Notch pathway activation induces neuroblastoma tumor cell growth arrest

Authors

  • Peter E. Zage MD, PhD,

    1. Division of Pediatrics, Children's Cancer Hospital, The University of Texas M.D. Anderson Cancer Center, Houston, Texas
    2. The University of Texas Graduate School of Biomedical Sciences, Houston, Texas
    Current affiliation:
    1. Department of Pediatrics, Pediatric Hematology/Oncology, Baylor College of Medicine, Houston, TX.
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  • Riitta Nolo PhD,

    1. Division of Pediatrics, Children's Cancer Hospital, The University of Texas M.D. Anderson Cancer Center, Houston, Texas
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  • Wendy Fang MD,

    1. Division of Pediatrics, Children's Cancer Hospital, The University of Texas M.D. Anderson Cancer Center, Houston, Texas
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  • John Stewart MD,

    1. Department of Pathology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas
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  • Guillermo Garcia-Manero MD,

    1. Department of Leukemia, The University of Texas M. D. Anderson Cancer Center, Houston, Texas
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  • Patrick A. Zweidler-McKay MD, PhD

    Corresponding author
    1. Division of Pediatrics, Children's Cancer Hospital, The University of Texas M.D. Anderson Cancer Center, Houston, Texas
    2. The University of Texas Graduate School of Biomedical Sciences, Houston, Texas
    • Division of Pediatrics, Children's Cancer Hospital, University of Texas M.D. Anderson Cancer Center, 1515 Holcombe Blvd, Unit 853, Houston, TX 77030.
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  • Conflict of interest: Nothing to declare.

  • Peter E. Zage and Riitta Nolo contributed equally to this manuscript.

Abstract

Background

Notch pathway signaling has critical roles in differentiation, proliferation, and survival, and has oncogenic or tumor suppressor effects in a variety of malignancies. The goal of this study was to evaluate the effects of Notch activation on human neuroblastoma cells.

Procedure

Quantitative RT-PCR, immunoblots, and immunohistochemistry were used to determine the expression of Notch receptors (Notch1-4), cleaved Notch1 (ICN1), and downstream targets (HES1-5) in human neuroblastoma cell lines and patient tumor samples. Notch pathway signaling was induced using intracellular Notch (ICN1-3) and HES gene constructs or direct culture on Notch ligands. Quantitative methylation-specific PCR was used to quantify methylation of the HES gene promoters, and the effects of treatment with decitabine were measured.

Results

Neuroblastoma cells express varying levels of Notch receptors and low levels of HES genes at baseline. However, no endogenous activation of the Notch pathway was detected in neuroblastoma cell lines or patient tumor samples. Expression of activated Notch intracellular domains and HES gene products led to growth arrest. The HES2 and HES5 gene promoters were found to be heavily methylated in most neuroblastoma lines, and HES gene expression could be induced through treatment with decitabine.

Conclusions

We report that neuroblastoma cell lines express multiple Notch receptors, which are inactive at baseline. Activation of the Notch pathway via ligand binding consistently resulted in growth arrest. HES gene expression appears to be regulated epigenetically and could be induced with decitabine. These findings support a tumor suppressor role for Notch signaling in neuroblastoma. Pediatr Blood Cancer 2012; 58: 682–689. © 2011 Wiley Periodicals, Inc.

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