Epigenetic silencing of AKAP12 in juvenile myelomonocytic leukemia.
Thomas Wilhelm, Daniel B Lipka, Tania Witte, Justyna A Wierzbinska, Silvia Fluhr, Monika Helf, Oliver Mücke, Rainer Claus, Carolin Konermann, Peter Nöllke, Charlotte M Niemeyer, Christian Flotho, Christoph Plass
Author Information
Thomas Wilhelm: a Division of Epigenomics and Cancer Risk Factors, German Cancer Research Center , Heidelberg , Germany.
Daniel B Lipka: b Regulation of Cellular Differentiation Group, Division of Epigenomics and Cancer Risk Factors, German Cancer Research Center , Heidelberg , Germany.
Tania Witte: a Division of Epigenomics and Cancer Risk Factors, German Cancer Research Center , Heidelberg , Germany.
Justyna A Wierzbinska: a Division of Epigenomics and Cancer Risk Factors, German Cancer Research Center , Heidelberg , Germany.
Silvia Fluhr: c Department of Pediatrics and Adolescent Medicine , Division of Pediatric Hematology-Oncology, University of Freiburg Medical Center , Freiburg , Germany.
Monika Helf: b Regulation of Cellular Differentiation Group, Division of Epigenomics and Cancer Risk Factors, German Cancer Research Center , Heidelberg , Germany.
Oliver Mücke: a Division of Epigenomics and Cancer Risk Factors, German Cancer Research Center , Heidelberg , Germany.
Rainer Claus: a Division of Epigenomics and Cancer Risk Factors, German Cancer Research Center , Heidelberg , Germany.
Carolin Konermann: a Division of Epigenomics and Cancer Risk Factors, German Cancer Research Center , Heidelberg , Germany.
Peter Nöllke: c Department of Pediatrics and Adolescent Medicine , Division of Pediatric Hematology-Oncology, University of Freiburg Medical Center , Freiburg , Germany.
Charlotte M Niemeyer: c Department of Pediatrics and Adolescent Medicine , Division of Pediatric Hematology-Oncology, University of Freiburg Medical Center , Freiburg , Germany.
Christian Flotho: c Department of Pediatrics and Adolescent Medicine , Division of Pediatric Hematology-Oncology, University of Freiburg Medical Center , Freiburg , Germany.
Christoph Plass: a Division of Epigenomics and Cancer Risk Factors, German Cancer Research Center , Heidelberg , Germany.
A-kinase anchor protein 12 (AKAP12) is a regulator of protein kinase A and protein kinase C signaling, acting downstream of RAS. Epigenetic silencing of AKAP12 has been demonstrated in different cancer entities and this has been linked to the process of tumorigenesis. Here, we used quantitative high-resolution DNA methylation measurement by MassARRAY to investigate epigenetic regulation of all three AKAP12 promoters (i.e., α, β, and γ) within a large cohort of juvenile myelomonocytic leukemia (JMML) patient samples. The AKAP12α promoter shows DNA hypermethylation in JMML samples, which is associated with decreased AKAP12α expression. Promoter methylation of AKAP12α correlates with older age at diagnosis, elevated levels of fetal hemoglobin and poor prognosis. In silico screening for transcription factor binding motifs around the sites of most pronounced methylation changes in the AKAP12α promoter revealed highly significant scores for GATA-2/-1 sequence motifs. Both transcription factors are known to be involved in the haematopoietic differentiation process. Methylation of a reporter construct containing this region resulted in strong suppression of AKAP12 promoter activity, suggesting that DNA methylation might be involved in the aberrant silencing of the AKAP12 promoter in JMML. Exposure to DNMT- and HDAC-inhibitors reactivates AKAP12α expression in vitro, which could potentially be a mechanism underlying clinical treatment responses upon demethylating therapy. Together, these data provide evidence for epigenetic silencing of AKAP12α in JMML and further emphasize the importance of dysregulated RAS signaling in JMML pathogenesis.
