Patients with FLT3-ITD mutated (FLT3-ITD+) Acute Myeloid Leukemia (AML), have frequently relapsed or refractory disease and FLT3-ITD+ inhibitors have limited efficacy. Rho kinases (ROCK) are constitutively activated by FLT3-ITD+ in AML via PI3 kinase and Rho GTPase. Upon activation by ROCK, LIM kinases (LIMK) inactivate cofilin by phosphorylation which affects cytoskeleton dynamics, cell growth and apoptosis. LIMK inhibition leads to cofilin activation via dephosphorylation and activated cofilin localizes to mitochondria inducing apoptosis. Thus, we investigated the therapeutic potential of the LIMK1/2 inhibitor CEL_Amide (LIMKi) in FLT3-ITD+ AML. Expression of LIMK1/2 in FLT3-ITD+ cell lines MOLM-13 and MV-4-11 cells could be detected by RT-qPCR and at the protein level. IC50 after LIMKi monotherapy was 440 nM in MOLM-13 cells and 420 nM in MV4-11 cells. Treatment with LIMKi decreased LIMK1 protein levels and repression of inactivating phosphorylation of cofilin in FLT3-ITD+ cells. Combination experiments with LIMKi and FLT3 inhibitors including midostaurin, crenolanib and gilteritinib were synergistic for treatment of MOLM-13 cells while combinations with quizartinib were additive. Combinations of LIMKi and the hypomethylating agent azacitidine or the ROCK inhibitor fasudil were additive. In NOD-SCID mice engrafted with MOLM13-LUC cells, the FLT3 inhibitor midostaurin and LIMKi delayed MOLM13-LUC engraftment as detected by in vivo bioluminescence imaging and the LIMKi and midostaurin combination prolonged significantly survival of leukemic mice. LIMK1/2 inhibition by the small molecule CEL_Amide seems to have promising activity in combination with FLT3 inhibitors in vitro as well as in vivo and may constitute a novel treatment strategy for FLT3-ITD+ AML.Copyright © 2020 Elsevier Ltd. All rights reserved.
About The Expert
Hanane Djamai
- Laboratoire de Transfert des Leucémies, EA3518, Institut de Recherche Saint Louis, University of Paris, Paris, France.
Jeannig Berrou
- Laboratoire de Transfert des Leucémies, EA3518, Institut de Recherche Saint Louis, University of Paris, Paris, France.
Mélanie Dupont
- Laboratoire de Transfert des Leucémies, EA3518, Institut de Recherche Saint Louis, University of Paris, Paris, France.
Anna Kaci
- Laboratoire de Transfert des Leucémies, EA3518, Institut de Recherche Saint Louis, University of Paris, Paris, France.
Jan Erik Ehlert
- Reaction Biology GmbH, Freiburg, Germany.
Holger Weber
- Reaction Biology GmbH, Freiburg, Germany.
André Baruchel
- Laboratoire de Transfert des Leucémies, EA3518, Institut de Recherche Saint Louis, University of Paris, Paris, France; Department of Pediatric Hemato-Immunology, Hôpital Robert Debré (Assistance Publique – Hôpitaux de Paris and University of Paris), Paris, France.
Fabrice Paublant
- CELLIPSE Company, Grenoble, France.
Renaud Prudent
- CELLIPSE Company, Grenoble, France.
Claude Gardin
- Laboratoire de Transfert des Leucémies, EA3518, Institut de Recherche Saint Louis, University of Paris, Paris, France; Hematology Department, Hôpital Avicenne (Assistance Publique-Hôpitaux de Paris and University Paris XIII), Bobigny, France.
Hervé Dombret
- Laboratoire de Transfert des Leucémies, EA3518, Institut de Recherche Saint Louis, University of Paris, Paris, France; Leukemia Unit, Hematology Department, Hôpital Saint-Louis (Assistance Publique-Hôpitaux de Paris and University of Paris), Paris, France.
Thorsten Braun
- Laboratoire de Transfert des Leucémies, EA3518, Institut de Recherche Saint Louis, University of Paris, Paris, France; Hematology Department, Hôpital Avicenne (Assistance Publique-Hôpitaux de Paris and University Paris XIII), Bobigny, France. Electronic address: thorsten.braun@aphp.fr.
References
PubMed