The proposed research will utilize selected aromatase inhibitors as biochemical tools in studying the active site of aromatase. Investigations by the P.I. have demonstrated enhanced affinity of microsomal aromatase for several 7 alpha-thioether substituted 4- androstene-3,17-diones, particularly analogs with aryl amine functionalities. New 7-substituted C19-steroids with enhanced affinity for the enzyme and/or greater metabolic stability have recently been developed and will be used to examine the aromatase protein. Specifically: (1) Aromatase will be purified from human placental microsomes by cholate solubilization, ammonium sulfate fractionation, and a combination of affinity and adsorption chromatography. (2) Radiolabeled 3H-and 125I- analogs of selected enzyme-activated inhibitors will be prepared. New synthetic compounds will be examined in microsomal preparations for inhibitory activity. (3) The radiolabeled enzyme- activated inhibitors prepared above will be incubated with purified aromatase preparations to examine the extent of irreversible binding. Inhibitor-bound aromatase protein will be isolated and treated with proteolytic enzymes and peptides will be separated by HPLC. The amino acid sequence of radiolabeled peptide fragments will be determined by microsequence analysis. Thus, radiolabeled analogs of selected inhibitors will be prepared and utilized to probe the active site of purified aromatase. Knowledge of the chemistry of the enzymatic """"""""pocket"""""""" of aromatase is critical in the further design and development of more effective and potent agents for the control of estrogenic processes and for the treatment of advanced estrogen-dependent breast cancer.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
1R01DK040255-01
Application #
3240439
Study Section
Biochemical Endocrinology Study Section (BCE)
Project Start
1988-05-01
Project End
1991-04-30
Budget Start
1988-05-01
Budget End
1989-04-30
Support Year
1
Fiscal Year
1988
Total Cost
Indirect Cost
Name
Ohio State University
Department
Type
Schools of Pharmacy
DUNS #
098987217
City
Columbus
State
OH
Country
United States
Zip Code
43210
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O'Reilly, J M; Li, N; Duax, W L et al. (1995) Synthesis, structure elucidation, and biochemical evaluation of 7 alpha- and 7 beta-arylaliphatic-substituted androst-4-ene-3,17-diones as inhibitors of aromatase. J Med Chem 38:2842-50
Brueggemeir, R W; Moh, P P; Ebrahimian, S et al. (1993) Steroidal inhibitors as chemical probes of the active site of aromatase. J Steroid Biochem Mol Biol 44:357-65
Ebrahimian, S; Chen, H H; Brueggemeier, R W (1993) Synthesis and biochemical studies of 7 alpha-substituted androsta-1,4-diene-3,17-diones as enzyme-activated irreversible inhibitors of aromatase. Steroids 58:414-22
Brueggemeier, R W; Katlic, N E; Kenreigh, C A et al. (1992) Aromatase inhibition by 7-substituted steroids in human choriocarcinoma cell culture. J Steroid Biochem Mol Biol 41:85-90
Li, P K; Brueggemeier, R W (1990) Synthesis and biochemical studies of 7-substituted 4,6-androstadiene-3,17-diones as aromatase inhibitors. J Med Chem 33:101-5
Li, P K; Brueggemeier, R W (1990) 7-substituted 1,4,6-androstatriene-3,17-diones as enzyme-activated irreversible inhibitors of aromatase. J Steroid Biochem 36:533-9
Chen, H H; Brueggemeier, R W (1990) Synthesis and biochemistry of fluorescent aromatase inhibitors. Steroids 55:123-7
Li, P K; Brueggemeier, R W (1990) 7-substituted steroidal aromatase inhibitors: structure-activity relationships and molecular modeling. J Enzyme Inhib 4:113-20

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