| First Author | Sun YM | Year | 2019 |
| Journal | Blood | Volume | 134 |
| Issue | 18 | Pages | 1533-1546 |
| PubMed ID | 31387917 | Mgi Jnum | J:282738 |
| Mgi Id | MGI:6379080 | Doi | 10.1182/blood.2019000802 |
| Citation | Sun YM, et al. (2019) circMYBL2, a circRNA from MYBL2, regulates FLT3 translation by recruiting PTBP1 to promote FLT3-ITD AML progression. Blood 134(18):1533-1546 |
| abstractText | Internal tandem duplication (ITD) mutations within FMS-like tyrosine kinase-3 (FLT3) occur in up to 30% of acute myeloid leukemia (AML) patients and confer a very poor prognosis. The oncogenic form of FLT3 is an important therapeutic target, and inhibitors specifically targeting FLT3 kinase can induce complete remission; however, relapse after remission has been observed due to acquired resistance with secondary mutations in FLT3, highlighting the need for new strategies to target FLT3-ITD mutations. Recent studies have reported that the aberrant formations of circular RNAs (circRNAs) are biological tumorigenesis-relevant mechanisms and potential therapeutic targets. Herein, we discovered a circRNA, circMYBL2, derived from the cell-cycle checkpoint gene MYBL2. circMYBL2 is more highly expressed in AML patients with FLT3-ITD mutations than in those without the FLT3-ITD mutation. We found that circMYBL2 knockdown specifically inhibits proliferation and promotes the differentiation of FLT3-ITD AML cells in vitro and in vivo. Interestingly, we found that circMYBL2 significantly influences the protein level of mutant FLT3 kinase, which contributes to the activation of FLT3-ITD-dependent signaling pathways. Mechanistically, circMYBL2 enhanced the translational efficiency of FLT3 kinase by increasing the binding of polypyrimidine tract-binding protein 1 (PTBP1) to FLT3 messenger RNA. Moreover, circMYBL2 knockdown impaired the cytoactivity of inhibitor-resistant FLT3-ITD+ cells, with a significant decrease in FLT3 kinase expression, followed by the inactivation of its downstream pathways. In summary, we are the first to reveal a circRNA that specifically influences FLT3-ITD AML and regulates FLT3 kinase levels through translational regulation, suggesting that circMYBL2 may be a potential therapeutic target for FLT3-ITD AML. |
