963 HOW DOES 5α-REDUCTASE ACTIVITY CHANGE DURING THE PROGRESSION OF CASTRATION RESISTANT PROSTATE CANCER?

Abstract

You have accessJournal of UrologyProstate Cancer: Basic Research V1 Apr 2012963 HOW DOES 5α-REDUCTASE ACTIVITY CHANGE DURING THE PROGRESSION OF CASTRATION RESISTANT PROSTATE CANCER? Takeo Kosaka, Akira Miyajima, Eiji Kikuchi, Takahiro Maeda, Hirohiko Nagata, and Mototsugu Oya Takeo KosakaTakeo Kosaka Tokyo, Japan More articles by this author , Akira MiyajimaAkira Miyajima Tokyo, Japan More articles by this author , Eiji KikuchiEiji Kikuchi Tokyo, Japan More articles by this author , Takahiro MaedaTakahiro Maeda Tokyo, Japan More articles by this author , Hirohiko NagataHirohiko Nagata Tokyo, Japan More articles by this author , and Mototsugu OyaMototsugu Oya Tokyo, Japan More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2012.02.1062AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Deregulation of the androgen-androgen receptor (AR) pathway is a hallmark of prostate cancer (PCA). Therapies targeting the androgen-AR axis at different levels including de novo steroid synthesis may be quite effective against PCA to improve the prognosis of patients. However, it has not been been fully elucidated how steroid-5α-reductase (SRD5As) contribute to the development of PCA or progression to castration-resistant prostate cancer (CRPC). In this study, we sought to determine the significance of dihydrotestosterone (DHT) and SRD5As activity in CRPC. METHODS Two human CRPC cell lines (C4-2 and C4-2AT6) were used in this study. C4-2AT6 was established from C4-2 grown in androgen ablated condition for six months. The expression of SRD5As was semi-quantified with qPCR. To ascertain the potential SRD5As activity, we cultured C4-2 and C4-2AT6 cells with the steroid precursors modified by stable isotope: 13C-[2,3,4]-androstenedione (13C-A-dione). The sequential biosynthesis of 13C-[2,3,4]-dihydrotestosterone (13C-DHT) and 13C-[2,3,4]-testosterone (13C-T) were analyzed by liquid chromatography/mass spectrometry (LC/MS). RESULTS The C4-2AT6 cells showed 0.48-fold decrease of SRD5A1, 1.4-fold increase in SRD5A2 and 2.6-fold increase in SRD5A3 expression than C4-2 cells. The DHT concentration (0.01 ± 0.008 pg/ml, p<0.001) detected by LC/MS in C4-2AT6 cultured supernatant was significantly lower than that of in C4-2 supernatant (0.46 ± 0.12 pg/ml). These results showed that DHT production was reduced in C4-2AT6 cells. LC/MS analysis can detect significant convergence of 13C-A-dione into 13C-DHT and 13C-T. The concentration of 13C-DHT/13C-T (DHT/T ratio) was thought to reflect the SRD5As activity. The concentration of 13C-DHT in C4-2 and C4-2AT6 was 779.6 ± 210.9 and 150 ± 58.5 pg/mL, respectively (p<0.001). The DHT/T ratio of C4-2 and C4-2AT6 cells was 0.07 ± 0.03 and 0.02 ±0.003, respectively (p<0.001), suggesting reduced SRD5As activity in C4-2AT6. The response of C4-2AT6 cells to DHT was significantly decreased, compared with C4-2 cells, indicating reduced dependency of mRNA expression of PSA and Nkx3.1 on DHT. CONCLUSIONS These results demonstrated that the direct evidences of the change of SRD5As activity, accompanied by the reduced ability to produce DHT in CRPC. These experimental models provide a bland new platform to investigate the significance of DHT and SRD5As in CRPC progression. © 2012 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 187Issue 4SApril 2012Page: e392-e393 Advertisement Copyright & Permissions© 2012 by American Urological Association Education and Research, Inc.MetricsAuthor Information Takeo Kosaka Tokyo, Japan More articles by this author Akira Miyajima Tokyo, Japan More articles by this author Eiji Kikuchi Tokyo, Japan More articles by this author Takahiro Maeda Tokyo, Japan More articles by this author Hirohiko Nagata Tokyo, Japan More articles by this author Mototsugu Oya Tokyo, Japan More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...