Epor Over-Expression In TEL-AML1 Positive ALL: Critical Roles for DNA Methylation, GATA-2 or MicroRNAs?
| Autor: | Marketa Zaliova, Marie E. Breen, Vivien M. Hodges, Jan Trka, Terence R.J. Lappin, Ken I. Mills |
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| Rok vydání: | 2010 |
| Předmět: | |
| Zdroj: | Blood. 116:3619-3619 |
| ISSN: | 1528-0020 0006-4971 |
| DOI: | 10.1182/blood.v116.21.3619.3619 |
| Popis: | Abstract 3619 Erythropoietin (Epo) and its receptor (EpoR) play vital roles in regulating red blood cell production. However, aberrant over-expression of EpoR has been reported in a wide range of tumours and hematological malignancies, particularly acute lymphoblastic leukemia (ALL) with the chromosomal translocation TEL-AML1 (ETV6/RUNX1). Around 25% of B-cell ALLs contain this chromosomal translocation which is associated with a favourable, prognosis but the role of EpoR is unknown. We have investigated whether methylation, transcription factors or miRNA regulation are implicated in the mechanism of the specific EpoR up-regulation associated with the TEL-AML1 rearrangement using two human B precursor cell line models. The pre-B REH cell line is TEL-AML1 positive whereas the pre-B NALM-6 cell line is TEL-AML1 negative; in addition the erythroleukemia cell line UT-7, which constitutively over- expresses EpoR was used as a positive control. Sequencing confirmed that the EpoR in these cell lines was wild type. Quantitative RT-PCR (RQ-PCR) of EpoR mRNA levels showed ~25 fold higher expression in REH cells compared to NALM-6 cells, verified by western blot analysis. RQ-PCR analysis of 20 pediatric ALL patient samples confirmed a 14-fold up-regulation (p DNA methylation is an epigenetic marker which can directly impact on gene transcription, with aberrant methylation reported in many cancers. The methylation status of 18 CpG sites over 342 bp within the EpoR promoter encompassing the GATA and Sp1 binding sites was analysed by pyrosequencing in REH and NALM-6 cells. Fifteen of the 18 CpG sites showed significantly higher (p The GATA family of zinc-finger proteins have well characterised roles in hematopoiesis and EpoR regulation. Measurement of the expression of all six GATA transcription factors, by RQ-PCR showed that only GATA-2 was significantly up-regulated in REH cells (p Furthermore, initial studies have indicated differential expression, between the REH and NALM-6 cell lines, in miRNA whose targets have been predicted (www.diana.pcbi.upenn.edu) to be EpoR and/or GATA-2. Further investigation of the modulation of EpoR expression by methylation, GATA-2 or miRNAs, will lead to a greater understanding of of the factors regulating the expression of EpoR and the potential for alternative forms of therapeutic intervention in patients with TEL-AML1 ALL. Disclosures: No relevant conflicts of interest to declare. |
| Databáze: | OpenAIRE |
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