SUPT6H controls estrogen receptor activity and cellular differentiation by multiple epigenomic mechanisms.
The estrogen receptor alpha (ERα) is the central transcriptional regulator of ductal mammary epithelial lineage specification and is an important prognostic marker in human breast cancer. Although antiestrogen therapies are initially highly effective at treating ERα-positive tumors, a large number of tumors progress to a refractory, more poorly differentiated phenotype accompanied by reduced survival. A better understanding of the molecular mechanisms involved in the progression from estrogen-dependent to hormone-resistant breast cancer may uncover new targets for treatment and the discovery of new predictive markers. Recent studies have uncovered an important role for transcriptional elongation and chromatin modifications in controlling ERα activity and estrogen responsiveness. The human Suppressor of Ty Homologue-6 (SUPT6H) is a histone chaperone that links transcriptional elongation to changes in chromatin structure. We show that SUPT6H is required for estrogen-regulated transcription and the maintenance of chromatin structure in breast cancer cells, possibly in part through interaction with RNF40 and regulation of histone H2B monoubiquitination (H2Bub1). Moreover, we demonstrate that SUPT6H protein levels decrease with malignancy in breast cancer. Consistently, SUPT6H, similar to H2Bub1, is required for cellular differentiation and suppression of the repressive histone mark H3K27me3 on lineage-specific genes. Together, these data identify SUPT6H as a new epigenetic regulator of ERα activity and cellular differentiation.
1] Center of Experimental Medicine, Department of Tumor Biology, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany [2] Institute of Molecular Oncology, University Medical Center Göttingen, Göttingen, Germany.
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Bedi
1] Institute of Pathology Nordhessen, Kassel, Germany [2] Center for Pathology and Forensic Medicine, Department of Pathology, University Medical Center Göttingen, Göttingen, Germany.
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Scheel
Institute of Molecular Oncology, University Medical Center Göttingen, Göttingen, Germany.
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Hennion
Institute of Molecular Oncology, University Medical Center Göttingen, Göttingen, Germany.
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Begus-Nahrmann
Institute of Pathology Nordhessen, Kassel, Germany.
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Rüschoff
1] Center of Experimental Medicine, Department of Tumor Biology, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany [2] Institute of Molecular Oncology, University Medical Center Göttingen, Göttingen, Germany.
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Johnsen
D001943:Breast Neoplasms / Q000473:pathology; D002454:Cell Differentiation; D045744:Cell Line, Tumor; D002843:Chromatin / Q000737:chemistry; D057890:Epigenomics; D047628:Estrogen Receptor alpha / Q000502:physiology*; D005260:Female; D006657:Histones / Q000378:metabolism; D006801:Humans; D014157:Transcription Factors / Q000502:physiology*; D054875:Ubiquitination
D002843:Chromatin; C506487:ESR1 protein, human; D047628:Estrogen Receptor alpha; D006657:Histones; C100927:SUPT6H protein, human; D014157:Transcription Factors