A prototype nonpeptidyl, hydrazone class, thrombopoietin receptor agonist, SB-559457, is toxic to primary human myeloid leukemia cells

• Published in: Blood Vol. 115; no. 1; pp. 89 - 93
• Main Authors: Kalota, Anna, Gewirtz, Alan M.
• Format: Journal Article
• Language: English
• Published: Washington, DC Elsevier Inc 07.01.2010; Americain Society of Hematology
• Subjects: Antineoplastic Agents - chemistry; Antineoplastic Agents - pharmacology; Antineoplastic Agents - toxicity; Biological and medical sciences; Cell Death - drug effects; Cell Proliferation - drug effects; Drug Screening Assays, Antitumor; Gene Expression Regulation, Leukemic - drug effects; Hematologic and hematopoietic diseases; Humans; Hydrazones - chemistry; Hydrazones - pharmacology; Hydrazones - toxicity; Leukemia, Myeloid - enzymology; Leukemia, Myeloid - genetics; Leukemia, Myeloid - pathology; Leukemias. Malignant lymphomas. Malignant reticulosis. Myelofibrosis; Medical sciences; Peptides - pharmacology; Phosphorylation - drug effects; Receptors, Thrombopoietin - agonists; Ribosomal Protein S6 Kinases, 70-kDa - metabolism; Transcription Factors - genetics; Transcription Factors - metabolism; Tumor Cells, Cultured; Human; Myeloproliferative syndrome; Agonist; Thrombopoietin receptor; Hematology; Toxicity; Primary; Chronic myelogenous leukemia; Malignant hemopathy; Hydrazone; Myeloid cell; Cancer
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood-2009-06-227751

Biologic characterization of SB-559457 (SB), a nonpeptidyl hydrazone class of thrombopoietin receptor (Mpl) agonist, revealed toxicity toward human leukemia cells. Antiproliferative effects followed by significant, nonapoptotic, cell death within 72 hours occurred in 24 of 26 acute myeloid leukemia, 0 of 6 acute lymphoblastic leukemia, and 3 of 6 chronic myeloid leukemia patient samples exposed to SB, but not recombinant human thrombopoietin (rhTpo), in liquid suspension culture. Further investigation revealed increased phosphorylation of p70S6/S6 kinases in SB-, but not in rhTpo-, treated cells. Expression profiling of cells exposed to SB versus rhTpo revealed statistically significant, more than 2-fold changes in GAPDH and REDD1 gene expression, confirmed by quantitative reverse-transcribed polymerase chain reaction. These genes, induced in energy or hypoxia stressed cells, have been implicated in cell death pathways, and may provide important clues to the mechanism of SB-induced, leukemic cell death. These results suggest that nonpeptidyl, hydrazone class Mpl agonists may be clinically useful antileukemic agents by virtue of their combined thrombopoietic and antileukemic effects.