Insulin-like growth factor binding protein-2 regulates β-catenin signaling pathway in glioma cells and contributes to poor patient prognosis.

Background: Upregulation of insulin-like growth factor binding protein 2 (IGFBP-2) is often associated with aggressiveness of glioblastoma (GBM) and contributes to poor prognosis for GBM patients. In view of the regulation of β-catenin by IGFBP-2 in breast cancer and the crucial role of β-catenin pathway in glioma invasion, proliferation and maintenance of glioma stem cells, the mechanism of regulation of β-catenin by IGFBP-2, and its role in GBM prognosis was studied.

Methods: Regulation of the β-catenin pathway was studied by immunocytochemistry, Western blot analysis, luciferase assays, and real-time RT-PCR.

Approach to Merosesquiterpenes via Lewis Acid Catalyzed Nazarov-Type Cyclization: Total Synthesis of Akaol A.

A Lewis acid catalyzed Nazarov-type cyclization of arylvinylcarbinol has been developed for the asymmetric synthesis of carbotetracyclic core of merosesquiterpenes. The reaction works only in the presence of 2 mol % of Sn(OTf)2 and Bi(OTf)3 in dichloroethane under elevated temperature. The methodology offers the synthesis of a variety of enantioenriched arylvinylcarbinols from commercially available (3aR)-sclareolide 9 in six steps with an eventual concise total synthesis of marine sesquiterpene quinol, akaol A (1a).

C1, a highly potent novel curcumin derivative, binds to tubulin, disrupts microtubule network and induces apoptosis.

We have synthesized a curcumin derivative, 4-{5-(4-hydroxy-3-methoxy-phenyl)-2-[3-(4-hydroxy-3-methoxy-phenyl)-acryloyl]-3-oxo-penta-1,4-dienyl}-piperidine-1-carboxylic acid tert-butyl ester (C1) that displays much stronger antiproliferative activity against various types of cancer cells including multidrug resistance cells than curcumin. C1 depolymerized both interphase and mitotic microtubules in MCF-7 cells and also inhibited the reassembly of microtubules in these cells. C1 inhibited the polymerization of purified tubulin, disrupted the lattice structure of microtubules and suppressed their GTPase activity in vitro The compound bound to tubulin with a dissociation constant of 2.

Selective recognition of c-MYC G-quadruplex DNA using prolinamide derivatives.

Herein we report the design, synthesis, biophysical and biological evaluation of triazole containing prolinamide derivatives as selective c-MYC G-quadruplex binding ligands. A modular synthetic route has been devised for prolinamide derivatives using a copper(i) catalyzed azide-alkyne cycloaddition (CuAAC). The Förster resonance energy transfer (FRET) melting assay indicates that prolinamide trimers can significantly stabilize G-quadruplex structures over duplex DNA compared to prolinamide dimers.

Dissecting the structural and functional features of the Luteinizing hormone receptor using receptor specific single chain fragment variables.

The Luteinizing hormone receptor (LHR) has a large extracellular domain (amino acid residues, a.a.1-355) and a transmembrane domain (TMD; a.

Regulation of Growth, Cell Shape, Cell Division, and Gene Expression by Second Messengers (p)ppGpp and Cyclic Di-GMP in Mycobacterium smegmatis.

Unlabelled: The alarmone (p)ppGpp regulates transcription, translation, replication, virulence, lipid synthesis, antibiotic sensitivity, biofilm formation, and other functions in bacteria. Signaling nucleotide cyclic di-GMP (c-di-GMP) regulates biofilm formation, motility, virulence, the cell cycle, and other functions. In Mycobacterium smegmatis, both (p)ppGpp and c-di-GMP are synthesized and degraded by bifunctional proteins Rel(Msm) and DcpA, encoded by rel(Msm) and dcpA genes, respectively.

Tailoring the degradation rate and release kinetics from poly(galactitol sebacate) by blending with chitosan, alginate or ethyl cellulose.

Despite significant advances in recent times, the investigation of discovering a perfect biomaterial is perennial. In this backdrop, blending of natural and synthetic polymers is gaining popularity since it is the easiest way to complement the drawbacks and attain a superlative material. Based on this, the objective of this study was to synthesize a novel polyester, poly(galactitol sebacate), and subsequently blend this polymer with one of the three natural polymers such as alginate, chitosan or ethyl cellulose.

Probing microenvironment of micelle and albumin using diethyl 6-(dimethylamino)naphthalene-2,3-dicarboxylate: An electroneutral solvatochromic fluorescent probe.

Synthesis, single-crystal X-ray characterization, and spectroscopic investigation of small, non-charged diethyl 6-(dimethylamino)naphthalene-2,3-dicarboxylate (DMNDC) by UV-Visible, steady-state, and time-resolved fluorescence reveal a series of interesting photophysical properties originating from the intrinsic intramolecular charge transfer (ICT) state, leading to diverse applications. Stokes shift, lifetime, and emission maxima of DMNDC show a very good correlation with ET(30) solvent polarity scale for a series of different polarity solvents, confirms that it has very good environment sensitivity. Furthermore, this dye has been found to be an exceptionally suitable probe for determining Critical Micelle Concentration (CMC) and probing self-organization processes of five different type of surfactant with structural diversity.

NIR-emitting chiral gold nanoclusters coated with γ-cyclodextrin are pH sensitive: Application as biomarker.

Unlabelled: Change in cellular pH due to onset of certain malfunctions needs to be tracked quickly so that treatment to cure such incidents may be started immediately. For example, microenvironment of a developing tumor is acidic due to high metabolic rate as well as low oxygen supply. Hence biomarkers that can sharply sense transition in pH could be of great use in the early detection of tumor formation.

Negative Cooperativity and High Affinity in Chitooligosaccharide Binding by a Mycobacterium smegmatis Protein Containing LysM and Lectin Domains.

LysM domains have been recognized in bacteria and eukaryotes as carbohydrate-binding protein modules, but the mechanism of their binding to chitooligosaccharides has been underexplored. Binding of a Mycobacterium smegmatis protein containing a lectin (MSL) and one LysM domain to chitooligosaccharides has been studied using isothermal titration calorimetry and fluorescence titration that demonstrate the presence of two binding sites of nonidentical affinities per dimeric MSL-LysM molecule. The affinity of the molecule for chitooligosaccharides correlates with the length of the carbohydrate chain.

Hydrogen-Bonded Complexes of Phenylacetylene-Acetylene: Who is the Proton Donor?

Hydrogen-bonded complexes of C2H2 and phenylacetylene (PhAc) were studied using matrix isolation infrared spectroscopy and quantum chemical computations. Both C2H2 and PhAc, being potential proton donors, the question arises as to which of the two species would be the proton donor in the PhAc-C2H2 complex; a question that this work primarily addresses. The molecular structures, vibrational frequencies, and interaction energies of the PhAc-C2H2 complexes were calculated at the M06-2X and MP2 levels of theory, employing both 6-311++G(d,p) and aug-cc-pVDZ basis sets.

Fluorescence Up-Conversion Studies of [2,2'-Bipyridyl]-3,3'-diol in Octyl-β-d-glucoside and Other Micellar Aggregates.

In this present work, excited state double proton transfer dynamics (ESIDPT) of 2,2'-bipyridyl-3,3'-diol (BP(OH)2) molecules has been probed in a nontoxic, biocompatible sugar surfactant assembly, namely, octyl-β-d-glucoside (OBG) micelle with the help of steady state and fluorescence up-conversion techniques. Moreover, the ultrafast double proton transfer dynamics in conventional micelles (SDS, CTAB) and bile salts aggregates have been probed and compared. Interestingly, in all these supramolecular aggregates, the ESIDPT dynamics is found to follow sequential pathway; however, the time-scale of proton transfer dynamics varies from 11 to 30 ps.

Unified Approach to the Spiro(pyrrolidinyl-oxindole) and Hexahydropyrrolo[2,3-b]indole Alkaloids: Total Syntheses of Pseudophrynamines 270 and 272A.

The first enantioselective total syntheses of architecturally interesting prenylated pyrroloindole alkaloids, (-)-pseudophrynamines 272A (3d) and 270 (3b), have been achieved starting from enantioenriched 2-oxindoles having all-carbon quaternary stereocenters. A common strategy involving a thio-urea catalyzed aldol reaction is employed for the total synthesis of both spiro(pyrrolidinyl-oxindole) and hexahydropyrrolo[2,3-b]indole alkaloids.

Pyridazine N-Oxides as Precursors of Metallocarbenes: Rhodium-Catalyzed Transannulation with Pyrroles.

Pyridazine N-oxides are used for the first time as precursors of metallocarbenes. These nitrogen-rich heterocycles led to the discovery of a novel acceptor and donor-acceptor enalcarbenoids. The synthetic utility of these metallocarbenes was demonstrated in the rhodium-catalyzed denitrogenative transannulation of pyridazine N-oxides with pyrroles to the valuable alkyl, 7-aryl, and 7-styryl indoles.

Computational Approach to Explore the B/A Junction Free Energy in DNA.

Protein-DNA interactions induce conformational changes in DNA such as B- to A-form transitions at a local level. Such transitions are associated with a junction free energy cost at the boundary of two different conformations in a DNA molecule. In this study, we performed umbrella sampling simulations to find the free energy values of the B-A transition at the dinucleotide and trinucleotide level of DNA.

Self-assembly of Metallamacrocycles Employing a New Benzil-based Organometallic Bisplatinum(II) Acceptor.

A benzil-based semi-rigid dinuclear-organometallic acceptor 4,4'-bis[trans-Pt(PEt(3))(2)(NO(3))(ethynyl)]benzil (bisPt-NO(3)) containing a Pt-ethynyl functionality was synthesized in good yield and characterized by multinuclear NMR ((1)H, (31)P, and (13)C), electrospray ionization mass spectrometry (ESI-MS), and single-crystal X-ray diffraction analysis of the iodide analogue bisPt-I. The stoichiometric (1:1) combination of the acceptor bisPt-NO(3) separately with four different ditopic donors (L(1)-L(4); L(1) = 9-ethyl-3,6-di(1H-imidazol-1-yl)-9H-carbazole, L(2) = 1,4-bis((1H-imidazol-1-yl)methyl)benzene, L(3) = 1,3-bis((1H-imidazol-1-yl)methyl)benzene and L(4) = 9,10-bis((1H-imidazol-1-yl) methyl)anthracene) yielded four [2 + 2] self-assembled metallacycles M(1)-M(4) in quantitative yields, respectively. All these newly synthesized assemblies were characterized by various spectroscopic techniques (NMR, IR, ESI-MS) and their sizes/shapes were predicted through geometry optimization employing the PM6 semi-empirical method.

Trimodal Control of Ion-Transport Activity on Cyclo-oligo-(1→6)-β-D-glucosamine-Based Artificial Ion-Transport Systems.

Cyclo-oligo-(1→6)-β-D-glucosamines functionalized with hydrophobic tails are reported as a new class of transmembrane ion-transport system. These macrocycles with hydrophilic cavities were introduced as an alternative to cyclodextrins, which are supramolecular systems with hydrophobic cavities. The transport activities of these glycoconjugates were manipulated by altering the oligomericity of the macrocycles, as well as the length and number of attached tails.

Evidence for N⁷ guanine methyl transferase activity encoded within the modular domain of RNA-dependent RNA polymerase L of a Morbillivirus.

Post-transcriptional modification of viral mRNA is essential for the translation of viral proteins by cellular translation machinery. Due to the cytoplasmic replication of Paramyxoviruses, the viral-encoded RNA-dependent RNA polymerase (RdRP) is thought to possess all activities required for mRNA capping and methylation. In the present work, using partially purified recombinant RNA polymerase complex of rinderpest virus expressed in insect cells, we demonstrate the in vitro methylation of capped mRNA.

An Eighteen Serum Cytokine Signature for Discriminating Glioma from Normal Healthy Individuals.

Glioblastomas (GBM) are largely incurable as they diffusely infiltrate adjacent brain tissues and are difficult to diagnose at early stages. Biomarkers derived from serum, which can be obtained by minimally invasive procedures, may help in early diagnosis, prognosis and treatment monitoring. To develop a serum cytokine signature, we profiled 48 cytokines in sera derived from normal healthy individuals (n = 26) and different grades of glioma patients (n = 194).

A versatile toolbox for posttranscriptional chemical labeling and imaging of RNA.

Cellular RNA labeling strategies based on bioorthogonal chemical reactions are much less developed in comparison to glycan, protein and DNA due to its inherent instability and lack of effective methods to introduce bioorthogonal reactive functionalities (e.g. azide) into RNA.

Role of spacer length in interaction between novel gemini imidazolium surfactants and Rhizopus oryzae lipase.

An insight into the effects of new ionic liquid-type gemini imidazolium cationic surfactants on the structure and function of the lipases is of prime importance for their potential application. Changes in the activity, stability and structure of Rhizopus oryzae lipase in the presence of novel gemini surfactants, [C16-3-C16im]Br2 and [C16-12-C16im]Br2 were probed in the present study. Surfactant with shorter spacer length, [C16-3-C16im]Br2 was found to be better in improving the hydrolytic activity and thermal stability of the lipase.

Orchestration of Structural, Stereoelectronic, and Hydrogen-Bonding Effects in Stabilizing Triplexes from Engineered Chimeric Collagen Peptides (Pro(X)-Pro(Y)-Gly)6 Incorporating 4(R/S)-Aminoproline.

Collagens are an important family of structural proteins found in the extracellular matrix with triple helix as the characteristic structural motif. The collagen triplex is made of three left-handed polyproline II (PPII) helices with each PPII strand consisting of repetitive units of the tripeptide motif X-Y-Gly, where the amino acids X and Y are most commonly proline (Pro) and 4R-hydroxyproline (Hyp), respectively. A C4-endo pucker at X-site and C4-exo pucker at Y-site have been proposed to be the key for formation of triplex, and the nature of pucker is dependent on both the electronegativity and stereochemistry of the substituent.

Influence of Steric Crowding on Diastereoselective Arabinofuranosylations.

The occurrence of arabinofuranosides on the cell surface of Mycobacterium tuberculosis (Mtb) and their significance in controlling disease spurred interest in developing strategies for their diastereoselective synthesis. Mtb uses enzymes to achieve diastereoselectivity through noncovalent interactions. Of the two possible glycosidic linkages, chemically, 1,2-trans linkage is relatively easy to synthesize by taking advantage of neighboring group participation, whereas synthesis of the 1,2-cis linkage is notoriously difficult.

A carboxy terminal domain of the L protein of rinderpest virus possesses RNA triphosphatase activity - The first enzyme in the viral mRNA capping pathway.

The large protein L of negative-sense RNA viruses is a multifunctional protein involved in transcription and replication of genomic RNA. It also possesses enzymatic activities involved in capping and methylation of viral mRNAs. The pathway for mRNA capping followed by the L protein of the viruses in the Morbillivirus genus has not been established, although it has been speculated that these viruses may follow the unconventional capping pathway as has been shown for some viruses of Rhabdoviridae family.