F604S exchange in FIP1L1-PDGFRA enhances FIP1L1-PDGFRA protein stability via SHP-2 and SRC: a novel mode of kinase inhibitor resistance
FIP1L1-PDGFRA is a constitutively activated kinase described in chronic eosinophilic leukemia (CEL) and hypereosinophilic syndrome (HES). Imatinib is clinically active in FIP1L1-PDGFRA-positive diseases. Using in vitro screening to identify imatinib-resistant mutations, we frequently detected a Phe...
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| Main Authors: | , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
12 March 2015
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| In: |
Leukemia
Year: 2015, Volume: 29, Issue: 8, Pages: 1763-1770 |
| ISSN: | 1476-5551 |
| DOI: | 10.1038/leu.2015.70 |
| Online Access: | Verlag, Volltext: http://dx.doi.org/10.1038/leu.2015.70 Verlag, Volltext: https://www-nature-com.ezproxy.medma.uni-heidelberg.de/articles/leu201570 
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| Author Notes: | S.P. Gorantla, K. Zirlik, A. Reiter, C. Yu, A.L. Illert, N. Von Bubnoff and J. Duyster |
| Summary: | FIP1L1-PDGFRA is a constitutively activated kinase described in chronic eosinophilic leukemia (CEL) and hypereosinophilic syndrome (HES). Imatinib is clinically active in FIP1L1-PDGFRA-positive diseases. Using in vitro screening to identify imatinib-resistant mutations, we frequently detected a Phe to Ser exchange at position 604 (F604S) of FIP1L1-PDGFRA alone or in combination with other exchanges. Surprisingly, FIP1L1-PDGFRA/F604S did not increase the biochemical or cellular IC50 value of imatinib when compared with unmutated FIP1L1-PDGFRA. However, FIP1L1-PDGFRA/F604S more efficiently induced growth factor independence in cell lines and primary mouse bone marrow cells. Pulse chase analysis revealed that the F604S exchange strongly stabilized FIP1L1-PDGFRA/F604S. The F604S mutation creates a binding site for the phosphatase domain of SHP-2, leading to lower autophosphorylation of FIP1L1-PDGFRA/F604S. This is associated with a reduced activation of SRC and CBL by FIP1L1-PDGFRA/F604S compared with the unmutated oncogene. As SRC inhibition and knockdown resulted in FIP1L1-PDGFRA stabilization, this explains the extended half-life of FIP1L1-PDGFRA/F604S. Interestingly, FIP1L1-PDGFRA/L629P, a recently identified mutation in an imatinib-resistant CEL patient, also showed protein stabilization similar to that observed with FIP1L1-PDGFRA/F604S. Therefore, resistance mutations in FIP1L1-PDGFRA that do not interfere with drug binding but rather increase target protein stability seem to be one of the drug-resistance mechanisms in FIP1L1-PDGFRA-positive disease. |
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| Item Description: | Gesehen am 14.02.2018 |
| Physical Description: | Online Resource |
| ISSN: | 1476-5551 |
| DOI: | 10.1038/leu.2015.70 |