Synergistic killing of FLT3ITD-positive AML cells by combined inhibition of tyrosine-kinase activity and N-glycosylation

• Published in: Oncotarget Vol. 8; no. 16; pp. 26613 - 26624
• Main Authors: Tsitsipatis, Dimitrios, Jayavelu, Ashok Kumar, Müller, Jörg P, Bauer, Reinhard, Schmidt-Arras, Dirk, Mahboobi, Siavosh, Schnöder, Tina M, Heidel, Florian, Böhmer, Frank-D
• Format: Journal Article
• Language: English
• Published: United States Impact Journals LLC 18-04-2017
• Subjects: Antineoplastic Agents - pharmacology; Apoptosis - drug effects; Apoptosis - genetics; Cell Line, Tumor; Drug Synergism; Endoplasmic Reticulum Stress; Extracellular Signal-Regulated MAP Kinases - metabolism; fms-Like Tyrosine Kinase 3 - genetics; fms-Like Tyrosine Kinase 3 - metabolism; Gene Duplication; Gene Expression; Glycosylation - drug effects; Humans; Leukemia, Myeloid, Acute - drug therapy; Leukemia, Myeloid, Acute - genetics; Leukemia, Myeloid, Acute - metabolism; Leukemia, Myeloid, Acute - pathology; Protein Kinase Inhibitors - pharmacology; Proto-Oncogene Proteins c-akt - metabolism; Research Paper; Tandem Repeat Sequences; Tumor Cells, Cultured; Tunicamycin - pharmacology; selective cytotoxicity; FLT3ITD; acute myeloid leukemia; tunicamycin
• ISSN: 1949-2553; 1949-2553
• DOI: 10.18632/oncotarget.15772

Fms-like tyrosine kinase 3 (FLT3) with internal tandem duplications (ITD) is a major oncoprotein in acute myeloid leukemia (AML), and confers an unfavorable prognosis. Interference with FLT3ITD signaling is therefore pursued as a promising therapeutic strategy. In this study we show that abrogation of FLT3ITD glycoprotein maturation using low doses of the N-glycosylation inhibitor tunicamycin has anti-proliferative and pro-apoptotic effects on FLT3ITD-expressing human and murine cell lines. This effect is mediated in part by arresting FLT3ITD in an underglycosylated state and thereby attenuating FLT3ITD-driven AKT and ERK signaling. In addition, tunicamycin caused pronounced endoplasmatic reticulum stress and apoptosis through activation of protein kinase RNA-like endoplasmic reticulum kinase (PERK) and activation of the gene encoding CCAAT-enhancer-binding protein homologous protein (CHOP). PERK inhibition with a small molecule attenuated CHOP induction and partially rescued cells from apoptosis. Combination of tunicamycin with potent FLT3ITD kinase inhibitors caused synergistic cell killing, which was highly selective for cell lines and primary AML cells expressing FLT3ITD. Although tunicamycin is currently not a clinically applicable drug, we propose that mild inhibition of N-glycosylation may have therapeutic potential in combination with FLT3 kinase inhibitors for FLT3ITD-positive AML.