PCV - Programme interdiciplinaire en physique et chimie du vivant

Les polyoxométallates comme inhibiteurs de la protéine kinase CK2 – POM-CK2

Submission summary

Perturbation of protein kinase-mediated cell signaling pathways can lead to various disease states. Protein kinase CK2 is a multifunctional kinase of medical importance as it is found dysregulated in many cancers. Therefore, CK2 is now considered to be a relevant target supporting the development of chemical inhibitors. Several CK2 inhibitors which share the common feature to behave as ATP-mimetics have been already described. In a preliminary study, we have identified polyoxometalates (inorganic aggregates of metal ions and oxygen, POMs) as new CK2 inhibitors. [P2Mo18O62]6– that has the most potent activity inhibits the kinase in the nanomolar range. It targets a domain outside of the ATP- and peptide substrate-binding sites. Several POM derivatives exhibit a strong inhibitory efficiency with IC50 values ≤ 10 nM. Furthermore, these inorganic compounds show a striking specificity for CK2 when tested in a panel of 29 kinases. Therefore, POMs are effective CK2 inhibitors in terms of both efficiency and selectivity and represent non-classical kinase inhibitors interacting with CK2 in a unique way. This novel binding mode may provide an exploitable mechanism for developing potent drugs with desirable properties, such as enhanced selectivity relative to ATP-mimetic inhibitors. In this project, we plan to explore these possibilities by a systematic study of the POM-CK2 complex. We plan to identify and characterize the binding site of POMs to CK2. This will be approached by a number of complementary techniques: (i) Co-crystallization; for this purpose, we will search for conditions where the POM is stabilized long enough to allow crystallization of the CK2-POM complex. (ii) Affinity labeling; we will prepare organic-inorganic hybrid POMs with reactive groups that will allow covalent attachment to the protein residues near the binding site. (iii) Site-directed mutagenesis to generate a POM-insensitive CK2 mutant. (iv) Mass spectrometry; the use of sophisticated mass spectrometric analyses will allow to characterize the POM-CK2 complex in solution. (v) Computer modeling; a combination of DFT methods and molecular mechanics will allow to obtain a deeper insight into the POM-protein interactions. These strategies all imply the synthesis of original organic-inorganic hybrid POMs, and the extensive measurements of their inhibitory efficiency. Such an integrated approach of chemical syntheses, biological studies, spectrometric analyses and computer modeling has not been realized with such inorganic compounds before. Furthermore, we plan to investigate the synergism of POMs with organic CK2 inhibitors, in particular when they are covalently linked. This method could yield even more potent and specific inhibitors. Last but not least, we plan to chemically modify the POMs to ensure their penetration into cells. We would thus be able to test and optimize their inhibitory efficiency on CK2 activity in cell assays. The effect of these chemically-modified POMs on key cellular signaling pathways will be explored by transcriptomic and proteomic approaches. Progress along this line will be useful also in other areas where POMs have shown interesting biological activity, but their low cell penetration limits their applications.

Project coordination

Bernold HASENKNOPF (Organisme de recherche)

The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.

Partner

Help of the ANR 270,000 euros
Beginning and duration of the scientific project: - 24 Months

Useful links

Explorez notre base de projets financés

 

 

ANR makes available its datasets on funded projects, click here to find more.

Sign up for the latest news:
Subscribe to our newsletter