Histone Lysine Trimethylation or Acetylation can be Modulated by Phytoestrogen, Estrogen or Anti-HDAC in Breast Cancer Cell Lines

Abstract

Aim: The isoflavones genistein, daidzein and equol (daidzein metabolite) have been reported to interact with epigenetic modifications, specifically hypermethylation of tumor suppressor genes. The objective of this study was to analyze and understand the mechanisms by which phytoestrogens act on chromatin in breast cancer cell lines. Materials & methods: Two breast cancer cell lines, MCF-7 and MDA-MB 231, were treated with genistein (18.5 µM), daidzein (78.5 µM), equol (12.8 µM), 17β-estradiol (10 nM) and suberoylanilide hydroxamic acid (1 µM) for 48 h. A control with untreated cells was performed. 17β-estradiol and an anti-HDAC were used to compare their actions with phytoestrogens. The chromatin immunoprecipitation coupled with quantitative PCR was used to follow soy phytoestrogen effects on H3 and H4 histones on H3K27me3, H3K9me3, H3K4me3, H4K8ac and H3K4ac marks, and we selected six genes (EZH2, BRCA1, ERα, ERβ, SRC3 and P300) for analysis. Results: Soy phytoestrogens induced a decrease in trimethylated marks and an increase in acetylating marks studied at six selected genes. Conclusion: We demonstrated that soy phytoestrogens tend to modify transcription through the demethylation and acetylation of histones in breast cancer cell lines.

KEYWORDS::

• acetylation
• breast cancer
• histone
• methylation
• soy phytoestrogens

Financial & competing interests disclosure

This work was supported by La Ligue Nationale Contre le Cancer, Comité de la Région Auvergne. The authors are indebted to P Déchelotte who contributed to this study. The authors also thank C Picard for immunohistochemical technique. A Dagdemir received a grant from Protema Saglik Hizm. A.S. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.

Ethical conduct of research

The authors state that they have obtained appropriate institutional review board approval or have followed the principles outlined in the Declaration of Helsinki for all human or animal experimental investigations. In addition, for investigations involving human subjects, informed consent has been obtained from the participants involved.

Additional information

Funding

This work was supported by La Ligue Nationale Contre le Cancer, Comité de la Région Auvergne. The authors are indebted to P Déchelotte who contributed to this study. The authors also thank C Picard for immunohistochemical technique. A Dagdemir received a grant from Protema Saglik Hizm. A.S. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed. No writing assistance was utilized in the production of this manuscript.