Article

Downregulation of death-associated protein kinase 1 (DAPK1) in chronic lymphocytic leukemia.

Department of Molecular Virology, Immunology, and Medical Genetics, Human Cancer Genetics Program, The Comprehensive Cancer Center at The Ohio State University, Columbus, OH 43214, USA.
Cell (Impact Factor: 33.12). 07/2007; 129(5):879-90. DOI: 10.1016/j.cell.2007.03.043
Source: PubMed

ABSTRACT The heritability of B cell chronic lymphocytic leukemia (CLL) is relatively high; however, no predisposing mutation has been convincingly identified. We show that loss or reduced expression of death-associated protein kinase 1 (DAPK1) underlies cases of heritable predisposition to CLL and the majority of sporadic CLL. Epigenetic silencing of DAPK1 by promoter methylation occurs in almost all sporadic CLL cases. Furthermore, we defined a disease haplotype, which segregates with the CLL phenotype in a large family. DAPK1 expression of the CLL allele is downregulated by 75% in germline cells due to increased HOXB7 binding. In the blood cells from affected family members, promoter methylation results in additional loss of DAPK1 expression. Thus, reduced expression of DAPK1 can result from germline predisposition, as well as epigenetic or somatic events causing or contributing to the CLL phenotype.

1 Follower
 · 
141 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: In spite of being the most prevalent adult leukemia in Western countries, the molecular mechanisms driving the establishment and progression of chronic lymphocytic leukemia (CLL) remain largely unknown. In recent years, the use of next-generation sequencing techniques has uncovered new and, in some cases, unexpected driver genes with prognostic and therapeutic value. The mutational landscape of CLL is characterized by high-genetic and epigenetic heterogeneity, low mutation recurrence and a long tail of cases with undefined driver genes. On the other hand, the use of deep sequencing has also revealed high intra-tumor heterogeneity and provided a detailed picture of clonal evolution processes. This phenomenon, in which aberrant DNA methylation can also participate, appears to be tightly associated to poor outcomes and chemo-refractoriness, thus providing a new subject for therapeutic intervention. Hence, and having in mind the limitations derived from the CLL complexity thus described, the application of massively parallel sequencing studies has unveiled a wealth of information that is expected to substantially improve patient staging schemes and CLL clinical management.
  • [Show abstract] [Hide abstract]
    ABSTRACT: Intratumoral heterogeneity plays a critical role in tumor evolution. To define the contribution of DNA methylation to heterogeneity within tumors, we performed genome-scale bisulfite sequencing of 104 primary chronic lymphocytic leukemias (CLLs). Compared with 26 normal B cell samples, CLLs consistently displayed higher intrasample variability of DNA methylation patterns across the genome, which appears to arise from stochastically disordered methylation in malignant cells. Transcriptome analysis of bulk and single CLL cells revealed that methylation disorder was linked to low-level expression. Disordered methylation was further associated with adverse clinical outcome. We therefore propose that disordered methylation plays a similar role to that of genetic instability, enhancing the ability of cancer cells to search for superior evolutionary trajectories. Copyright © 2014 Elsevier Inc. All rights reserved.
    Cancer Cell 12/2014; 26(6):813-25. DOI:10.1016/j.ccell.2014.10.012 · 23.89 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: DAPK1 can induce apoptosis in several cells; to determine the effect of DAPK1 would provide a new potential therapeutic strategy for treating pancreatic cancer. The aim of the present study was to investigate the effect of DAPK1 gene on proliferation, migration, and invasion of carcinoma of pancreas BxPC-3 cell line and explore the possible mechanisms. In our study, DAPK1 over-expressed cells were established by using the lentiviral transfection method, and DAPK1 obviously increased in BxPC-3 cells after transient transfection. Cell Counting Kit-8 (CCK-8) assay was used to determine the BxPC-3 cells proliferation after transfection. Apoptosis of the BxPC-3 cells was determined by using flow cytometry analysis. In addition, cell adhesion assay and in vitro invasion assay were performed. Western blotting was used to determine the protein expressions of caspase-3, DAPK1, VEGF, PEDF, MMP2, AKT, P-AKT, P-ERK, Bcl2, and Bax. Our results demonstrated that DAPK1 gene over-expression can suppress the proliferation, migration, and invasion of carcinoma of pancreas BxPC-3 cell line, and the possible mechanisms may be correlated to induction of mitochondria-mediated apoptosis, down-regulations of MMP-2 and VEGF, up-regulations of PEDF, through the PI3K/Akt and ERK pathways.

Full-text (2 Sources)

Download
31 Downloads
Available from
Jul 10, 2014