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Concordant effects of aromatase inhibitors on gene expression in ER+ Rat and human mammary cancers and modulation of the proteins coded by these genes. Cancer Prev Res (Phila) 2013 Nov;6(11):1151-61



Pubmed ID


Pubmed Central ID




Scopus ID

2-s2.0-84887878472   9 Citations


Aromatase inhibitors are effective in therapy/prevention of estrogen receptor-positive (ER⁺) breast cancers. Rats bearing methylnitrosourea (MNU)-induced ER⁺ mammary cancers were treated with the aromatase inhibitor vorozole (1.25 mg/kg BW/day) for five days. RNA expression showed 162 downregulated and 180 upregulated (P < 0.05 and fold change >1.5) genes. Genes modulated by vorozole were compared with published data from four clinical neoadjuvant trials using aromatase inhibitors (anastrozole or letrozole). More than 30 genes and multiple pathways exhibited synchronous changes in animal and human datasets. Cell-cycle genes related to chromosome condensation in prometaphase [anaphase-prometaphase complex (APC) pathway, including Aurora-A kinase, BUBR1B, TOP2, cyclin A, cyclin B CDC2, and TPX-2)] were downregulated in animal and human studies reflecting the strong antiproliferative effects of aromatase inhibitors. Comparisons of rat arrays with a cell culture study where estrogen was removed from MCF-7 cells showed decreased expression of E2F1-modulated genes as a major altered pathway. Alterations of the cell cycle and E2F-related genes were confirmed in a large independent set of human samples (81 pairs baseline and two weeks anastrozole treatment). Decreases in proliferation-related genes were confirmed at the protein level for cyclin A2, BuRB1, cdc2, Pttg, and TPX-2. Interestingly, the proteins downregulated in tumors were similarly downregulated in vorozole-treated normal rat mammary epithelium. Finally, decreased expression of known estrogen-responsive genes (including TFF, 1,3, progesterone receptor, etc.) were decreased in the animal model. These studies demonstrate that gene expression changes (pathways and individual genes) are similar in humans and the rat model.

Author List

Lu Y, You M, Ghazoui Z, Liu P, Vedell PT, Wen W, Bode AM, Grubbs CJ, Lubet RA


Pengyuan Liu PhD Adjunct Professor in the Physiology department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Aromatase Inhibitors
Biomarkers, Tumor
Breast Neoplasms
Gene Expression Profiling
Gene Expression Regulation, Neoplastic
Immunoenzyme Techniques
Mammary Neoplasms, Experimental
Oligonucleotide Array Sequence Analysis
RNA, Messenger
Real-Time Polymerase Chain Reaction
Receptors, Estrogen
Reverse Transcriptase Polymerase Chain Reaction