Péter Bánhegyi

Signalling Inhibitors Against Mycobacterium tuberculosis – Early Days of a New Therapeutic Concept in Tuberculosis

Tuberculosis causes nearly two million deaths per year world-wide. In addition multidrug-resistant mycobacterial strains rapidly emerge so novel therapeutic approaches are needed. Recently, several promising mycobacterial target molecules were identified, which are involved in bacterial or host cell signalling e.g. the serine/threonine protein kinases, PknB and PknG, NAD kinase and the NAD synthetase. Here we describe some early efforts in the development of novel signal transduction inhibitory anti-mycobacterial drugs using a multiple target approach, with special emphasis on the kinase inhibitory field. Initially, we are using the Nested Chemical Library (NCL) technology and pharmacophore modelling. A hit-finding library, consisting of approximately 19000 small molecules with a bias for prototypic kinase inhibitors from our NCL library and commercial sources was virtually screened against these validated target molecules. Protein structures for the virtual screening were taken from the published three dimensional crystal structures of the enzymes. The hits from the virtual screening were subsequently tested in enzymatic assay systems. Potent hits were then tested for biological activity in macrophages, infected with mycobacteria. The final goal of this exercise is not only to identify potent anti-mycobacterial substances, but also a common pharmacophore for the mycobacterial target PknG in combination with PknB, NAD kinase and/or NAD synthetase. This common pharmacophore still needs to be a unique pharmacophore for the mycobacterial target proteins over human off-targets. Such a pharmacophore might then drive the optimization of a completely new profile of an antibiotic agent with activity against latent mycobacteria and resistance mycobacterial strains.

Prediction Oriented QSAR Modelling of EGFR Inhibition

Epidermal Growth Factor Receptor (EGFR) is a high priority target in anticancer drug research. Thousands of very effective EGFR inhibitors have been developed in the last decade. The known inhibitors are originated from a very diverse chemical space but--without exception--all of them act at the Adenosine TriPhosphate (ATP) binding site of the enzyme. We have collected all of the diverse inhibitor structures and the relevant biological data obtained from comparable assays and built prediction oriented Quantitative Structure-Activity Relationship (QSAR) which models the ATP binding pockets interactive surface from the ligand side. We describe a QSAR method with automatic Variable Subset Selection (VSS) by Genetic Algorithm (GA) and goodness-of-prediction driven QSAR model building, resulting an externally validated EGFR inhibitory model built from pIC50 values of a diverse structural set of 623 EGFR inhibitors. Repeated Trainings/Evaluations (RTE) were used to obtain model fitness values and the effectiveness of VSS is amplified by using predictive ability scores of descriptors. Numerous models were generated by different methods and viable models were collected. Then, intensive RTE were applied to identify ultimate models for external validations. Finally, suitable models were validated by statistical tests. Since we use calculated molecular descriptors in the modeling, these models are suitable for virtual screening for obtaining novel potential EGFR inhibitors.

Synthesis and Characterization of Novel Quinazoline Type Inhibitors for Mutant and Wild-Type EGFR and RICK Kinases

The development of selective protein kinase inhibitors has become an important area of drug discovery for the treatment of different diseases. We report the synthesis and characterization of a series of novel quinazoline derivatives against three therapeutically important and pharmacologically related kinases: 1) epidermal growth factor receptor (EGFR; wild type and mutant) in the field of cancer, 2) receptor-interacting caspase-like apoptosis-regulatory kinase (RICK) in the field of inflammation, and 3) pUL97 of human cytomegalovirus (HCMV). For reference purpose we have synthesized the four clinically relevant quinazolines, including the lead compounds, which we previously identified for RICK and pUL97. A total of 52 quinazoline derivatives were synthesized and tested on the basis of these leads to specifically target the hydrophobic pocket of the ATP-binding site. Selected compounds were tested on wild-type and mutant forms of EGFR, RICK, and pUL97 kinases; their logP and logS values for assessing suitability as drugs were calculated and hit or lead compounds identified.

Novel compounds reducing IRS-1 serine phosphorylation for treatment of diabetes

Activation of various interacting stress kinases, particularly the c-Jun N-terminal kinases (JNK), and a concomitant phosphorylation of insulin receptor substrate 1 (IRS-1) at serine 307 play a central role both in insulin resistance and in β-cell dysfunction. IRS-1 phosphorylation is stimulated by elevated free fatty acid levels through different pathways in obesity. A series of novel pyrido[2,3-d]pyrimidin-7-one derivatives were synthesized as potential antidiabetic agents, preventing IRS-1 phosphorylation at serine 307 in a cellular model of lipotoxicity and type 2 diabetes.

New method for the synthesis of 2-acylamino-1-benzothiophene-3-carboxamide derivatives from the corresponding esters

Abstract An unusual chemical method has been applied for the preparation of 1-benzothiophene-3-carboxamide derivatives from esters by reaction with lithium amide in tetrahydrofurane.

Characterization of new, efficient Mycobacterium tuberculosis topoisomerase-I inhibitors and their interaction with human ABC multidrug transporters

Drug resistant tuberculosis (TB) is a major worldwide health problem. In addition to the bacterial mechanisms, human drug transporters limiting the cellular accumulation and the pharmacological disposition of drugs also influence the efficacy of treatment. Mycobacterium tuberculosis topoisomerase-I (MtTopo-I) is a promising target for antimicrobial treatment. In our previous work we have identified several hit compounds targeting the MtTopo-I by in silico docking. Here we expand the scope of the compounds around three scaffolds associated with potent MtTopo-I inhibition. In addition to measuring the effect of newly generated compounds on MtTopo-I activity, we characterized the compounds’ antimicrobial activity, toxicity in human cells, and interactions with human multidrug transporters. Some of the newly developed MtTopo-I inhibitors have strong antimicrobial activity and do not harm mammalian cells. Moreover, our studies revealed significant human ABC drug transporter interactions for several MtTopo-I compounds that may modify their ADME-Tox parameters and cellular effects. Promising new drug candidates may be selected based on these studies for further anti-TB drug development.

Novel compounds with potent CDK9 inhibitory activity for the treatment of myeloma

Cyclin-dependent kinases (CDKs) and Polo-like kinases (PLKs) play key role in the regulation of the cell cycle. The aim of our study was originally the further development of our recently discovered polo-like kinase 1 (PLK1) inhibitors. A series of new 2,4-disubstituted pyrimidine derivatives were synthesized around the original hit, but their PLK1 inhibitory activity was very poor. However the novel compounds showed nanomolar CDK9 inhibitory activity and very good antiproliferative effect on multiple myeloma cell lines (RPMI-8226).

Discovery and optimization of novel benzothiophene-3-carboxamides as highly potent inhibitors of Aurora kinases A and B

Aurora kinases as regulators of cell division have become promising therapeutic targets recently. Here we report novel, low molecular weight benzothiophene-3-carboxamide derivatives designed and optimized for inhibiting Aurora kinases. The most effective compound 36 inhibits Aurora kinases in vitro in the nanomolar range and diminishes HCT 116 cell viability blocking cytokinesis and inducing apoptosis. According to western blot analysis, the lead molecule inhibits Aurora kinases equipotently to VX-680 (Tozasertib) and similarly synergizes with other targeted drugs.