Cyclooxygenase-2 inhibition by novel Bisaryl imidazolyl imidazole derivatives increases Bax/Bcl-2 ratio and upregulates Caspase-3 gene expression in Caco-2 colorectal cancer cell line

Cyclooxygenase-2 (COX-2) inhibitors including celecoxib inhibit cell growth and induce apoptosis in cancer cells. In this study, the relation of Bax (an apoptosis promoter) to Bcl-2 (an apoptosis inhibitor) ratio with the apoptosis co-ordination enzyme, caspase-3 was investigated in correlation with the treatment of 4,5-bisaryl imidazolyl imidazoles as novel selective COX-2 inhibitors in Caco-2 colorectal cancer cells. Recently, the organic reactions under microwave irradiation attracted attention of scientists due to their high reaction rate, mild reaction conditions and the formation of clean products. Therefore, a microwave-assisted method was used to synthesize our compounds. The effects of these COX-2 inhibitors on the proliferation of Caco-2 cells were evaluated by MTT assay. cDNA microarray and clustering analysis were used to evaluate effects of our synthetic compounds on gene expression pattern of 112 genes involved in apoptosis pathways. Bax, Bcl-2 and caspase-3 mRNA expression and their relationship were analyzed by quantitative real-time PCR. Results indicated that proliferation of Caco-2 cells after treatment with 4,5-bisaryl imidazolyl imidazoles on Caco-2 cells were time and dose dependent. We conclude that increase in Bax/Bcl-2 ratio leads to an up-regulation in caspase-3 mRNA expression.     

Functional and structural alterations induced by copper in xanthine oxidase

Xanthine oxidase （XO）, a key enzyme in purine metabolism, produces reactive oxygen species causing vascular injuries and chronic heart failure. Here, copper＇s ability to alter XO activity and structure was investigated in vitro after pre-incubation of the enzyme with increasing Cue＋ concentrations for various periods of time. The enzymatic activity was measured by following XO-catalyzed xanthine oxidation to uric acid under steady-state kinetics conditions. Structural alterations were assessed by electronic absorption, fluorescence, and circular dichroism spectroscopy. Results showed that Cu^2＋ either stimulated or inhibited XO activity, depending on metal concentration and preincubation length, the latter also determining the inhibition type. Cu^2＋-xo complex formation was characterized by modifications in XO electronic absorption bands, intrinsic fluorescence, and α-helical and β-sheet content. Apparent dissociation constant values implied high- and low-affinity Cu^2＋ binding sites in the vicinity of the enzyme＇s reactive centers. Data indicated that Cu^2＋ binding to high-affinity sites caused alterations around XO molybdenum and flavin adenine dinucleotide centers, changes in secondary structure, and moderate activity inhibition; binding to low affinity sites caused alterations around all XO reactive centers including FeS, changes in tertiary structure as reflected by alterations in spectral properties, and drastic activity inhibition. Stimulation was attributed to transient stabilization of XO optimal conformation. Results also emphasized the potential role of copper in the regulation of XO activity stemming from its binding properties.     

EDC3 phosphorylation regulates growth and invasion through controlling P‐body formation and dynamics

Regulation of mRNA stability and translation plays a critical role in determining protein abundance within cells. Processing bodies (P‐bodies) are critical regulators of these processes. Here, we report that the Pim1 and 3 protein kinases bind to the P‐body protein enhancer of mRNA decapping 3 (EDC3) and phosphorylate EDC3 on serine (S)161, thereby modifying P‐body assembly. EDC3 phosphorylation is highly elevated in many tumor types, is reduced upon treatment of cells with kinase inhibitors, and blocks the localization of EDC3 to P‐bodies. Prostate cancer cells harboring an EDC3 S161A mutation show markedly decreased growth, migration, and invasion in tissue culture and in xenograft models. Consistent with these phenotypic changes, the expression of integrin β1 and α6 mRNA and protein is reduced in these mutated cells. These results demonstrate that EDC3 phosphorylation regulates multiple cancer‐relevant functions and suggest that modulation of P‐body activity may represent a new paradigm for cancer treatment.     

Hydrogels Composed of Cyclodextrin Inclusion Complexes with PLGA-PEG-PLGA Triblock Copolymers as Drug Delivery Systems

Although conventional pharmaceuticals have many drug dosage forms on the market, the development of new therapeutic molecules and the low efficacy of instant release formulations for the treatment of some chronic diseases and specific conditions encourage scientists to invent different delivery systems. To this purpose, a supramolecular hydrogel consisting of the tri-block copolymer PLGA-PEG-PLGA and α-cyclodextrin was fabricated for the first time and characterised in terms of rheological, morphological, and structural properties. Naltrexone hydrochloride and vitamin B12 were loaded, and their release profiles were determined.