| First Author | Taylor SJ | Year | 2015 |
| Journal | Exp Hematol | Volume | 43 |
| Issue | 3 | Pages | 191-206.e1 |
| PubMed ID | 25534201 | Mgi Jnum | J:230276 |
| Mgi Id | MGI:5755912 | Doi | 10.1016/j.exphem.2014.11.009 |
| Citation | Taylor SJ, et al. (2015) Loss of c-Cbl E3 ubiquitin ligase activity enhances the development of myeloid leukemia in FLT3-ITD mutant mice. Exp Hematol 43(3):191-206.e1 |
| abstractText | Mutations in the Fms-like tyrosine kinase 3 (FLT3) receptor tyrosine kinase (RTK) occur frequently in acute myeloid leukemia (AML), with the most common involving internal tandem duplication (ITD) within the juxtamembrane domain. Fms-like tyrosine kinase 3-ITD mutations result in a mislocalized and constitutively activated receptor, which aberrantly phosphorylates signal transducer and activator of transcription 5 (STAT5) and upregulates the expression of its target genes. c-Cbl is an E3 ubiquitin ligase that negatively regulates RTKs, including FLT3, but whether it can downregulate mislocalized FLT3-ITD remains to be resolved. To help clarify this, we combined a FLT3-ITD mutation with a loss-of-function mutation in the RING finger domain of c-Cbl that abolishes its E3 ligase activity. Mice transplanted with hematopoietic stem cells expressing both mutations rapidly develop myeloid leukemia, indicating strong cooperation between the two. Although the c-Cbl mutation was shown to cause hyperactivation of another RTK, c-Kit, it had no effect on enhancing FLT3-ITD protein levels or STAT5 activation. This indicates that c-Cbl does not downregulate FLT3-ITD and that the leukemia is driven by independent pathways involving FLT3-ITD's activation of STAT5 and mutant c-Cbl's activation of other RTKs, such as c-Kit. This study highlights the importance of c-Cbl's negative regulation of wild-type RTKs in suppressing FLT3-ITD-driven myeloid leukemia. |
