Estrogen-related receptors alpha, beta and gamma expression and function is associated with transcriptional repressor EZH2 in breast carcinoma
Abstract Background Orphan nuclear receptors ERRα, ERRβ and ERRγ that belong to NR3B or type IV nuclear receptor family are well studied for their role in breast cancer pathophysiology. Their homology with the canonical estrogen receptor dictates their possible contributing role in mammary gland dev...
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BMC
2018-06-01
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Series: | BMC Cancer |
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Online Access: | http://link.springer.com/article/10.1186/s12885-018-4586-0 |
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author | Kanchan Kumari Amit K. Adhya Arabinda Kumar Rath P. B. Reddy Sandip K. Mishra |
author_facet | Kanchan Kumari Amit K. Adhya Arabinda Kumar Rath P. B. Reddy Sandip K. Mishra |
author_sort | Kanchan Kumari |
collection | DOAJ |
description | Abstract Background Orphan nuclear receptors ERRα, ERRβ and ERRγ that belong to NR3B or type IV nuclear receptor family are well studied for their role in breast cancer pathophysiology. Their homology with the canonical estrogen receptor dictates their possible contributing role in mammary gland development and disease. Although function and regulation of ERRα, ERRγ and less about ERRβ is reported, role of histone methylation in their altered expression in cancer cells is not studied. Transcriptional activity of nuclear receptors depends on co-regulatory proteins. The present study for the first time gives an insight into regulation of estrogen-related receptors by histone methylation specifically through methyltransferase EZH2 in breast cancer. Methods Expression of ERRα, ERRβ, ERRγ and EZH2 was assessed by immunohistochemistry in four identical tissue array slides that were prepared as per the protocol. The array slides were stained with ERRα, ERRβ, ERRγ and EZH2 simultaneously. Array data was correlated with expression in MERAV expression dataset. Pearson correlation coeficient r was calculated from the partial matrix expression values available at MERAV database to study the strength of association between EZH2 and three orphan nuclear receptors under study. By western blot and real time PCR, their correlated expression was studied in breast cancer cell lines MCF-7, MDA-MB-231, T47D and MDA-MB-453 including normal breast epithelial MCF-10A cells at both protein and RNA level. Regulation of ERRα, ERRβ, ERRγ by EZH2 was further investigated upon overexpression and silencing of EZH2. The interaction between ERRs and EZH2 was validated in vivo by CHIP-qPCR. Results We found a negative correlation between estrogen-related receptors and Enhancer of Zeste Homolog 2, a global repressor gene. Immunohistochemistry in primary breast tumors of different grades showed a correlated expression of estrogen-related receptors and EZH2. Their correlated expression was further validated using online MERAV expression dataset where a negative correlation of variable strengths was observed in breast cancer. Ectopic expression of EZH2 in low EZH2-expressing normal breast epithelial cells abrogated their expression and at the same time, its silencing enhanced the expression of estrogen-related receptors in cancerous cells. Global occupancy of EZH2 on ERRα and ERRβ was observed in-vivo. Conclusion Our findings identify EZH2 as a relevant coregulator for estrogen-related receptors in breast carcinoma. |
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spelling | doaj.art-7d10adac21ac4c5984f550df882dc6e12022-12-22T02:39:02ZengBMCBMC Cancer1471-24072018-06-0118111110.1186/s12885-018-4586-0Estrogen-related receptors alpha, beta and gamma expression and function is associated with transcriptional repressor EZH2 in breast carcinomaKanchan Kumari0Amit K. Adhya1Arabinda Kumar Rath2P. B. Reddy3Sandip K. Mishra4Cancer Biology Laboratory, Department of Gene Function and Regulation, Institute of Life Sciences, Bhubaneswar. Utkal UniversityDepartment of Pathology, AIIMSHemalata Hospitals, ChandrashekharpurDepartment of Microbiology and Biotechnology, Govt. PG College RatlamCancer Biology Laboratory, Department of Gene Function and Regulation, Institute of Life Sciences, Bhubaneswar. Utkal UniversityAbstract Background Orphan nuclear receptors ERRα, ERRβ and ERRγ that belong to NR3B or type IV nuclear receptor family are well studied for their role in breast cancer pathophysiology. Their homology with the canonical estrogen receptor dictates their possible contributing role in mammary gland development and disease. Although function and regulation of ERRα, ERRγ and less about ERRβ is reported, role of histone methylation in their altered expression in cancer cells is not studied. Transcriptional activity of nuclear receptors depends on co-regulatory proteins. The present study for the first time gives an insight into regulation of estrogen-related receptors by histone methylation specifically through methyltransferase EZH2 in breast cancer. Methods Expression of ERRα, ERRβ, ERRγ and EZH2 was assessed by immunohistochemistry in four identical tissue array slides that were prepared as per the protocol. The array slides were stained with ERRα, ERRβ, ERRγ and EZH2 simultaneously. Array data was correlated with expression in MERAV expression dataset. Pearson correlation coeficient r was calculated from the partial matrix expression values available at MERAV database to study the strength of association between EZH2 and three orphan nuclear receptors under study. By western blot and real time PCR, their correlated expression was studied in breast cancer cell lines MCF-7, MDA-MB-231, T47D and MDA-MB-453 including normal breast epithelial MCF-10A cells at both protein and RNA level. Regulation of ERRα, ERRβ, ERRγ by EZH2 was further investigated upon overexpression and silencing of EZH2. The interaction between ERRs and EZH2 was validated in vivo by CHIP-qPCR. Results We found a negative correlation between estrogen-related receptors and Enhancer of Zeste Homolog 2, a global repressor gene. Immunohistochemistry in primary breast tumors of different grades showed a correlated expression of estrogen-related receptors and EZH2. Their correlated expression was further validated using online MERAV expression dataset where a negative correlation of variable strengths was observed in breast cancer. Ectopic expression of EZH2 in low EZH2-expressing normal breast epithelial cells abrogated their expression and at the same time, its silencing enhanced the expression of estrogen-related receptors in cancerous cells. Global occupancy of EZH2 on ERRα and ERRβ was observed in-vivo. Conclusion Our findings identify EZH2 as a relevant coregulator for estrogen-related receptors in breast carcinoma.http://link.springer.com/article/10.1186/s12885-018-4586-0EZH2Orphan nuclear receptorsBreast cancer |
spellingShingle | Kanchan Kumari Amit K. Adhya Arabinda Kumar Rath P. B. Reddy Sandip K. Mishra Estrogen-related receptors alpha, beta and gamma expression and function is associated with transcriptional repressor EZH2 in breast carcinoma BMC Cancer EZH2 Orphan nuclear receptors Breast cancer |
title | Estrogen-related receptors alpha, beta and gamma expression and function is associated with transcriptional repressor EZH2 in breast carcinoma |
title_full | Estrogen-related receptors alpha, beta and gamma expression and function is associated with transcriptional repressor EZH2 in breast carcinoma |
title_fullStr | Estrogen-related receptors alpha, beta and gamma expression and function is associated with transcriptional repressor EZH2 in breast carcinoma |
title_full_unstemmed | Estrogen-related receptors alpha, beta and gamma expression and function is associated with transcriptional repressor EZH2 in breast carcinoma |
title_short | Estrogen-related receptors alpha, beta and gamma expression and function is associated with transcriptional repressor EZH2 in breast carcinoma |
title_sort | estrogen related receptors alpha beta and gamma expression and function is associated with transcriptional repressor ezh2 in breast carcinoma |
topic | EZH2 Orphan nuclear receptors Breast cancer |
url | http://link.springer.com/article/10.1186/s12885-018-4586-0 |
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