CDK inhibitors in the vascular system
Prof. Dr. Angelika Vollmar, Ludwig Maximillians University, Germany
 

Cellular test systems for the development of protein kinase inhibitors
Dr. Jan Ehlert, ProQinase/KTB Tumorforschungs GmbH, Germany
 

Kinome profiling on peptide arrays for kinase inhibitor characterization
Dr. Jos Joore, Pepscan Systems BV, The Netherlands
 

CDK inhibitors in the vascular system
Prof. Dr. Angelika Vollmar, Ludwig Maximillians University, Germany

Inhibitors of cyclin-dependent kinases (CDKs) are promising drug candidates for the treatment of tumor diseases. In the vascular system, inhibition of cell proliferation by CDKs is of interest in two pathological settings: inhibition of vascular smooth muscle (VSMC) proliferation prevents atherosclerosis and restenosis, and inhibition of endothelial cell (EC) proliferation suppresses tumor angiogenesis. We have tested the effects of 8 CDK inhibitors (olomoucine, roscovitine, aminopurvalanol, indirubin-3`-monoxime, kenpaullone, alsterpaullone,

 hymenialdisine, and aloisine A) on VSMC and EC with respect to proliferation, cell cycle inhibition, and induction of apoptosis. The nature of the (non-CDK) kinases involved in the observed biological effects was investigated. Of the compounds tested, aminopurvalanol, indirubin-3`-monoxime, and alsterpaullone were most potent, with nearly complete inhibition of proliferation at 10 µM. These effects seem not to be due to CDK inhibition alone, but to a combined action on both, CDKs, and the kinases GSK3 and MEKK1/2.

Prof. Dr. Angelika Vollmar

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Cellular test systems for the development of protein kinase inhibitors
Dr. Jan Ehlert, ProQinase/KTB Tumorforschungs GmbH, Germany

Jan Ehlert, Bettina Mutschler & Michael H G Kubbutat – ProQinase/KTB Tumourforschungs GmbH, Germany

Cellular assays are necessary to reduce the high number of “hit” compounds identified in high-throughput in vitro screens to a number that could be reasonably tested in vivo. Besides assays analyzing general cellular effects such as toxicity or permeability, more sophisticated cellular assays allow for quantification of the kinase-specific inhibitory potency of compounds. Hence, this type of assay provides crucial information in target-orientated drug development. The challenge in establishing protein kinase specific

cellular assays is to reach kinase specificity of the readout. To increase readout reliability, several aspects such as controlled kinase activation, traceability of specific substrates and morphological effects have to be considered. Miniaturization of such cellular assays moreover enables increasing throughput allowing for more streamlined drug discovery. Here we report on the development of cellular test systemswith intermediate throughput for Aurora B, ErbB2 and PKB/Akt1 applicable for the development of protein kinase inhibitors.

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Kinome profiling on peptide arrays for kinase inhibitor characterization
Dr. Jos Joore, Pepscan Systems BV, The Netherlands
 

We have developed peptide substrate microarrays for the analysis of protein kinases. These microarrays allow us to perform ‘kinomics’, i.e. studying snapshots of total kinase activity in a cell or tissue. In this way we have investigated kinase activity in frozen tumor samples, cell lines, plant tissues and blood cells. This method provides a radically different view of the effects of kinase inhibitors on signal transduction in cells and tissues, allowing novel ways to evaluate such compounds as therapeutics against cancer, inflammatory- and other diseases.

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