TREATMENT WITH 5-AZACYTIDINE RESULTS IN EXPRESSION OF LONG TERMINAL REPEAT (LTR) ELEMENTS IN PERIPHERAL BLOOD MONONUCLEAR CELLS OF PATIENTS WITH MDS AND AML: FIRST PILOT STUDY.
Author(s): ,
Michael Daskalakis
Affiliations:
Hematology and Central Hematology Laboratory,Inselspital, Bern University Hospital, University of Bern,Bern,Switzerland;Laboratory for Hematopoiesis and Molecular Genetics, Department of BioMedical Research (DBMR),University of Bern,Bern,Switzerland
,
Monika Haubitz
Affiliations:
Laboratory for Hematopoiesis and Molecular Genetics, Department of BioMedical Research (DBMR),University of Bern,Bern,Switzerland
,
Daniela Steiner
Affiliations:
Laboratory for Hematopoiesis and Molecular Genetics, Department of BioMedical Research (DBMR),University of Bern,Bern,Switzerland
,
Monika Helf
Affiliations:
Cancer Epigenomics,German Cancer Research Center (DKFZ),Heidelberg,Germany
,
Ashish Goyal
Affiliations:
Cancer Epigenomics,German Cancer Research Center (DKFZ),Heidelberg,Germany
,
David Brocks
Affiliations:
Department of Computer Science and Applied Mathematics and Department of Biological Regulation,Weizmann Institute,Rehovot,Israel
,
Lisa Pleyer
Affiliations:
Department of Internal Medicine III with Hematology, Medical Oncology, Hemostaseology, Infectious Diseases and Rheumatology,Paracelsus Medical University Salzburg,Salzburg,Austria
,
Richard Greil
Affiliations:
Department of Internal Medicine III with Hematology, Medical Oncology, Hemostaseology, Infectious Diseases and Rheumatology,Paracelsus Medical University Salzburg,Salzburg,Austria
,
Christoph Plass
Affiliations:
Cancer Epigenomics,German Cancer Research Center (DKFZ),Heidelberg,Germany
,
Gabriela M. Baerlocher
Affiliations:
Hematology and Central Hematology Laboratory,Inselspital, Bern University Hospital, University of Bern,Bern,Switzerland;Laboratory for Hematopoiesis and Molecular Genetics, Department of BioMedical Research (DBMR),University of Bern,Bern,Switzerland
Elisabeth Oppliger Leibundgut
Affiliations:
Hematology and Central Hematology Laboratory,Inselspital, Bern University Hospital, University of Bern,Bern,Switzerland;Laboratory for Hematopoiesis and Molecular Genetics, Department of BioMedical Research (DBMR),University of Bern,Bern,Switzerland
EHA Library. Daskalakis M. Jun 14, 2019; 266242; PF442
Michael Daskalakis
Michael Daskalakis
Contributions
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Abstract

Abstract: PF442

Type: Poster Presentation

Presentation during EHA24: On Friday, June 14, 2019 from 17:30 - 19:00

Location: Poster area

Background

Epigenetic drugs are used for the treatment of several hematologic malignancies, but their pharmacological mechanism remains poorly understood. By genome wide analysis of transcription start sites (TSS), methylation status and chromatin dynamics, we showed for DNA methyltransferase and histone deacetylase inhibitors (DNMTi and HDACi) global reactivation of long terminal repeat elements (LTRs) in vitro (cell line models) and in vivo (neuroblastoma mouse xenograft model). The LTR reactivation is resulting in numerous fusion transcripts that encode novel protein isoforms which have the potential to influence cell proliferation, seem to be an explanation for the priming effect of epigenetic therapy and might be used as a potential marker for epigenetic treatment response.

Aims

To investigate the reactivation of LTRs in sequential peripheral blood samples of AML and MDS patients upon epigenetic drug treatment with 5-Azacytidine (DNMT-inhibitor) by qRT-PCR and ddPCR and to correlate the expression results with treatment response.

Methods

Sequential RNA samples from peripheral blood mononuclear cells (PBMCs) of three AML and four MDS patients treated with 5-Azacytidine were analyzed. Consensus primers covering the transcript variants of LTR12C as well as particular primers for specific LTR elements were used. Expression of LTRs was analyzed by qRT-PCR technique with SYBRGreen as well as ddPCR technique with EvaGreen. Expression results were associated with treatment response.

Results

In AML and MDS patients, we could detect LTR expression in sequential samples from PBMCs over time with 5-Azacytidine treatment. LTR12C expression values measured by qRT-PCR were confirmed by ddPCR and allowed to assess specific LTR elements. Patients with response to 5-Azacytidine showed increased LTR12C expression whereas patients without treatment response had no increase in LTR12C expression. In contrast to the results from our previous NSCLC cell line model, specific LTR elements were only partially expressed in sequential PBMC samples from AML patients treated with 5-Azacytidine.

Conclusion

In this first in-vivo pilot study, we detected LTR expression in sequential PBMC samples of AML and MDS patients treated with 5-Azacytidine. In this group of patients, treatment response correlated with LTR expression over several treatment cycles with 5-Azacytidine. These are the first results in AML and MDS patients showing expression of LTRs upon epigenetic drug treatment. Larger patient cohorts are necessary to confirm these results by either PCR- or genome wide-analysis of transcription start sites (TSS) (Cap analysis of gene expression (CAGE) sequencing) as well as to evaluate the association of LTR expression and treatment response.

Session topic: 24. Gene therapy, cellular immunotherapy and vaccination - Biology & Translational Res

Keyword(s): Azacitidine, Epigenetic, Immune response, Retrovirus

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