Knockdown of miR-128a induces Lin28a expression and reverts myeloid differentiation blockage in acute myeloid leukemia

Luciana De Luca,Oreste Villani,Geppino Falco,Vitina Grieco,Francesco La Rocca,Valentina Campia,Daniela Cilloni,Filomena Nozza,Antonella Caivano,Pellegrino Musto,Gabriella Bianchino,Daniela Tagliaferri,Stefania Trino,Luigi Del Vecchio,Francesca D'Alessio,Ilaria Laurenzana

doi:10.1038/cddis.2017.253

Abstract

Lin28A is a highly conserved RNA-binding protein that concurs to control the balance between stemness and differentiation in several tissue lineages. Here, we report the role of miR-128a/Lin28A axis in blocking cell differentiation in acute myeloid leukemia (AML), a genetically heterogeneous disease characterized by abnormally controlled proliferation of myeloid progenitor cells accompanied by partial or total inability to undergo terminal differentiation. First, we found Lin28A underexpressed in blast cells from AML patients and AML cell lines as compared with CD34+ normal precursors. In vitro transfection of Lin28A in NPM1-mutated OCI-AML3 cell line significantly triggered cell-cycle arrest and myeloid differentiation, with increased expression of macrophage associate genes (EGR2, ZFP36 and ANXA1). Furthermore, miR-128a, a negative regulator of Lin28A, was found overexpressed in AML cells compared with normal precursors, especially in acute promyelocytic leukemia (APL) and in ‘AML with maturation’ (according to 2016 WHO classification of myeloid neoplasms and acute leukemia). Its forced overexpression by lentiviral infection in OCI-AML3 downregulated Lin28A with ensuing repression of macrophage-oriented differentiation. Finally, knockdown of miR-128a in OCI-AML3 and in APL/AML leukemic cells (by transfection and lentiviral infection, respectively) induced myeloid cell differentiation and increased expression of Lin28A, EGR2, ZFP36 and ANXA1, reverting myeloid differentiation blockage. In conclusion, our findings revealed a new mechanism for AML differentiation blockage, suggesting new strategies for AML therapy based upon miR-128a inhibition.

Highlights

Stratifying Acute myeloid leukemia (AML) according to the WHO classification,[4] Lin28A value was found underexpressed in all AML subtypes (Figure 1b) compared with controls
Stratifying AML cases according to the principal genomic alterations detected in our cohort of patients and in GSE 15434 data set, we found lower expression of Lin28A in AML patients independent of their specific alterations (Figure 1c and Supplementary Figure 1b)
Stratifying AML cases for morphologic features, we found, at variance with Lin28A, elevated expression levels of miR-128a in AML with maturation and acute promyelocytic leukemia (APL) cases compared with controls (Figure 4b)

Summary

Introduction

Acute myeloid leukemia (AML) is a heterogeneous hematopoietic stem cell neoplasm, characterized by rapid growth and/or impaired differentiation of leukemic cells with abnormal accumulation.[1,2,3] Recurring chromosomal aberrations and gene mutations contribute to AML pathogenesis and are the most important tools for classification and prognosis assessment of AML.[2,3,4] there are some known deregulated pathways involved in the maintenance of leukemic stem cells such as hedgehog,[5,6] tyrosine kinase receptors (e.g. Flt3),[3,7] Wnt and Notch.[8,9,10,11] Notwithstanding, a successful target therapy is not yet available. Lin[28] is regulated by miR-128,28 a microRNA able to hold hematopoietic cells in an early progenitor stage, blocking their. The miR-128a/Lin28A axis in acute myeloid leukemia L De Luca et al differentiation towards more mature cells.[29,30] this microRNA was found associated with AML.[31,32,33] it will be appealing to gain further insights into the role of miR-128a/Lin28A axis in induction and maintenance of an early differentiation status in AML

Methods

Results

Conclusion