ABSTRACT
New monolithic HPLC columns were prepared by γ-radiation-triggered polymerization of hexyl methacrylate and ethylene glycol dimethacrylate monomers in the presence of porogenic solvents. Polymerization was carried out directly within capillary (250-200 µm I.D.) and nano (100-75 µm I.D.) fused-silica tubes yielding highly efficient columns for cap(nano)-LC applications. The columns were applied in the complete separation of core (H2A, H2B, H3, and H4) and linker (H1) histones under gradient elution with UV and/or electrospray ionization (ESI) ion trap mass spectrometry (MS) detections. Large selectivity towards H1, H2A-1, H2A-2, H2B, H3-1, H3-2 and H4 histones and complete separation were obtained within 8 min time windows, using fast gradients and very high linear flow velocities, up to 11 mm/s for high throughput applications. The method developed was the basis of a simple and efficient protocol for the evaluation of post-translational modifications (PTMs) of histones from NCI-H460 human non-small-cell lung cancer (NSCLC) and HCT-116 human colorectal carcinoma cells. The study was extended to monitoring the level of histone acetylation after inhibition of Histone DeACetylase (HDAC) enzymes with suberoylanilide hydroxamic acid (SAHA), the first HDAC inhibitor approved by the FDA for cancer therapy. Attractive features of our cap(nano)-LC/MS approach are the short analysis time, the minute amount of sample required to complete the whole procedure and the stability of the polymethacrylate-based columns. A lab-made software package ClustMass was ad hoc developed and used to elaborate deconvoluted mass spectral data (aligning, averaging, clustering) and calculate the potency of HDAC inhibitors, expressed through a Relative half maximal Inhibitory Concentration parameter, namely R_IC(50) and an averaged acetylation degree.
Subject(s)
Chromatography, High Pressure Liquid/instrumentation , Chromatography, High Pressure Liquid/methods , Gamma Rays , Histone Deacetylase Inhibitors/chemistry , Mass Spectrometry/methods , Cluster Analysis , HCT116 Cells , Histone Deacetylase Inhibitors/analysis , Histone Deacetylase Inhibitors/metabolism , Histones/chemistry , Humans , Hydroxamic Acids/analysis , Hydroxamic Acids/chemistry , Hydroxamic Acids/metabolism , Methacrylates/chemistry , Polymerization/radiation effects , Temperature , VorinostatABSTRACT
1-[(Aryl)(4-aryl-1H-pyrrol-3-yl)methyl]-1H-imidazoles were recently reported by our group as potent anti-Candida agents belonging to the antifungal azole class. In the present paper the synthesis, anti-Candida activities, and QSAR studies on a novel series of N-substituted 1-[(aryl)(4-aryl-1H-pyrrol-3-yl)methyl]-1H-imidazole derivatives are reported. The newly synthesized azoles were tested against 12 strains of Candida albicans together with bifonazole, miconazole, itraconazole, fluconazole, and compounds 1a, 1b, 3a, 3b, and 3c used as reference drugs. In general, tested derivatives showed good antifungal activities, and the most potent compound was 1d (MIC(90) = 0.032 microg/mL), which was from 4- to 250-fold more potent than reference drugs. Catalyst software was applied to develop a quantitative pharmacophore model to be used for the rational design of new antifungal azoles. Some key interactions, as well as excluded volumes, further to the coordination bond of azole antifungals with the demethylase enzyme, are highlighted.
