title: Activation of the aryl-hydrocarbon receptor inhibits invasive and metastatic features of human breast cancer cells and promotes breast cancer cell differentiation.
abstract: The current statistics associated with breast cancer continue to show a relatively high recurrence rate together with a poor survival for aggressive metastatic disease. These findings reflect, in part, the pharmaceutical intractability of processes involved in the metastatic process and highlight the need to identify additional drug targets for the treatment of late-stage disease. In the current study, we report that ligand activation of the aryl-hydrocarbon receptor (AhR) inhibits multiple aspects of the metastatic process in a panel of breast cancer cell lines that represent the major breast cancer subtypes. Specifically, it was observed that treatment with exogenous AhR agonists significantly inhibited cell invasiveness and motility in the Boyden chamber assay and inhibited colony formation in soft agar regardless of estrogen receptor (ER), progesterone receptor, or human epidermal growth factor receptor 2 status. Knockdown of the AhR using small interfering RNA duplexes demonstrated that the inhibition of invasiveness was receptor dependent and that endogenous receptor activity was protective in each cell type examined. The inhibition of invasiveness and anchorage-independent growth correlated with the ability of exogenous AhR agonists to promote differentiation. Finally, exogenous AhR agonists were able to promote differentiation in a putative mammary cancer stem cell line. Cumulatively, these results suggest that the AhR plays an important role in mammary epithelial differentiation and, as such, represent a promising therapeutic target for a range of phenotypically distinct human breast cancers.
authors.affiliation: The Hamner Institutes for Health Sciences, Genomic Biology and Bioinformatics, Research Triangle Park, North Carolina 27709, USA.
authors.forename: Julie M
authors.initials: JM
authors.lastname: Hall
authors.forename: Melissa A
authors.initials: MA
authors.lastname: Barhoover
authors.forename: Dmitri
authors.initials: D
authors.lastname: Kazmin
authors.forename: Donald P
authors.initials: DP
authors.lastname: McDonnell
authors.forename: William F
authors.initials: WF
authors.lastname: Greenlee
authors.forename: Russell S
authors.initials: RS
authors.lastname: Thomas
mesh_terms: D000230:Adenocarcinoma / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D002454:Cell Differentiation / Q000187:drug effects; D045744:Cell Line, Tumor; D048430:Cell Shape / Q000187:drug effects; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D008024:Ligands; D009361:Neoplasm Invasiveness / Q000517:prevention & control*; D009362:Neoplasm Metastasis / Q000517:prevention & control*; D009367:Neoplasm Staging; D014411:Neoplastic Stem Cells / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering; D051381:Rats; D018336:Receptors, Aryl Hydrocarbon / Q000819:agonists* / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D046888:Tissue Array Analysis
chemical_list: D015415:Biomarkers; D008024:Ligands; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D018336:Receptors, Aryl Hydrocarbon