The tyrosine kinase FES is an essential effector of KITD816V proliferation signal

Abstract

KIT is a tyrosine kinase receptor that is aberrantly activated in several neoplasms. In human pathologies, the most frequent mutation of KIT occurs at codon 816. The resulting KIT mutant protein is activated in the absence of ligand and is resistant to the clinically available inhibitors of KIT. In this report, we provide evidence for an essential function of the cytoplasmic tyrosine kinase FES downstream of KIT D816V . FES is phosphorylated on tyrosine residues in cells that carry KIT D816V mutation, and this phosphorylation is KIT dependent. Reduction of FES expression using RNA interference results in decreased cell proliferation in human or murine cells harboring KIT D816V IntroductionThe proto-oncogene c-kit encodes a receptor with tyrosine kinase activity which is essential for hematopoiesis and the development of melanoblasts, germ cells, and interstitial cells of Cajal. Gain-offunction mutations of KIT are implicated in human pathologies. These mutations have been classified as regulatory-type mutations when they affect domains of the receptor necessary for maintaining KIT autoinhibition and structural-type mutations when they directly affect the catalytic domain. Juxtamembrane mutations of KIT are commonly found in gastrointestinal stromal tumors (GISTs), 1 whereas kinase domain mutations are mainly found in mastocytosis, 2 hematologic neoplasms, [3][4][5] and germ-cell tumors. [6][7][8] Very recently, both juxtamembrane and kinase domain mutations of KIT have also been reported in melanomas. 9 The most frequent mutation affects codon 816 in human c-kit cDNA, which corresponds to codon 814 in the homologous mouse sequence. 10 Whereas tyrosine kinase inhibitors such as imatinib are very efficient on wild-type KIT (KIT WT ) and KIT juxtamembrane mutations, KIT D816V is resistant to this treatment. [11][12][13] Therefore, drugs that could target this mutant or an essential downstream effector would be useful tools for the study and the treatment of the associated diseases.Signaling proteins activated downstream of gain-of-function mutants of KIT include many proteins shown previously to participate in wild-type KIT receptor signal transduction. 14,15 They include the classical phosphatidylinositol 3-kinase (PI3K) and extracellular signal-regulated kinase (ERK) pathways, as well as a number of signaling proteins activated by many cell-surface receptors such as p38, JNK, VAV, STAT-1, STAT-3, and STAT-5. Activation of PI3K is critical for both WT and mutant KIT in all models studied, while the activation of the mitogen-activated protein (MAP) kinases ERK-1 and ERK-2 appears to be dependent on the cellular context. The importance of each protein or signaling pathway activated downstream of KIT D816V has yet to be fully evaluated.Fps/fes was originally identified as an oncogene from avian (fps) and feline (fes) retroviruses. FES (feline sarcoma) and FER (FES-related) proteins are the only 2 members of a subfamily of cytoplasmic protein tyrosine kinase. 16 FES has been shown to associate with growth factor an...

Target interaction profiling of midostaurin and its metabolites in neoplastic mast cells predicts distinct effects on activation and growth

“…Among these were FES, AAK1, and BIKE. FES is of particular interest, because this target has recently been implicated in KIT D816V-driven MC proliferation (47). In the present study, we were able to confirm that FES is a relevant KIT-downstream kinase target in HMC-1.2 cells.…”

Global target profile of the kinase inhibitor bosutinib in primary chronic myeloid leukemia cells

“…31,32 Further complementing the profiles obtained by chemical proteomics, dasatinib was far less active than bosutinib against the STE20s, which predominantly carry a methionine gatekeeper residue, exhibiting in most cases an IC 50 of greater than 10 mM for inhibition. As expected, neither KIT nor PDGFR are targeted by bosutinib; however, the FES tyrosine kinase, which is important for signaling by KIT D816V, 33 was inhibited, suggesting that despite resistance of this mutant to bosutinib, there may still be a clinical effect on D816V-positive malignancies. Finally, the Ca 2 þ /calmodulin-dependent protein kinases CAMK1D and CAMK2G, the neurotrophin-binding receptor tyrosine kinases TRKA/B and AXL, a recently reported target of bosutinib found to be involved in breast cancer cell motility and invasivity, 15 were selectively inhibited by bosutinib, whereas RIPK2 was inhibited only by dasatinib.…”

FES kinases are required for oncogenic FLT3 signaling

“…The human fes A-siRNA and fes B-siRNA, the human fer 1-siRNA, and the control-siRNA were described earlier. 13 The human fer 2-siRNA targeted the human fer sequence 5 0 -GGAG UGACCUGAAGAAUUCUU-3 0 (Dharmacon Research, Lafayette, CO, USA). The human flt3-siRNA was a mix of the following four duplexes 5 0 -CAAGAAACGACACCGGAUAUU-3 0 , 5 0 -GAAUUUAAGUCGUGUGUUCUU-3 0 , 5 0 -GCAAUGAUAU UUGGGACUAUU-3 0 , and 5 0 -CGCAACAGCUUAUGGAAUU UU-3 0 (SMARTpool siRNA, Dharmacon Research).…”

“…12 We have reported recently a function for FES downstream of the activated D816V KIT receptor, the most frequent oncogenic KIT mutant. 13 KIT mutations occur in about 5% of AML cases 14 and are implicated in the majority of gastro-intestinal stromal tumors 15 and mastocytosis. 16 In erythroleukemia and mastocytoma cell lines that harbor activating KIT mutations, FES has an essential role in KIT-dependent cell proliferation.…”

“…16 In erythroleukemia and mastocytoma cell lines that harbor activating KIT mutations, FES has an essential role in KIT-dependent cell proliferation. 13 KIT and FLT3 are closely related receptors. Both are mutated in pathologies and both share similar gain-of-function mutations, arising from mutations in the catalytic domain and in the juxtamembrane regulatory region.…”