Novel approaches to targeting protein tyrosine kinases

Protein kinases, a diverse group of cellular enzymes, play fundamental roles in maintaining normal cellular functions such as growth, cell cycle control, proliferation, differentiation, migration, cellular survival and apoptotic induction. They participate in a variety of cellular signalling cascades, such as the Ras/Raf/MAPKinase and PI3Kinase pathways. After G-protein-coupled receptors, protein kinases are considered the second most important class of drug targets. Abnormal kinase activities have been linked either directly or indirectly to over 400 human diseases, particularly those which display proliferative or inflammatory characteristics. Examples include neurological and cardiovascular diseases, psoriasis, asthma, rheumatoid arthritis and crucially cancer.