Identification of estrogen-induced genes downregulated by AhR agonists in MCF-7 breast cancer cells using suppression subtractive hybridization
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Updated: Oct 9, 2026
Profiling of Estrogen-regulated MicroRNAs in Breast Cancer Cells
Published on: February 21, 2014
1Department of Veterinary Physiology and Pharmacology, A&M University, College Station, TX 77843, USA.
Abstract:
Aryl hydrocarbon receptor (AhR) agonists inhibit 17beta-estradiol (E2) induced growth of MCF-7 human breast cancer cells in vitro and rodent mammary tumor growth in vivo. Genes associated with inhibitory AhR-estrogen receptor (ER) crosstalk were investigated in MCF-7 human breast cancer cells using poly(A)(+)RNA from cells treated with either 1 nM E2 (target) or E2 plus 1 nM 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) (reference) or 25 microM diindolylmethane (DIM) as AhR agonists in MCF-7 cells. Suppression subtractive hybridization (SSH) was subsequently used to identify 33 genes with sequence homology to known human genes that are induced by E2 and inhibited by AhR agonists in MCF-7 cells; two unknown genes were also identified. Many of these genes are involved in cell proliferation and these include cell cycle regulators (cdc28/cdc2-associated protein), nucleotide synthases (thymidylate synthase), early intermediate genes (early growth response alpha, EGRalpha) and other proteins involved in signaling pathways (calmodulin, ATP synthase alpha subunit). Thus SSH has identified a diverse spectrum of new genes that are affected by inhibitory AhR-ER crosstalk and among this group are a subset of genes that may be critical for the in vivo antitumorigenic effects of AhR agonists.
Insights
Aryl hydrocarbon receptor (AhR) agonists inhibit breast cancer cell growth by interfering with estrogen receptor (ER) signaling. This study identified new genes regulated by this crosstalk, offering potential therapeutic targets.
Area of Science:
- Molecular Biology
- Endocrinology
- Cancer Research
Background:
- Aryl hydrocarbon receptor (AhR) agonists are known to inhibit estrogen receptor (ER)-mediated growth of breast cancer cells.
- Understanding the molecular mechanisms of this inhibitory crosstalk is crucial for developing targeted therapies.
Purpose of the Study:
- To identify genes regulated by the inhibitory crosstalk between AhR and ER signaling in MCF-7 human breast cancer cells.
- To investigate the role of these genes in the anti-proliferative effects of AhR agonists.
Main Methods:
- MCF-7 cells were treated with 17beta-estradiol (E2), E2 plus 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), or diindolylmethane (DIM).
- Poly(A)(+)RNA was isolated, and Suppression Subtractive Hybridization (SSH) was employed to identify differentially expressed genes.
Main Results:
- SSH identified 33 known human genes and 2 unknown genes induced by E2 and inhibited by AhR agonists.
- Many identified genes are involved in cell proliferation, including cell cycle regulators, nucleotide synthases, and signaling pathway proteins.
- Specific examples include cdc28/cdc2-associated protein, thymidylate synthase, early growth response alpha (EGRalpha), calmodulin, and ATP synthase alpha subunit.
Conclusions:
- This study identified a diverse set of genes affected by AhR-ER crosstalk in breast cancer cells.
- A subset of these genes may be critical mediators of the antitumorigenic effects of AhR agonists in vivo.
- These findings provide novel molecular targets for breast cancer therapy.
