ß, ß-Dimethylacrylshikonin induces mitochondria-dependent apoptosis of human lung adenocarcinoma cells in vitro via p38 pathway activation.

AIM: ß, ß-Dimethylacrylshikonin (DMAS) is an anticancer compound extracted from the roots of Lithospermum erythrorhizon. In the present study, we investigated the effects of DMAS on human lung adenocarcinoma cells in vitro and explored the mechanisms of its anti-cancer action. METHODS: Human lung adenocarcinoma A549 cells were tested. Cell viability was assessed using an MTT assay, and cell apoptosis was evaluated with flow cytometry and DAPI staining. The expression of the related proteins was detected using Western blotting. The mitochondrial membrane potential was measured using a JC-1 kit, and subcellular distribution of cytochrome c was analyzed using immunofluorescence staining. RESULTS: Treatment of A549 cells with DMAS suppressed the cell viability in dose- and time-dependent manners (the IC50 value was 14.22 and 10.61 µmol/L, respectively, at 24 and 48 h). DMAS (7.5, 10, and 15 µmol/L) dose-dependently induced apoptosis, down-regulated cIAP-2 and XIAP expression, and up-regulated Bax and Bak expression in the cells. Furthermore, DMAS resulted in loss of mitochondrial membrane potential and release of cytochrome c in the cells, and activated caspase-9, caspase-8, and caspase-3, and subsequently cleaved PARP, which was abolished by pretreatment with Z-VAD-FMK, a pan-caspase inhibitor. DMAS induced sustained p38 phosphorylation in the cells, while pretreatment with SB203580, a specific p38 inhibitor, blocked DMAS-induced p38 activation and apoptosis. CONCLUSION: DMAS inhibits the growth of human lung adenocarcinoma A549 cells in vitro via activation of p38 signaling pathway.

Effect of glycyrrhizic acid on rhein renal penetration: a microdialysis study in rats.

1. Rhein (RH), a primary active component isolated from rhubarb, is effective in protecting against the progression of diabetic nephropathy (DN) progression. Glycyrrhizic acid (GA), an active constituent of liquorice, is also considered to be a protective agent against DN. Here, we evaluated the effect of GA on the renal penetration of RH in rats. 2. Plasma and renal pharmacokinetics were profiled to estimate kidney penetration. After rats were anesthetized, the carotid artery was used for blood collection and a microdialysis probe was inserted into the kidney cortex to collect dialysate samples. 3. When co-administered with GA, the Vss and CL values of RH in plasma increased by 25% and 34%, respectively. The Cmax in kidney dialysates significantly increased 1.3-fold (p<0.05). There was no change in AUC0-∞ in kidney dialysates, but a significant decrease (2×fold) in the plasma was observed. The AUC0-∞kidney/AUC0-∞plasma ratio of RH, representing kidney penetration, increased by 1.4-fold in the group pre-treated with GA compared to the RH alone group. 4. These results demonstrate that GA increases the renal penetration of RH efficiently and may exert a synergistic effect, although the molecular mechanism of interaction requires further investigation.

Pressurized CEC coupled with QTOF-MS for urinary metabolomics.

Pressurized CEC (pCEC) coupled with ESI-QTOF-MS using a sheathless interface was applied for metabolomics to develop an alternative analytical method for metabolic profiling of complex biofluid samples such as urine. The hyphenated system was investigated with mixed standards and pooled urine samples to evaluate its precision, repeatability, linearity, sensitivity, and selectivity. The applied voltage, mobile phase, and gradient elution were optimized and applied for the analysis of urinary metabolites. Multivariate data analysis was subsequently performed and used to distinguish lung cancer patients from healthy controls successfully. High separation efficiency has been achieved in pCEC due to the EOF. For metabolite identification, the pCEC-MS separation mechnism was helpful for discriminating the fragment ions of glutamine conjugates from co-eluted metabolites. Three glutamine conjugates, including phenylacetylglutamine, acylglutamine C8:1, and acylglutamine C6:1 were identified among 16 differential urinary metabolites of lung cancer. Receiver-operating-characteristic analysis of acylglutamine C8:1 resulted in an area-under-curve value of 0.882. Overall, this work suggests that this pCEC-ESI-QTOF-MS method may provide a novel and useful platform for metabolomic studies due to its superior separation and identification.

Determination and pharmacokinetic study of the diacid metabolite of norcantharidin in beagle plasma by use of liquid chromatography-tandem mass spectrometry.

Because norcantharidin (NCTD) is unstable and subject to ring opening and hydrolysis, the diacid metabolite of norcantharidin (DM-NCTD) is the stable form of NCTD found in normal saline solution. Conversion of NCTD to DM-NCTD is almost 100%, making it possible to determine and investigate the pharmacokinetics of DM-NCTD converted from NCTD. In this paper, a sensitive, simple and selective liquid chromatographic-tandem mass spectrometric method was developed and validated for determination of DM-NCTD in beagle plasma. DM-NCTD was detected in multiple-reaction monitoring (MRM) mode by using the dehydrated ion 169.3 as precursor ion and its product ion 123.1 as the detected ion. Ribavirin was used as internal standard and detected in MRM mode by use of precursor ions, resulting in a product ion transition of m/z 267.1 → 135.1. This method was successfully used for a pharmacokinetic study of DM-NCTD in beagles after intravenous administration of DM-NCTD in normal saline solution at doses of 0.39, 0.78, and 1.6 mg kg(-1). DM-NCTD had dose-dependent kinetics across the dosage range investigated, with enhanced T(1/2α) and AUC(0-12) and apparently decreasing V(d) and CL with increasing dosage. After single-dose administration, T(1/2α) ranged from 0.20 to 0.55 h, AUC(0-12) from 1.81 to 43.6 µg mL(-1) h(-1), V(d) from 228 to 55.9 mL kg(-1), and CL from 220 to 36.5 mL kg(-1) h(-1) (P < 0.01). The results indicated nonlinear pharmacokinetic behavior of DM-NCTD in beagles, suggesting that the risk of DM-NCTD in normal saline solution intoxication may be non-proportionally increased at higher doses.

Cryptotanshinone induces cell cycle arrest and apoptosis of multidrug resistant human chronic myeloid leukemia cells by inhibiting the activity of eukaryotic initiation factor 4E.

Cryptotanshinone (CPT), a diterpene quinone isolated from Salvia miltiorrhiza, is recently reported to have obvious anticancer activities against diverse cancer cells. However, the effect and regulatory mechanism of CPT remain unclear in human chronic myeloid leukemia (CML) cells. In this study, we investigated the antiproliferative activity of CPT on the multidrug resistant CML cells K562/ADM. Our results demonstrated that CPT decreased the cell viability of K562/ADM cells by inducing cell cycle arrest and apoptosis through suppressing the expression of cyclin D1 and Bcl-2. Further studies indicated that CPT mainly functions at post-transcriptional levels, suggesting the involvement of eukaryotic initiation factor 4E (eIF4E). CPT significantly reduced the expression and activity of eIF4E in K562/ADM cells. Overexpression of eIF4E obvious conferred resistance to the CPT antiproliferation and proapoptotic activity as well as the cyclin D1 and Bcl-2 expressions. Knockdown of eIF4E significantly reduced the inhibitory effect of CPT in K562/ADM, confirming the participation of eIF4E during CPT function process. More importantly, the relative inhibitory efficiency of CPT positively correlated with the reductions on eIF4E in primary CML specimens. These results demonstrated that CPT played antitumor roles in K562/ADM cells by inhibiting the eIF4E regulatory system. Our results provide a novel anticancer mechanism of CPT in human CML cells.

[Mechanisms of (2-methyl-n-butyl) shikonin induced apoptosis of gastric cancer SGC-7901 cells].

This study is to investigate the effect of (2-methyl-n-butyl) shikonin (MBS) on inducing apoptosis of human gastric cancer cell line SGC-7901 and the role of ERK1/2 signal pathway in the apoptosis. MTT assay was used to detect SGC-7901 cell proliferation. DNA condensation was measured by DAPI stain. Cell apoptosis was analyzed by flow cytometry. Mitochondrial membrane potential (MMP) was analyzed by JC-1 staining. The protein expressions of Bcl-2, Bax, Survivin, cleaved caspase-9, cleaved caspase-3, cleaved PARP, p-ERK1/2, ERK1/2, p-JNK, JNK, p-p38 and p38 were detected by Western blotting. The results showed that MBS reduced the cell viability of SGC-7901 cells in a dose- and time-dependent manner. The IC50 at 24 h and 48 h for SGC-7901 cells was 10.113 and 4.196 micromolL(-1), respectively. After being treated with MBS, the typical nuclear condensation was observed in SGC-7901 cells by DAPI stain. Apoptosis in SGC-7901 cells was induced by MBS in a dose dependent manner. The protein expression of Bcl-2 was down-regulated, while the protein expressions of cleaved caspase-9, cleaved caspase-3, cleaved PARP, p-ERK1/2 and p-JNK were up-regulated after MBS treatment. U0126, a specific MAP kinase (MEK1/2) inhibitor, blocked the ERK1/2 activation by MBS. MMP was decreased by MBS treatment. It can be concluded that MBS could inhibit SGC-7901 cell proliferation and induce apoptosis. Mitochondrial apoptosis pathway, ERK1/2 signal pathway and JNK signal pathway might be involved in this process.

[Mechanism of platycodin D-induced apoptosis in A549 human lung cancer cells].

OBJECTIVE: To investigate the molecular mechanism of platycodin D showing the inhibitory effect on proliferation and induced apoptosis of humane long cancer cells A549. METHOD: Humane long cancer cells A549 were cultured in vitro, with the final PD concentration of 5-20 micromol x L(-1). PD's inhibitory effect on cell proliferation was examined by MTT assay. Morphological changes in cells were observed with microscope. The cell apoptosis rate was detected by Annexin V-FITC/PI double staining. The change of mitochondrial membrane potential was detected by JC-1. The protein expressing of leaved Caspase-3, cleaved Caspase-9, cleaved PARP, Bcl-2, Bcl-xl, Bak and Bax were detected by Western blot analysis. RESULT: PD could inhibit the proliferation of A549 cells and show stronger effect with the increase of concentration and over time. Compared with the control group, PDs of different concentration showed significant increase in the cell apoptosis rate, decrease in mitochondrial membrane potential after 24 h. Protein electrophoresis inspection showed cut segments in both protein Caspase-3 and Caspase-9 and notable fractures with time. Further study found that PD decreased Bcl-2, Bcl-xl proteins and increased Bax, Bak proteins after processing A549 cells. CONCLUSION: PD shows notable effect on cytotoxicity and can induce A549 cell apoptosis. It causes decrease in mitochondrial membrane potential by regulating Bax, Bak, Bcl-2 and Bcl-xl expressions, and thus activating caspase and finally causing long cancer cell apoptosis.

Physalis alkekengi var. franchetii Extracts Exert Antitumor Effects on Non-Small Cell Lung Cancer and Multiple Myeloma by Inhibiting STAT3 Signaling.

BACKGROUND: Physalis alkekengi var. franchetii is an herb that possesses various ethnopharmacological applications. Herein, our current study focuses on the antitumor effect of a combination of physalins, which are regarded as the most representative secondary metabolites from calyces of Physalis alkekengi var. franchetii. MATERIALS AND METHODS: We mainly investigated the antitumor activity of the physalins extracted from Physalis alkekengi var. franchetii on both solid and hematologic cancers. The main cells used in this study were NCI-H1975 and U266 cells. The major assays used were the CCK-8 assay, Western blot analyses, immunofluorescence assay and Annexin V assay, and a xenograft mouse model was used. RESULTS: The results showed that physalins exhibited a strong antitumoural effect on both non-small cell lung cancer (NSCLC) and multiple myeloma (MM) cells by suppressing constitutive STAT3 activity and further inhibiting the downstream target gene expression induced by STAT3 signaling, which resulted in the enhanced apoptosis of tumor cells. Moreover, physalins significantly reduced tumor growth in xenograft models of lung cancer. CONCLUSION: Collectively, these findings demonstrated that the physalins from Physalis alkekengi var. franchetii may potentially act as cancer preventive or chemotherapeutic agents for NSCLC and MM by inhibiting the STAT3 signaling pathway. The present study served as a promising guide to further explore the precise mechanism of Physalis alkekengi var. franchetii in cancer treatment.

Development and application of a rapid HPLC method for simultaneous determination of hyperoside, isoquercitrin and eleutheroside E in Apocynum venetum L. and Eleutherococcus senticosus.

Apocynum venetum L. and Eleutherococcus senticosus have been used for hundreds of years to treat hypertension in China. In previous research, there was not a suitable quality control of method for the formulas of Apocynum venetum L. and Eleutherococcus senticosus. It is urgent and essential to develop modern analytical methods for Apocynum venetum L. and Eleutherococcus senticosus to ensure the quality of the formulas. A rapid approach for simultaneous determination of hyperoside, isoquercitrin and eleutheroside E in Apocynum venetum L. and Eleutherococcus senticosus by high-performance liquid chromatography with a diode array detector was described and validated. The full method validation, including the linearity, limits of detection and quantification, precision, repeatability, stability and recovery, was examined. All target components, including isomers of hyperoside and isoquercitrin, were baseline separated in 35 min. The developed method was sensitive, reliable and feasible. With this method, the optimal decoction conditions of Apocynum venetum L. and Eleutherococcus senticosus were selected, and their quality analysis was carried out. Furthermore, an herbal compatibility study of Apocynum venetum L. and Eleutherococcus senticosus based on detecting variations in the content of their active ingredients was performed by the developed HPLC method. It could be an alternative for the quantitative analysis of herbs that contain hyperoside, isoquercitrin or (and) eleutheroside E in the future.

Nystatin interferes with the effects of N-methyl-N'-nitro-N-nitrosoguanidine on sphingolipid metabolism in human FL cells.

Previously we have shown that an alkylating agent N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) can induce receptor clustering and the activation of a downstream signal molecule NF-kappaB, and that the receptor clustering is associated with changes in sphingolipids metabolism. On the other hand, the polyene antibiotic nystatin can block MNNG-induced receptor clustering. In this study, using a lipidomic approach, we further evaluated whether nystatin influenced the effects of MNNG on sphingolipids metabolism. It was found that nystatin itself induced changes in the sphingolipids profile in human amnion FL cells to a certain extent, including an increase or decrease of some sphingolipid species. Interestingly, nystatin can block, at least partially, the changes of sphingolipids-induced by MNNG. In addition, nystatin can also partially inhibit the activation of NF-kappaB induced by MNNG. Neither MNNG nor nystatin affects the mRNA levels of serine palmitoyltransferase, acid sphingomyelinase (ASM), and sphingomyelin synthase, key enzymes in the sphingolipids biosynthesis pathway. However, MNNG can activate ASM and neutral sphingomyelinase, while nystatin preincubation inhibits the activation. Taken together, these data suggested that nystatin interferes with the effects of MNNG, and might elicit its function through altered sphingolipids metabolism.

[Biological effects and toxicology studies of melamine and its derivative cyanuric acid].

Melamine (Tripolycyanamide) and its derivatives have recently become a public concern on food safety. To better understand melamine and its major derivative cyanuric acid.literature on their chemical properties, metabolism, biological effects, relevant toxicology studies, and the detection methods is reviewed. Studies indicate that the acute toxicity of melamine and cyanuric acid is low. In mammalian, these compounds are hardly metabolized in vivo and are rapidly eliminated in the urine. When used in large dosage,these compounds demonstrate marked renal toxicity,as well as toxic effect towards heart. The renal toxicity is exemplified by the calculi formation, acute renal failure, and subsequently induced carcinomas of the urinary bladder. Among the tested species, male cats and rats are more prone to be affected by the compounds. The HPLC/MS/MS is becoming the mainstay of the detection methods. Despite of the achieved knowledge on melamine and cyanuric acid, further research is warranted to unveil the mechanism of underlying susceptibility of kidney, to develop better analytic methods,and to explore possible biomarkers for better clinical diagnosis.

Evaluation of sphingolipids changes in brain tissues of rats with pentylenetetrazol-induced kindled seizures using MALDI-TOF-MS.

Abnormal lipid metabolism has been implicated in the pathogenesis of many neural system diseases, including epilepsy. Pentylenetetrazol (PTZ)-induced kindling in rodents is considered a model of human absence epilepsy and myoclonic, generalized tonic-clonic seizure. In an effort to further understand the mechanism for PTZ-induced seizure, we analyzed crude lipids and sphingolipids in the cortex, hippocampus, and brain stem of normal and PTZ-rats using delayed extraction matrix-assisted laser desorption ionization time-of-flight mass spectrometry (DE MALDI-TOF-MS). It was found that phosphatidylcholines dominated the crude lipids in different tissues and there were no obvious differences in crude lipid profiles of different tissues between normal and PTZ-rats. However, ceramide, sphingomyelins, and ceramide-monohexoside were differently distributed in normal and PTZ-rats. Using the reference mass spectra method established in our laboratory, it was shown that sphingomyelins and ceramide-monohexoside levels were elevated in the brain tissues of PTZ-rats. Ceramide levels were found to be higher in brain stem than in cortex and hippocampus of normal rats, and PTZ caused a general decrease in ceramide levels. These data suggest that changes in sphingolipid metabolism contribute to PTZ-induced seizure.

Serum metabolomics analysis reveals that obvious cardioprotective effects of low dose Sini decoction against isoproterenol-induced myocardial injury in rats.

BACKGROUND: Sini decoction (SND) is used for cardiovascular disease over thousands of years in China. However, it is still lacking of dose-response relationship of SND in cardiovascular disease at the metabolic level. PURPOSE: The present study is designed to explore the cardioprotective effects of different dosages of SND pretreatment on the isoproterenol (ISO)-induced myocardial injury and elucidate the mechanism underlying this protective effect. METHODS: The cardioprotective effects of different dosages of SND pretreatment on the isoproterenol-induced myocardial injury were compared through a serum metabolomics approach based on ultraperformance liquid chromatography coupled to quadrupole-time-of-flight mass spectrometry (UPLC-Q-TOF-MS). In addition, the cardioprotective effects were evaluated by serum biochemical analysis and histopathological examination of myocardial tissue. Finally, in view of the fact that these perturbed bile acid and phospholipid metabolisms are connected with NF-κB signaling pathway, nuclear expression of NF-κB p65 and the activation of NF-κB were analyzed by immunohistochemistry, immunoblotting and electrophoretic mobility shift assay (EMSA), respectively. RESULTS: The cardioprotective effect was observed in SND pretreatment groups, especially in low dosage SND group. The results of serum enzyme activities and histopathology were consistent with the above effect. Meanwhile, fifteen latent biomarker candidates were identified involving glucose, phospholipid, bile acid and amino acid metabolisms. Among them, five bile acids including ursodeoxycholic acid, murideoxycholic acid, muricholic acid, hyodeoxycholic acid and cholic acid, were for the first time identified as latent pathological biomarkers related to ISO-induced myocardial injury. Further, different dose SND groups exerted different of inhibition degrees to the activation of NF-κB, which was obvious in the SND-L group. CONCLUSION: The results revealed that Sini decoction protreatment protects myocardium better at a low dose level and one of possible cardioprotective mechanisms is modulating NF-κB signaling pathway against isoproterenol-induced myocardial injury through regulating phospholipid and bile acid metabolisms.

Expression of mTOR in Primary Pterygium and its Correlation with α-Smooth Muscle Actin.

PURPOSE: Mammalian target of rapamycin (mTOR) is a serine/threonine protein kinase that has been shown to affect many cellular functions, such as cell growth, proliferation, and metabolism. However, there has been minimal focus on the expression of mTOR in pterygium. The purpose of this study was to investigate the expression of mTOR and the correlation between the levels of mTOR and α-smooth muscle actin (α-SMA, a marker of transdifferentiation) in pterygium. METHODS: Primary pterygium samples from 28 patients and normal conjunctival samples from 16 patients were surgically removed and analyzed. The expression levels of mTOR and α-SMA in the excised specimens were assessed using immunohistochemistry and Western blotting. Furthermore, correlations between the mTOR and α-SMA expression levels were studied. RESULTS: The expression of mTOR and α-SMA was significantly higher in the pterygium tissues than in normal conjunctiva tissues. A significant positive correlation was detected between the number of mTOR-immunopositive fibroblasts and the number of α-SMA-immunopositive fibroblasts (ρ = 0.463, p = 0.0078). Additionally, mTOR expression was significantly correlated with α-SMA expression (ρ = 0.269, p = 0.031) in pterygium. CONCLUSIONS: There was an increased expression of mTOR in pterygium samples compared to that in normal conjunctival tissues, with a positive correlation with α-SMA expression. These findings might be involved in the pathogenesis of pterygium.

Deinococcus radiodurans Toxin-Antitoxin MazEF-dr Mediates Cell Death in Response to DNA Damage Stress.

Here we identified a functional MazEF-dr system in the exceptionally stress-resistant bacterium D. radiodurans. We showed that overexpression of the toxin MazF-dr inhibited the growth of Escherichia coli. The toxic effect of MazF-dr was due to its sequence-specific endoribonuclease activity on RNAs containing a consensus 5'ACA3', and it could be neutralized by MazE-dr. The MazF-dr showed a special cleavage preference for the nucleotide present before the ACA sequence with the order by U>A>G>C. MazEF-dr mediated the death of D. radiodurans cells under sub-lethal dose of stresses. The characteristics of programmed cell death (PCD) including membrane blebbing, loss of membrane integrity and cytoplasm condensation occurred in a fraction of the wild-type population at sub-lethal concentration of the DNA damaging agent mitomycin C (MMC); however, a MazEF-dr mutation relieved the cell death, suggesting that MazEF-dr mediated cell death through its endoribonuclease activity in response to DNA damage stress. The MazEF-dr-mediated cell death of a fraction of the population might serve as a survival strategy for the remaining population of D. radiodurans under DNA damage stress.

Liquid chromatography-tandem mass spectrometry evaluation of the pharmacokinetics of a diacid metabolite of norcantharidin loaded in folic acid-targeted liposomes in mice.

A previous study has reported diacid metabolite (DM) as the stable form of norcantharidin (NCTD), which is almost 100% metabolized to DM-NCTD. However, the unreliable pharmacokinetic characteristics of DM-NCTD could result in low bioavailability, hindering the clinical use of DM-NCTD in the treatment of diseases. A liposomal drug delivery system could overcome the shortcomings of DM-NCTD by improving the relative bioavailability (Fr), reducing drug toxicity, and increasing the therapeutic efficacy. However, there are no data concerning the pharmacokinetics of a DM-NCTD-loaded liposomal drug delivery system in animals, which is required for assessing its safety profile. Therefore, a rapid and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the determination of DM-NCTD in mouse plasma. Standard curves were linear (r=0.9966) over the range 10.0-1.00×10(4)ng/ml in mouse plasma with a lower limit of quantification (LLOQ) of 10ng/ml. This study successfully investigated the pharmacokinetics of DM-NCTD and DM-NCTD encapsulated in polyethylene glycol (PEG)-Liposomes (DM-NCTD/PEG-Liposome) or folic acid (FA)-PEG-Liposomes (DM-NCTD/FA-PEG-Liposome) in Kunming mice after a single intravenous dose of 2mg/kg. The plasma profile data of the three groups adhered to a two-compartment model. Compared with the DM-NCTD group, the Liposome groups had longer circulation times following intravenous administration in mice, and the Fr of DM-NCTD increased significantly (P<0.05). Furthermore, the area under the concentration-time curve (AUC) declined with an increase in the volume of distribution (Vd) from the PEG-Liposome to the FA-PEG-Liposome groups, which indicates a more efficient removal of the drug from the plasma of the FA-PEG-Liposome group. This result suggests a possible increased risk of DM-NCTD intoxication in normal tissues with FA-PEG-Liposomes. Based on this study, further investigation of the biodistribution of DM-NCTD/FA-PEG-Liposomes in healthy animals is warranted. In addition, the plausibility of formulating a safe DM-NCTD-loaded system without increasing toxicity against normal tissues needs to be determined.

Biosynthesis of gold nanoparticles by the extreme bacterium Deinococcus radiodurans and an evaluation of their antibacterial properties.

Deinococcus radiodurans is an extreme bacterium known for its high resistance to stresses including radiation and oxidants. The ability of D. radiodurans to reduce Au(III) and biosynthesize gold nanoparticles (AuNPs) was investigated in aqueous solution by ultraviolet and visible (UV/Vis) absorption spectroscopy, electron microscopy, X-ray diffraction (XRD), dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). D. radiodurans efficiently synthesized AuNPs from 1 mM Au(III) solution in 8 h. The AuNPs were of spherical, triangular and irregular shapes with an average size of 43.75 nm and a polydispersity index of 0.23 as measured by DLS. AuNPs were distributed in the cell envelope, across the cytosol and in the extracellular space. XRD analysis confirmed the crystallite nature of the AuNPs from the cell supernatant. Data from the FTIR and XPS showed that upon binding to proteins or compounds through interactions with carboxyl, amine, phospho and hydroxyl groups, Au(III) may be reduced to Au(I), and further reduced to Au(0) with the capping groups to stabilize the AuNPs. Biosynthesis of AuNPs was optimized with respect to the initial concentration of gold salt, bacterial growth period, solution pH and temperature. The purified AuNPs exhibited significant antibacterial activity against both Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria by damaging their cytoplasmic membrane. Therefore, the extreme bacterium D. radiodurans can be used as a novel bacterial candidate for efficient biosynthesis of AuNPs, which exhibited potential in biomedical application as an antibacterial agent.

Evaluation of the change in sphingolipids in the human multiple myeloma cell line U266 and gastric cancer cell line MGC-803 treated with arsenic trioxide.

Arsenic trioxide (As2O3) has been found to display anticancer activity against many types of tumors and has been developed into an anticancer drug in clinical treatments. Sphingolipids are membrane lipids that participate in many signal transduction pathways. In this paper, the changes in sphingolipids of the human multiple myeloma cell line U266 and the gastric cancer cell line MGC-803 treated with arsenic trioxide were investigated using an HPLC-ESI-MS/MS method. Analytes were separated by an XBridge BEH C8 column used for Cer, HexCer, LacCer and SM chromatographic separation, and a Capcell PAK MG II C18 column was used for Sph, dhSph, S1P and dhS1P chromatographic separation and gradient elution with acetonitrile-water containing 0.1% formic acid as a mobile phase. A tandem mass spectrometer QTrap in SRM mode was employed in combination with RPLC as a detector for quantitative analysis. The ceramide/sphingolipid internal standard (IS) mixture was used to quantify the levels of sphingolipids. The distributions of sphingolipids were found to be different in the human multiple myeloma cell line U266 and the gastric cancer cell line MGC-803. Ceramide (Cer), hexosylceramide (HexCer) and dihexosylceramide (Hex2Cer) levels in U266 cell line are higher than those in MGC-803 cell line. Additionally, sphingomyelin (SM), sphingosine-1-phosphate (S1P) and sphinganine-1-phosphate (dhS1P) levels in the MGC-803 cell line are higher than those in the U266 cell line. When treated with arsenic trioxide (1-5µM iAs(III)(As(III) ions)), the levels of Hex2Cer in the human multiple myeloma cell line U266 decreased, and the levels of S1P and dhS1P in the human gastric cancer cell line MGC-803 decreased. The decrease of Hex2Cer, S1P and dhS1P in the human multiple myeloma cell line U266 and gastric cancer cell line MGC-803 were observed when the concentration of iAs(III) is 1.0µM. Therefore, arsenic trioxide exhibits anti-cancer activity by altering the sphingolipid pathway in the human multiple myeloma cell line U266 and the gastric cancer cell line MGC-803.

[Relationship between antibacterial activity of aloe and its anthaquinone compounds].

OBJECTIVE: To investigate the relationship between the antibacterial activity of aloe and its contents of anthaquinone compounds, measure and compale antibacterial activities of aloin and aloe-emodin, and analyse the effect of glycoside on the antibacterial activity of aloin. METHOD: The antibacterial activities of the extracts from the outer leaf of Aloe saponaria Haw, aloin and aloe-emodin against three Gram-negative and two Gram-positive bacteria were investigated with the method of agar diffusion. The antibacterial effect of aloin on E. coli was further studied with scanning electron microscopy. RESULT: The antibacterial activities of aloe showed to be dependent on the dose of anthraquinone, aloin (1 g x L(-1)) exhibited higher antibacterial activity [inhibition diameter > (7. 1 +/- 0.15) mm] than Aloe-emodin (inhibition diameter < 5.0 mm), and aloin changed the morphology of E. coli and damaged the outer cell structrue. CONCLUSION: Anthraquinone compounds are the active antibacterial components in aloe and aloin is the main active compound. The glycoside makes it easy for aloin to invade cells and enhances its activity.

Activation of JNK/p38 pathway is responsible for α-methyl-n-butylshikonin induced mitochondria-dependent apoptosis in SW620 human colorectal cancer cells.

α-Methyl-n-butylshikonin (MBS), one of the active components in the root extracts of Lithospermum erythrorhizon, posses antitumor activity. In this study, we assess the molecular mechanisms of MBS in causing apoptosis of SW620 cells. MBS reduced the cell viability of SW620 cells in a dose-and time-dependent manner and induced cell apoptosis. Treatment of SW620 cells with MBS down-regulated the expression of Bcl-2 and up-regulated the expression of Bak and caused the loss of mitochondrial membrane potential. Additionally, MBS treatment led to activation of caspase-9, caspase-8 and caspase-3, and cleavage of PARP, which was abolished by pretreatment with the pan-caspase inhibitor Z-VAD-FMK. MBS also induced significant elevation in the phosphorylation of JNK and p38. Pretreatment of SW620 cells with specific inhibitors of JNK (SP600125) and p38 (SB203580) abrogated MBS-induced apoptosis. Our results demonstrated that MBS inhibited growth of colorectal cancer SW620 cells by inducing JNK and p38 signaling pathway, and provided a clue for preclinical and clinical evaluation of MBS for colorectal cancer therapy.