Exploiting cellular pathways to develop new treatment strategies for AML

Abstract

The standard approaches to the treatment of acute myeloid leukemia (AML) have been predominantly based on cytarabine and anthracyclines. Yet, the outcomes associated with AML continue to be poor, especially for those patients who are older or carry higher-risk disease. In recent years, extensive research has led to the development and study of novel agents which target AML by diverse and varied mechanisms. Among these are targeted therapeutics such as kinase inhibitors and oligonucleotide constructs. These aim to suppress the production or activity of proteins, such as FLT3 and BCL2, among others, and thus disrupt related signaling cascades essential for leukemogenesis and proliferation. In addition, other agents like flavopiridol appear to target the myeloid blast by various mechanisms including suppression of cyclin-dependent kinases and interference with nucleotide synthesis. Another class of novel therapies includes inhibitors of histone deacetylase, which cause growth arrest and apoptosis through histone acetylation and resultant conformational changes. Clinical trials are now studying these and other agents alone and in combination with traditional cytotoxic therapies, with some encouraging results. In this review, we aim to provide a summary of the preclinical and clinical investigations of selected promising agents currently under study.

Keywords: Acute myeloid leukemia; FLT3; Flavopiridol; HDAC inhibitor; PARP; Targeted therapies.

Figure 1

The phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) and FMS-like tyrosine kinase 3 (FLT3) cascades in acute myeloid leukemia, and relevant targeted therapies. BAD—bcl-2 antagonist of cell death; CDK2—cyclin-dependent kinase 2; EGFR—epidermal growth factor receptor; PDK1—phosphoinositide-dependent kinase 1; PIP2—phosphatidylinositol-4,5-bisphosphate; PIP3—phosphatidylinositol-3,4,5-trisphosphate; TSC1, TSC2—tuberous sclerosis proteins 1 and 2; VEGF—vascular endothelial growth factor; PIM—Proviral integration site for Moloney murine leukemia virus.