Breast Cancer Research and Treatment

, Volume 105, Issue 2, pp 139–155 | Cite as

Unmasking of epigenetically silenced genes reveals DNA promoter methylation and reduced expression of PTCH in breast cancer

  • Ido WolfEmail author
  • Shikha Bose
  • Julian C. Desmond
  • Bryan T. Lin
  • Elizabeth A. Williamson
  • Beth Y. Karlan
  • H. Phillip Koeffler
Preclinical Study


A pharmacological-based global screen for epigenetically silenced tumor suppressor genes was performed in MCF-7 and MDA-MB-231 breast cancer cells. Eighty-one genes in MCF-7 cells and 131 in MDA-MB-231 cells were identified, that had low basal expression and were significantly upregulated following treatment. Eighteen genes were studied for methylation and/or expression in breast cancer; PTCH, the receptor for the hedgehog (Hh) pathway and a known tumor suppressor gene, was selected for further analysis. Methylation of the PTCH promoter was found in MCF-7 cells and in breast cancer samples, and correlated with low PTCH expression. Immunohistochemical analysis of breast tissue arrays revealed high expression of PTCH in normal breast compared to ductal carcinomas in situ (DCIS) and invasive ductal carcinomas; furthermore, association was found between PTCH expression and favorable prognostic factors. PTCH is an inhibitor of the Hh pathway, and its silencing activates the pathway and promotes growth. Indeed, high activity of the Hh pathway was identified in MCF-7 cells and overexpression of PTCH inhibited the pathway. Moreover, treatment with cyclopamine, an inhibitor of the pathway, reduced cell growth and slowed the cell cycle in these cells. Thus, unmasking of epigenetic silencing in breast cancer enabled us to discover a large number of candidate tumor suppressor genes. Further analysis suggested a role of one of these genes, PTCH, in breast cancer tumorigenesis.


Breast cancer Methylation PTCH GLI1 Hedgehog pathway 



This work was supported in part by the Inger Fund, Alec Borden Trust, Rountree Trust and the Mary Barry Foundation and by grants from the Women’s Cancer Research Institute, Samuel Oschin Comprehensive Cancer Institute at Cedars-Sinai Medical Center. HPK is a member of the Molecular Biology Institute and Jonsson Comprehensive Cancer Center at UCLA, and holds the endowed Mark Goodson Chair of Oncology Research at Cedars-Sinai Medical Center/UCLA School of Medicine. IW is the Mary Barry Medical Bridges Foundation Fellow. We thank PA Beachy (Johns Hopkins University School of Medicine, MD) for the PTCH and Gli-luciferase expression vectors.

Supplementary material

10549_2006_9440_MOESM1_ESM.xls (134 kb)
Supplemental Table 1 ESM1 (XLS 135 KB)
10549_2006_9440_MOESM2_ESM.xls (168 kb)
Supplemental Table 2 ESM2 (XLS 168 KB)
10549_2006_9440_MOESM3_ESM.doc (32 kb)
Supplemental Table 3 ESM3 (DOC 32KB)


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Copyright information

© Springer Science+Business Media, LLC 2007

Authors and Affiliations

  • Ido Wolf
    • 1
    • 5
    Email author
  • Shikha Bose
    • 2
  • Julian C. Desmond
    • 1
  • Bryan T. Lin
    • 3
  • Elizabeth A. Williamson
    • 1
  • Beth Y. Karlan
    • 4
  • H. Phillip Koeffler
    • 1
  1. 1.Division of Hematology/Oncology, Cedars-Sinai Medical CenterUCLA School of MedicineLos AngelesUSA
  2. 2.Department of Anatomic Pathology, Cedars-Sinai Medical CenterUCLA School of MedicineLos AngelesUSA
  3. 3.Tarzana Regional Medical CenterTarzanaUSA
  4. 4.Women’s Cancer Research Institute, Cedars-Sinai Medical CenterUCLA School of MedicineLos AngelesUSA
  5. 5.Institute of OncologyChaim-Sheba Medical CenterTel-HashomerIsrael

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