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After third year of the project
Several hundred natural extracts have been prepared from cyanobacteria, fungi
and also from plants. Activity screening of the extracts and that of pure
compounds isolated from the extracts has been done. In addition several hundred
synthetic compounds targeted to various protein kinases have been synthesised.
Groups oriented to synthetic organic chemistry (WP3) use modern methods of
organic synthesis to prepare compounds that are based on natural product
screening (WP1) or virtual screening of known chemicals (WP2). These synthesis
products can be tested in various protein kinase binding and activity assays to
find the hit molecules. This provides essential feed-back information for the
molecular modellers and synthetic chemists to refine the chemical structure of
the found hits within the iterative process of drug discovery and development.
The Protein Kinase Research Consortium (PKRC) chemical library has been
established and databases of synthesised and extracted compounds has been
generated. Computational tools for generation of 3D models of protein kinases
and for virtual screening of protein kinase-targeted compounds have been
developed within the Consortium. Tens of thousands of compounds have been
screened virtually and the promising hits have been submitted for experimental
validation to further testing within Consortium.
A number of the novel compounds show biological activity in various assay
systems utilising purified kinase enzyme preparations. Several recombinant
protein kinase domains have been expressed and used in the screening for ligand
binding. Indeed, there are more than 150 different kinase activity assays
available within the Consortium, thus the binding affinity and biological
activity of potential protein kinase inhibitors/activators are screened with the
help of extensive collaboration.
Rational drug design relies on three dimensional models of proteins and more
specifically of the active site – the ligand binding site. In order to determine
the crystal structure of the critical binding sites of different kinases, large
quantities of various protein kinases have been produced in cell cultures.
Structures of different kinase/inhibitor complexes and a novel protein kinase
have been solved (WP4)
Protein kinases represent a significant therapeutic target in many pathologies
as they represent the effectors of cell signalling pathways that control a
variety of cell functions including cell proliferation, differentiation and cell
death. In WP5 various model systems for a range of diseases have been utilised
to test therapeutic potential of novel compounds of both natural and synthetic
origin. The diseases include cancer (with leukaemia as a specific disease
targeted as well as breast cancer, glial and gastric tumours), epilepsy, heart
disease and post-stroke neurodegeneration, leishmaniasis and inflammatory
disease.
The protein kinases that have been the focus of the project include Tyrosine
Kinases (receptor and cytoplasmic), Protein kinase C, MAP kinases and Cyclin
Dependent Kinases. In the third year most partners have proceeded to second and
third generation of compounds expressing activity on selected kinases. Some
partners are ready to move to preclinical in vivo animal studies – or have
already done so. Also larger scale synthesis of some compounds has been started.
Several protein kinase inhibitors showed inhibitory activity in a vascular
smooth muscle proliferation assay and therefore it is possible that in the
future protein kinase inhibitors may be used in the treatment of re-stenosis
after balloon surgery (angioplasty) of coronary arteries. More than 100
compounds originating from consortium laboratories have been tested in
anti-parasite assays against Leishmania species. Some compounds show promising
activity and this observation can open new avenues in the treatment strategies
of parasite diseases in the future. Leishmanial protein kinases have also been
cloned and expressed.
Natural and synthetic compounds have been tested in models of leukaemia and
already 3 plant and 3 synthetic PKC-modulating compounds show high potency
against leukaemic cells in cell culture. The effects of selected inhibitors on
neuronal excitotoxicity (models of neuronal death identified during stroke) were
tested and identified as neuroprotective agents. One protein kinase inhibitor
was shown to display neuroprotective effect in an animal model of stroke. The
lead compound and its potential successors will be further studied for a
possible novel stroke therapy. Some of these inhibitors may also modulate
neuronal excitability and may represent a new approach for epileptic treatment.
Expected impact
The research groups of Pro-KinaseResearch consortium represent different
disciplines of science with the same focus of interest: the protein kinases. Our
research efforts aim at the discovery of new means by which the activity of
protein kinases can be modified. Our research will increase the possibility for
development of clinically useful drugs having a novel mechanism of action.
In Europe and other areas of the world with high standard of living diseases
such as cancer, autoimmune diseases, cardiovascular diseases and neurological
diseases are an increasing threat to public health. In developing countries
parasitic infectious diseases such as malaria and leishmania are enormous health
problems. In the future, innovations based on our results can be available to a
global drug market to combat diseases mentioned above.
See also our
scientific publications.
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