title: Epigenetic Loss of MLH1 Expression in Normal Human Hematopoietic Stem Cell Clones is Defined by the Promoter CpG Methylation Pattern Observed by High-Throughput Methylation Specific Sequencing.
abstract: Normal human hematopoietic stem and progenitor cells (HPC) lose expression ofMLH1, an important mismatch repair (MMR) pathway gene, with age. Loss of MMR leads to replication dependent mutational events and microsatellite instability observed in secondary acute myelogenous leukemia and other hematologic malignancies. Epigenetic CpG methylation upstream of theMLH1promoter is a contributing factor to acquired loss ofMLH1expression in tumors of the epithelia and proximal mucosa. Using single molecule high-throughput bisulfite sequencing we have characterized the CpG methylation landscape from -938 to -337 bp upstream of theMLH1transcriptional start site (position +0), from 30 hematopoietic colony forming cell clones (CFC) either expressing or not expressingMLH1. We identify a correlation betweenMLH1promoter methylation and loss ofMLH1expression. Additionally, using the CpG site methylation frequencies obtained in this study we were able to generate a classification algorithm capable of sorting the expressing and non-expressing CFC. Thus, as has been previously described for many tumor cell types, we report for the first time a correlation between the loss ofMLH1expression and increasedMLH1promoter methylation in CFC derived from CD34+selected hematopoietic stem and progenitor cells.
authors: Department of Pathology, Case Western Reserve University, Cleveland, OH, 44106, USA; Division of Hematology and Oncology, Case Western Reserve University, Cleveland, OH, 44106, USA; Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, OH, 44106, USA.
authors: Jonathan
authors: J
authors: Kenyon
authors: Division of Infectious Disease, Department of Medicine, Case School of Medicine and the Center for AIDS Research, Case Western Reserve University, Cleveland, OH, 44106, USA.
authors: Gabrielle
authors: G
authors: Nickel-Meester
authors: Division of Hematology and Oncology, Case Western Reserve University, Cleveland, OH, 44106, USA; Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, OH, 44106, USA.
authors: Yulan
authors: Y
authors: Qing
authors: Division of Hematology and Oncology, Case Western Reserve University, Cleveland, OH, 44106, USA.
authors: Gabriela
authors: G
authors: Santos-Guasch
authors: Division of Hematology and Oncology, Case Western Reserve University, Cleveland, OH, 44106, USA.
authors: Ellen
authors: E
authors: Drake
authors: Department of Epidemiology & Biostatistics, Case Western Reserve University, Cleveland, OH, 44106, USA.
authors: PingfuFu
authors: Department of Mathematics, Texas State University, San Marcos, TX, 78666, USA.
authors: Shuying
authors: S
authors: Sun
authors: RNA Center, Case Western Reserve University, Cleveland, OH, 44106, USA.
authors: Xiaodong
authors: X
authors: Bai
authors: Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, OH, 44106, USA; Center for Stem Cell and Regenerative Medicine, Case Western Reserve University and University Hospitals of Cleveland, Cleveland, OH, 44106, USA.
authors: David
authors: D
authors: Wald
authors: Division of Infectious Disease, Department of Medicine, Case School of Medicine and the Center for AIDS Research, Case Western Reserve University, Cleveland, OH, 44106, USA.
authors: Eric
authors: E
authors: Arts
authors: Department of Pathology, Case Western Reserve University, Cleveland, OH, 44106, USA; Division of Hematology and Oncology, Case Western Reserve University, Cleveland, OH, 44106, USA; Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, OH, 44106, USA; Center for Stem Cell and Regenerative Medicine, Case Western Reserve University and University Hospitals of Cleveland, Cleveland, OH, 44106, USA; Seidman Cancer Center, University Hospitals of Cleveland, Cleveland, OH, 44106, USA.
authors: Stanton L
authors: SL
authors: Gerson
keywords: Epigenetics; Hematopoietic stem cells; High throughput bisulfite sequencing; Mismatch repair