MIR29B regulates expression of MLLT11 (AF1Q), an MLL fusion partner, and low MIR29B expression associates with adverse cytogenetics and poor overall survival in AML

University of Colorado Cancer Center, University of Colorado-Denver, Aurora, CO, USA.
British Journal of Haematology (Impact Factor: 4.96). 06/2011; 153(6):753-7. DOI: 10.1111/j.1365-2141.2011.08662.x
Source: PubMed

ABSTRACT MLLT11, an MLL fusion partner, is a poor prognostic biomarker for paediatric acute myeloid leukaemia (AML), adult normal cytogenetics AML, and adult myelodysplastic syndrome. MLLT11 is highly regulated during haematopoietic progenitor differentiation and development but its regulatory mechanisms have not been defined. In this study, we demonstrate by transfection experiments that MIR29B directly regulates MLLT11 expression in vitro. MIR29B expression level was also inversely related to MLLT11 expression in a cohort of 56 AML patients (P<0·05). AML patients with low MIR29B/elevated MLLT11 expression had poor overall survival (P=0·038). Therefore, MIR29B may be a potential prognostic biomarker for AML patients.

  • [Show abstract] [Hide abstract]
    ABSTRACT: This study was designed to learn the expression status of miR-24 and its clinical relevance in patients with acute myeloid leukemia (AML). We detected the miR-24 expression levels using real-time quantitative PCR in 84 AML patients and investigated the clinical significance of miR-24 expression in AML. There was no difference in clinical parameters between cases with miR-24 high expression and with miR-24 low expression. The frequency of miR-24 high expression was higher in patients with t(8;21) than in others (82% (9/11) versus 44% (32/72), P=0.026). The levels of miR-24 expression had no correlation with the mutations of nine genes (FLT3-ITD, NPM1, C-KIT, IDH1/IDH2, DNMT3A, N/K-RAS and C/EBPA). Meanwhile, among the group who obtained CR, the cases with miR-24 high expression had no difference in overall survival (OS) and relapse-free survival (RFS) than those with miR-24 low expression (P=0.612 and 0.665, respectively). These findings implicated that miR-24 high regulation is a common event in AML with t(8;21), and it might serve as a novel and selective therapeutic target for the treatment of AML with t(8;21).
  • [Show abstract] [Hide abstract]
    ABSTRACT: Dysregulation of microRNA let-7a-3 has been identified in several solid tumors and is associated with prognosis of patients. However, the pattern of let-7a-3 expression and the impact on prognosis has not yet been studied in acute myeloid leukemia (AML). The purpose of this study is to investigate the expression status of let-7a-3 and its clinical significance in AML patients using real-time quantitative PCR. Overexpression of let-7a-3 was identified in 25 of 102 (25%) de novo AML. There was no significant difference in age, blood parameters, FAB/WHO subtypes, karyotype risks and nine gene mutations (FLT3-ITD, NPM1, C-KIT, IDH1/IDH2, DNMT3A, C/EBPA and N/K-RAS) between patients with and without let-7a-3 overexpression (P>0.05). The patients with let-7a-3 overexpression had similar rates of complete remission (CR) as those without let-7a-3 overexpression (50% vs. 56%, P=0.693). Although the overall survival (OS) of AML patients with let-7a-3 overexpression (median 12 months,) was shorter than those without overexpression (median 25 months), the difference was not statistically significant (P=0.228). However, among those 51 obtained CR, patients with let-7a-3 overexpression had significantly shorter OS than those without let-7a-3 overexpression (P=0.029). The difference in relapse-free survival (RFS) was also significant between two groups (P=0.005). These findings suggest that let-7a-3 overexpression is a common event and is associated with poor clinical outcome in AML.
    Leukemia research 09/2013; 37(12). DOI:10.1016/j.leukres.2013.09.022 · 2.69 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: AF1Q, a mixed lineage leukemia gene fusion partner, is identified as a poor prognostic biomarker for pediatric acute myeloid leukemia (AML), adult AML with normal cytogenetic and adult myelodysplastic syndrome. AF1Q is highly regulated during hematopoietic progenitor differentiation and development but its regulatory mechanism has not been defined clearly. In the present study, we used pharmacological and genetic approaches to influence chaperone-mediated autophagy (CMA) and explored the degradation mechanism of the AF1Q. Pharmacological inhibitors of lysosomal degradation, such as chloroquine, increased AF1Q levels, whereas activators of CMA, including 6-aminonicotinamide and nutrient starvation, decreased AF1Q levels. AF1Q interacts with HSPA8 and LAMP-2A, which are core components of the CMA machinery. Knockdown of HSPA8 or LAMP-2A increased AF1Q protein levels, whereas overexpression showed the opposite effect. Using an amino acid deletion AF1Q mutation plasmid, we identified that AF1Q had a KFERQ-like motif which was recognized by HSPA8 for CMA-dependent proteolysis. In conclusion, we demonstrate for the first time that AF1Q can be degraded in lysosomes by CMA.
    Experimental Cell Research 05/2014; 327(1). DOI:10.1016/j.yexcr.2014.05.013 · 3.37 Impact Factor