US EPA

5919966 

Journal Article 

Novel aromatase inhibitors by structure-guided design 

Ghosh, D; Lo, J; Morton, D; Valette, D; Xi, J; Griswold, J; Hubbell, S; Egbuta, C; Jiang, W; An, J; Davies, HM 

2012 

Yes 

Journal of Medicinal Chemistry
ISSN: 0022-2623
EISSN: 1520-4804 

55 

19 

8464-8476 

English 

22951074 

10.1021/jm300930n 

Human cytochrome P450 aromatase catalyzes with high specificity the synthesis of estrogens from androgens. Aromatase inhibitors (AIs) such as exemestane, 6-methylideneandrosta-1,4-diene-3,17-dione, are preeminent drugs for the treatment of estrogen-dependent breast cancer. The crystal structure of human placental aromatase has shown an androgen-specific active site. By utilization of the structural data, novel C6-substituted androsta-1,4-diene-3,17-dione inhibitors have been designed. Several of the C6-substituted 2-alkynyloxy compounds inhibit purified placental aromatase with IC(50) values in the nanomolar range. Antiproliferation studies in a MCF-7 breast cancer cell line demonstrate that some of these compounds have EC(50) values better than 1 nM, exceeding that for exemestane. X-ray structures of aromatase complexes of two potent compounds reveal that, per their design, the novel side groups protrude into the opening to the access channel unoccupied in the enzyme-substrate/exemestane complexes. The observed structure-activity relationship is borne out by the X-ray data. Structure-guided design permits utilization of the aromatase-specific interactions for the development of next generation AIs.