VE) has been intensively studied as a chemopreventive agent for various cancer types. Preclinical investigations have suggested that VE succinate (VES) is the most effective analog of VE in cancer cells; however, no study of VES in RCC has been done. We investigated the anticancer activity of VES against RCC. METHODS: Cytotoxicity was assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Cell morphologic changes and cell viability were evaluated using phase-contrast microscopy and the trypan blue dye-exclusion test, respectively. Caspase activity was measured with a quantitative colorimetric assay. RESULTS: VES exerted dose- and time-dependent cytotoxicities against ACHN, a human RCC cell line, but VE and VE acetate did not. The cytotoxic effect was also observed in 2 other RCC cell lines, Caki-1 and Caki-2, and in primary RCC cells derived from 8 patients. Hoechst 33258 staining and DNA ladder analysis demonstrated that VES induced apoptosis in RCC cells. However, VES did not affect activation of caspase-3, -6, -8, or -9. Furthermore, inhibitors specific to caspase-8, -9, -6, and -3 did not block VES cytotoxicity and neither did the general caspase inhibitor VAD. CONCLUSIONS: VES might induce apoptosis and cytotoxicity against RCC cells in a caspase-independent manner and has potential in vivo applications in the treatment of drug-and/or immunotherapy-resistant RCC.

The tumor suppressor gene H-Rev107 functions as a novel Ca2+-independent cytosolic phospholipase A1/2 of the thiol hydrolase type.

H-Rev107 is a protein that was previously cloned as a negative regulator of proto-oncogene Ras and classified as a class II tumor suppressor. Its structural similarity to lecithin retinol acyltransferase and Ca2+-independent phosphatidylethanolamine (PE) N-acyltransferase led us to analyze H-Rev107 as an enzyme involved in phospholipid metabolism. Here, we show that recombinant H-Rev107s from rat, human, and mouse possess phospholipase (PL) A1 or A2 activity toward phosphatidylcholine (PC). Further examination with purified recombinant protein revealed that H-Rev107 functions as a cytosolic Ca2+-independent PLA(1/2) for PC and PE with higher PLA1 activity than PLA2 activity. Dithiothreitol and iodoacetic acid exhibited stimulatory and inhibitory effects, respectively. Histidine-21 and cysteine-111 of rat H-Rev107 were presumed to form a catalytic dyad based on database analysis, and their single mutants were totally inactive. These results suggested that H-Rev107 is a hydrolase of the thiol type. The N-terminal proline-rich and C-terminal hydrophobic domains of H-Rev107 were earlier reported to be responsible for the regulation of cell proliferation. Analysis of deletion mutants indicated that these domains are also catalytically essential, suggesting relevance of the catalytic activity to the anti-proliferative activity.

cDNA cloning and characterization of human and mouse Ca(2+)-independent phosphatidylethanolamine N-acyltransferases.

The formation of N-acylphosphatidylethanolamine by N-acylation of phosphatidylethanolamine (PE) is the initial step in the biosynthetic pathway of bioactive N-acylethanolamines, including the endocannabinoid anandamide and the anti-inflammatory substance N-palmitoylethanolamine. We recently cloned a rat enzyme capable of catalyzing this reaction, and referred to the enzyme as Ca(2+)-independent N-acyltransferase (iNAT). Here we report cDNA cloning and characterization of human and mouse iNATs. We cloned iNAT-homologous cDNAs from human and mouse testes, and overexpressed them in COS-7 cells. The purified recombinant proteins abstracted an acyl group from both sn-1 and sn-2 positions of phosphatidylcholine, and catalyzed N-acylation of PE as well as phospholipase A(1)/A(2)-like hydrolysis. The iNAT activity was mainly detected in soluble rather than particulate fractions, and was only slightly increased by Ca(2+). These results demonstrated that the human and mouse homologues function as iNAT. As for the organ distribution of iNAT, human testis and pancreas and mouse testis exhibited by far the highest expression level, suggesting its physiological importance in the specific organs. Moreover, mutagenesis studies showed crucial roles of His-154 and Cys-241 of rat iNAT in the catalysis and a possible role of the N-terminal domain in membrane association or protein-protein interaction.

4-Hydr-oxy-2,2,6,6-tetra-methyl-piperidinium hydrogensulfate monohydrate.

In the title compound, C(9)H(20)NO(+)·HO(4)S(-)·H(2)O, the piperi-dinium ring adopts a chair conformation. Inter-molecular O-H⋯O and N-H⋯O hydrogen bonds form an extensive three-dimensional network, which consolidates the crystal structure.

Low concentrations of doxorubicin sensitizes human solid cancer cells to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-receptor (R) 2-mediated apoptosis by inducing TRAIL-R2 expression.

There is accumulating evidence suggesting that tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-receptor (R) 2 is a promising molecular target for cancer therapy. Therefore, we investigated the effect of chemotherapeutic agents on TRAIL-R2-mediated apoptosis and cytotoxicity in various human solid cancer cells. Treatment of the ACHN human renal cell carcinoma (RCC) cell line with agonistic TRAIL-R2 antibody (lexatumumab) in combination with 5-fluorouracil, vinblastine, paclitaxel, or docetaxel did not overcome resistance to these agents. However, treatment with lexatumumab in combination with doxorubicin had a synergistic cytotoxicity. Synergy was also achieved in two other human RCC cell lines, Caki-1 and Caki-2, and in eight primary RCC cell cultures. Sequential treatment with doxorubicin followed by lexatumumab induced significantly more cytotoxicity than reverse treatment or simultaneous treatment. Low concentrations of doxorubicin (0.1 and 1 microg/mL) significantly increased TRAIL-R2 expression at both the mRNA and protein levels. Furthermore, the combination of doxorubicin and lexatumumab significantly enhanced caspase 8 activity, Bid cleavage, Bcl-xL decrease, release of cytochrome c, and caspase 9 and caspase 3 activity, and induced synergistic apoptosis. The activation of caspases and apoptosis induced with lexatumumab and doxorubicin was blocked by the human recombinant DR5:Fc chimeric protein. In addition, synergistic cytotoxicity was also observed in human prostate, bladder, and lung cancer cells, but was inhibited by the DR5:Fc chimeric protein. These findings suggest that doxorubicin sensitizes solid cancer cells to TRAIL-R2-mediated apoptosis by inducing TRAIL-R2 expression, and that the combination treatment with lexatumumab and doxorubicin might be a promising targeted therapy for cancers, including RCC, prostate, bladder, and lung cancers.

Discovery and characterization of a Ca2+-independent phosphatidylethanolamine N-acyltransferase generating the anandamide precursor and its congeners.

N-Acylphosphatidylethanolamines (NAPEs) are precursors of bioactive N-acylethanolamines, including the endocannabinoid anandamide. In animal tissues, NAPE is formed by transfer of a fatty acyl chain at the sn-1 position of glycerophospholipids to the amino group of phosphatidylethanolamine (PE), and this reaction is believed to be the principal rate-limiting step in N-acylethanolamine synthesis. However, the Ca2+-dependent, membrane-associated N-acyltransferase (NAT) responsible for this reaction has not yet been cloned. In this study, on the basis of the functional similarity of NAT to lecithin-retinol acyltransferase (LRAT), we examined a possible PE N-acylation activity in two rat LRAT homologous proteins. Upon overexpression in COS-7 cells, one protein, named rat LRAT-like protein (RLP)-1, catalyzed transfer of a radioactive acyl group from phosphatidylcholine (PC) to PE, resulting in the formation of radioactive NAPE. However, the RLP-1 activity was detected mainly in the cytosolic rather than membrane fraction and was little stimulated by Ca2+. Moreover, RLP-1 did not show selectivity with respect to the sn-1 and sn-2 positions of PC as an acyl donor and therefore could generate N-arachidonoyl-PE (anandamide precursor) from 2-arachidonoyl-PC and PE. In contrast, under the same assay conditions, partially purified NAT from rat brain was highly Ca2+-dependent, membrane-associated, and specific for the sn-1-acyl group of PC. RLP-1 mRNA was expressed predominantly in testis among various rat tissues, and the testis cytosol exhibited an RLP-1-like activity. These results reveal that RLP-1 can function as a PE N-acyltransferase, catalytically distinguishable from the known Ca2+-dependent NAT.

[Determination of cinnamic acid in rat plasma after oral administration of subing orally disintegrating tablets and study of its pharmacokinetics behavior].

OBJECTIVE: To develop a RP-HPLC method for determination of cinnamic acid in rat plasma. METHOD: The plasma samples were acidified with acetic acid and extracted with chloroform. Cinnamic acid was separated on a Kromasil C18 column (250 mm x 4.6 mm, 5 microm) eluted with a mobile phase of methanol-acetonitrile-water-glacial acetic acid (25:20:55:0.3) at a flow rate of 1.0 mL x min(-1) and room temperature with UV detection at 278 nm, carbamazepine as internal standard. RESULT: The standard curve was linear over the range of 4.0 to approximately 400 ng x mL (-1) r = 0..99 9. The LOQ was 4.0 ng x mL(-1), the mean extraction recovery of the spiked samples at low, middle and high levels was 86.4%, while the mean method recovery was 100.3%. The RSD of intra-day and inter-day were both less than 6.0%. CONCLUSION: The method was sensitive, specific, accurate and precise, which was used to study the pharmacokinetic profile of cinnamic acid in rat plasma after oral administration of the Subing orally disintegrating tablets.

Study of the physicochemical properties of trimethoprim with beta-cyclodextrin in solution.

The behavior of trimethoprim (TMP) in aqueous solutions containing different concentration of beta-cyclodextrin (beta-CD) was characterized by the solubility method, UV spectrophotometry and differential scanning calorimetry (DSC). The UV spectra enhancement of TMP as result of complex with beta-CD was investigated. Complexation with beta-CD increase the TMP aqueous solubility and the phase solubility diagram was A(L) type. Thermodynamic parameters of the complex process, K, DeltaG, DeltaH and DeltaS, were determined from the phase solubility diagram at 298 and 318 K, respectively. The experimental results indicated that the complex process was an enthalpy-driven process. Mechanism of the complex of beta-CD with TMP was further discussed using the molecular model program. Results showed that the 3,4,5-trimethoxybenzyl group of the TMP was partly embedded in the cavity of beta-CD.