Rapamycin-mediated mTOR inhibition attenuates survivin and sensitizes glioblastoma cells to radiation therapy

Survivin, an antiapoptotic protein, is elevated in most malignancies and attributes to radiation resistance in tumors including glioblastoma multiforme. The downregulation of survivin could sensitize glioblastoma cells to radiation therapy. In this study, we investigated the effect of rapamycin, an inhibitor of mammalian target of rapamycin (mTOR), in attenuating survivin and enhancing the therapeutic efficacy for glioblastoma cells, and elucidated the underlying mechanisms. Here we tested various concentrations of rapamycin (1-8 nM) in combination with radiation dose 4 Gy. Rapamycin effectively modulated the protein kinase B (Akt)/mTOR pathway by inhibiting the phosphorylation of Akt and mTOR proteins, and this inhibition was further enhanced by radiation. The expression level of survivin was decreased in rapamycin pre-treatment glioblastoma cells followed by radiation; meanwhile, the phosphorylation of H2A histone family member X (H2AX) at serine-139 (γ-H2AX) was increased. p21 protein was also induced on radiation with rapamycin pre-treatment, which enhanced G1 arrest and the accumulation of cells at G0/subG1 phase. Furthermore, the clonogenic cell survival assay revealed a significant dose-dependent decrease in the surviving fraction for all three cell lines pre-treated with rapamycin. Our studies demonstrated that targeting survivin may be an effective approach for radiosensitization of malignant glioblastoma.     

No evidence that facial attractiveness,femininity, averageness,or coloration are cues to susceptibility to infectious illnesses in a university sample of young adult women

Previous reports that women with attractive faces are healthier have been widely cited as evidence that sexual selection has shaped human mate preferences. However, evidence for correlations between women's physical health and facial attractiveness is equivocal. Moreover, positive results on this issue have generally come from studies of self-reported health in small samples. The current study took standardized face photographs of women who completed four different health questionnaires assessing susceptibility to infectious illnesses (N?=?590). Of these women, 221 also provided a saliva sample that was assayed for immunoglobulin A (a marker of immune function). Analyses showed no significant correlations between rated facial attractiveness and either scores on any of the health questionnaires or salivary immunoglobulin A. Furthermore there was no compelling evidence that objective measures of sexual dimorphism of face shape, averageness of face shape, or facial coloration were correlated with any of our health measures. While other measures of health may yet reveal robust associations with facial appearance, these null results do not support the prominent and influential assumption that women's facial attractiveness is a cue of young adult women's susceptibility to infectious illnesses, at least in our study population.     

Cell surface carbohydrates of embryonal carcinoma cells: polysaccharidic side chains of F9 antigens and of receptors to two lectins, FBP and PNA

Three cell surface components of mouse embryonal carcinoma (EC) cells, F9 antigens and the receptors to the lectins FBP and PNA, have been isolated from radiolabeled EC cells by indirect immunoprecipitation. All three were efficiently labeled with fucose, galactose and glucosamine, but scarcely at all with mannose. The high molecular weight glycopeptides characteristic of early embryonic cells were released as the major glycopeptides upon pronase digestion of the three markers. The binding sites to the two lectins are present in the high molecular weight glycopeptides. Furthermore, a close correlation exists between the disappearance of the high molecular weight glycopeptides from differentiating EC cells and the disappearance of the three markers from the surface of these cells. The large glycopeptides from the three markers have the following properties in common. First, they are not mucin-type glycopeptides with short oligosaccharides, glycolipids and acidic mucopolysaccharides, nor are they products of incomplete pronase digestion of conventional complex-type glycopeptides. Second, they do not contain appreciable amounts of Fucα1→2Gal or Fucα1→6GlcNAc linkages. Third, a significant fraction of the glycopeptides have the GlcNAcβ→Gal sequence in their core structure. We propose that the cell surface markers of EC cells have a class of large carbohydrate chains not found in typical surface markers of adult cells such as H-2, la and LETS.     

Functional validation of miRNAs targeting genes of DNA double-strand break repair to radiosensitize non-small lung cancer cells

DNA-Double strand breaks (DSBs) generated by radiation therapy represent the most efficient lesions to kill tumor cells, however, the inherent DSB repair efficiency of tumor cells can cause cellular radioresistance and impact on therapeutic outcome. Genes of DSB repair represent a target for cancer therapy since their down-regulation can impair the repair process making the cells more sensitive to radiation. In this study, we analyzed the combination of ionizing radiation (IR) along with microRNA-mediated targeting of genes involved in DSB repair to sensitize human non-small cell lung cancer (NSCLC) cells. MicroRNAs are natural occurring modulators of gene expression and therefore represent an attractive strategy to affect the expression of DSB repair genes. As possible IR-sensitizing targets genes we selected genes of homologous recombination (HR) and non-homologous end joining (NHEJ) pathway (i.e. RAD51, BRCA2, PRKDC, XRCC5, LIG1). We examined these genes to determine whether they may be real targets of selected miRNAs by functional and biological validation. The in vivo effectiveness of miRNA treatments has been examined in cells over-expressing miRNAs and treated with IR. Taken together, our results show that hsa-miR-96-5p and hsa-miR-874-3p can directly regulate the expression of target genes. When these miRNAs are combined with IR can decrease the survival of NSCLC cells to a higher extent than that exerted by radiation alone, and similarly to radiation combined with specific chemical inhibitors of HR and NHEJ repair pathway.     

Engineering stilbene metabolic pathways in microbial cells

Numerous in vitro and in vivo studies on biological activities of phytostilbenes have brought to the fore the remarkable properties of these compounds and their derivatives, making them a top storyline in natural product research fields. However, getting stilbenes in sufficient amounts for routine biological activity studies and make them available for pharmaceutical and/or nutraceutical industry applications, is hampered by the difficulty to source them through synthetic chemistry-based pathways or extraction from the native plants. Hence, microbial cell cultures have rapidly became potent workhorse factories for stilbene production. In this review, we present the combined efforts made during the past 15?years to engineer stilbene metabolic pathways in microbial cells, mainly the Saccharomyces cerevisiae baker yeast, the Escherichia coli and the Corynebacterium glutamicum bacteria. Rationalized approaches to the heterologous expression of the partial or the entire stilbene biosynthetic routes are presented to allow the identification and/or bypassing of the major bottlenecks in the endogenous microbial cell metabolism as well as potential regulations of the genes involved in these metabolic pathways. The contributions of bioinformatics to synthetic biology are developed to highlight their tremendous help in predicting which target genes are likely to be up-regulated or deleted for controlling the dynamics of precursor flows in the tailored microbial cells. Further insight is given to the metabolic engineering of microbial cells with “decorating” enzymes, such as methyl and glycosyltransferases or hydroxylases, which can act sequentially on the stilbene core structure. Altogether, the cellular optimization of stilbene biosynthetic pathways integrating more and more complex constructs up to twelve genetic modifications has led to stilbene titers ranging from hundreds of milligrams to the gram-scale yields from various carbon sources. Through this review, the microbial production of stilbenes is analyzed, stressing both the engineering dynamic regulation of biosynthetic pathways and the endogenous control of stilbene precursors.     

Discovery of MK-1832, a Kv1.5 inhibitor with improved selectivity and pharmacokinetics

Selective inhibition of Kv1.5, which underlies the ultra-rapid delayed rectifier current, I_Kur, has been pursued as a treatment for atrial fibrillation. Here we describe the discovery of MK-1832, a Kv1.5 inhibitor with improved selectivity versus the off-target current I_Ks, whose inhibition has been associated with ventricular proarrhythmia. MK-1832 exhibits improved selectivity for I_Kur over I_Ks (>3000-fold versus 70-fold for MK-0448), consistent with an observed larger window between atrial and ventricular effects in vivo (>1800-fold versus 210-fold for MK-0448). MK-1832 also exhibits an improved preclinical pharmacokinetic profile consistent with projected once daily dosing in humans.     

Epigallocatechin-3-gallate inhibits bacterial virulence and invasion of host cells

Increasing antibiotic resistance and beneficial effects of host microbiota has motivated the search for anti-infective agents that attenuate bacterial virulence rather than growth. For example, we discovered that specific flavonoids such as baicalein and quercetin from traditional medicinal plant extracts could attenuate Salmonella enterica serovar Typhimurium type III protein secretion and invasion of host cells. Here, we show epigallocatechin-3-gallate from green tea extracts also inhibits the activity of S. Typhimurium type III protein effectors and significantly reduces bacterial invasion into host cells. These results reveal additional dietary plant metabolites that can attenuate bacterial virulence and infection of host cells.     

Hsp83 regulates the fate of germline stem cells in Drosophila ovary

正In adult tissues,stem cells are defined by their unique capacity to self-renew and produce differentiated cells to maintain tissue homeostasis.Drosophila ovarian germline stem cells(GSCs)provide a powerful model for investigating the regulatory mechanisms underlying stem cell fate determination in vivo(Chen and Mckearin,     

Discovery of a bicyclo[4.3.0]nonane derivative DS88790512 as a potent,selective, and orally bioavailable blocker of transient receptor potential canonical 6 (TRPC6)

In this study, we aimed to synthesize a novel blocker of transient receptor potential canonical 6 (TRPC6). The sp² carbon atoms of the aminoindane skeleton of the known inhibitor were replaced with sp³ carbon atoms to increase the molecular complexity, measured by fraction sp³ (Fsp³). The representative compound, a bicyclo[4.3.0]nonane derivative DS88790512, inhibited TRPC6 with an IC₅₀ value of 11?nM. Notably, DS88790512 exhibited excellent selectivity against hERG and hNa_V1.5 channels, and was identified as an orally bioavailable compound.     

Ultrashort nanosecond electric pulses evoke heterogeneous patterns of Ca2+ release from the endoplasmic reticulum of adrenal chromaffin cells

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Development of a stereoselective and scalable process for the preparation of a methylcyclobutanol-pyridyl ether

The evolution of a scalable process for the preparation of methylcyclobutanol-pyridyl ether 1 is described. Key aspects of this development including careful control of the stereochemistry, elimination of chromatography, and application to kilogram-scale synthesis are addressed.     

Development of a novel NURR1/NOT agonist from hit to lead and candidate for the potential treatment of Parkinson's disease

In the course of a programme aimed at identifying Nurr1/NOT agonists for potential treatment of Parkinson’s disease, a few hits from high throughput screening were identified and characterized. A combined optimization pointed to a very narrow and stringent structure activity relationship. A comprehensive program of optimization led to a potent and safe candidate drug displaying neuroprotective and anti-inflammatory activity in several in vitro and in vivo models.     

An apparatus for safe and convenient handling of anhydrous, liquid hydrogen fluoride at controlled temperatures and reaction times. Application to the generation of oligosaccharides from polysaccharides

β-d-Gal-(1 → 4)-β-d-GlcNAc-OC₆H₄NO₂-p (p-nitrophenyl N-acetyl-β-lactosaminide) and β-d-Gal-(1 → 6)-β-d-GlcNAc-OC₆H₄NO₂-p (p-nitrophenyl N-acetyl-β-isolactosaminide) were regioselectively synthesized from lactose and p-nitrophenyl 2-acetamido-2-deoxy-glucopyranoside, employing transglycosylation by the β-d-galactosidase from Bacillus circulans and by controlling the concentration of organic solvent in the reaction system. The (1 → 4)-linked disaccharide was formed exclusively when the concentration of organic solvent was high, whereas the (1 → 6)-linked isomer was produced with a low concentration. Further utilization of the transglycosylation by the enzyme led to the regioselective formation of β-d-Gal-(1 → 4)-d-GalNAc and β-d-Gal-(1 → 4)-β-d-GalNAc-OC₆H₄NO₂-p. With the enzyme, β-d-galactosyl transfer occurred preferentially at the O-4 position of GlcNAc and GalNAc, regardless of the configuration of the hydroxyl group.