ABSTRACT
The convenient and efficient synthesis of two macrocyclic ligands (15- and 18-membered) based on a dipyrido-6,7,8,9-tetrahydrophenazine (dpqc) or 2,2':6',2''-terpyridine (tpy) heterocycle and a DTTA (diethylenetriaminetriacetic acid) skeleton is described. In these ligands the DTTA skeleton contains an additional extracyclic functionality (NH(2) group) suitable for covalent attachment to bioactive molecules. These octa- and nonadentate ligands form very stable and luminescent neutral lanthanide complexes in aqueous solutions at physiological pH. The corresponding Eu(III) and Tb(III) complexes are characterized by a maximum absorption wavelength compatible with nitrogen laser excitation (337 nm) and attractive lifetimes and quantum yields. Further introduction of a maleimide bioconjugatable handle in the Eu(III) complexes was investigated and a valuable luminescence brightness above 1500 dm(3) mol(-1) cm(-1) at 337 nm was obtained with the corresponding Eu(III) tpy-derivative. Finally, these two luminescent chelates were grafted onto thiol residues of a model antibody (Mab GSS11) without loss of their luminescent properties.
Subject(s)
Chelating Agents/chemistry , Lanthanoid Series Elements/chemistry , Luminescent Agents/chemistry , Macrocyclic Compounds/chemistry , Antibodies, Monoclonal/chemistry , Chelating Agents/chemical synthesis , Lanthanoid Series Elements/chemical synthesis , Luminescent Agents/chemical synthesis , Macrocyclic Compounds/chemical synthesis , Maleimides/chemical synthesis , Maleimides/chemistry , Pentetic Acid/analogs & derivatives , Pentetic Acid/chemical synthesis , Pentetic Acid/chemistry , Phenazines/chemical synthesis , Phenazines/chemistry , Pyridines/chemical synthesis , Pyridines/chemistryABSTRACT
A series of pyrrolic analogs and two series of regioisomeric pyrazolic analogs of the marine alkaloids granulatimide and isogranulatimide were prepared. The synthesis of the two first ones was based on the condensation reaction of diversely 5-substituted 3-bromoindoles with pyrrole or pyrazole followed by addition of the intermediates on maleimide or dibromomaleimide, respectively, the so-obtained acyclic adducts being finally photocyclized to the desired analogs. Compounds of the last series were obtained by reacting different 5-substituted-indole-3-glyoxylates with N-Boc-pyrazole-3-acetamide and subsequent photochemical cyclization of the adducts. All the compounds were evaluated for their in vitro growth inhibitory properties toward eight cancer cell lines. Several compounds were also assayed for their ability to abrogate the G2-cell cycle checkpoint or to inhibit a panel of Ser/Thr kinases. Lastly, computer-assisted phase-contrast microscopy (quantitative videomicroscopy) revealed that the three most potent compounds (4a, 9a, 9e), with IC(50) growth inhibitory concentrations ranging between 10 and 20 µM, displayed cytostatic, not cytotoxic, anticancer effects.
Subject(s)
Alkaloids/chemical synthesis , Alkaloids/pharmacology , Aquatic Organisms/chemistry , Imidazoles/chemical synthesis , Imidazoles/pharmacology , Indoles/chemical synthesis , Indoles/pharmacology , Animals , Antineoplastic Agents/chemical synthesis , Antineoplastic Agents/pharmacology , Cell Line, Tumor , Cell Proliferation/drug effects , Chemistry Techniques, Synthetic , G2 Phase Cell Cycle Checkpoints/drug effects , Humans , M Phase Cell Cycle Checkpoints/drug effects , Mice , Protein Kinase Inhibitors/chemical synthesis , Protein Kinase Inhibitors/pharmacologyABSTRACT
Our docking program, Fitted, implemented in our computational platform, Forecaster, has been modified to carry out automated virtual screening of covalent inhibitors. With this modified version of the program, virtual screening and further docking-based optimization of a selected hit led to the identification of potential covalent reversible inhibitors of prolyl oligopeptidase activity. After visual inspection, a virtual hit molecule together with four analogues were selected for synthesis and made in one-five chemical steps. Biological evaluations on recombinant POP and FAPα enzymes, cell extracts, and living cells demonstrated high potency and selectivity for POP over FAPα and DPPIV. Three compounds even exhibited high nanomolar inhibitory activities in intact living human cells and acceptable metabolic stability. This small set of molecules also demonstrated that covalent binding and/or geometrical constraints to the ligand/protein complex may lead to an increase in bioactivity.
Subject(s)
Protease Inhibitors/pharmacology , Serine Endopeptidases/metabolism , User-Computer Interface , Animals , Cell Line, Tumor , Drug Evaluation, Preclinical , Drug Stability , Humans , Microsomes, Liver/metabolism , Models, Molecular , Prolyl Oligopeptidases , Protease Inhibitors/chemical synthesis , Protease Inhibitors/chemistry , Protease Inhibitors/metabolism , Protein Conformation , Rats , Serine Endopeptidases/chemistry , Structure-Activity Relationship , Substrate SpecificityABSTRACT
Granulatimide and isogranulatimide are alkaloids obtained from marine sources which have been shown to inhibit cell-cycle G2-checkpoint, targeting more particularly checkpoint 1 kinase (Chk1). At a structural level, they possess a characteristic pyrrolocarbazole framework also shared by the well-known rebeccamycin and staurosporine microbial metabolites which have been described to inhibit topoisomerase I and diverse kinases, respectively. This review reports precisely on the synthesis and kinase inhibitory activities of pyrrolocarbazole-based analogues of granulatimide.
