Genomic modelling of the ESR1 Y537S mutation for evaluating function and new therapeutic approaches for metastatic breast cancer
File(s)
Published version
Author(s)
Type
Journal Article
Abstract
Drugs that inhibit estrogen receptor-α (ER) activity have been highly
successful in treating and reducing breast cancer progression in ER-positive
disease. However, resistance to these therapies presents a major clinical
problem. Recent genetic studies have shown that mutations in the ER gene
are found in >20% of tumours that progress on endocrine therapies.
Remarkably, the great majority of these mutations localise to just a few amino
acids within or near the critical helix 12 region of the ER hormone binding
domain, where they are likely to be single allele mutations. Understanding
how these mutations impact on ER function is a prerequiste for identifying
methods to treat breast cancer patients featuring such mutations. Towards
this end, we used CRISPR-Cas9 genome editing to make a single allele
knockin of the most commonly mutated amino acid residue, tyrosine 537, in
the estrogen-responsive MCF7 breast cancer cell line. Genomic analyses
using RNA-seq and ER ChIP-seq demonstrated that the Y537S mutation
promotes constitutive ER activity globally, resulting in estrogen-independent
growth. MCF7-Y537S cells were resistant to the anti-estrogen tamoxifen and
fulvestrant. Further, we show that the basal transcription factor TFIIH is
constitutively recruited by ER-Y537S, resulting in ligand-independent
phosphorylation of Serine 118 (Ser118) by the TFIIH kinase, CDK7. The
CDK7 inhibitor, THZ1 prevented Ser118 phosphorylation and inhibited growth
of MCF7-Y537S cells. These studies confirm the functional importance of ER
mutations in endocrine resistance, demonstrate the utility of knockin
mutational models for investigating alternative therapeutic approaches and
highlight CDK7 inhibition as a potential therapy for endocrine resistant breast
cancer mediated by ER mutations.
successful in treating and reducing breast cancer progression in ER-positive
disease. However, resistance to these therapies presents a major clinical
problem. Recent genetic studies have shown that mutations in the ER gene
are found in >20% of tumours that progress on endocrine therapies.
Remarkably, the great majority of these mutations localise to just a few amino
acids within or near the critical helix 12 region of the ER hormone binding
domain, where they are likely to be single allele mutations. Understanding
how these mutations impact on ER function is a prerequiste for identifying
methods to treat breast cancer patients featuring such mutations. Towards
this end, we used CRISPR-Cas9 genome editing to make a single allele
knockin of the most commonly mutated amino acid residue, tyrosine 537, in
the estrogen-responsive MCF7 breast cancer cell line. Genomic analyses
using RNA-seq and ER ChIP-seq demonstrated that the Y537S mutation
promotes constitutive ER activity globally, resulting in estrogen-independent
growth. MCF7-Y537S cells were resistant to the anti-estrogen tamoxifen and
fulvestrant. Further, we show that the basal transcription factor TFIIH is
constitutively recruited by ER-Y537S, resulting in ligand-independent
phosphorylation of Serine 118 (Ser118) by the TFIIH kinase, CDK7. The
CDK7 inhibitor, THZ1 prevented Ser118 phosphorylation and inhibited growth
of MCF7-Y537S cells. These studies confirm the functional importance of ER
mutations in endocrine resistance, demonstrate the utility of knockin
mutational models for investigating alternative therapeutic approaches and
highlight CDK7 inhibition as a potential therapy for endocrine resistant breast
cancer mediated by ER mutations.
Date Issued
2016-10-17
Date Acceptance
2016-08-29
Citation
Oncogene, 2016, 36, pp.2286-2296
ISSN
1476-5594
Publisher
Nature Publishing Group
Start Page
2286
End Page
2296
Journal / Book Title
Oncogene
Volume
36
Copyright Statement
© The Author(s) 2016. This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/ 4.0/ © The Author(s) 2016
License URL
Sponsor
Cancer Research UK
Grant Number
14549
Subjects
Science & Technology
Life Sciences & Biomedicine
Biochemistry & Molecular Biology
Oncology
Cell Biology
Genetics & Heredity
ESTROGEN-RECEPTOR-ALPHA
LIGAND-BINDING DOMAIN
ER-ALPHA
ENDOCRINE RESISTANCE
POSTMENOPAUSAL WOMEN
ANTITUMOR-ACTIVITY
GENE-EXPRESSION
RETINOIC ACID
TYROSINE 537
PHOSPHORYLATION
Antineoplastic Agents
Breast Neoplasms
CRISPR-Cas Systems
Cell Proliferation
Cyclin-Dependent Kinases
Estrogen Antagonists
Estrogen Receptor alpha
Estrogens
Female
Gene Knock-In Techniques
Histones
Humans
MCF-7 Cells
Mutation
Phosphorylation
Serine
Tamoxifen
1112 Oncology And Carcinogenesis
1103 Clinical Sciences
Oncology & Carcinogenesis
Publication Status
Published