INTEGRATED SYSTEM FOR THE SCREENING OF THE SPECIFICITY OF PROTEIN-KINASE INHIBITORS

Tyrosine protein kinases (TPKs) play a major role in the transformatio n of cells. They are currently used as molecular targets for new gener ations of anticancer compounds. Numerous TPKs have been described from various tissues using either classical molecular biochemical techniqu es or cloning strategies. As a natural extension of these discoveries, a large number of ''specific'' inhibitors have been described in the literature. The major problem with these inhibitors is that there is n o simple way to compare their specificity and/or selectivity from one report to another. We have set up a simple, straightforward technique to compare the inhibitory potency of 14 classical inhibitors towards s ix well-described and at least partially purified protein kinases. Thi s technique is based on a new assay, easy to carry out and non-restric tive in terms of the type of protein substrate used. It permits direct comparisons between the results obtained from various sources. Data o btained showed that, when assessed in this integrated system, specific ity and selectivity of many ''classical'' inhibitors are often weak, t hus demonstrating that a universal technique such as ours is essential for the molecular screening of new protein kinase inhibitors. Compoun ds showing specificity for this panel of protein kinases will be more easily targeted to some defined types of oncogene and of transformed c ells.