Formal Total Synthesis of Manzacidin B via Sequential Diastereodivergent Henry Reaction.

A formal total synthesis of manzacidin B is described. β,β-Disubstituted γ-hydroxy-β-aminoalcohol, the key structure of manzacidin B, is stereoselectively constructed via sequential Henry reactions. By taking advantage of noncovalent interactions, such as intramolecular hydrogen bonding and chelation, we could diastereodivergently control the stereoselectivity of the Henry reaction.

A Unique Procedure to Identify Cell Surface Markers Through a Spherical Self-Organizing Map Applied to DNA Microarray Analysis.

To identify cell-specific markers, we designed a DNA microarray platform with oligonucleotide probes for human membrane-anchored proteins. Human glioma cell lines were analyzed using microarray and compared with normal and fetal brain tissues. For the microarray analysis, we employed a spherical self-organizing map, which is a clustering method suitable for the conversion of multidimensional data into two-dimensional data and displays the relationship on a spherical surface.

Characterization of cancer stem-like cells derived from mouse induced pluripotent stem cells transformed by tumor-derived extracellular vesicles.

Several studies have shown that cancer niche can perform an active role in the regulation of tumor cell maintenance and progression through extracellular vesicles-based intercellular communication. However, it has not been reported whether this vesicle-mediated communication affects the malignant transformation of normal stem cells/progenitors. We have previously reported that the conditioned medium derived from the mouse Lewis Lung Carcinoma (LLC) cell line can convert mouse induced pluripotent stem cells (miPSCs) into cancer stem cells (CSCs), indicating that normal stem cells when placed in an aberrant microenvironment can give rise to functionally active CSCs.

Mouse induced pluripotent stem cell microenvironment generates epithelial-mesenchymal transition in mouse Lewis lung cancer cells.

Induced pluripotent stem (iPS) cells may be a powerful tool in regenerative medicine, but their potential tumorigenicity is a significant challenge for the clinical use of iPS cells. Previously, we succeeded in converting miPS cells into cancer stem cells (CSCs) under the conditions of tumor microenvironment. Both stem cells and tumor cells are profoundly influenced by bi-directional communication with their respective microenvironment, which dictates cell fate determination and behavior.

Development of 111In-labeled liposomes for vulnerable atherosclerotic plaque imaging.

Unlabelled: Macrophage infiltration is a common characteristic feature of atherosclerotic-vulnerable plaques. Macrophages recognize phosphatidylserine (PS) exposed on the surface of apoptotic cells, which triggers the engulfment of the apoptotic cells by macrophages through phagocytosis. In this study, we prepared radiolabeled PS liposomes for detection of vulnerable plaques.

Cancer stem cells maintain a hierarchy of differentiation by creating their niche.

The self-renewal and differentiation properties of cancer stem cells (CSCs) are regulated and maintained by the CSC niche. However, the mechanism of this maintenance, especially the maintenance contributed by differentiated cancer cells, remains to be fully elucidated. Recently, we have established a model of CSCs, miPS-LLCcm, from mouse induced pluripotent stem cells (miPSCs).

Steering target selectivity and potency by fragment-based de novo drug design.

Kinase inhibitors: Ligand-based de novo design is validated as a viable technology for rapidly generating innovative compounds possessing the desired biochemical profile. The study discloses the discovery of the most selective vascular endothelial growth factor receptor-2 (VEGFR-2) kinase inhibitor (right in scheme) known to date as prime lead for antiangiogenic drug development.

Nano-micrometer-architectural acidic silica prepared from iron oxide of Leptothrix ochracea origin.

We prepared nano-micrometer-architectural acidic silica from a natural amorphous iron oxide with structural silicon which is a product of the iron-oxidizing bacterium Leptothrix ochracea. The starting material was heat-treated at 500 °C in a H2 gas flow leading to segregation of α-Fe crystalline particles and then dissolved in 1 M hydrochloric acid to remove the α-Fe particles, giving a gray-colored precipitate. It was determined to be amorphous silica containing some amount of iron (Si/Fe = ~60).

Acidic amorphous silica prepared from iron oxide of bacterial origin.

Microporous and mesoporous silica derived from biogenous iron oxide is an attractive catalyst for various organic reactions. Biogenous iron oxide contains structural silicon, and amorphous silica remains after iron oxide is dissolved in concentrated hydrochloric acid. The amorphous silica containing slight amounts of iron (Si/Fe = ∼150) is composed of ∼6-nm-diameter granular particles.

Chlorotoxin Fused to IgG-Fc Inhibits Glioblastoma Cell Motility via Receptor-Mediated Endocytosis.

Chlorotoxin is a 36-amino acid peptide derived from Leiurus quinquestriatus (scorpion) venom, which has been shown to inhibit low-conductance chloride channels in colonic epithelial cells. Chlorotoxin also binds to matrix metalloproteinase-2 and other proteins on glioma cell surfaces. Glioma cells are considered to require the activation of matrix metalloproteinase-2 during invasion and migration.

Eosinophil cationic protein enhances stabilization of β-catenin during cardiomyocyte differentiation in P19CL6 embryonal carcinoma cells.

Prior to gastrulation, the Wnt signaling pathway through stabilized β-catenin enhances the differentiation of mouse ES cell into cardiomyocytes. We have recently shown that cardiomyocyte differentiation is enhanced by eosinophil cationic protein (ECP) through accelerated expression of marker genes of early cardiac differentiation. Furthermore, ECP enhanced the expression of Wnt3a in P19CL6 cells which were stimulated to differentiate into cardiomyocytes by DMSO.

Eosinophil cationic protein enhances cardiomyocyte differentiation of P19CL6 embryonal carcinoma cells by stimulating the FGF receptor signaling pathway.

We investigated the functional role of eosinophil cationic protein (ECP) in regulating cardiomyogenesis using mouse P19CL6 embryonic carcinoma cells. ECP was confirmed to accelerate the cardiomyocyte differentiation of P19CL6 cells by enhancing the rate and area size of beating of cardiomyocyte and by facilitating the expression of cardiomyocyte-specific genes, such as GATA4 and α-MHC. Since cardiomyocyte differentiation in vivo is considered to follow mesoderm induction, the induction of Brachyury, a marker of mesoderm, was assessed.

The conformational polymorphism of the green fluorescent protein.

Green fluorescent protein (GFPuv) has been widely used as a reporter fused to individual targeting sequences. However, its state in liquid and its effect on other proteins are still unclear. The conformational polymorphisms of glutathione-S-transferase-green fluorescent protein (GST-GFPuv), GFPuv and GST were analyzed by native polyacrylamide gel, indicating that GST was in many different states while GFPuv and GST-GFPuv were only in four and two slightly different states.

A model of cancer stem cells derived from mouse induced pluripotent stem cells.

Cancer stem cells (CSCs) are capable of continuous proliferation and self-renewal and are proposed to play significant roles in oncogenesis, tumor growth, metastasis and cancer recurrence. CSCs are considered derived from normal stem cells affected by the tumor microenvironment although the mechanism of development is not clear yet. In 2007, Yamanaka's group succeeded in generating Nanog mouse induced pluripotent stem (miPS) cells, in which green fluorescent protein (GFP) has been inserted into the 5'-untranslated region of the Nanog gene.

Visible-light-derived photocatalyst based on TiO(2-δ)Nδ with a tubular structure.

We succeeded in achieving visible-light responsiveness on a tubular TiO(2) sample through the treatment of a tubular TiO(2) that has a large surface area with an aqueous solution of ammonia or triethylamine at room temperature and subsequent calcination at 623 K, which produced a nitrided tubular TiO(2) sample. It was found that the ease of nitridation is dependent on the surface states; washing the tubular TiO(2) sample with an aqueous acidic solution is very effective and indispensable. This treatment causes the appearance of acidic sites on the tubular TiO(2), which was proved by the following experiments: NH(3) temperature-programmed desorption and two types of organic reactions exploiting the acid properties.

Enhanced internalization of ErbB2 in SK-BR-3 cells with multivalent forms of an artificial ligand.

Targeting and down-regulation of ErbB2, a member of EGF receptor family, is regarded as one of the key aspect for cancer treatment because it is often overexpressed in breast and ovarian cancer cells. Although natural ligands for ErbB2 have not been found, unlike other ErbB receptors, EC-1, a 20-amino acid circular peptide, has been shown to bind to ErbB2 as an artificial ligand. Previously we showed EC-1 peptide did not induce the internalization of ErbB2 in SK-BR-3 cells.

Domino double Michael-Claisen cyclizations: a powerful general tool for introducing quaternary stereocenters at C4 of cyclohexane-1,3-diones and total synthesis of diverse families of sterically congested alkaloids.

Reactions of substituted acetone derivatives with acrylic acid esters (>200 mol %) in the presence of t-BuOK (200 mol %) in t-BuOH-THF (1:1 by volume) turned out to proceed as a cascade process consisting of the first Michael addition, the second Michael addition, and the last Claisen reaction to afford 4,4-disubstituted cyclohexane-1,3-diones. Only more substituted enolates play the role of a Michael donor in this cascade process, and therefore the ketone took up two alkoxycarbonylethyl groups on the same carbon bearing more substituents. Such intermediates were followed by intramolecular Claisen reactions leading to cyclohexane-1,3-diones bearing quaternary stereogenic centers at C(4), which bears an alkoxycarbonylethyl group and the substituent of the starting acetone derivatives.

Intramolecular anionic diels-alder reactions of 1-aryl-4-oxahepta-1,6-diyne systems in DMSO.

Base-promoted cycloaddition reactions of 1-aryl- or 1-aryl-7-substituted-4-oxahepta-1,6-diyne systems in DMSO have proven to involve an anionic intramolecular Diels-Alder process taking place even at room temperature in spite of the reaction suffering from temporary disruption of aromaticity. Although initially formed alpha-arylallenide anion can be protonated by DMSO, it can be back to the allenide anion probably because of a small acidity difference between alpha-arylallene and DMSO. The alpha-arylallenide anion in combination with the alpha-aryl substituent can constitute an anionic diene structure that undergoes the intramolecular Diels-Alder reaction involving the C(6)-yne part, a very fast process probably because of the increased HOMO-1 level of the anionic diene, as shown by DFT calculations.

Conversion of D-glucose to cyclitol with hydroxymethyl substituent via intramolecular silyl nitronate cycloaddition reaction: application to total synthesis of (+)-cyclophellitol.

[reaction: see text] A diastereoisomeric mixture of 1-nitro-6-heptene-2,3,4,5-tetraol derivative (A) was prepared by Henry reaction between d-glucose-based aldehyde and nitromethane. Only the (2S)-isomer of A led to cyclitol (B) via nitronate-olefin cycloaddition on treatment with TMS-Cl and Et(3)N in the presence of catalytic DMAP followed by acid treatment. (+)-Cyclophellitol (1) was synthesized from B in eight steps.

Intramolecular cycloaddition reactions of silyl nitronate tethered to vinylsilyl group: 2-nitroalkanols as precursors for amino polyols.

[reaction: see text] A method for converting 2-nitroalkanols to precursors for stereodefined amino polyols is described. Diphenylvinylsilylation of the 2-nitroalkanols' hydroxy groups and subsequent silyl nitronate generation by using TMS-Cl and Et(3)N in CH(3)CN at 0 degrees C to room temperature led to fused-bicyclic heterocycles through stereoselective intramolecular nitronate-olefin [3 + 2] cycloaddition reaction. Some examples for transforming the cycloadducts to amino polyols are also presented.

Dicobalt octacarbonyl promoted rearrangement of 4-isoxazolines to acylaziridines: dramatic rate acceleration with very high substrate tolerance.

[reaction: see text] Dicobalt octacarbonyl [Co(2)(CO)(8)] in acetonitrile at 75 degrees C triggers the cleavage of the N-O bond of 4-isoxazolines (1) to bring about the valence rearrangement to 2-acylaziridines (2). The isoxazolines were stable at 75 degrees C in the absence of the cobalt complex.