Consecutive epigenetically-active agent combinations act in ID1-RUNX3-TET2 and HOXA pathways for Flt3ITD+ve AML

Inhibitor of DNA binding proteins revealed as orchestrators of steady state, stress and malignant hematopoiesis

Adult mammalian hematopoiesis is a dynamic cellular process that provides a continuous supply of myeloid, lymphoid, erythroid/megakaryocyte cells for host survival. This process is sustained by regulating hematopoietic stem cells (HSCs) quiescence, proliferation and activation under homeostasis and stress, and regulating the proliferation and differentiation of downstream multipotent progenitor (MPP) and more committed progenitor cells. Inhibitor of DNA binding (ID) proteins are small helix-loop-helix (HLH) proteins that lack a basic (b) DNA binding domain present in other family members, and function as dominant-negative regulators of other bHLH proteins (E proteins) by inhibiting their transcriptional activity. ID proteins are required for normal T cell, B cell, NK and innate lymphoid cells, dendritic cell, and myeloid cell differentiation and development. However, recent evidence suggests that ID proteins are important regulators of normal and leukemic hematopoietic stem and progenitor cells (HSPCs). This chapter will review our current understanding of the function of ID proteins in HSPC development and highlight future areas of scientific investigation.

FMS-Like Tyrosine Kinase 3 Inhibitors for the Treatment of Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is the most common acute leukemia of adults, with a five-year survival that remains poor (approximately 25%). Knowledge and understanding of AML genomics have expanded tremendously over the past decade and are now included in AML prognostication and treatment decisions. FMS-like tyrosine kinase 3 (FLT3) is a Class III receptor tyrosine kinase (RTK) expressed primarily in the cell membranes of early hematopoietic progenitor cells, found in 28% of all patients with AML. FLT3 is the second most frequent mutation in adult AML following Nuclear-cytoplasmic shuttling phosphoprotein (NPM1), which is found in 50% of cases.¹ FLT3 inhibitors are promising new molecular therapeutics increasingly becoming standard of care for both newly diagnosed and relapsed/refractory FLT3 positive AML. This review will focus on the clinical trials/evidence, similarities, differences, clinical toxicities, and drug interactions relevant to treating clinicians as pertains to 5 FLT3-inhibitors: midostaurin, sorafenib, gilteritinib, crenolanib, and quizartinib.