- Inhibitors for the bacterial ectonucleotidase Lp1NTPDase from Legionella pneumophila
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Legionella pneumophila is an aerobic, Gram-negative bacterium of the genus Legionella, which constitutes the major causative agent of Legionnaires’ disease. Recently a nucleoside triphosphate diphosphohydrolase (NTPDase) from L. pneumophila was identified and termed Lp1NTPDase; it was found to be a structural and functional homolog of mammalian NTPDases catalyzing the hydrolysis of ATP to ADP and ADP to AMP. Its activity is believed to contribute to the virulence of Legionella pneumophila. Therefore Lp1NTPDase inhibitors are considered as novel antibacterial drugs. However, only weakly potent compounds are available so far. In the present study, a capillary electrophoresis (CE)-based enzyme assay for monitoring the Lp1NTPDase activity was established. The enzymatic reaction was performed in a test tube followed by separation of substrate and products by CE and subsequent quantification by UV analysis. After kinetic characterization of the enzyme, a series of 1-amino-4-ar(alk)ylamino-2-sulfoanthraquinone derivatives structurally related to the anthraquinone dye Reactive Blue 2, a non-selective ecto-NTPDase inhibitor, was investigated for inhibitory activity on Lp1NTPDase using the CE-based enzyme assay. Derivatives bearing a large lipophilic substituent (e.g., fused aromatic rings) in the 4-position of the 1-amino-2-sulfoanthraquinone showed the highest inhibitory activity. Compounds with IC50values in the low micromolar range were identified. The most potent inhibitor was 1-amino-4-[phenanthrene-9-yl-amino]-9,10-dioxo-9,10-dihydroanthracene-2-sulfonate (28, PSB-16131), with an IC50-value of 4.24?μM. It represents the most potent Lp1NTPDase inhibitor described to date. These findings may serve as a starting point for further optimization. Lp1NTPDase inhibition provides a novel approach for the (immuno)therapy of Legionella infections.
- Fiene, Amelie,Baqi, Younis,Malik, Enas M.,Newton, Patrice,Li, Wenjin,Lee, Sang-Yong,Hartland, Elizabeth L.,Müller, Christa E.
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p. 4363 - 4371
(2016/08/23)
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- Discovery of potent competitive antagonists and positive modulators of the P2X2 receptor
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Evaluation and optimization of anthraquinone derivatives related to Reactive Blue 2 at P2X2 receptors yielded the first potent and selective P2X2 receptor antagonists. The compounds were tested for inhibition of ATP (10 μM) mediated currents in Xenopus oocytes expressing the rat P2X2 receptor. The most potent antagonists were sodium 1-amino-4-[3-(4,6-dichloro[1,3,5]triazine-2- ylamino)phenylamino]- 9,10-dioxo-9,10-dihydroanthracene-2-sulfonate (63, PSB-10211, IC50 8 6 nM) and disodium 1-amino- 4-[3-(4,6-dichloro[1,3, 5]triazine-2-ylamino)-4-sulfophenylamino]-9,10-dioxo-9,10-dihydroanthracene- 2-sulfonate (57, PSB-1011, IC50 79 nM). Compound 57 exhibited a competitive mechanism of action (pA2 7.49). It was >100-fold selective versus P2X4, P2X7, and several investigated P2Y receptor subtypes (P2Y24612); selectivity versus P2X1 and P2X3 receptors was moderate (>5-fold). Compound 57 was >13-fold more potent at the homomeric P2X2 than at the heteromeric P2X2/3 receptor. Several anthraquinone derivatives were found to act as positive modulators of ATP effects at P2X2 receptors, for example, sodium 1-amino-4-(3-phenoxyphenylamino)-9,10-dioxo-9,10- dihydroanthracene-2-sulfonate (51, PSB-10129, EC50 489 nM), which led to about a 3-fold increase in the ATP-elicited current.
- Baqi, Younis,Hausmann, Ralf,Rosefort, Christiane,Rettinger, Jürgen,Schmalzing, Günther,Müller, Christa E.
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experimental part
p. 817 - 830
(2011/04/15)
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- Development of potent and selective inhibitors of ecto-5′- nucleotidase based on an anthraquinone scaffold
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ecto-5′-Nucleotidase (eN, CD73) plays a major role in controlling extracellular adenosine levels. eN inhibitors have potential as novel drugs, for example, for the treatment of cancer. In the present study, we synthesized and investigated a series of 55 anthraquinone derivatives as potential inhibitors of eN, 11 of which are novel compounds and another 11 of which had previously been described but have now been synthesized by an improved method. We identified several potent inhibitors of rat eN. The most potent compounds were l-amino-4-[4-fluoro-2-carboxyphenylamino]-9,10-dioxo-9,10-dihydroanthracene-2- sulfonate (45, PSB-0952, K1 = 260 nM) and 1-amino-4-[2- anthracenylamino]-9,10-dioxo-9,10dihydroanthracene-2-sulfonate (52, PSB-0963, 150 nM), with 52 being the most potent eN inhibitor described to date. Selected compounds were further characterized and found to exhibit a competitive mechanism of inhibition. Investigations of ecio-nucleoside triphosphate diphosphohydrolases (NTPDases) and the P2Y receptor subtypes P2Y2, P2Y4, P2Y6, and P2Y12 showed that compound 45 exhibited the highest degree of selectivity ( > 150-fold).
- Baqi, Younis,Lee, Sang-Yong,Iqbal, Jamshed,Ripphausen, Peter,Lehr, Anne,Scheiff, Anja B.,Zimmennann, Herbert,Bajorath, Jürgen,Müller, Christa E.
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experimental part
p. 2076 - 2086
(2010/08/19)
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