MicroRNA-150 Expression Induces Myeloid Differentiation of Human Acute Leukemia Cells and Normal Hematopoietic Progenitors

Abstract

In acute myeloid leukemia (AML) and blast crisis (BC) chronic myeloid leukemia (CML) normal differentiation is impaired. Differentiation of immature stem/progenitor cells is critical for normal blood cell function. MicroRNAs (miRNAs or miRs) are small non-coding RNAs that interfere with gene expression by degrading messenger RNAs (mRNAs) or blocking protein translation. Aberrant miRNA expression is a feature of leukemia and miRNAs also play a significant role in normal hematopoiesis and differentiation. We have identified miRNAs differentially expressed in AML and BC CML and identified a new role for miR-150 in myeloid differentiation. Expression of miR-150 is low or absent in BC CML and AML patient samples and cell lines. We have found that expression of miR-150 in AML cell lines, CD34+ progenitor cells from healthy individuals, and primary BC CML and AML patient samples at levels similar to miR-150 expression in normal bone marrow promotes myeloid differentiation of these cells. MYB is a direct target of miR-150, and we have identified that the observed phenotype is partially mediated by MYB. In AML cell lines, differentiation of miR-150 expressing cells occurs independently of retinoic acid receptor α (RARA) signaling. High-throughput gene expression profiling (GEP) studies of the AML cell lines HL60, PL21, and THP-1 suggest that activation of CEPBA, CEBPE, and cytokines associated with myeloid differentiation in miR-150 expressing cells as compared to control cells contributes to myeloid differentiation. These data suggest that miR-150 promotes myeloid differentiation, a previously uncharacterized role for this miRNA, and that absent or low miR-150 expression contributes to blocked myeloid differentiation in acute leukemia cells.

Deregulated KLF4 Expression in Myeloid Leukemias Alters Cell Proliferation and Differentiation through MicroRNA and Gene Targets

“…Notably, gene expression changes identified by RT-qPCR with KLF4 overexpression were similar to those we observed with miR-150 overexpression, in particular with regard to S100A8 and S100A9 (Fig. 2B) (22). KLF2 and KLF4 overexpression inhibited proliferation of THP-1 cells and induced expression of a known, and well-characterized, downstream target gene of KLF4, the cell cycle inhibitor CDKN1A, which in other work has been shown to limit cell proliferation and promote differentiation ( Fig.…”

“…In AML primary patient samples and cell lines, we demonstrated that expression of miR-150 decreases cell proliferation and promotes myeloid differentiation (22). Our observations are supported by a study in which it was observed that miR-150 reexpression in an MLL-AF9 rearranged murine model of AML inhibited leukemia cell growth (23).…”

“…The line indicates the mean expression in normal hematopoietic progenitors. cells (22). We confirmed overexpression of the individual KLFs by quantitative RT-PCR (RT-qPCR) and Western blotting (data not shown).…”

“…Previously, we showed that miRNA 150 (miR-150) expression is low or absent in pediatric and adult AML patient samples across various cytogenetic and molecular risk groups and in normalkaryotype (NK) AML cases, suggesting that miR-150 loss occurs pervasively in AML (22)(23)(24). In AML primary patient samples and cell lines, we demonstrated that expression of miR-150 decreases cell proliferation and promotes myeloid differentiation (22).…”

The Role of Immune Modulatory MicroRNAs in Tumors

“…In this context, Moles and coworkers [118] demonstrated that both miRNA-223 and miRNA-150 target STAT1 3′-UTR and reduce STAT1 expression, which in turn results in reduced expression of IFN-γ-regulated genes. The expression of miRNA-150 is upregulated in CD19 + B cells from chronic lymphocytic leukemia [119,120], while in chronic myeloid leukemia [121,122], ALL [123] and mantel cell carcinoma miRNA-150 is downregulated. Moreover, miRNA-150 is upregulated in adult T-cell leukemia/lymphoma cells.…”