Mutations of FLT3/ITD confer resistance to multiple tyrosine kinase inhibitors

• Published in: Leukemia Vol. 27; no. 1; pp. 48 - 55
• Main Authors: Williams, A B, Nguyen, B, Li, L, Brown, P, Levis, M, Leahy, D, Small, D
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.01.2013; Nature Publishing Group
• Subjects: 631/208/737; 631/67/1059/2326; 692/699/67/1990/283/1897; Animals; Antibodies; BCR-ABL tyrosine kinase inhibitors; Benzenesulfonates - pharmacology; Blotting, Western; Cancer Research; Cells, Cultured; Critical Care Medicine; Cytokines; Drug resistance; Drug Resistance, Neoplasm - genetics; fms-Like Tyrosine Kinase 3 - genetics; Gene mutations; Genetic aspects; Granulocytes; Health aspects; Hematology; Humans; Immunoprecipitation; Intensive; Internal Medicine; Kinases; Leukemia; Leukemia, Erythroblastic, Acute - drug therapy; Leukemia, Erythroblastic, Acute - genetics; Leukemia, Erythroblastic, Acute - pathology; Medical prognosis; Medicine; Medicine & Public Health; Mice; Mice, Inbred BALB C; Mutagenesis; Mutation; Mutation - genetics; Niacinamide - analogs & derivatives; Oncology; original-article; Phenylurea Compounds; Phosphorylation - drug effects; Physiological aspects; Precursor Cells, B-Lymphoid - cytology; Precursor Cells, B-Lymphoid - drug effects; Precursor Cells, B-Lymphoid - metabolism; Protein Kinase Inhibitors - pharmacology; Protein tyrosine kinase; Pyridines - pharmacology; Tandem Repeat Sequences - drug effects; Tandem Repeat Sequences - genetics; United States; United States > US; Baltimore Maryland; tyrosine kinase inhibitors; mutant FLT3; drug resistance; acute myeloid leukemia
• ISSN: 0887-6924; 1476-5551
• DOI: 10.1038/leu.2012.191

FMS-like tyrosine kinase 3 (FLT3) normally functions in the survival/proliferation of hematopoietic stem/progenitor cells, but its constitutive activation by internal tandem duplication (ITD) mutations correlates with a poor prognosis in AML. The development of FLT3 tyrosine kinase inhibitors (TKI) is a promising strategy, but resistance that arises during the course of treatment caused by secondary mutations within the mutated gene itself poses a significant challenge. In an effort to predict FLT3 resistance mutations that might develop in patients, we used saturation mutagenesis of FLT3/ITD followed by selection of transfected cells in FLT3 TKI. We identified F621L, A627P, F691L and Y842C mutations in FLT3/ITD that confer varying levels of resistance to FLT3 TKI. Western blotting confirmed that some FLT3 TKI were ineffective at inhibiting FLT3 autophosphorylation and signaling through MAP kinase, STAT5 and AKT in some mutants. Balb/c mice transplanted with the FLT3/ITD Y842C mutation confirmed resistance to sorafenib in vivo but not to lestaurtinib. These results indicate a growing number of FLT3 mutations that are likely to be encountered in patients. Such knowledge, combined with known remaining sensitivity to other FLT3 TKI, will be important to establish as secondary drug treatments that can be substituted when these mutants are encountered.