Synergism of FAK and tyrosine kinase inhibition in Ph+ B-ALL

Abstract

BCR-ABL1 + B progenitor acute lymphoblastic leukemia (Ph + B-ALL) is an aggressive disease that frequently responds poorly to currently available therapies. Alterations in IKZF1 , which encodes the lymphoid transcription factor Ikaros, are present in over 80% of Ph + ALL and are associated with a stem cell–like phenotype, aberrant adhesion molecule expression and signaling, leukemic cell adhesion to the bone marrow stem cell niche, and poor outcome. Here, we show that FAK1 is upregulated in Ph + B-ALL with further overexpression in IKZF1-altered cells and that the FAK inhibitor VS-4718 potently inhibits aberrant FAK signaling and leukemic cell adhesion, potentiating responsiveness to tyrosine kinase inhibitors, inducing cure in vivo. Thus, targeting FAK with VS-4718 is an attractive approach to overcome the deleterious effects of FAK overexpression in Ph + B-ALL, particularly in abrogating the adhesive phenotype induced by Ikaros alterations, and warrants evaluation in clinical trials for Ph + B-ALL, regardless of IKZF1 status.