pyrazolone and pyridazine

Screening of a small chemical library (Medicines for Malaria Venture Pathogen Box) identified two structurally related pyrazolone (inhibitor 1) and pyridazine (inhibitor 2) DNMT3A inhibitors with low micromolar inhibition constants. The uncompetitive and mixed type inhibition patterns with DNA and AdoMet suggest these molecules act through an allosteric mechanism, and thus are unlikely to bind to the enzyme's active site. Unlike the clinically used mechanism based DNMT inhibitors such as decitabine or azacitidine that act via the enzyme active site, the inhibitors described here could lead to the development of more selective drugs. Both inhibitors show promising selectivity for DNMT3A in comparison to DNMT1 and bacterial DNA cytosine methyltransferases. With further study, this could form the basis of preferential targeting of de novo DNA methylation over maintenance DNA methylation.

Topics: Azacitidine; Catalytic Domain; Decitabine; DNA; DNA (Cytosine-5-)-Methyltransferases; DNA Methylation; DNA Methyltransferase 3A; Drug Evaluation, Preclinical; Enzyme Inhibitors; Humans; Protein Binding; Pyrazolones; Pyridazines; Small Molecule Libraries

Ligands of the FPR2 receptor initiate many signaling pathways including activation of phospholipase C, protein kinase C, the mitogen-activated protein kinase, and phosphatidylinositol 3-kinase/protein kinase B pathway. The possible actions include also calcium flux, superoxide generation, as well as migration and proliferation of monocytes. FPR2 activation may induce a pro- and anti-inflammatory effect depending on the ligand type. It is also found that this receptor is involved in tumor growth. Most of currently known FPR2 ligands are agonists since they were designed based on N-formyl peptides, which are natural agonists of formyl receptors. Since the non-peptide drugs are indispensable for effective treatment strategies, we performed a docking study of such ligands employing a generated dual template homology model of the FPR2 receptor. The study revealed different binding modes of particular classes of these drugs. Based on the obtained docking poses we proposed a detailed location of three hydrophobic pockets in orthosteric binding site of FPR2. Our model emphasizes the importance of aromatic stacking, especially with regard to residues His102(3.29) and Phe257(6.51), for binding of FPR2 ligands. We also identified other residues important for non-peptide ligand binding in the binding site of FPR2.

Topics: Benzimidazoles; Binding Sites; Hydrophobic and Hydrophilic Interactions; Ligands; Models, Molecular; Molecular Docking Simulation; Phenylurea Compounds; Protein Conformation; Pyrazolones; Pyridazines; Quinazolinones; Receptors, Formyl Peptide; Receptors, Lipoxin; Structure-Activity Relationship

A new series of pyrazolone-pyridazine conjugates 3 and 4a-l were synthesized and characterized by spectroscopic means and elemental analyses. All compounds were tested in vivo for their anti-inflammatory and analgesic properties against diclofenac, as reference compound. The synthesized compounds were also evaluated for their ability to inhibit the production of certain inflammatory cytokines such as TNF-α and IL-6 in serum samples. The ulcerogenic potential of the synthesized compounds was also determined. IC50 values for inhibition of COX-1 and COX-2 enzymes were investigated in vitro for the most active candidates. Molecular docking was performed on the active site of COX-2 to predict their mode of binding to the amino acids. Among the synthesized derivatives, compounds 4c and 4e showed good analgesic and anti-inflammatory activities with lower ulcer index than the reference drug.

Topics: Analgesics; Animals; Anti-Inflammatory Agents, Non-Steroidal; Carrageenan; Cyclooxygenase 1; Cyclooxygenase 2; Cyclooxygenase Inhibitors; Cytokines; Dose-Response Relationship, Drug; Edema; Humans; Mice; Models, Molecular; Molecular Structure; Pyrazolones; Pyridazines; Structure-Activity Relationship