Aryl hydrocarbon receptor-mediated antiestrogenic and antitumorigenic activity of diindolylmethane

Ichen Chen, Andrew McDougal, Fan Wang, Stephen Safe

Research output: Contribution to journalArticle

244 Scopus citations

Abstract

Phytochemicals such as indole-3-carbinol (I3C) and sulforaphane are components of cruciferous vegetables which exhibit antitumorigenic activity associated with altered carcinogen metabolism and detoxification. Diindolylmethane (DIM) is a major acid-catalyzed metabolite of I3C formed in the gut that binds to the aryl hydrocarbon receptor (AhR) and treatment of MCF-7 human breast cancer cells with 10-50 μM DIM resulted in rapid formation of the nuclear AhR complex and induction of CYP1A1 gene expression was observed at concentrations > 50 μM. Previous studies have demonstrated that 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a high affinity AhR ligand, inhibits 17β-estradiol (E2)-induced responses in MCF-7 cells and growth of E2-dependent 7,12-dimethylbenzanthracene (DMBA)-induced mammary tumors in female Sprague-Dawley rats. Results of this study show that like TCDD, DIM inhibits E2-induced proliferation of MCF-7 cells, reporter gene activity in cells transiently transfected with an E2-responsive plasmid (containing a frog vitellogenin A2 gene promoter insert) and down-regulates the nuclear estrogen receptor. Moreover, DIM (5 mg/kg every other day) also inhibits DMBA-induced mammary tumor growth in Sprague-Dawley rats and this was not accompanied by induction of hepatic CYP1A1-dependent activity. Thus, DIM represents a new class of relatively non-toxic AhR-based antiestrogens that inhibit E2-dependent tumor growth in rodents and current studies are focused on development of analogs for clinical treatment of breast cancer.

Original languageEnglish (US)
Pages (from-to)1631-1639
Number of pages9
JournalCarcinogenesis
Volume19
Issue number9
DOIs
StatePublished - Sep 1998

ASJC Scopus subject areas

  • Cancer Research

Fingerprint Dive into the research topics of 'Aryl hydrocarbon receptor-mediated antiestrogenic and antitumorigenic activity of diindolylmethane'. Together they form a unique fingerprint.

Cite this