Epigenetic silencing of miR564 contributes to the leukemogenesis of t(8;21) acute myeloid leukemia.

The AML1-ETO oncoprotein, which results from t(8;21) translocation, is considered an initial event of t(8;21) acute myeloid leukemia (AML). However, the precise mechanisms of the oncogenic activity of AML1-ETO is yet to be fully determined. The present study demonstrates that AML1-ETO triggers the heterochromatic silencing of microRNA-564 (miR564) by binding at the AML1 binding site along the miR564 promoter region and recruiting chromatin-remodeling enzymes. Suppression of miR564 enhances the oncogenic activity of the AML1-ETO oncoprotein by directly inhibiting the expression of CCND1 and the DNMT3A genes. Ectopic expression of miR564 can induce retardation of G1/S transition, reperform differentiation, promote apoptosis, as well as inhibit the proliferation and colony formation of AML1-ETO+ leukemia cells in vitro. Enhanced miR564 levels can significantly inhibit the tumor proliferation of t(8;21)AML in vivo. We first identify an unexpected and important epigenetic circuitry of AML1-ETO/miR564/CCND1/DNMT3A that contributes to the leukemogenesis in vitro/vivo of AML1-ETO+ leukemia, indicating that miR564 enhancement could provide a potential therapeutic method for AML1-ETO+ leukemia.

Yang E ，Guan W ，Gong D ，Gao X ，Han C ，Zhang J ，Wang H ，Wang M ，Li Y ，Yu L ... -  《-》

Epigenetic silencing of microRNA-193a contributes to leukemogenesis in t(8;21) acute myeloid leukemia by activating the PTEN/PI3K signal pathway.

Li Y ，Gao L ，Luo X ，Wang L ，Gao X ，Wang W ，Sun J ，Dou L ，Li J ，Xu C ，Wang L ，Zhou M ，Jiang M ，Zhou J ，Caligiuri MA ，Nervi C ，Bloomfield CD ，Marcucci G ，Yu L ... -  《-》

Epigenetic Silencing of Eyes Absent 4 Gene by Acute Myeloid Leukemia 1-Eight-twenty-one Oncoprotein Contributes to Leukemogenesis in t(8;21) Acute Myeloid Leukemia.

Huang S ，Jiang MM ，Chen GF ，Qian K ，Gao HH ，Guan W ，Shi JL ，Liu AQ ，Liu J ，Wang BH ，Li YH ，Yu L ... -  《-》

The Hematopoietic Transcription Factors RUNX1 and ERG Prevent AML1-ETO Oncogene Overexpression and Onset of the Apoptosis Program in t(8;21) AMLs.

The t(8;21) acute myeloid leukemia (AML)-associated oncoprotein AML1-ETO disrupts normal hematopoietic differentiation. Here, we have investigated its effects on the transcriptome and epigenome in t(8,21) patient cells. AML1-ETO binding was found at promoter regions of active genes with high levels of histone acetylation but also at distal elements characterized by low acetylation levels and binding of the hematopoietic transcription factors LYL1 and LMO2. In contrast, ERG, FLI1, TAL1, and RUNX1 bind at all AML1-ETO-occupied regulatory regions, including those of the AML1-ETO gene itself, suggesting their involvement in regulating AML1-ETO expression levels. While expression of AML1-ETO in myeloid differentiated induced pluripotent stem cells (iPSCs) induces leukemic characteristics, overexpression increases cell death. We find that expression of wild-type transcription factors RUNX1 and ERG in AML is required to prevent this oncogene overexpression. Together our results show that the interplay of the epigenome and transcription factors prevents apoptosis in t(8;21) AML cells.

Mandoli A ，Singh AA ，Prange KHM ，Tijchon E ，Oerlemans M ，Dirks R ，Ter Huurne M ，Wierenga ATJ ，Janssen-Megens EM ，Berentsen K ，Sharifi N ，Kim B ，Matarese F ，Nguyen LN ，Hubner NC ，Rao NA ，van den Akker E ，Altucci L ，Vellenga E ，Stunnenberg HG ，Martens JHA ... -  《Cell Reports》

A novel epigenetic AML1-ETO/THAP10/miR-383 mini-circuitry contributes to t(8;21) leukaemogenesis.

DNA methylation patterns are frequently deregulated in t(8;21) acute myeloid leukaemia (AML), but little is known of the mechanisms by which specific gene sets become aberrantly methylated. Here, we found that the promoter DNA methylation signature of t(8;21)+ AML blasts differs from that of t(8;21)- AMLs. This study demonstrated that a novel hypermethylated zinc finger-containing protein, THAP10, is a target gene and can be epigenetically suppressed by AML1-ETO at the transcriptional level in t(8;21) AML. Our findings also show that THAP10 is a bona fide target of miR-383 that can be epigenetically activated by the AML1-ETO recruiting co-activator p300. In this study, we demonstrated that epigenetic suppression of THAP10 is the mechanistic link between AML1-ETO fusion proteins and tyrosine kinase cascades. In addition, we showed that THAP10 is a nuclear protein that inhibits myeloid proliferation and promotes differentiation both in vitro and in vivo Altogether, our results revealed an unexpected and important epigenetic mini-circuit of AML1-ETO/THAP10/miR-383 in t(8;21) AML, in which epigenetic suppression of THAP10 predicts a poor clinical outcome and represents a novel therapeutic target.

Li Y ，Ning Q ，Shi J ，Chen Y ，Jiang M ，Gao L ，Huang W ，Jing Y ，Huang S ，Liu A ，Hu Z ，Liu D ，Wang L ，Nervi C ，Dai Y ，Zhang MQ ，Yu L ... -  《-》