Function and regulation of Rab GTPases in cancers.

The Rab small GTPases are characterized by the distinct intracellular localization and modulate various endocytic, transcytic and exocytic transport pathways. Rab proteins function as scaffolds that connect signaling pathways and intracellular membrane trafficking processes through the recruitment of effectors, such as tethering factors, phosphatases, motors and kinases. In different cancers, Rabs play as either an onco-protein or a tumor suppressor role, highly dependending on the context. The molecular mechanistic research has revealed that Rab proteins are involved in cancer progression through influences on migration, invasion, metabolism, exosome secretion, autophagy, and drug resistance of cancer cells. Therefore, targeting Rab GTPases to recover the dysregulated vesicle transport systems may provide potential strategy to restrain cancer progression. In this review, we discuss the regulation of Rab protein level and activity in modulating pathways involved in tumor progression, and propose that Rab proteins may serve as a prognostic factor in different cancers.

Enantioselective Synthesis of Chiral Amides by a Phosphoric Acid Catalyzed Asymmetric Wolff Rearrangement.

The enantioselective addition of potent nucleophiles to ketenes poses challenges due to competing background reactions and poor stereocontrol. Herein, we present a method for enantioselective phosphoric acid catalyzed amination of ketenes generated from α-aryl-α-diazoketones. Upon exposure to visible light, the diazoketones undergo Wolff rearrangement to generate ketenes. The phosphoric acid not only accelerates ketene capture by amines to form a single configuration of aminoenol intermediates but also promotes an enantioselective proton-transfer reaction of the intermediates to yield the products. Mechanistic studies elucidated the reaction pathway and explained how the catalyst expedited the transformation and controlled the enantioselectivity.

A Spiro Phosphamide Catalyzed Enantioselective Proton Transfer of Ylides in a Free Carbene Insertion into N-H Bonds.

Free carbene readily causes multiple side reactions due to its high energy, thus its asymmetric transformation is very difficult. We present here our findings of high-pKa Brønsted acid catalysts that enable free carbene insertion into N-H bonds of amines to prepare chiral α-amino acid derivatives with high enantioselectivity. Under irradiation with visible light, diazo compounds produce high-energy free carbenes that are captured by amines to form free ylide intermediates, and then the newly designed high-pKa Brønsted acids, chiral spiro phosphamides, promote the proton transfer of ylides to afford the products. Computational and kinetic studies uncover the principle for the rational design of proton-transfer catalysts and explain how the catalysts accelerate this transformation and provide stereocontrol.

Absorption mechanism of oxymatrine in cultured Madin-Darby canine kidney cell monolayers.

Context Oxymatrine (OMT) is beneficial to human health by exerting various biological effects. Objective To investigate the absorption mechanism of OMT and discover absorption enhancers using Madin-Darby canine kidney (MDCK) cell monolayers. Materials and methods Concentration effects on the transport of OMT were measured in the range of 1.0 × 10(-5)-1.0 × 10(-3) M in 2 h. Then, the effect of time, direction, temperature and pH on the transport of OMT at 10(-4) M was studied. Moreover, Papp of OMT was determined in the absence/presence of cyclosporine and surfactants at 100 µM to further confirm the relative transport mechanism. Results The Papp AP→BL ranged from (3.040 ± 0.23) × 10(-6) to (3.697 ± 0.19) × 10(-6 )cm/s as the concentration varied from 10(-5) to 10(-3) M. OMT showed similar Papp at 4 and 37 °C (p > 0.05). Increasing the apical pH 7.4 and 8.0 resulted in Papp versus pH 5.0 (p < 0.01). Furthermore, in the presence of cyclosporine and surfactants including sodium citrate, sodium dodecyl sulphate (SDS) and deoxysodium cholate, Papp was (0.318 ± 0.033) × 10(-5), (0.464 ± 0.048) × 10(-5), (0.897 ± 0.115) × 10(-5) and (1.341 ± 0.122) × 10(-5 )cm/s, respectively. In the presence of surfactants, Papp significantly increased up to 1.5-4.3-fold (p < 0.05). Discussion and conclusion OMT transport across MDCK cell monolayers was by passive diffusion. Sodium citrate, SDS and deoxysodium cholate serve as excellent absorption enhancers which are useful for the related research improving the oral bioavailability of OMT.

Activation of prostaglandin E2-EP4 signaling reduces chemokine production in adipose tissue.

Inflammation of adipose tissue induces metabolic derangements associated with obesity. Thus, determining ways to control or inhibit inflammation in adipose tissue is of clinical interest. The present study tested the hypothesis that in mouse adipose tissue, endogenous prostaglandin E2 (PGE2) negatively regulates inflammation via activation of prostaglandin E receptor 4 (EP4). PGE2 (5-500 nM) attenuated lipopolysaccharide-induced mRNA and protein expression of chemokines, including interferon-γ-inducible protein 10 and macrophage-inflammatory protein-1α in mouse adipose tissue. A selective EP4 antagonist (L161,982) reversed, and two structurally different selective EP4 agonists [CAY10580 and CAY10598] mimicked these actions of PGE2. Adipose tissue derived from EP4-deficient mice did not display this response. These findings establish the involvement of EP4 receptors in this anti-inflammatory response. Experiments performed on adipose tissue from high-fat-fed mice demonstrated EP4-dependent attenuation of chemokine production during diet-induced obesity. The anti-inflammatory actions of EP4 became more important on a high-fat diet, in that EP4 activation suppressed a greater variety of chemokines. Furthermore, adipose tissue and systemic inflammation was enhanced in high-fat-fed EP4-deficient mice compared with wild-type littermates, and in high-fat-fed untreated C57BL/6 mice compared with mice treated with EP4 agonist. These findings provide in vivo evidence that PGE2-EP4 signaling limits inflammation. In conclusion, PGE2, via activation of EP4 receptors, functions as an endogenous anti-inflammatory mediator in mouse adipose tissue, and targeting EP4 may mitigate adipose tissue inflammation.

ARID1A restrains EMT and stemness of ovarian cancer cells through the Hippo pathway.

Genes encoding subunits of SWI/SNF (BAF) chromatin­remodeling complexes are recurrently mutated in a broad array of tumor types, and among the subunits, ARID1A is the most frequent target with mutations. In the present study, it was reported that ARID1A inhibits the epithelial­mesenchymal transition (EMT) and stemness of ovarian cancer cells, accompanied by reduced cell viability, migration and colony formation, suggesting that ARID1A acts as a tumor suppressor in ovarian cancer. Mechanistically, ARID1A exerts its inhibitory effects on ovarian cancer cells by activating the Hippo signaling pathway. Conversely, the overexpression of a gain­of­function transcriptional co­activator with PDZ­binding motif (TAZ) mutant (TAZ­Ser89) effectively reverses the effects induced by ARID1A. In addition, activation of Hippo signaling apparently upregulates ARID1A protein expression, whereas ectopic expression of TAZ­Ser89 results in the markedly decreased ARID1A levels, indicating a feedback of ARID1A­TAZ in regulating ovarian cancer cell EMT and stemness. Thus, the present study uncovered the role of ARID1A through the Hippo/TAZ pathway in modulating EMT and stemness of ovarian cancer cells, and providing with evidence that TAZ inhibitors could effectively prevent initiation and metastasis of ovarian cancer cases where ARID1A is lost or mutated.

Enantioselective synthesis of chiral amides by carbene insertion into amide N-H bond.

Chiral amides are important structure in many natural products and pharmaceuticals, yet their efficient synthesis from simple amide feedstock remains challenge due to its weak Lewis basicity. Herein, we describe our study of the enantioselective synthesis of chiral amides by N-alkylation of primary amides taking advantage of an achiral rhodium and chiral squaramide co-catalyzed carbene N-H insertion reaction. This method features mild condition, rapid reaction rate (in all cases 1 min) and a wide substrate scope with high yield and excellent enantioselectivity. Further product transformations show the synthetic potential of this reaction. Mechanistic studies reveal that the non-covalent interactions between the catalyst and reaction intermediate play a critical role in enantiocontrol.

Chronic hypotony management using endoscopy-assisted vitrectomy after severe ocular trauma or vitrectomy.

AIM: To report outcomes of endoscopy-assisted vitrectomy (EAV) in patients with chronic hypotony following severe ocular trauma or vitrectomy. METHODS: This was a retrospective, noncomparative case series. Ciliary bodies were evaluated using ultrasound biomicroscopy pre-operatively and direct visualisation intraoperatively. All selected individuals (seven patients/seven eyes) underwent EAV. Removal of ciliary membrane and traction, gas/silicone oil tamponade (GT/SOT), and scleral buckling (SB) were performed in selected eyes. Outcome measurements mainly included intraocular pressure (IOP) and best-corrected visual acuity (BCVA). RESULTS: Seven eyes from 7 male aphakic patients with a mean age of 45 (range, 20-68)y were included in this study; the average follow-up time was 12 (9-15)mo. GT was performed in 2 eyes; membrane peeling (MP) and SOT in 2 eyes; and MP, SOT, and SB in 3 eyes. The mean pre- and post-operative IOP were 4.5 (range, 4.0±0.11 to 4.8±0.2) mm Hg and 9.9 (range, 5.6±0.17 to 12.1±0.2) mm Hg at 52wk (12mo), respectively. BCVA improved in six eyes; one eye still showed light perception, and no bulbi phthisis was observed. CONCLUSION: Endoscopy offers improved judgment and recognition and has an improved prognosis for chronic hypotony. Therefore, endoscopy can be an effective and promising operative technique for chronic traumatic hypotony management.

"Mini-community" simulation revealed the differences of endophytic fungal communities between the above- and below-ground tissues of Ephedra sinica Stapf.

The microecology of endophytic fungi in special habitats, such as the interior of different tissues from a medicinal plant, and its effects on the formation of metabolites with different biological activities are of great importance. However, the factors affecting fungal community formation are unclear. This study is the first to utilize "mini-community" remodeling to understand the above phenomena. First, high-throughput sequencing technology was applied to explore the community composition and diversity of endophytic fungi in the above-ground tissues (Ea) and below-ground tissues (Eb) of Ephedra sinica. Second, fungi were obtained through culture-dependent technology and used for "mini-community" remodeling in vitro. Then, the effects of environmental factors, partner fungi, and plant tissue fluid (internal environment) on endophytic fungal community formation were discussed. Results showed that environmental factors played a decisive role in the selection of endophytic fungi, that is, in Ea and Eb, 93.8% and 25.3% of endophytic fungi were halophilic, respectively, and 10.6% and 60.2% fungi were sensitive to high temperature (33 °C), respectively. Meanwhile, pH had little effect on fungal communities. The internal environment of the plant host further promoted the formation of endophytic fungal communities.

Protective effects of lipoic acid-niacin dimers against blue light-induced oxidative damage to retinal pigment epithelium cells.

AIM: To evaluate the protective effects of lipoic acid-niacin (N2L) dimers against blue light (BL)-induced oxidative damage to human retinal pigment epithelium (hRPE) cells in vitro. METHODS: hRPE cells were divided into a control group (CG), a BL group, an N2L plus BL irradiation group, an α-lipoic acid (ALA) plus BL group, an ALA-only group, and an N2L-only group. hRPE cellular viability was detected by performing 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) bromide assays, and apoptosis was evaluated by annexin-V-PE/7-AAD staining followed by flow cytometry. Ultrastructural changes in subcellular organelles were observed by transmission electron microscopy. Reactive oxygen species formation was assayed by flow cytometry. The expression levels of the apoptosis-related proteins BCL-2 associated X protein (BAX), B-cell leukmia/lymphoma 2 (BCL-2), and caspase-3 were quantified by Western blot analysis. RESULTS: BL exposure with a light density of 4±0.5 mW/cm2 exceeding 6h caused hRPE toxicity, whereas treatment with a high dose of N2L (100 mol/L) or ALA (150 mol/L) maintained cell viability at control levels. BL exposure caused vacuole-like degeneration, mitochondrial swelling, and reduced microvillus formation; however, a high dose of N2L or ALA maintained the ultrastructure of hRPE cells and their organelles. High doses of N2L and ALA also protected hRPE cells from BL-induced apoptosis, which was confirmed by Western blot analysis: BCL-2 expression significantly increased, while BAX and caspase-3 expression slightly decreased compared to the CG. CONCLUSION: High-dose N2L treatment (>100 mol/L) can reduce oxidative damage in degenerating hRPE cells exposed to BL with an efficacy similar to ALA.

Pharmacokinetics of isochlorgenic acid C in rats by HPLC-MS: Absolute bioavailability and dose proportionality.

ETHNOPHARMACOLOGICAL RELEVANCE: Isochlorgenic acid C (IAC), one of the bioactive compounds of Lonicera japonica, exhibited diverse pharmacological effects. However, its pharmacokinetic properties and bioavailability remained unresolved. AIM OF THE STUDY: To determine the absolute bioavailability in rats and the dose proportionality on the pharmacokinetics of single oral dose of IAC. MATERIALS AND METHODS: A validated HPLC-MS method was developed for the determination of IAC in rat plasma. Plasma concentration versus time data were generated following oral and intravenous dosing. The pharmacokinetic analysis was performed using DAS 3.0 software analysis. Absolute bioavailability in rats was determined by comparing pharmacokinetic data after administration of single oral (5, 10 and 25mgkg(-1)) and intravenous (5mgkg(-1)) doses of IAC. The dose proportionality of AUC(0-∞) and Cmax were analyzed by linear regression. RESULTS: Experimental data showed that absolute oral bioavailability of IAC in rats across the doses ranged between 14.4% and 16.9%. The regression analysis of AUC(0-∞) and Cmax at the three doses (5, 10 and 25mgkg(-1)) indicated that the equations were y=35.23x+117.20 (r=0.998) and y=121.03x+255.74 (r=0.995), respectively. CONCLUSIONS: A new HPLC-MS method was developed to determine the bioavailability and the dose proportionality of IAC. Bioavailability of IAC in rats was poor and both Cmax and AUC(0-∞) of IAC had a positive correlation with dose. Evaluation of the pharmacokinetics of IAC will be useful in assessing concentration-effect relationships for the potential therapeutic applications of IAC.

The Disposition of Oxymatrine in the Vascularly Perfused Rat Intestine-Liver Preparation and Its Metabolism in Rat Liver Microsomes.

The study was aimed to investigate the absorption and metabolism of oxymatrine (OMT) which contributed to its poor bioavailability. Determinations of OMT absorption and metabolism in rats were evaluated using techniques of the in situ perfused rat intestine-liver preparation and recirculated intestine preparation. Furthermore, chemical inhibition experiments in rat liver microsomes were used to determine the principal cytochrome P450 (CYP) isoforms involved in OMT metabolism. In the intestine-liver preparation, the steady state liver extraction ratio (0.753 ± 0.054) of OMT was 33 times higher than that for the intestine (0.023 ± 0.002). The portal vein mainly consisted of OMT, and was devoid of the metabolite matrine, whereas both OMT and matrine were detected in hepatic vein. With the intestine preparation, the extent of OMT absorption at the end of 120 min of perfusion was 4.79 ± 0.352%. The first-order rate constant for OMT absorption was 0.05 ± 0.003 min(-1). The inhibitor of CYP3A2 had strong inhibitory effect on OMT metabolism in a concentration-dependent manner, and value was reduced to 29.73% of control. The 2 perfusion techniques indicated that poor bioavailability of OMT in rats is due mostly to poor absorption and higher hepatic elimination and CYP3A2 appears to contribute to OMT metabolism in rat liver.

Comparative study of cytochrome P450 expression in three permanent human hepatocytes / 中国药理学与毒理学杂志

OBJECTIVE To investigate the expression differences of seven cytochrome P450 (CYP) isoforms between L02, LX-2 and HepG2 cells and identify the most suitable cell type for different CYP researches. METHODS L02, LX-2 and HepG2 cells were treated with omeprazole (Ome), dexamethasone(Dex), phenobarbital sodium (Phe), isoniazid (Iso) and rifampicin (Rif) at 5, 10, 20 and 40 μmol • L-1. Cell viability was analyzed by CCK-8 assay. The gene expressions of CYP1A2, CYP2B6, CYP2C9, CYP2C19, CYP2D6, CYP2E1 and CYP3A4 in LX-2 cells were assessed by real-time quantitative PCR (RT-qPCR). The protein expressions of these seven CYP isoforms in L02, LX-2 and HepG2 cells were assessed by Western blotting. Furthermore, CYP3A4 activity in the three types of cells treated with Rif 5, 10, 20 and 40 μmol • L-1 for 24 h was validated by Luciferin-PFBE. RESULTS Cell viabilities of all the three hepatocytes were over 80% when exposed to Ome, Dex, Phe, Iso and Rif (≤40 μmol • L-1) for 24 h. According to the RT-qPCR, Phe could significantly enhance the gene expressions of CYP2B6 (P<0.05) and CYP2D6 (P<0.01) in LX-2 cells. The results of Western blotting exhibited protein expression differences of seven CYP isoforms between L02, LX-2 and HepG2 cells treated with Ome, Dex, Phe, Iso and Rif (≤40 μmol-L-1) for 24 h. CYP2C9 [Integrated absorbance (IA)=1.58±0.07], CYP2C19 (IA= 0.95±0.03) and CYP3A4 (IA=1.29±0.05) had higher expression abundances in L02 cells, CYP2B6 (IA= 1.48±0.01) and CYP2D6 (IA=1.46±0.02) in LX-2 cells, and CYP1A2 (IA=1.62±0.19) and CYP2E1 (IA= 1.49±0.10) in HepG2 cells. Additionally, CYP3A4 activity in L02, LX-2 and HepG2 cells could not be up-regulated by Rif. CONCLUSION The most suitable cell type for different CYP researches is L02 for CYP2C9, CYP2C19 and CYP3A4, LX-2 for CYP2B6 and CYP2D6, HepG2 for CYP1A2 and CYP2E1, respectively.

Ophiopogonin D protects cardiomyocytes against ophiopogonin D'-induced injury through suppressing endoplasmic reticulum stress / 中国中药杂志

This study is aimed to investigate the intervention effect and possible mechanism of ophiopogonin D( OPD) in protecting cardiomyocytes against ophiopogonin D'( OPD')-induced injury,and provide reference for further research on toxicity difference of saponins from ophiopogonins. CCK-8 assay was used to evaluate the effect of OPD and OPD' on cell viability. The effect of OPD on OPD'-induced cell apoptosis was measured by flow cytometry. Morphologies of endoplasmic reticulum were observed by endoplasmic reticulum fluorescent probe. PERK,ATF-4,Bip and CHOP mRNA levels were detected by Real-time quantitative polymerase chain reaction( PCR) analysis. ATF-4,phosphorylated PERK and e IF2α protein levels were detected by Western blot assay. RESULTS:: showed that treatment with OPD'( 6 μmol·L-1) significantly increased the rate of apoptosis; expressions of endoplasmic reticulum stress related genes were increased. The morphology of the endoplasmic reticulum was changed. In addition,different concentrations of OPD could partially reverse the myocardial cell injury caused by OPD'. The experimental results showed that OPD'-induced myocardial toxicity may be associated with the endoplasmic reticulum stress,and OPD may modulate the expression of CYP2 J3 to relieve the endoplasmic reticulum stress caused by OPD'.

Diagnostic Value of Combined Examination of Copeptin and High Sensitivity Cardiac Troponin T in Patients at Early Stage of Acute Myocardial Infarction / 中国循环杂志

Objective: To investigate the diagnostic value of combined examination of copeptin and high sensitivity cardiac troponin T (hs-cTnT) in patients at the early stage of acute myocardial infarction (AMI) . Methods: A total of 272 patients were enrolled in this study, all of them suffered from chest pain and admitted within 4 hours. The patients were divided into 4 groups according to coronary artery angiography (CAG) results. Control group, the patients with normal CAG,n=64, UAP group (unstable angina pectoris),n=50, STEMI group,n=82, NSTEMI group,n=76. All patients received in-hospital observation, plasma levels of copeptin and hs-cTnT were examined at admission and at 6 hours after the chest pain respectively. Results: Within 4 hours of chest pain, combined examination of copeptin and hs-cTnT had the higher sensitivity for diagnosing AMI than a single detection of hs-cTnT with the cut-off point of hs-cTnT ≤ 14ng/L and Copeptin < 14pmol/L. In NSTEMI group, the AUC (area under curve) for combined examination was 0.97 (95% CI 0.88-0.99), AUC for single hs-cTnT detection was 0.75 (95% CI 0.62-0.87),P<0.05. In STEMI group, the AUC for combined examination was 0.97 (95% CI 0.88-0.99), AUC for single hs-cTnT detection was 0.74 (95% CI 0.60-0.88),P< 0.05. The AUC for combined examination of copeptin and hs-cTnT in diagnosing early AMI was 0.912 (95% CI 0.812-0.961) which was higher than single detection of hs-cTnT, AUC 0.851 (95% CI 0.713-0.936), Z=2.553,P<0.05. Conclusion: Combined examination of copeptin and hs-cTnT had the higher sensitivity and accuracy for diagnosing the patients at the early stage of AMI, it may help the risk stratiifcation of chest pain which is valuable in clinical practice.

Practice and experience of mini-clinical evaluation exercise carried out in internal residents / 中华医学教育探索杂志

Mini-clinical evaluation exercise(Mini-CEX) is a new tool used to evaluate clinical skill of internal residents.Through necessity,operation and practice of Mini-CEX applied in internal residents' clinical teaching,the paper makes it known that Mini-CEX is consistent with six requisitions of resident competence raised by Accreditation Council of Graduate Medical Education (ACGME).It increases medical and directorial quality,and is combined with doctor training abroad.Mini-CEX should be spread in training and examination of internal residents.

Relationship between the extent of coronary artery lesions and plasma brain natriuretic peptide / 中华急诊医学杂志

Objective To explore the relationship between the extent of coronary artery lesions and plasma brain natriurefic peptide(BNP)levels in the patients with coronary artery disease(CAD)except for congestive heart failure(CHF).Method Seventy CAD patients without CHF evidenced by dinical manifestation and coronary arte- riography(CAG)from Cardiology Depamnent of the First Affiliated Hospital of Zhejiang University School of Medicine,China,were enrolled in the study.These patients were diagnozed under coronary arteriography(CAG) during March to May of 2007.They were divided into 3 groups:stable angina goup(24 patients),unstable angina group(25 patients),myocardial infarction group(21 patients).Twenty patients without coronary history and with normal CAG served as controls.Plasma BNP concentrations were measured with ELASA before CAG.The coronary lesion vessels and scores were estimated after CAG.The relationship between BNP levels and the coronary lesion vessels,as well as scores in CAD was analyzed.The data were expressed as(x±s)and was analyzed by using 2 independent samples test and spearman correlation with SPSS 13.0.A P value less than 0.01 indicated statistical significance.Results The plasma BNP concentrations in the patients,especially in the patients with myocardial infarction,were significantly higher than those in the controls.Spearman analysis showed that there was a positive correlation between the BNP levels and coronary lesion vessels(r1=0.309,P=0.01),also between BNP and coronary lesion score(r2=0.279,P=0.01).Conclusions In the patients without congestive heart failure,the more serious the coronary artery lesions,the higher the plasma BNP concentrations were.The degree of myocardial ischemia caused by coronary artery lesions was correlated with the plasma BNP level.Plasma BNP concentration could be valuable for the extent of coronary artery lesions in the patients of coronary artery disease.

Values of Coronary Arteriongraphy in Diagnosing Angina / 医学研究杂志

Objective To evaluate the value of coronary arteriongraphy(CAG)in diagnosing angina.Methods 219 patients with angina in clinical analysis were selected and divided into 2 groups:the stable angina(SA)group and unstable angina(UA)group.They all were accepted CAG first time.Then analysis were carried out between clinical diagnosis and results of CAG.Results The total positive rate of CAG in diagnosing angina is 58.90%.The positive rate of SA group(56.52%)shows no significant difference with that of UA group(60.00%).Single vessel lesion and multiple vessels lesion of SA group have little difference,however,the main coronary artery lesions of UA group is single vessel.Conclusions CAG is extremely important in diagnosing angina,but it has its own limit.Experience and new technique should be applied to retrieve locatization of CAG.