title: Epigenetic silencing of AKAP12 in juvenile myelomonocytic leukemia.
abstract: 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.
authors.affiliation: a Division of Epigenomics and Cancer Risk Factors, German Cancer Research Center , Heidelberg , Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Wilhelm
authors.affiliation: b Regulation of Cellular Differentiation Group, Division of Epigenomics and Cancer Risk Factors, German Cancer Research Center , Heidelberg , Germany.
authors.forename: Daniel B
authors.initials: DB
authors.lastname: Lipka
authors.affiliation: a Division of Epigenomics and Cancer Risk Factors, German Cancer Research Center , Heidelberg , Germany.
authors.forename: Tania
authors.initials: T
authors.lastname: Witte
authors.affiliation: a Division of Epigenomics and Cancer Risk Factors, German Cancer Research Center , Heidelberg , Germany.|b Regulation of Cellular Differentiation Group, Division of Epigenomics and Cancer Risk Factors, German Cancer Research Center , Heidelberg , Germany.
authors.forename: Justyna A
authors.initials: JA
authors.lastname: Wierzbinska
authors.affiliation: c Department of Pediatrics and Adolescent Medicine , Division of Pediatric Hematology-Oncology, University of Freiburg Medical Center , Freiburg , Germany.|d Hermann Staudinger Graduate School, University of Freiburg , Freiburg , Germany.
authors.forename: Silvia
authors.initials: S
authors.lastname: Fluhr
authors.affiliation: b Regulation of Cellular Differentiation Group, Division of Epigenomics and Cancer Risk Factors, German Cancer Research Center , Heidelberg , Germany.
authors.forename: Monika
authors.initials: M
authors.lastname: Helf
authors.affiliation: a Division of Epigenomics and Cancer Risk Factors, German Cancer Research Center , Heidelberg , Germany.|b Regulation of Cellular Differentiation Group, Division of Epigenomics and Cancer Risk Factors, German Cancer Research Center , Heidelberg , Germany.
authors.forename: Oliver
authors.initials: O
authors.lastname: Mücke
authors.affiliation: a Division of Epigenomics and Cancer Risk Factors, German Cancer Research Center , Heidelberg , Germany.|e Department of Medicine , Division of Hematology, Oncology and Stem Cell Transplantation, University of Freiburg Medical Center , Freiburg , Germany.
authors.forename: Rainer
authors.initials: R
authors.lastname: Claus
authors.affiliation: a Division of Epigenomics and Cancer Risk Factors, German Cancer Research Center , Heidelberg , Germany.
authors.forename: Carolin
authors.initials: C
authors.lastname: Konermann
authors.affiliation: c Department of Pediatrics and Adolescent Medicine , Division of Pediatric Hematology-Oncology, University of Freiburg Medical Center , Freiburg , Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Nöllke
authors.affiliation: c Department of Pediatrics and Adolescent Medicine , Division of Pediatric Hematology-Oncology, University of Freiburg Medical Center , Freiburg , Germany.|f German Cancer Consortium (DKTK).
authors.forename: Charlotte M
authors.initials: CM
authors.lastname: Niemeyer
authors.affiliation: c Department of Pediatrics and Adolescent Medicine , Division of Pediatric Hematology-Oncology, University of Freiburg Medical Center , Freiburg , Germany.|f German Cancer Consortium (DKTK).
authors.forename: Christian
authors.initials: C
authors.lastname: Flotho
authors.affiliation: a Division of Epigenomics and Cancer Risk Factors, German Cancer Research Center , Heidelberg , Germany.|f German Cancer Consortium (DKTK).
authors.forename: Christoph
authors.initials: C
authors.lastname: Plass
mesh_terms: D054758:A Kinase Anchor Proteins / Q000235:genetics*; D018797:Cell Cycle Proteins / Q000235:genetics*; D045744:Cell Line, Tumor; D002675:Child, Preschool; D019175:DNA Methylation; D005260:Female; D020868:Gene Silencing; D011905:Genes, ras; D006801:Humans; D007223:Infant; D054429:Leukemia, Myelomonocytic, Juvenile / Q000235:genetics*; D008297:Male; D011401:Promoter Regions, Genetic; D015398:Signal Transduction
chemical_list: D054758:A Kinase Anchor Proteins; C491162:AKAP12 protein, human; D018797:Cell Cycle Proteins
keywords: AKAP12; Azacytidine; DNA methylation; Epigenetics; Hematopoiesis; Juvenile myelomonocytic leukemia; Leukemia