Synergistic cooperation between ABT-263 and MEK1/2 inhibitor: effect on apoptosis and proliferation of acute myeloid leukemia cells.

// Kelly Airiau 1, 2 , Valerie Prouzet-Mauleon 1 , Benoit Rousseau 3 , Arnaud Pigneux 1, 2 , Marie Jeanneteau 2 , Manon Giraudon 2 , Kaoutar Allou 1, 2 , Pierre Dubus 4 , Francis Belloc 1, 2, * , Francois-Xavier Mahon 1, 2, * 1 Laboratoire d’Hematopoiese Leucemique et Cibles Therapeutiques, INSERM 1035, Universite Bordeaux, Bordeaux, France 2 CHU Bordeaux, Hopital Haut-Leveque, Laboratoire d’Hematologie, Pessac, France 3 Animalerie A2, Universite Bordeaux Segalen, Bordeaux, France 4 EA 2406 Histologie et Pathologie, Universite Bordeaux, Bordeaux, France * These authors have contributed equally to this work Correspondence to: Francois-Xavier Mahon, e-mail: francois-xavier.mahon@u-bordeaux.fr Keywords: acute myeloid leukemia, MEK inhibitors, BH3 mimetic drugs Received: June 28, 2015      Accepted: November 16, 2015      Published: November 27, 2015 ABSTRACT In spite of intensive research to improve treatment of acute myeloid leukemia (AML) more than half of all patients continue to develop a refractory disease. Therefore there is need to improve AML treatment. The overexpression of the BCL-2 family anti-apoptotic members, like BCL-2 or BCL-xL has been largely reported in lymphoid tumors but also in AML and other tumors. To counteract the anti-apoptotic effect of BCL-2, BH3 mimetics have been developed to target cancer cells. An increase in activity of ERK1/2 mitogen activated protein (MAP) kinase has also been reported in AML and might be targeted by MEK1/2 inhibitors. Hence, in the current work, we investigated whether the association of a BH3 mimetic such ABT-263 and the MEK1/2 inhibitor pimasertib (MEKI), was efficient to target AML cells. A synergistic increasing of apoptosis was observed in AML cell lines and in primary cells without affecting normal bone marrow cells. Such cooperation was confirmed on tumor growth in a mouse xenograft model of AML. In addition we demonstrated that MEKI sensitized the cells to apoptosis through its ability to promote a G1 cell cycle arrest. So, this combination of a MAP Kinase pathway inhibitor and a BH3 mimetic could be a promising strategy to improve the treatment of AML.