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).

Synthesis and characterization of amino acid substituted sunitinib analogues for the treatment of AML.

Acute myeloid leukemia (AML) is the most common type of leukemia in adults. Sunitinib, a multikinase inhibitor, was the first Fms-like tyrosine kinase 3 (FLT3) inhibitor clinically used against AML. Off-target effects are a major concern for multikinase inhibitors. As targeted delivery may reduce such undesired side effects, our goal was to develop novel amino acid substituted derivatives of sunitinib which are potent candidates to be used conjugated with antibodies and peptides. In the current paper we present the synthesis, physicochemical and in vitro characterization of sixty two Fms-like tyrosine kinase 3-internal tandem duplication (FLT3-ITD) mutant kinase inhibitors, bearing amino acid moieties, fit to be conjugated with peptide-based delivery systems via their carboxyl group. We determined the solubility, pKa, CHI and LogP values of the compounds along with their inhibition potential against FLT3-ITD mutant kinase and on MV4-11 cell line. The ester derivatives of the compounds inhibit the growth of the MV4-11 leukemia cell line at submicromolar concentration.

[Pyrido[2,3-b]pyrazines inhibiting both erlotinib-sensitive and erlotinib-resistant cell lines, and their preparation via regioselective condensation reaction]. / Erlotinib-érzékeny és erlotinib-rezisztens sejtvonalakat gátló pirido[2,3-b] pirazinok, és eloállításuk régiószelektív kondenzációs reakcióval.

The EGFR inhibitor erlotinib possesses high anti-tumor effect but despite the good clinical responses in most of the cases recrudescence occures. This can be attributed to a secondary, acquired mutation causing resistance to tyrosine kinase inhibitors. In our work we were looking for small-molecule inhibitors, which simultaneously affect on the proliferation of erlotinib-sensitive PC9 cells and PC9-ER erlotinib-resistant cells. A set of molecules were selected from Vichem Chemie Research Ltd.'s kinase inhibitor compound library (Nested Chemical Library™). According to the results of medium throughput screening (MTS) of this set of compounds, novel structures with pyrido[2,3-b]pyrazine core were designed. These compounds were proved to be effective inhibitors of resistant cells in phenotypic screening. Based on these results structure-activity relationships were set up. The pyrido[2,3-b]pyrazine core was synthesized by a condensation reaction, which resulting two asymmetric products. In the reaction two regioisomer intermediates formed, and one of the products is the intermediate of the effective compounds. This condensation reaction was optimized, the regioisomers were identified by NMR analysis and X-ray crystallography. As a result of optimization we found that lower reaction temperature and replacement of dimethylformamide solvent with trifluoroacetic acid provided the undesired isomer in less than 2 % ratio.

Synthesis and biological evaluation of novel pyrido[2,3-b]pyrazines inhibiting both erlotinib-sensitive and erlotinib-resistant cell lines.

A series of novel pyrido[2,3-b]pyrazines were synthesized as potential antitumor agents for erlotinib-resistant tumors. Known signal inhibitor compounds from our Nested Chemical Library were tested in phenotypic assays on erlotinib-sensitive PC9 and erlotinib-resistant PC9-ER cell lines to find a compound class to be active on erlotinib resistant cell lines. Based on the screening data, novel pyrido[2,3-b]pyrazines were designed and synthesized. The effect of the substituent position of the heteroaromatic moiety in position 7 and the importance of unsubstituted position 2 of the pyridopyrazine core were explored. Compound 7n had an IC50 value of 0.09 µM for the inhibition of PC9 and 0.15 µM for the inhibition of PC9-ER. We found that some lead compounds of these structures overcome erlotinib-resistance which might become promising drug candidates to fight against NSCLC with EGFR T790M mutation. The signaling network(s) involved in the mechanism(s) of action of these novel compounds in overcoming erlotinib resistance remain to be elucidated.

[Development and study of structure-activity relationship of drugs against Mycobacterium tuberculosis]. / Mycobacterium tuberculosis ellenes hatóanyagok fejlesztése és szerkezet-hatás összefüggéseinek vizsgálata.

Tuberculosis is considered to be one of the major health problem not only in the less developed countries but in the economically developed countries as well. Roughly one third of the world's population are infected with Mycobacterium tuberculosis and a significant part of them are carriers of latent tuberculosis. From ten percent of these latent infections are developing the active TB disease and fifty percent of them die from the illness without appropriate treatment. The drug-resistant Mycobacterium tuberculosis (MDR-TB, XDR-TB) and TB-HIV co-infection attracted attention to the most serious infectious disease. Inhibition of alternative signaling pathways were an important part of the research strategies for cancer and inflammatory diseases in recent years. In case of Mycobacterium tuberculosis such pathways were also identified, for example, three serine-threonine kinases (PknA, PknB, PknG) which are necessary and essential for bacterial growth. In this paper we summarize our best anti-TB active compounds, their biological effects and structure-activity relationships using in silico modeling, biochemical measurements and tests on active bacteria.

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.

Small-molecule inhibitors of NADPH oxidase 4.

NOX enzymes are the major contributors in many oxidative damage related diseases. Unfortunately, at present no specific NOX inhibitor is available. Here, we describe the discovery and development of novel NOX4 inhibitors. Compound libraries were tested in a cell-based assay as a primary screen, monitoring H2O2 production. Twenty-four compounds inhibited Nox4 activity with low-micromolar IC(50) values of which three were selected for further drug development.

Tyrosine kinase inhibitors - small molecular weight compounds inhibiting EGFR.

Abnormally elevated EGFR kinase activity can lead to various pathological states, including proliferative diseases such as cancer. The development of selective protein kinase inhibitors has become an important area of drug discovery for the potential treatment of a variety of solid tumors such as breast, ovarian and colorectal cancers, NSCLC, and carcinoma of the head and neck. There are three small molecule EGFR kinase inhibitor drugs in clinical use (gefitinib, erlotinib and lapatinib), and several others are currently undergoing clinical development. This review summarizes the development of EGFR kinase inhibitors, and includes descriptions of the binding modes, the importance of a multiple-targets strategy, the effects of sensitizing and resistance mutations in the EGFR, and molecular diagnostic approaches. In addition, the use of target fishing for selectivity profiling, off-target identification and quantitative structure-activity relationship modeling for the prediction of EGFR inhibition is discussed.

Biochemical assay-based selectivity profiling of clinically relevant kinase inhibitors on mutant forms of EGF receptor.

Gefitinib and erlotinib are potent EGFR tyrosine kinase inhibitors (potentially) useful for the treatment of non-small-cell lung cancer (NSCLC). Clinical responses, however, in NSCLC patients have been linked to the presence of certain activating mutations of EGFR. We used an ELISA-based biochemical assay to confirm the selective inhibitory efficacy of gefitinib and erlotinib on the activated mutant receptor. Our results are in line with the clinical observations providing evidence for the predictive power of the kinase assay. Four additional compounds were also investigated: CI-1033 and EKB-569 had dramatic inhibitory effects on all EGFR forms, whereas PD153035 and AG1478 were active on wild-type and activating mutant protein. In docking simulations with wild-type EGFR, our inhibitory data are in good agreement with the binding scores. These data confirm that anilinoquinazolines are good starting structures for the next generation of selective drugs against mutant EGFR, whereas CI-1033 and EKB-569 may represent advances for patients with both wild-type and anilinoquinazoline-resistant mutant tumors.