Differential Dependence On Wnt Signaling Allows Chemical Mediated Eradication of Human Acute Leukemia without Affecting Normal Blood Stem Cells

Abstract 3278

Specific targets of signaling pathways that control self-renewal and survival of acute myeloid leukemic stem cells (LSCs) vs. normal hematopoietic stem cells (HSCs) are largely unknown. Here, using a small molecule (CWP232228) derived from a parent compound that inhibits Wnt/TCF targets, we demonstrate reduction of primary human AML-blast growth and clonogenic capacity ex vivo, without effects on normal hematopoietic progenitors. Upon establishment of AML or normal hematopoiesis in immune-deficient recipients, in vivo administration of CWP232228 reduced leukemic disease and abolished LSC self-renewal, with no effect on normal HSC function. In vivo gene profiling and ex vivo molecular studies revealed that CWP232228 induces apoptosis and differentiation of AML-blasts via inhibition of Wnt/b-catenin signaling and activation of non-canonical Wnt signaling which phenocopies the effects of this small molecule. Our study reveals an in vivo differential dependence of AML on canonical vs. non-canonical Wnt signaling that allows therapeutic targeting of LSCs whilst sparing normal HSCs.