Synthesis and SAR of diazepine and thiazepine TACE and MMP inhibitors

Potent and selective TACE and MMP inhibitors utilizing the diazepine and thiazepine ring systems were synthesized and evaluated for biological activity in in vitro and in vivo models of TNF-alpha release. Oral activity in the mouse LPS model of TNF-alpha release was seen. Efficacy in the mouse collagen induced arthritis model was achieved with diazepine 20.     

Design, synthesis, and activity of achiral analogs of 2-quinolones and indoles as non-thiol farnesyltransferase inhibitors

Beginning with the structure of tipifarnib (1), a series of inhibitors of FTase have been synthesized by transposition of the D-ring to the imidazole and subsequent modification of the 2-quinolone motif. The compounds in the new series may be achiral and have structural features that allow for analogs that are difficult or impossible to make in the tertiary carbon-based tipifarnib series. The most potent compound (4d) is 4 times more active in vitro against FTase than tipifarnib.     

Synthesis and preliminary biological evaluation of new anti-tubulin agents containing different benzoheterocycles

A new series of compounds, in which the 2-amino-4-methoxyphenyl ring of phenstatin analogue 5 was replaced with 2- or 3-amino-benzoheterocycles, was synthesized and evaluated for antiproliferative activity and inhibition of colchicine binding. The lack of activity of 3',4'-dimethoxy- and 4'-methoxy-benzoyl derivatives (8 and 9, respectively) indicates that the 3',4',5'-trimethoxybenzoyl moiety is critical for the activity. Two compounds, 7 and 11, displayed potent antiproliferative activity, with IC50 values ranging from 25 to 100 nM against a variety of cancer cell lines. Derivative 11 was more active than CA-4 as an inhibitor of tubulin polymerization. The results demonstrated that the antiproliferative activity was correlated with inhibition of tubulin polymerization.     

Design, synthesis, and structural analysis of inhibitors of influenza neuraminidase containing a 2,3-disubstituted tetrahydrofuran-5-carboxylic acid core

(+/-)-(2R,3R,5R)-[2-(1'-S-acetamido-3'-methyl)butyl-3-methoxycarbonyl]tetrahydrofuran-5-carboxylic acid (9) and (+/-)-(2R,3R,5R)-[2-(1'-S-acetamido-3'-methyl)butyl-3-(4'-imidazolyl)]tetrahydrofuran 5-carboxylic acid (14) were synthesized as inhibitors of influenza neuraminidase (NA). Both compounds 9 and 14 inhibit influenza NA A with an IC(50) of about 0.5 microM and NA B with an IC(50) of 1.0 microM.     

Control of Shugoshin function during fission-yeast meiosis

Meiosis consists of a single round of DNA replication followed by two consecutive nuclear divisions. During the first division (MI), sister kinetochores must orient toward the same pole to favor reductional segregation. Correct chromosome segregation during the second division (MII) requires the retention of centromeric cohesion until anaphase II. The spindle checkpoint protein Bub1 is essential for both processes in fission yeast . When bub1 is deleted, the Shugoshin protein Sgo1 is not recruited to centromeres, cohesin Rec8 does not persist at centromeres, and sister-chromatid cohesion is lost by the end of MI. Deletion of bub1 also affects kinetochore orientation because sister centromeres can move to opposite spindle poles in approximately 30% of MI divisions. We show here that these two functions are separable within the Bub1 protein. The N terminus of Bub1 is necessary and sufficient for Sgo1 targeting to centromeres and the protection of cohesion, whereas the C-terminal kinase domain acts together with Sgo2, the second fission-yeast Shugoshin protein, to promote sister-kinetochore co-orientation during MI. Additional analyses suggest that the protection of centromeric cohesion does not operate when sister kinetochores attach to opposite spindle poles during MI. Sgo1-mediated protection of centromere cohesion might therefore be regulated by the mode of kinetochore attachment.     

The prokaryotic enzyme DsbB may share key structural features with eukaryotic disulfide bond forming oxidoreductases

Three different classes of thiol-oxidoreductases that facilitate the formation of protein disulfide bonds have been identified. They are the Ero1 and SOX/ALR family members in eukaryotic cells, and the DsbB family members in prokaryotic cells. These enzymes transfer oxidizing potential to the proteins PDI or DsbA, which are responsible for directly introducing disulfide bonds into substrate proteins during oxidative protein folding in eukaryotes and prokaryotes, respectively. A comparison of the recent X-ray crystal structure of Ero1 with the previously solved structure of the SOX/ALR family member Erv2 reveals that, despite a lack of primary sequence homology between Ero1 and Erv2, the core catalytic domains of these two proteins share a remarkable structural similarity. Our search of the DsbB protein sequence for features found in the Ero1 and Erv2 structures leads us to propose that, in a fascinating example of structural convergence, the catalytic core of this integral membrane protein may resemble the soluble catalytic domain of Ero1 and Erv2. Our analysis of DsbB also identified two new groups of DsbB proteins that, based on sequence homology, may also possess a catalytic core similar in structure to the catalytic domains of Ero1 and Erv2.     

Dispersal, habitat differences, and comparative phylogeography of Southeast Asian seahorses (Syngnathidae: Hippocampus)

Four distinct phylogeographical patterns across Southeast Asia were observed for four species of seahorse (genus Hippocampus) with differing ecologies. For all species, genetic differentiation (based on cytochrome b sequence comparisons) was significantly associated with sample site (Phi(ST) = 0.190-0.810, P < 0.0001) and with geographical distance (Mantel's r = 0.37-0.59, P < 0.019). Geographic locations of genetic breaks were inconsistent across species in 7/10 comparisons, although some similarities across species were also observed. The two shallow-water species (Hippocampus barbouri and Hippocampus kuda) have colonized the Sunda Shelf to a lesser degree than the two deeper-water species (Hippocampus spinosissimus and Hippocampus trimaculatus). In all species the presence of geographically restricted haplotypes in the Philippines could indicate past population fragmentation and/or long-distance colonization. A nested clade analysis (NCA) revealed that long-distance colonization and/or fragmentation were likely the dominant forces that structure populations of the two shallow-water species, whereas range expansion and restricted dispersal with isolation by distance were proportionally more important in the history of the two deeper-water species. H. trimaculatus has the most widespread haplotypes [average clade distance (D(c)) of nonsingleton haplotypes = 1169 km], indicating potentially high dispersal capabilities, whereas H. barbouri has the least widespread haplotypes (average D(c) = 67 km) indicating potentially lower dispersal capabilities. Pleistocene separation of marine basins and postglacial flooding of the Sunda Shelf are extrinsic factors likely to have contributed to the phylogeographical structure observed, whereas differences among the species appear to reflect their individual ecologies.     

Neural differentiation of murine embryonic stem cells ES

Pluripotent murine embryonic stem (ES) cells can differentiate into all cell types both in vivo and in vitro. Based on their capability to proliferate and differentiate, these ES cells appear as a very promising tool for cell therapy. The understanding of the molecular mechanisms underlying the neural differentiation of the ES cells is a pre-requisite for selecting adequately the cells and conditions which will be able to correctly repair damaged brain and restore altered cognitive functions. Different methods allow obtaining neural cells from ES cells. Most of the techniques differentiate ES cells by treating embryoid bodies in order to keep an embryonic organization. More recent techniques, based on conditioned media, induce a direct differentiation of ES cells into neural cells, without going through the step of embryonic bodies. Beyond the fact that these techniques allow obtaining large numbers of neural precursors and more differentiated neural cells, these approaches also provide valuable information on the process of differentiation of ES cells into neural cells. Indeed, sequential studies of this process of differentiation have revealed that globally ES cells differentiating into neural cells in vitro recapitulate the molecular events governing the in vivo differentiation of neural cells. Altogether these data suggest that murine ES cells remain a highly valuable tool to obtain large amounts of precursor and differentiated neural cells as well as to get a better understanding of the mechanisms of neural differentiation, prior to a potential move towards the use of human ES cells in therapy.