ABSTRACT
Hereditary leiomyomatosis and renal cell cancer (HLRCC) is a cancer syndrome caused by inactivating germline mutations in fumarate hydratase (FH) and subsequent accumulation of fumarate. Fumarate accumulation leads to profound epigenetic changes and the activation of an anti-oxidant response via nuclear translocation of the transcription factor NRF2. The extent to which chromatin remodeling shapes this anti-oxidant response is currently unknown. Here, we explored the effects of FH loss on the chromatin landscape to identify transcription factor networks involved in the remodeled chromatin landscape of FH-deficient cells. We identify FOXA2 as a key transcription factor that regulates anti-oxidant response genes and subsequent metabolic rewiring cooperating without direct interaction with the anti-oxidant regulator NRF2. The identification of FOXA2 as an anti-oxidant regulator provides additional insights into the molecular mechanisms behind cell responses to fumarate accumulation and potentially provides further avenues for therapeutic intervention for HLRCC.
Subject(s)
Carcinoma, Renal Cell , Kidney Neoplasms , Leiomyomatosis , Neoplastic Syndromes, Hereditary , Skin Neoplasms , Uterine Neoplasms , Female , Humans , Fumarate Hydratase/genetics , Antioxidants , NF-E2-Related Factor 2/genetics , Leiomyomatosis/genetics , Uterine Neoplasms/genetics , Skin Neoplasms/genetics , Neoplastic Syndromes, Hereditary/genetics , Chromatin , Kidney Neoplasms/genetics , Carcinoma, Renal Cell/genetics , Hepatocyte Nuclear Factor 3-beta/geneticsABSTRACT
The cytokine interleukin-6 (IL6) and its downstream effector STAT3 constitute a key oncogenic pathway, which has been thought to be functionally connected to estrogen receptor α (ER) in breast cancer. We demonstrate that IL6/STAT3 signaling drives metastasis in ER+ breast cancer independent of ER. STAT3 hijacks a subset of ER enhancers to drive a distinct transcriptional program. Although these enhancers are shared by both STAT3 and ER, IL6/STAT3 activity is refractory to standard ER-targeted therapies. Instead, inhibition of STAT3 activity using the JAK inhibitor ruxolitinib decreases breast cancer invasion in vivo. Therefore, IL6/STAT3 and ER oncogenic pathways are functionally decoupled, highlighting the potential of IL6/STAT3-targeted therapies in ER+ breast cancer.
Subject(s)
Breast Neoplasms/genetics , Enhancer Elements, Genetic/genetics , Estrogen Receptor alpha/genetics , Interleukin-6/genetics , STAT3 Transcription Factor/genetics , Signal Transduction/genetics , Animals , Antineoplastic Agents, Hormonal/pharmacology , Breast Neoplasms/drug therapy , Breast Neoplasms/pathology , Estrogen Receptor alpha/metabolism , Female , Fulvestrant/pharmacology , Gene Expression Profiling/methods , Gene Expression Regulation, Neoplastic , Humans , Interleukin-6/metabolism , Kaplan-Meier Estimate , MCF-7 Cells , Mice, Inbred NOD , Mice, Knockout , Mice, SCID , Neoplasm Metastasis , STAT3 Transcription Factor/metabolism , Xenograft Model Antitumor Assays/methodsABSTRACT
Using genome-wide clustered regularly interspaced short palindromic repeats (CRISPR) screens to understand endocrine drug resistance, we discovered ARID1A and other SWI/SNF complex components as the factors most critically required for response to two classes of estrogen receptor-alpha (ER) antagonists. In this context, SWI/SNF-specific gene deletion resulted in drug resistance. Unexpectedly, ARID1A was also the top candidate in regard to response to the bromodomain and extraterminal domain inhibitor JQ1, but in the opposite direction, with loss of ARID1A sensitizing breast cancer cells to bromodomain and extraterminal domain inhibition. We show that ARID1A is a repressor that binds chromatin at ER cis-regulatory elements. However, ARID1A elicits repressive activity in an enhancer-specific, but forkhead box A1-dependent and active, ER-independent manner. Deletion of ARID1A resulted in loss of histone deacetylase 1 binding, increased histone 4 lysine acetylation and subsequent BRD4-driven transcription and growth. ARID1A mutations are more frequent in treatment-resistant disease, and our findings provide mechanistic insight into this process while revealing rational treatment strategies for these patients.
Subject(s)
Breast Neoplasms/drug therapy , Cell Cycle Proteins/metabolism , DNA-Binding Proteins/metabolism , Histone Deacetylase 1/metabolism , Transcription Factors/metabolism , Acetylation , Animals , Breast Neoplasms/mortality , Breast Neoplasms/pathology , Cell Cycle Proteins/genetics , Cell Proliferation , Clustered Regularly Interspaced Short Palindromic Repeats , DNA-Binding Proteins/genetics , Drug Resistance, Neoplasm/genetics , Estrogen Receptor alpha/genetics , Estrogen Receptor alpha/metabolism , Female , Gene Expression Regulation, Neoplastic , Hepatocyte Nuclear Factor 3-alpha/genetics , Hepatocyte Nuclear Factor 3-alpha/metabolism , Histone Deacetylase 1/genetics , Humans , MCF-7 Cells , Mice, Inbred NOD , Transcription Factors/genetics , Xenograft Model Antitumor AssaysABSTRACT
An amendment to this paper has been published and can be accessed via a link at the top of the paper.