Effect of AEE788 and/or Celecoxib on colon cancer cell morphology using advanced microscopic techniques

Analysis of changes in cancer cell morphology and cytoskeletal element induced by external stimuli is focus of current cancer chemotherapeutic studies. Cancer cell cytoskeleton is complex network of interwoven protein fibers composed of microtubules, microfilaments and intermediate filaments. These interwoven protein fibers are responsible for maintaining cell morphology, movement, adhesion and transmembrane signal transmission. In this study, morphological and cytoskeletal changes induced by AEE788 and/or Celecoxib on colon cancer cell HCT 15 were analyzed using advanced microscopic techniques. Cell proliferation assay was used for determining IC₅₀ of AEE788 and/or Celecoxib on HCT 15. Confocal microscopic analysis of AEE788 and/or Celecoxib treated HCT 15 was performed using Rhodamine-Phalloidin (actin stain) and Hoechst 33342 (nuclear stain). Atomic force (AFM) and scanning electron microscopic (SEM) studies were also performed to analyze cell morphology and cell wall extension (filopodia and lamellipodia). In addition, quantitative analysis of morphological parameters was studied using cellular image processing technique. This is the first report that combination of AEE788 and Celecoxib additively increase growth inhibition and cell death on human colon cancer cell HCT 15 as estimated by cell proliferation assay. Morphological analysis of AEE788 or Celecoxib treated HCT 15 cell for 24 h have not revealed significant change in morphology under phase contrast microscopy. But, slight morphological changes were observed in combination (AEE788 + Celecoxib) treated HCT 15 for 24 h. In contrast, high resolution confocal laser fluorescence and atomic force microscopic studies have revealed cell shrinkage, disorganized actin filament and, loss of filopodia and lamellipodia. These changes were more prominent in combination of AEE788 and Celecoxib treated HCT 15 than either drug alone. These results may suggest antiproliferative and antimetastatic activity of AEE788 and/or Celecoxib. Quantitative analysis of morphological parameters using cellular image processing technique have shown decrease in mean area, perimeter, compactness and eccentricity of combination drug treated cells than either drug alone. These results further support the confocal and AFM study. Scanning electron microscopic study of AEE788 and/or Celecoxib treated HCT 15 has also shown morphological changes and loss of filopodia and lamellipodia. In conclusion, this investigation of morphological and cytoskeletal changes using advanced microscopic techniques present a significant foundation for evaluating anticancer activity of a drug and form a new strategy for evaluating effect of AEE788 and/or Celecoxib on colon cancer.     

Spectroscopic and spectrometric studies of anion recognition with calix[4]pyrroles in different reaction conditions

The binding studies of calix[4]pyrroles (1–6) with fluoro, chloro, bromo, iodo and sulphato anions generated from normal-tetrabutylammoniumfluoride, normal-tetrabutylammoniumchloride, normal-tetrabutylammoniumbromide, normal-tetrabutylammoniumiodide, and normal-tetrabutylammoniumsulphate respectively were investigated by electrospray ionization mass spectrometry (ESI-MS) in dichloromethane–acetonitrile in negative ion mode. The efficacy of a particular calix[4]pyrrole to bind with anions was found maximum at low cone voltage of the instrument, at high cone voltage the binding was suppressed due to removal of anion from the cavity of the macrocycles. The binding strength was found inversely proportional to the size of anion for a particular calix[4]pyrrole. The fragmentation pattern of calix[4]pyrrole was observed at higher cone voltage of ESI-MS and was interpreted. The association constants of calix[4]pyrroles and anions obtained from electronic transition studies were in good agreement with that observed from ¹H NMR titration studies.     

Fluorometric and isothermal titration calorimetric studies on binding interaction of a telechelic polymer with sodium alkyl sulfates of varying chain length

Steady-state fluorescence measurements and isothermal titration calorimetric experiments have been performed to study the interaction between a telechelic polymer, pyrene-end-capped poly(ethylene oxide) (PYPY), and sodium alkyl sulfate surfactants having decyl, dodecyl, and tetradecyl hydrocarbon tails. Fluorometric results suggest polymer-surfactant interaction in the very low range of polymer concentrations. The relative variation in the excimer to monomer pyrene emission intensities with varying surfactant concentration reveals that initial addition of surfactant favors intramolecular preassociation until the surfactant molecules start binding with the ethylene oxide (EO) chain. With the growing number of surfactant aggregates along the EO chain, the association becomes hindered due to the polyelectrolyte effect. The results from microcalorimetric titrations in the low concentration range of PYPY solution (approximately 10(-6) M) with alkyl sulfates suggest two kinds of surfactant-polymer interactions, one with the polymer hydrophobic end groups and the other with the ethylene oxide backbone. The overall polymer-surfactant interaction starts at a much lower surfactant concentration for the hydrophobically modified polymers compared to that in the case of unsubstituted poly(ethylene oxide) homopolymer. From the experiments critical aggregation concentration values and the second critical concentration where free micelles start forming have been determined. An endeavor has been made to unveil the mechanism underlying the corresponding associations of the surfactants with the polymer.     

Influence of reagent rotation on (H-, D2) and (D-, H2) collisions: a quantum mechanical study

Time-independent quantum mechanical (TIQM) approach (helicity basis truncated at k = 2) has been used for computing differential and integral cross sections for the exchange reaction H- + D2 (v = 0, j = 0-4) --> HD + D- and D- + H2 (v = 0, j = 0-3) --> HD + H- in three dimensions on an accurate ab initio potential energy surface. It is shown that the j-weighted differential reaction cross section values are in good agreement with the experimental results reported by Zimmer and Linder at four different relative translational energies (Etrans = 0.55, 0.93, 1.16 and 1.48 eV) for (H-, D2) and at one relative translational energy (Etrans = 0.6 eV) by Haufler et al. for both (H-, D2) and (D-, H2) collisions. The j-weighted integral reaction cross section values are in good agreement with the crossed beam measurements by Zimmer and Linder in the Etrans range 0.5-1.5 eV and close to the guided ion beam results by Haufler et al. for (H-, D2) in the range 0.8-1.2 eV. Time-dependent quantum mechanical (TDQM) results obtained using centrifugal sudden approximation are reported in the form of integral reaction cross section values as a function of Etrans in the range 0.3-3.0 eV for both reactions in three dimensions on the same potential energy surface. The TDQM reaction cross section values decline more sharply than the TIQM results with increase in the initial rotational quantum number (j) for the D2 molecules in their ground vibrational state (v = 0) for (H-, D2) collisions. The computed j-weighted reaction cross section values are in good agreement with the experimental results reported by Zimmer and Linder for (H-, D2) collisions and guided ion beam results by Haufler et al. for both (H-, D2) and (D-, H2) collisions for energies below the threshold for electron detachment channel.     

Converting gem-dimethyl groups into cyclopropanes via Pd-catalyzed sequential C-H activation and radical cyclization

A novel route to the synthesis of cyclopropane derivatives is described. 1,1-Dimethyls in 2-(1,1-dimethylalkyl)dimethyloxazolines are first converted into 1,3-diiodide derivatives via Pd-catalyzed sequential C-H activation and then radically cyclized to provide 2-(1-alkylcylclopropyl)dimethyloxazolines. The use of EtOAc as a solvent is crucial for the diiodination of the functionalized substrates. [reaction: see text]     

Triphenylphosphine chalcogenides as efficient ligands for room temperature palladium(II)-catalyzed Suzuki-Miyaura reaction

A simple catalytic system based on PdCl₂ and triphenylphosphine chalcogenides (PPh₃X; X = O, S, Se) is found to be highly effective (up to 97% isolated yield) in the room temperature Suzuki-Miyaura reactions. Under the same experimental conditions, triphenylphosphine chalcogenides as ligands show superior activities compared to free triphenylphosphine.     

Oxidation of propane to acrylic acid and acetic acid over alkaline earth-doped Mo-V-Sb-Ox catalysts

Alkaline earth metal (Mg, Ca, Sr and Ba)-doped Mo-V-Sb-Ox catalysts, prepared by a dry-up method, have been investigated for their catalytic performance in the oxidation of propane under different reaction conditions. The catalysts have been characterized by N2 adsorption-desorption, temperature-programmed desorption (TPD) of NH3, SEM and XRD. Influence of water vapor on the catalytic performance, particularly on the selectivities to acetic acid and acrylic acid, has also been studied. The selectivity to acrylic acid was improved significantly by the doping of alkaline earth metals to Mo-V-Sb-Ox catalysts. The surface acidic sites of the catalyst decreased with the doping of the catalyst with alkaline earth metals, which ultimately was found to be beneficial for obtaining high selectivity to acrylic acid. The catalytic activity and product selectivities were found to be influenced by the reaction temperature, C3H8/O2 ratio and space velocity. A significant improvement in the selectivity to acrylic acid has also been observed by the addition of water vapor in the feed of propane and oxygen in the oxidation of propane.     

Sigma-chelation-directed C-H functionalizations using Pd(II) and Cu(II) catalysts: regioselectivity, stereoselectivity and catalytic turnover

Recent progress in sigma-chelation directed C-H functionalization from the authors' group is described to illustrate the challenges and opportunities in the development of synthetically-useful catalytic reactions involving C-H activation as the key step. Emphasis is placed on strategies for developing catalysis under mild conditions and controlling regio- and stereoselectivity.     

Synthesis of derivatives of 4,5-dihydrofuran,furan, and hexahydrobenzofuran from conjugated alkenynes

The regiochemistry of the reaction of 1,2- and 1-substituted derivatives of 1-buten-3-yne and its 4- and 2,4-substituted derivatives of the isoprenoid type with acetoacetic ester and acetylacetone in the presence of the manganese(III) acetate-copper(II) acetate oxidative system was studied. Derivatives of 4,5-dihydrofuran, furan, and hexahydrobenzofuran were obtained.Communication 137 from the series Reactions of unsaturated compounds. See [1] for communication 136.Translated from Khimiya Geterotsiklicheskikh Soedinenii, Vol. 24, No. 3, pp. 317–323, March, 1988.     

Chemistry of 1,2,4-trioxanes relevant to their mechanism of action. Part 1: Reaction with Fe(II) salts

Reactions of 6-(1′-phenylvinyl)-1,2,4-trioxanes 2-5, with FeCl₂·4H₂O, FeBr₂, and a combination of hemin (bovine) and reduced glutathione (GSH) under various conditions have been studied.