ATP-competitive Plk1 inhibitors induce caspase 3-mediated Plk1 cleavage and activation in hematopoietic cell lines

Résumé fourni par la source

// Maeva Dufies 1, 2 , Damien Ambrosetti 3 , Sonia Boulakirba 1, 4 , Anne Calleja 1, 4 , Coline Savy 1, 4 , Nathan Furstoss 1 , Marwa Zerhouni 1 , Julien Parola 2 , Lazaro Aira-Diaz 1 , Sandrine Marchetti 1 , Francois Orange 5 , Sandra Lacas-Gervais 5 , Frederic Luciano 1, 4 , Arnaud Jacquel 1, 4 , Guillaume Robert 1, 4 , Gilles Pagès 2 and Patrick Auberger 1, 4 1 Université Côte d’Azur, C3M/Inserm U1065, Nice, France 2 Université Côte d’Azur, Institute for Research on Cancer and Aging of Nice (IRCAN), CNRS UMR 7284, INSERM U 1081, Nice, France 3 Université Côte d’Azur, CHU Nice, Department of Pathology, Nice, France 4 Equipe Labellisée par la Fondation ARC (2017-2020), Paris, France 5 Université Côte d’Azur, CCMA, Nice, France Correspondence to: Patrick Auberger, email: auberger@unice.fr Keywords: Plk1; caspases; hematopoietic cells; G2M arrest; mitotic catastrophe Received: December 11, 2017 Accepted: December 18, 2017 Published: December 23, 2017 ABSTRACT Polo-like kinases (Plks) define a highly conserved family of Ser/Thr kinases with crucial roles in the regulation of cell division. Here we show that Plk1 is cleaved by caspase 3, but not by other caspases in different hematopoietic cell lines treated with competitive inhibitors of the ATP-binding pocket of Plk1. Intriguingly, Plk1 was not cleaved in cells treated with Rigosertib, a non-competitive inhibitor of Plk1, suggesting that binding of the inhibitor to the ATP binding pocket of Plk1 triggers a conformational change and unmasks a cryptic caspase 3 cleavage site on the protein. Cleavage occurs after Asp-404 in a DYSD/K sequence and separates the kinase domain from the two PBDs of Plk1. All Plk1 inhibitors triggered G2/M arrest, activation of caspases 2 and 3, polyploidy, multiple nuclei and mitotic catastrophe, albeit at higher concentrations in the case of Rigosertib. Upon BI-2536 treatment, Plk1 cleavage occurred only in the cytosolic fraction and cleaved Plk1 accumulated in this subcellular compartment. Importantly, the cleaved N-Terminal fragment of Plk1 exhibited a higher enzymatic activity than its non-cleaved counterpart and accumulated into the cytoplasm conversely to the full length and the C-Terminal Plk1 fragments that were found essentially into the nucleus. Finally, the DYSD/K cleavage site was highly conserved during evolution from c. elegans to human. In conclusion, we described herein for the first time a specific cleavage of Plk1 by caspase 3 following treatment of cancer cells with ATP-competitive inhibitors of Plk1.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.