A small molecular agent YL529 inhibits VEGF-D-induced lymphangiogenesis and metastasis in preclinical tumor models in addition to its known antitumor activities

Background

The lymph node metastasis is a key early step of the tumor metastatic process. VEGFD-mediated tumor lymphangiogenesis plays a key role, since down-regulation of p-VEGFR-3 could block the lymph node metastasis. YL529 has been reported to possess potent anti-angiogenesis and antitumor activities; however, its roles in tumor-associated lymphangiogenesis and lymphatic metastasis remain unclear.

Method

We investigated the effect of YL529 on tumor-associated lymphangiogenesis and lymph node metastasis using in vitro lymph node metastasis models and in vivo subcutaneous tumor models in C57 BL/6 mice.

Result

We found that YL529 inhibited VEGF-D-induced survival, proliferation and tube-formation of Human Lymphatic Endothelial Cells. Furthermore, in established in vitro and in vivo lymph node metastasis models using VEGF-D-LL/2 cells, YL529 significantly inhibited the tumor-associated lymphangiogenesis and metastasis. At molecular level, YL529 down-regulated p-VEGFR-3, p-JNK and Bax while up-regulated Bcl-2.

Conclusion

YL529 provided the therapeutic benefits by both direct effects on tumor cells and inhibiting lymphangiogenesis and metastasis via the VEGFR-3 signaling pathway, which may have significant direct clinical implications.

Molecular cloning, characterization and expression analysis of a Doublesex gene from Daphnia carinata (Crustacea: Cladocera) during different reproductive stages

To better understand the reproductive transformation mechanism of Daphnia carinata, a Doublesex (Dsx) gene was cloned based on rapid amplification of cDNA ends (RACE), and was designated DapcaDsx2. Next, we compared similarities and assumed homology based on deduced amino acid sequences. It showed 97.52, 87.94, and 85.11% identity to orthologous genes in D. magna, D. pulex, and D. galeata respectively. Phylogenetic analysis revealed that DapcaDsx2 clustered in the same class, and was evolutionarily more distant to sequences from other species. qRT-PCR showed that DapcaDsx2 was most abundantly expressed during sexual reproduction (P < 0.05). Using digoxigenin-labeled RNA probes, we studied DapcaDsx2 expression in parthenogenetic and sexual females by whole-mount in situ hybridization. The results revealed that DapcaDsx2 was mainly expressed in the second antennae and several sites of the ventral carapace, whereas higher expression levels were found in sexual than in parthenogenetic females. This suggests that the DapcaDsx2 gene is involved in switching modes of reproduction and in sexual differentiation.

High-resolution transmission electron microscopy study on reversion of Al2CuMg precipitates in Al-Cu-Mg alloys under irradiation

Image deconvolution analyses showed that reversion of S-Al2CuMg precipitates occurred in an Al-Cu-Mg alloy during high-resolution transmission electron microscopy observations. A fraction of Mg and Cu atoms in the precipitates diffused into Al matrix due to electron beam irradiation at 300kV, resulting in structural/chemical reversion of the precipitates. The structural reversion of the S-Al2CuMg precipitates is closely related with irradiation-induced displacement of atoms. The strong attraction between Cu and Mg atoms might assist the sub-threshold displacement of Cu atoms. One transitional structure is determined to be S''-Al10Cu3Mg3, a precursor of S-Al2CuMg. Two other transitional structures, Al3CuMg and Al18Cu5Mg5 which have the same lattice parameters of a=c=0.405nm as that of S''-Al10Cu3Mg3, but different b values, are suggested.

5-Methoxyquinoline Derivatives as a New Class of EZH2 Inhibitors

A series of quinoline derivatives was synthesized and biologically evaluated as Enhancer of Zeste Homologue 2 (EZH2) inhibitors. Structure-activity relationship (SAR) studies led to the discovery of 5-methoxy-2-(4-methyl-1,4-diazepan-1-yl)-N-(1-methylpiperidin-4-yl)quinolin-4-amine (5k), which displayed an IC₅₀ value of 1.2 μM against EZH2, decreased global H3K27me3 level in cells and also showed good anti-viability activities against two tumor cell lines. Due to the low molecular weight and the fact that no quinoline derivative has been reported as an EZH2 inhibitor, this compound could serve as a lead compound for further optimization.

A beam-membrane structure micromachined differential pressure flow sensor

A beam-membrane structure micromachined flow sensor is designed, depending on the principle of differential pressure caused by the mass flow, which is directly proportional to the square flow rate. The FSI (fluid structure interaction) characteristics of the differential pressure flow sensor are investigated via numerical analysis and analog simulation. The working mechanism of the flow sensor is analyzed depending on the FSI results. Then, the flow sensor is fabricated and calibrated. The calibration results show that the beam-membrane structure differential pressure flow sensor achieves ideal static characteristics and works well in the practical applications.

Impact of hard vs. soft wheat and monensin level on rumen acidosis in feedlot heifers

Many feedlot finishing diets include wheat when the relative wheat prices are low. This study was conducted to examine the responses in ruminal pH and fermentation as well as site and extent of digestion from substituting soft or hard wheat for barley grain and to determine whether an elevated monensin concentration might decrease indicators of ruminal acidosis in feedlot heifers. Five ruminally cannulated beef heifers were used in a 5 × 5 Latin square with 2 × 2 + 1 factorial arrangement. Treatments included barley (10% barley silage, 86% barley, 4% supplement, with 28 mg monensin/kg DM) and diets where barley was substituted by either soft or hard wheat with either 28 or 44 mg monensin/kg diet DM. Intake of DM was not affected by grain source, whereas increasing monensin with wheat diets reduced (P < 0.02) DMI. Mean ruminal pH was lower (P < 0.04) and durations of pH < 5.8 and pH < 5.5 greater (P < 0.03) for wheat than for barley diets. However, ruminal pH was not affected by wheat type or monensin level. Total VFA concentrations were greater (P < 0.03) for wheat than barley diets with no effect of wheat type. The molar proportion of propionate was greater (P < 0.04), whereas butyrate (P < 0.01) and ratio of acetate to propionate tended to be lower (P < 0.09), with the high as compared to low level of monensin. Replacing barley with wheat in finishing diets did not affect the duodenal flow or the digestibility of OM, likely as a result of greater (P < 0.01) NDF digestion from barley offsetting the increased (P < 0.03) supply of digested starch from wheat. Feeding soft vs. hard wheat delivered a greater (P < 0.03) duodenal supply of OM and nonammonia N with no differences in total tract nutrient digestion. The increased monensin concentration decreased the flow of OM (P < 0.01), total N (P < 0.05), and microbial protein (P < 0.05) to the small intestine due to decreased DMI. These results indicated that hard and soft wheat exhibited digestive characteristics similar to barley, but ruminal pH measurements indicate that compared with barley, wheat increased the risk of ruminal acidosis. Although an increased level of monensin had limited impact on ruminal indicators of acidosis, an increase in propionate would be expected to improve efficiency of feed use by heifers fed wheat-based finishing diets.

A prediction model of drug-induced ototoxicity developed by an optimal support vector machine (SVM) method

Drug-induced ototoxicity, as a toxic side effect, is an important issue needed to be considered in drug discovery. Nevertheless, current experimental methods used to evaluate drug-induced ototoxicity are often time-consuming and expensive, indicating that they are not suitable for a large-scale evaluation of drug-induced ototoxicity in the early stage of drug discovery. We thus, in this investigation, established an effective computational prediction model of drug-induced ototoxicity using an optimal support vector machine (SVM) method, GA-CG-SVM. Three GA-CG-SVM models were developed based on three training sets containing agents bearing different risk levels of drug-induced ototoxicity. For comparison, models based on naïve Bayesian (NB) and recursive partitioning (RP) methods were also used on the same training sets. Among all the prediction models, the GA-CG-SVM model II showed the best performance, which offered prediction accuracies of 85.33% and 83.05% for two independent test sets, respectively. Overall, the good performance of the GA-CG-SVM model II indicates that it could be used for the prediction of drug-induced ototoxicity in the early stage of drug discovery.

Synthesis and biological evaluation of novel benzamide derivatives as potent smoothened antagonists

A series of novel benzamide derivatives were prepared and evaluated using cell-based measurements. Among these compounds, 10f significantly inhibited Hedgehog signaling and showed equivalent or more potency than GDC-0449 in different tests. Furthermore, compound 10f potently inhibited the proliferation of Daoy, a medulloblastoma cell line that is reported to be resistant to GDC-0449, which indicated a promising prospect in the treatment of Hedgehog signaling pathway related cancer in clinical trial.

Anisotropic two-dimensional electron gas at the LaAlO₃/SrTiO₃ (110) interface

The observation of a high-mobility two-dimensional electron gas between two insulating complex oxides, especially LaAlO₃/SrTiO₃, has enhanced the potential of oxides for electronics. The occurrence of this conductivity is believed to be driven by polarization discontinuity, leading to an electronic reconstruction. In this scenario, the crystal orientation has an important role and no conductivity would be expected, for example, for the interface between LaAlO₃ and (110)-oriented SrTiO₃, which should not have a polarization discontinuity. Here we report the observation of unexpected conductivity at the LaAlO₃/SrTiO₃ interface prepared on (110)-oriented SrTiO₃, with a LaAlO₃-layer thickness-dependent metal-insulator transition. Density functional theory calculation reveals that electronic reconstruction, and thus conductivity, is still possible at this (110) interface by considering the energetically favourable (110) interface structure, that is, buckled TiO₂/LaO, in which the polarization discontinuity is still present. The conductivity was further found to be strongly anisotropic along the different crystallographic directions with potential for anisotropic superconductivity and magnetism, leading to possible new physics and applications.

Although LaAlO₃ and SrTiO₃ are both insulators, when they are brought together at a (100) interface, a highly conducting two-dimensional electron gas forms between them. Annandi et al. show that this also happens at a (110) interface, counter to expectations that it should not.

¹H NMR-based metabolic profiling of human rectal cancer tissue

Background

Rectal cancer is one of the most prevalent tumor types. Understanding the metabolic profile of rectal cancer is important for developing therapeutic approaches and molecular diagnosis.

Methods

Here, we report a metabonomics profiling of tissue samples on a large cohort of human rectal cancer subjects (n = 127) and normal controls (n = 43) using ¹H nuclear magnetic resonance (¹H NMR) based metabonomics assay, which is a highly sensitive and non-destructive method for the biomarker identification in biological systems. Principal component analysis (PCA), partial least squares discriminant analysis (PLS-DA) and orthogonal projection to latent structure with discriminant analysis (OPLS-DA) were applied to analyze the ¹H-NMR profiling data to identify the distinguishing metabolites of rectal cancer.

Results

Excellent separation was obtained and distinguishing metabolites were observed among the different stages of rectal cancer tissues (stage I = 35; stage II = 37; stage III = 37 and stage IV = 18) and normal controls. A total of 38 differential metabolites were identified, 16 of which were closely correlated with the stage of rectal cancer. The up-regulation of 10 metabolites, including lactate, threonine, acetate, glutathione, uracil, succinate, serine, formate, lysine and tyrosine, were detected in the cancer tissues. On the other hand, 6 metabolites, including myo-inositol, taurine, phosphocreatine, creatine, betaine and dimethylglycine were decreased in cancer tissues. These modified metabolites revealed disturbance of energy, amino acids, ketone body and choline metabolism, which may be correlated with the progression of human rectal cancer.

Conclusion

Our findings firstly identify the distinguishing metabolites in different stages of rectal cancer tissues, indicating possibility of the attribution of metabolites disturbance to the progression of rectal cancer. The altered metabolites may be as potential biomarkers, which would provide a promising molecular diagnostic approach for clinical diagnosis of human rectal cancer. The role and underlying mechanism of metabolites in rectal cancer progression are worth being further investigated.

Accuracy of vessel-encoded pseudocontinuous arterial spin-labeling in identification of feeding arteries in patients with intracranial arteriovenous malformations

BACKGROUND AND PURPOSE

Identifying feeding arteries of intracranial AVMs is very important for preoperative evaluation. DSA remains the reference standard for diagnosis but is invasive. Our aim was to evaluate the diagnostic accuracy of vessel-encoded pseudocontinuous arterial spin-labeling in identifying feeding arteries of intracranial AVMs by using DSA as the criterion standard.

MATERIALS AND METHODS

Eighteen patients with AVMs were examined with vessel-encoded pseudocontinuous arterial spin-labeling and DSA. Three postlabeling delays (postlabeling delay = 1, 1.3, and 1.6 seconds) were applied in 6 patients, and a single postlabeling delay (1 second) was applied in the remainder. Perfusion-weighted images were decoded into individual vascular territories with standard and relative tagging efficiencies, respectively. The supply fraction of each feeding artery to the AVM was calculated. The within-subject ANOVA was applied to compare supply fractions acquired across 3 postlabeling delays. Receiver operating characteristic analysis curves were calculated to evaluate the diagnostic accuracy of vessel-encoded pseudocontinuous arterial spin-labeling for identifying the feeding arteries of AVMs.

RESULTS

There were no significant differences in supply fractions of the 3 major arteries to AVMs acquired with 3 postlabeling delays (P > .05). For vessel-encoded pseudocontinuous arterial spin-labeling with standard labeling efficiencies, the area under the receiver operating characteristic analysis curve was 0.942. The optimal cutoff of the supply fraction for identifying feeding arteries was 15.17%, and the resulting sensitivity and specificity were 84.62% and 93.33%, respectively. For vessel-encoded pseudocontinuous arterial spin-labeling with relative labeling efficiencies, the area under the receiver operating characteristic analysis curve was 0.957. The optimal cutoff of the supply fraction was 11.73%, which yielded an 89.74% sensitivity and 93.33% specificity.

CONCLUSIONS

The contribution fraction of each feeding artery of the AVM can be reliably estimated by using vessel-encoded pseudocontinuous arterial spin-labeling. Vessel-encoded pseudocontinuous arterial spin-labeling with either standard or relative labeling efficiencies offers a high level of diagnostic accuracy compared with DSA for identifying feeding arteries.

1H-NMR based metabonomic profiling of human esophageal cancer tissue

BACKGROUND

The biomarker identification of human esophageal cancer is critical for its early diagnosis and therapeutic approaches that will significantly improve patient survival. Specially, those that involves in progression of disease would be helpful to mechanism research.

METHODS

In the present study, we investigated the distinguishing metabolites in human esophageal cancer tissues (n = 89) and normal esophageal mucosae (n = 26) using a (1)H nuclear magnetic resonance ((1)H-NMR) based assay, which is a highly sensitive and non-destructive method for biomarker identification in biological systems. Principal component analysis (PCA), partial least squares-discriminant analysis (PLS-DA) and orthogonal partial least-squares-discriminant analysis (OPLS-DA) were applied to analyse (1)H-NMR profiling data to identify potential biomarkers.

RESULTS

The constructed OPLS-DA model achieved an excellent separation of the esophageal cancer tissues and normal mucosae. Excellent separation was obtained between the different stages of esophageal cancer tissues (stage II = 28; stage III = 45 and stage IV = 16) and normal mucosae. A total of 45 metabolites were identified, and 12 of them were closely correlated with the stage of esophageal cancer. The downregulation of glucose, AMP and NAD, upregulation of formate indicated the large energy requirement due to accelerated cell proliferation in esophageal cancer. The increases in acetate, short-chain fatty acid and GABA in esophageal cancer tissue revealed the activation of fatty acids metabolism, which could satisfy the need for cellular membrane formation. Other modified metabolites were involved in choline metabolic pathway, including creatinine, creatine, DMG, DMA and TMA. These 12 metabolites, which are involved in energy, fatty acids and choline metabolism, may be associated with the progression of human esophageal cancer.

CONCLUSION

Our findings firstly identify the distinguishing metabolites in different stages of esophageal cancer tissues, indicating the attribution of metabolites disturbance to the progression of esophageal cancer. The potential biomarkers provide a promising molecular diagnostic approach for clinical diagnosis of human esophageal cancer and a new direction for the mechanism study.

Lentiviral vector-mediated knockdown of Lrb in the arcuate nucleus promotes diet-induced obesity in rats

Obesity is currently a worldwide pandemic. Leptin resistance is a main mechanism of obese human and rodents. The downregulation of the long form of the leptin receptor (Lrb) was involved in leptin resistance in diet-induced obese rats. In the studies, we investigated whether arcuate nucleus (ARC) silencing of Lrb would promote diet-induced obesity in rats. Lentiviral vectors expressing Lrb-shRNA were administered to 5-week-old male rats by ARC injection. Following viral delivery, the rats were provided with a high-fat diet (HFD) or a chow diet (CD). After 8 weeks of the diet, serum leptin, and insulin concentrations were measured by RIA, gene expression of Lrb in the ARC was detected by a real-time RT-PCR, and leptin signaling was examined by western blot. The Lrb-shRNA knocked down the expression of Lrb mRNA in infected regions by 54% for the HFD rats and 47% for the CD rats respectively. The Lrb knockdown reduced Stats3 activation and increased expression of Npy mRNA. The rats with reduced Lrb in the ARC showed a significant increase in energy intake and body weight (BW) again when fed with a HFD. By contrast, there were no effects of Lrb reduction on energy intake or BW when rats maintained on a low-fat chow. Our results provide evidence that Lrb knockdown selectively in the ARC promotes diet-induced obesity and associated metabolic complications in rats.

Current methods and research progress in nanomaterials risk assessment

Nanomaterials have unique physicochemical properties compared with those bulk materials of the same composition. Possible undesirable results of these capabilities are harmful interactions with biological systems and the environment, with the potential to generate toxicity. A number of studies on the effects of Nanomaterials in vitro and in vivo systems have been published. However, while the number of nanomaterials types and applications continues to increase, studies to characterize their effects after exposure and to address their potential toxicity are few in comparison, there is still a need for further studies that conclusively establish their safety/toxicity. The establishment of principles and test procedures to ensure safe manufacture and use of nanomaterials in the marketplace is urgently required and achievable. The major goal of this review is to summarize 1) analytical techniques applied for characterization of nanomaterials, 2) current analytical methods to assess nanomaterials toxicity in vitro and in vivo; 3) research progress of polymeric nanomaterials toxicity; 4) outlook.

Metabolomics: a revolution for novel cancer marker identification

The repertoire of small-molecular-weight substances present in cells, tissue and body fluids are known as the metabolites. The global analysis of metabolites, such as by high-resolution ¹H nuclear magnetic resonance spectroscopy and mass spectrometry, is integral to the rapidly expanding field of metabolomics, which is making progress in various diseases. In the area of cancer and metabolic phenotype, the integrated analysis of metabolites may provide a powerful platform for detecting changes related to cancer diagnosis and discovering novel biomarkers. In this review, metabolomics including the technologies in metabolomics research and extracting information from metabolomics datasets are described. Then we discuss the challenges and opportunities in metabolomics for finding metabolic processes in cancer and discovering novel cancer biomarkers. Finally, we assess the clinical applicability of metabolomics.

Knockdown of core 1 beta 1, 3-galactosyltransferase prolongs skin allograft survival with induction of galectin-1 secretion and suppression of CD8+ T cells: T synthase knockdown effects on galectin-1 and CD8+ T cells

Core 1 beta 1,3-galactosyltransferase also known as T-antigen-synthase or T-synthase is a key enzyme for the synthesis of the common core 1 O-glycan structure (T-antigen). Although T-synthase is known to be important in human immune-related diseases, the effects of T-synthase and T-antigen on host immune responses remain poorly defined. In this study, a T-synthase-specific short hairpin RNA (shRNA) was transfected into murine colon carcinoma CT26 cells or mouse muscle tissues via intramuscular electroporation to assess the effects of T-synthase on T cells and cytokines. T-synthase knockdown significantly induced galectin-1 secretion both in vivo and in vitro and strongly enhanced Th2 cytokine (IL-10 and IL-4) production in vivo. Further, the increased production of galectin-1 induced by T-synthase knockdown promoted CD8(+) T-cell apoptosis, which, when combined with the increased production of CD4(+) T cell-derived Th2 cytokines prolonged the survival of skin allografts in mice. Our data suggest core 1 beta 1,3-galactosyltransferase-shRNA could serve not only as a useful tool in organ transplantation but also as a powerful tool for investigating O-glycans and glycoprotein synthesis and function.

A novel anticancer agent, SKLB70359, inhibits human hepatic carcinoma cells proliferation via G0/G1 cell cycle arrest and apoptosis induction

Hepatocellular carcinoma is one of the most common cancers in worldwide. We previously reported a novel thienopyridine derivative 3-amino-6-(3,4-dichlorophenyl) thieno[2,3-b]pyridine-2-carboxamide (SKLB70359) which possesses anticancer activity against hepatocellular carcinoma. In present study, we further investigated its anticancer activity and possible mechanism. The SKLB70359 treatment decreased the viability of a panel of hepatocellular carcinoma cell lines in a concentration- and time-dependent manner with IC(50) 0.4 ~ 2.5 μM. The mechanism study showed that SKLB70359 induced G0/G1 cell cycle arrest and then led to apoptotic cell death of HepG2 cell. The SKLB70359 induced G0/G1 cell cycle arrest was characterized by down-regulation of cyclin-dependent kinase 2 (CDK2), CDK4, CDK6 expression and up-regulation of p53, p21(WAF1). Activating of caspase-3 and caspase-9 was also observed. Meanwhile, proliferation inhibitory effect of SKLB70359 was associated with decreased level of phosphorylated p44/42 mitogen activated protein kinase (p44/42 MAPK) and phosphorylated retinoblastoma protein (Rb). Moreover, SKLB70359 exhibit less toxicity to non-cancer cells than tumor cells. In conclusion, the findings in this study suggested that SKLB70359 have potential anticancer efficacy via G0/G1 cell cycle arrest and apoptosis induction. Its potential to be a candidate of anticancer agent is worth being further investigated.

Syntheses and cell-based phenotypic screen of novel 7-amino pyrido[2,3-d]pyrimidine-6-carbonitrile derivatives as potential antiproliferative agents

A series of N-3-substituted 7-aminopyrido[2,3-d]pyrimidin-6-carbonitrile derivatives was readily synthesized and their anti-proliferative activities on five types of tumor cells were evaluated through a cell-based phenotypic screening approach. Compound 3k was found to be potent on human colon cancer SW620 cells with an IC₅₀ value of 12.5 μM. Structural optimization of compound 3k led to compound 4a with improved anti-proliferative potency on SW620 cells with an IC₅₀ value of 6.9 μM. Further cell-cycle analyses suggested that compound 4a induced apoptosis of SW620 cells in a concentration-dependent manner.

Analysis of HLA-DM polymorphisms in the Chinese Han population

Non-classical human leukocyte antigen (HLA)-DM plays an important and unique role in the processing and presentation of exogenous antigens. Polymorphisms of certain genes and frequency of alleles in populations may indicate susceptibility to certain diseases. In this study, the analysis of HLA-DMA and HLA-DMB gene polymorphisms and haplotypes in the Chinese Han population was conducted to obtain population genetic data. HLA-DM typing has been performed previously by other groups by polymerase chain reaction (PCR)-restriction fragment length polymorphism and PCR-sequence-specific oligonucleotide probe techniques. In this study, we established a TaqMan PCR typing method as an alternative to these techniques to survey the frequency of DMA and DMB alleles in the population. Genotyping was conducted in 1000 unrelated individuals of Han nationality in South and North China using TaqMan PCR typing. Four different DMA alleles and six different DMB alleles were detected. All loci met the Hardy-Weinberg equilibrium principle that both allele and genotype frequencies in a population remain constant. We found that the DMA*01:01 (69.35%) and DMB*01:01 (52.5%) alleles were more frequent in Chinese Hans. Analysis of the haplotypes for two loci of DMA and DMB showed that a highly significant positive linkage disequilibrium (LD) presented for DMA*01:01-DMB*01:02, DMA*01:01-DMB*01:03, DMA*01:01-DMB*01:04, DMA*01:02-DMB*01:01, DMA*01:02-DMB*01:05, DMA*01:03-DMB*01:07, and DMA*01:04-DMB*01:01 haplotypes. Analysis of haplotypes for four loci associated with antigen processing (DMA-DMB-TAP1-TAP2) showed a highly significant LD in DMA*01:01-DMB*01:04-TAP1*02:01:01-TAP2*01:02, DMA*01: 02-DMB*01:05-TAP1*01:01-TAP2*01:01, and DMA*01:01-DMB*01:03-TAP1* 04:01-TAP2*01:01 haplotypes. The comparison between the Chinese Han population and non-Chinese populations showed that no significant differences were found at the HLA-DMA locus in the Chinese Han population compared with people of German nationality, whereas significant differences presented when compared with Turkish, American Caucasian, Japanese, French, and Italian nationalities. However, at the HLA-DMB locus, highly significant differences presented in the Chinese Han population compared with Germans and Italians. This study lays the foundations for further disease association analyses.

Novel benzothiazole, benzimidazole and benzoxazole derivatives as potential antitumor agents: synthesis and preliminary in vitro biological evaluation

In a previous hit-to-lead research program targeting anticancer agents, two promising lead compounds, 1a and 1b, were found. However, the poor solubility of 1a and 1b made difficult further in vivo studies. To solve this problem, a lead optimization was conducted through introducing N-methyl-piperazine groups at the 2-position and 6-position. To our delight, the optimized analogue 1d showed comparable antiproliferative activity in vitro with better solubility, compared with 1a. Based on this result, the replacement of the benzothiazole scaffold with benzimidazole and benzoxazole moieties afforded 1f and 1g, whose activities were fundamentally retained. In the preliminary in vitro biological evaluation, the immunofluorescence staining of HCT116 cells indicated that 1d, 1f and 1g led to cytosolic vacuolization which was not induced by 1a at low micromolecular concentrations. These results suggest that these optimized compounds might potentially constitute a novel class of anticancer agents, which merit further studies.

Metal-insulator transition in SrTiO(3-x) thin films induced by frozen-out carriers

We report optical, electrical and magnetotransport properties of oxygen deficient SrTiO(3) (SrTiO(3-x)) thin films fabricated by pulsed laser deposition technique. The oxygen vacancies (O(vac)) in the thin film are expected to be uniform. By comparing its electrical properties to those of bulk SrTiO(3-x), it was found that O(vac) in bulk SrTiO(3-x) is far from uniform over the whole material. The metal-insulator transition (MIT) observed in the SrTiO(3-x) film was found to be induced by the carrier freeze-out effect. The low temperature frozen state can be reexcited by Joule heating, electric and intriguingly magnetic field.

GABAergic excitotoxicity injury of the immature hippocampal pyramidal neurons' exposure to isoflurane

BACKGROUND

Certain anesthetics exhibit neurotoxicity in the brains of immature but not mature animals. γ-Aminobutyric acid (GABA), the primary inhibitory neurotransmitter in the adult brain, is excitatory on immature neurons via its action at the GABAA receptor, depolarizing the membrane potential and inducing a cytosolic Ca2+ increase ([Ca2+]i), because of a reversed transmembrane chloride gradient. Recent experimental data from several rodent studies have demonstrated that exposure to isoflurane during an initial phase causes neuronal excitotoxicity and apoptosis. GABAA receptor-mediated synaptic voltage-dependent calcium channels' (VDCCs) overactivation and Ca2+ influx are involved in these neural changes.

METHODS

We monitored [Ca2+]i using Fluo-4 AM fluorescence imaging. Using whole-cell patch clamp techniques, IVDCC (voltage-dependent calcium channel currents) were recorded from primary cultures of rat hippocampal neurons (5-day culture) exposed to isoflurane. To further investigate the neurotoxicity of high cytosolic-free calcium after isoflurane in a dose- and time-dependent manner, the possibility of increased caspase-3 levels was evaluated by Western blot and quantitative real-time polymerase chain reaction. Statistical significance was assessed using the Student t test or 1-way analysis of variance followed by the Tukey post hoc test.

RESULTS

Under control conditions, isoflurane enhanced the GABA-induced [Ca2+]i increase in a dose-dependent manner. Dantrolene and nicardipine markedly inhibited this enhancement mediated by isoflurane. Moreover, in Ca2+-free media, pretreatment with isoflurane did not show any influence on the caffeine-induced increase of [Ca2+]i. Similarly, using whole-cell recording, isoflurane increased the peak amplitude of IVDCC in the cultured neurons from rat hippocampus by depolarization pulses. Isoflurane (0.25, 0.5, 0.75, and 1 minimum alveolar concentration [MAC]) potentiated IVDCC peak current amplitude by 109.11%±9.03%, 120.56%±11.46%, 141.33%±13.87%, and 146.78%±15.87%, respectively. To analyze variation in protein levels, the effect of treatments with isoflurane on caspase-3 activity was dose- and time-dependent, reaching a maximal caspase-3 activity after exposure to 1 MAC for 6 hours (P<0.001). However, in the mRNA levels, hippocampal caspase-3 mRNA levels began to be significantly increased in isoflurane-treated developing rat hippocampal neurons after 6 hours of exposure to 0.25 MAC isoflurane (P<0.001).

CONCLUSIONS

Isoflurane-mediated enhancement of GABA-triggered [Ca2+]i release results from membrane depolarization with subsequent activation of VDCCs and further Ca2+-induced Ca2+ release from the ryanodine-sensitizing Ca2+ store. An increase in [Ca2+]i, caused by activation of the GABAA receptor and opening of VDCCs, is necessary for isoflurane-induced calcium overload of immature rat hippocampal neurons, which may be involved in the mechanism of an isoflurane-induced neurotoxic effect in the developing rodent brain.

Hollow fiber liquid-phase microextraction for the determination of nimesulide in human plasma and its application to a pharmacokinetic study

A hollow fiber liquid-phase microextraction (HF-LPME) method in combination with HPLC-UV for the determination of nimesulide in human plasma was developed and validated. A small volume of dihexyl ether contained within a polypropylene hollow fiber was used for the extraction of nimesulide from acidified plasma solutions. Factors affecting the extraction efficiency were optimized and discussed. With HPLC-UV as the end analysis technique, the procedure was validated for nimesulide in the concentration range of 50-5000 ng/mL. The intra- and inter-assay precisions were less than 9.1%, and accuracy was within 3.2%. The lower limit of quantification (LLOQ) was 50 ng/mL. Enrichment factor from 144-fold to 156-fold was achieved at three quality control (QC) concentrations. The mean extraction recovery was greater than 41.2%. This method was successfully applied for the evaluation of pharmacokinetics of nimesulide after single oral doses of 100 mg nimesulide to six healthy Chinese volunteers.