Open AccessERα promotes transcription of tumor suppressor gene ApoA-I by establishing H3K27ac-enriched chromatin microenvironment in breast cancer cells
Author(s) -
Bingjie Wang,
Yinghui Shen,
Tianyu Li,
Li Tan
Publication year - 2021
Publication title -
journal of zhejiang university. science b
Language(s) - English
Resource type - Journals
eISSN - 1862-1783
pISSN - 1673-1581
DOI - 10.1631/jzus.b2100393
Subject(s) - estrogen receptor , chromatin , cancer research , biology , brd4 , fulvestrant , chromatin remodeling , cancer cell , histone , chemistry , bromodomain , cancer , breast cancer , gene , genetics
Apolipoprotein A-I (ApoA-I), the main protein component of high-density lipoprotein (HDL), plays a pivotal role in reverse cholesterol transport (RCT). Previous studies indicated a reduction of serum ApoA-I levels in various types of cancer, suggesting ApoA-I as a potential cancer biomarker. Herein, ectopically overexpressed ApoA-I in MDA-MB-231 breast cancer cells was observed to have antitumor effects, inhibiting cell proliferation and migration. Subsequent studies on the mechanism of expression regulation revealed that estradiol (E2)/estrogen receptor α (ERα) signaling activates ApoA-I gene transcription in breast cancer cells. Mechanistically, our ChIP-seq data showed that ERα directly binds to the estrogen response element (ERE) site within the ApoA-I gene and establishes an acetylation of histone 3 lysine 27 (H3K27ac)-enriched chromatin microenvironment. Conversely, Fulvestrant (ICI 182780) treatment blocked ERα binding to ERE within the ApoA-I gene and downregulated the H3K27ac level on the ApoA-I gene. Treatment with p300 inhibitor also significantly decreased the ApoA-I messenger RNA (mRNA) level in MCF7 cells. Furthermore, the analysis of data from The Cancer Genome Atlas (TCGA) revealed a positive correlation between ERα and ApoA-I expression in breast cancer tissues. Taken together, our study not only revealed the antitumor potential of ApoA-I at the cellular level, but also found that ERα promotes the transcription of ApoA-I gene through direct genomic effects, and p300 may act as a co-activator of ERα in this process.