title: Human 3α-hydroxysteroid dehydrogenase type 3: structural clues of 5α-DHT reverse binding and enzyme down-regulation decreasing MCF7 cell growth.
abstract: Human 3α-HSD3 (3α-hydroxysteroid dehydrogenase type 3) plays an essential role in the inactivation of the most potent androgen 5α-DHT (5α-dihydrotestosterone). The present study attempts to obtain the important structure of 3α-HSD3 in complex with 5α-DHT and to investigate the role of 3α-HSD3 in breast cancer cells. We report the crystal structure of human 3α-HSD3·NADP(+)·A-dione (5α-androstane-3,17-dione)/epi-ADT (epiandrosterone) complex, which was obtained by co-crystallization with 5α-DHT in the presence of NADP(+) Although 5α-DHT was introduced during the crystallization, oxidoreduction of 5α-DHT occurred. The locations of A-dione and epi-ADT were identified in the steroid-binding sites of two 3α-HSD3 molecules per crystal asymmetric unit. An overlay showed that A-dione and epi-ADT were oriented upside-down and flipped relative to each other, providing structural clues for 5α-DHT reverse binding in the enzyme with the generation of different products. Moreover, we report the crystal structure of the 3α-HSD3·NADP(+)·4-dione (4-androstene-3,17-dione) complex. When a specific siRNA (100 nM) was used to suppress 3α-HSD3 expression without interfering with 3α-HSD4, which shares a highly homologous active site, the 5α-DHT concentration increased, whereas MCF7 cell growth was suppressed. The present study provides structural clues for 5α-DHT reverse binding within 3α-HSD3, and demonstrates for the first time that down-regulation of 3α-HSD3 decreases MCF7 breast cancer cell growth.
authors.affiliation: Laboratory of Molecular Endocrinology and Oncology, Centre Hospitalier Universitaire de Quebec Research Center (CHUL, CHU) and Laval University, Québec City, Québec, G1V4G2, Canada Key Laboratory for Space Bioscience and Biotechnology, Institute of Special Environmental Biophysics, School of Life Sciences, Northwestern Polytechnical University, Xi'an 710072, P.R. China.
authors.forename: Bo
authors.initials: B
authors.lastname: Zhang
authors.affiliation: School of Life Sciences, Fudan University, Shanghai 200433, P.R. China.
authors.forename: Xiao-Jian
authors.initials: XJ
authors.lastname: Hu
authors.affiliation: Laboratory of Molecular Endocrinology and Oncology, Centre Hospitalier Universitaire de Quebec Research Center (CHUL, CHU) and Laval University, Québec City, Québec, G1V4G2, Canada.
authors.forename: Xiao-Qiang
authors.initials: XQ
authors.lastname: Wang
authors.affiliation: Laboratory of Molecular Endocrinology and Oncology, Centre Hospitalier Universitaire de Quebec Research Center (CHUL, CHU) and Laval University, Québec City, Québec, G1V4G2, Canada.
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Thériault
authors.affiliation: Laboratory of Molecular Endocrinology and Oncology, Centre Hospitalier Universitaire de Quebec Research Center (CHUL, CHU) and Laval University, Québec City, Québec, G1V4G2, Canada.
authors.forename: Dao-Wei
authors.initials: DW
authors.lastname: Zhu
authors.affiliation: Key Laboratory for Space Bioscience and Biotechnology, Institute of Special Environmental Biophysics, School of Life Sciences, Northwestern Polytechnical University, Xi'an 710072, P.R. China.
authors.forename: Peng
authors.initials: P
authors.lastname: Shang
authors.affiliation: Laboratory of Molecular Endocrinology and Oncology, Centre Hospitalier Universitaire de Quebec Research Center (CHUL, CHU) and Laval University, Québec City, Québec, G1V4G2, Canada.
authors.forename: Fernand
authors.initials: F
authors.lastname: Labrie
authors.affiliation: Laboratory of Molecular Endocrinology and Oncology, Centre Hospitalier Universitaire de Quebec Research Center (CHUL, CHU) and Laval University, Québec City, Québec, G1V4G2, Canada Shanghai Engineer and technology Research Center of Reproductive Health Drug and Devices, Shanghai 200032, P.R. China sheng-xiang.lin@crchudequebec.ulaval.ca.
authors.forename: Sheng-Xiang
authors.initials: SX
authors.lastname: Lin
mesh_terms: D045002:3-alpha-Hydroxysteroid Dehydrogenase (B-Specific) / Q000737:chemistry* / Q000378:metabolism; D001665:Binding Sites / Q000502:physiology; D003460:Crystallization; D013196:Dihydrotestosterone / Q000737:chemistry* / Q000378:metabolism; D015536:Down-Regulation / Q000502:physiology*; D006131:Growth Inhibitors / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D061986:MCF-7 Cells; D011485:Protein Binding / Q000502:physiology; D017433:Protein Structure, Secondary; D014961:X-Ray Diffraction
chemical_list: D006131:Growth Inhibitors; D013196:Dihydrotestosterone; D045002:3-alpha-Hydroxysteroid Dehydrogenase (B-Specific)
keywords: 3α-hydroxysteroid dehydrogenase type 3 (3α-HSD3); 5α-dihydrotestosterone (5α-DHT); aldo-keto reductase 1C2 (AKR1C2); cancer cell growth; crystal structure