The Pediatric Cancer Genome Project

St. Jude Children's Research Hospital-Washington University Pediatric Cancer Genome Project, Memphis, Tennessee, USA.
Nature Genetics (Impact Factor: 29.65). 08/2012; 44(6):619-22. DOI: 10.1038/ng.2287
Source: PubMed
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    ABSTRACT: The DEAD-box RNA helicase DDX3X is frequently mutated in pediatric medulloblastoma. We dissect how these mutants affect DDX3X function with structural, biochemical, and genetic experiments. We identify an N-terminal extension ("ATP-binding loop", ABL) that is critical for the stimulation of ATP hydrolysis by RNA. We present crystal structures that suggest the ABL interacts dynamically with ATP and confirm the interaction occurs in solution by NMR chemical shift perturbation (CSP) and isothermal calorimetry (ITC). DEAD-box helicases require interaction between two conserved RecA-like helicase domains, D1 and D2 for function. We use NMR CSP to show that DDX3X interacts specifically with double-stranded RNA (dsRNA) through its D1 domain, with contact mediated by residues G302 and G325. Mutants of these residues, G302V and G325E, are associated with pediatric medulloblastoma. These mutants are defective in RNA-stimulated ATP hydrolysis. We show that DDX3X complements the growth defect in a ded1 temperature-sensitive strain of S. pombe, but the cancer-associated mutants G302V and G325E do not complement and exhibit protein expression defects. Taken together, our results suggest that impaired translation of important mRNA targets by mutant DDX3X represents a key step in the development of medulloblastoma. Copyright © 2015. Published by Elsevier Ltd.
    Journal of Molecular Biology 02/2015; 123(9). DOI:10.1016/j.jmb.2015.02.015 · 3.96 Impact Factor
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    ABSTRACT: Significant advances have been made over the past 25 years in our understanding of the most common adult solid tumors such as breast, colon, lung and prostate cancer. Much less is known about childhood solid tumors because they are rare and because they originate in developing organs during fetal development, childhood and adolescence. It can be very difficult to study the cellular origins of pediatric solid tumors in developing organs characterized by rapid proliferative expansion, growth factor signaling, developmental angiogenesis, programmed cell death, tissue reorganization and cell migration. Not only has the etiology of pediatric cancer remained elusive because of their developmental origins, but it also makes it more difficult to treat. Molecular targeted therapeutics that alter developmental pathway signaling may have devastating effects on normal organ development. Therefore, basic research focused on the mechanisms of development provides an essential foundation for pediatric solid tumor translational research. In this article, we describe new resources available for the developmental biology and oncology research communities. In a companion paper, we present the detailed characterization of an orthotopic xenograft of a pediatric solid tumor derived from sympathoadrenal lineage during development. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.
    Developmental Biology 04/2015; 87. DOI:10.1016/j.ydbio.2015.02.002 · 3.64 Impact Factor
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    ABSTRACT: Introducing whole genome sequencing (WGS) into pediatric cancer research at diagnosis poses unique challenges related to informed consent. WGS requires tissue obtained prior to initiating treatment, when families may be overwhelmed with uncertainty and fear. Motivation to participate may be high without fully understanding the range of possible results, including secondary findings. Little is known about parental knowledge, attitudes, and beliefs about this type of research. A qualitative study was conducted to investigate parental knowledge about genetic concepts and WGS, thoughts about the informed consent process, and preferences for secondary findings. Focus groups were conducted with parents/guardians of children with cancer and semi-structured interviews were conducted in a control group without cancer. All transcripts were analyzed using content analysis. Four focus groups included 15 participants; eight semi-structured interviews included 10 participants. Basic knowledge about genetics was limited to heredity. Some knowledge of genomic analysis was present in 3/15 focus group participants. Major factors related to participation in WGS research were: (i) hope for their child and future children; (ii) no additional procedures; (iii) and protection of privacy. All favored a two-step consent process, first to store extra tissue from a diagnostic biopsy/resection, followed by consenting to WGS research, one-to-two months later. The desire to receive secondary findings was high among both groups, but there were individuals who did not want these results, fearing increased anxiety. Parents/guardians of children with cancer have limited knowledge about WGS. A two-step consent process may improve their ability to provide meaningful informed consent. Pediatr Blood Cancer © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.
    Pediatric Blood & Cancer 04/2015; DOI:10.1002/pbc.25520 · 2.56 Impact Factor


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