Inhibition of CDC25B Phosphatase Through Disruption of Protein–Protein Interaction

Abstract

CDC25 phosphatases are key cell cycle regulators and represent very attractive but challenging targets for anticancer drug discovery. Here, we explored whether fragment-based screening represents a valid approach to identify inhibitors of CDC25B. This resulted in identification of 2-fluoro-4-hydroxybenzonitrile, which directly binds to the catalytic domain of CDC25B. Interestingly, NMR data and the crystal structure demonstrate that this compound binds to the pocket distant from the active site and adjacent to the protein–protein interaction interface with CDK2/Cyclin A substrate. Furthermore, we developed a more potent analogue that disrupts CDC25B interaction with CDK2/Cyclin A and inhibits dephosphorylation of CDK2. Based on these studies, we provide a proof of concept that targeting CDC25 phosphatases by inhibiting their protein–protein interactions with CDK2/Cyclin A substrate represents a novel, viable opportunity to target this important class of enzymes.

Phosphatases and kinases regulating CDC25 activity in the cell cycle: clinical implications of CDC25 overexpression and potential treatment strategies

“…Further in vivo studies are required to establish LGH00031 as an efficient CDC25 inhibitor [84]. 2-fluoro-4-hydroxybenzonitrile, a CDC25B inhibitor, binds to its catalytic domain and prevents protein-protein interaction with CDK2/Cyclin A [85]. Anti-cancer drug, NSC 95397, inhibits CDC25A and decreases NF-kB-mediated NO production [86].…”

“…Novellino and colleagues [85] identified molecules that inactivate/inhibit CDC25B at micromolar concentration in vitro, inhibit breast (MCF-7), prostate (PC-3), and leukemia (K562) cancer cell proliferation, and significantly affect the cell cycle progression. These molecules were identified by an experimental and virtual screenings of both National Cancer Institute (NCI) Diversity Set and ZINC34 databases.…”

Crystal structures of the apo form and a complex of human LMW-PTP with a phosphonic acid provide new evidence of a secondary site potentially related to the anchorage of natural substrates

“…It is worth to mention that, in the case of another phosphatase, CDC25B, residues located far from the active site have been reported as involved in substrate recognition 51 and recent results proved that targeting the enzyme at this region disrupt protein-protein interactions. 52 …”

Developing Antagonists for the Met-HGF/SF Protein–Protein Interaction Using a Fragment-Based Approach

“…Many essential cellular functions are carried out by multiprotein assemblies, and so it is not surprising that many human diseases, such as neurodegenerative diseases (43) and metabolic diseases (44) as well as cancer (45), can be caused by aberrant PPI. The development of novel chemical moieties targeting PPIs has recently turned previously "undruggable" targets into tractable macromolecular sites (42,46,47), and examples for successful campaigns can be found in the literature (42,48,49).…”