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Epigenetic Regulation of WNT and Hedgehog Oncogenic Signaling in Breast Cancer Cells in Response to Dietary Polyphenols
Author(s) -
Stefanska Barbara,
Kurzava Lucinda,
Lubecka Katarzyna,
Beetch Megan,
Flower Kirsty,
Flanagan James M
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.646.63
Subject(s) - wnt signaling pathway , smoothened , biology , hedgehog signaling pathway , hedgehog , gli1 , cancer research , cyclopamine , sonic hedgehog , epigenetics , dna methylation , frizzled , microbiology and biotechnology , signal transduction , genetics , gene expression , gene
The Wnt and Hedgehog signaling pathways play roles in embryonic and stem cell developmental processes but can become overactive in human cancers, contributing to cancer cell invasion and metastasis. Crosstalk occurs between these two pathways in cancer due to the ability of Hedgehog signaling proteins to regulate activity of the Wnt pathway, and vice versa. This interdependent regulation allows for cancer therapies to mutually target the activity of both pathways. Interestingly, certain dietary polyphenolic compounds suppress the Hedgehog and Wnt signals in cancer. In our study, polyphenols were shown to modify epigenetic marks in genes positively regulating these pathways including SHH, a Hedgehog signaling protein, GLI2, a transcriptional activator of Hedgehog signaling, and four Wnt signaling ligands including WNT4, WNT6, WNT9A, and WNT10B. Using the polyphenol resveratrol from grapes, we examine the role of DNA methylation in regulation of Hedgehog and Wnt signaling in breast cancer. Non‐invasive MCF‐7 and invasive MCF10CA1a human breast cancer cell lines were used as an experimental model. Following genome‐wide DNA methylation analysis with Illumina 450K array, pyrosequencing and QPCR were performed to assess methylation and expression of the selected positive regulators and downstream targets of Hedgehog and Wnt signaling. We found 6,347 CpG sites differentially methylated upon 9‐day treatment of MCF10CA1a breast cancer cells with 15μM resveratrol compared to untreated cells. A majority of those CpG sites were hypermethylated and located within genes functionally associated with oncogenic signaling pathways, including Hedgehog and Wnt. Resveratrol led to increased methylation of enhancer regions of SHH, GLI2, and WNT4, and CpG island regions of WNT6, WNT9A, and WNT10B. Increase in methylation of these genes was confirmed by pyrosequencing in breast cancer cells with high and low invasive potential. Along with increased methylation of these regions, the expression of these genes decreased following resveratrol treatment. This was associated with downregulation of Hedgehog target gene Bcl‐2 and Wnt target gene EpCam, as well as a mutual target FOXM1, in invasive MCF10CA1a breast cancer cells. Our results provide insight into regulation of oncogenic signals in cancer and support for epigenetic‐targeting strategies as an effective anti‐cancer approach. Support or Funding Information This study was supported by the Purdue University Center for Cancer Research, Indiana CTSI (UL1TR001108), Women's Global Health Institute, and USDA National Institute of Food and Agriculture (Hatch project 1005656) granted to BS.