OBJECTIVES: To investigate the androgen response of hormone-dependent prostate cancer cells under hypoxia and to examine the effect of geldanamycin (GA), a heat shock protein 90 (Hsp90)-specific inhibitor, on the androgen response. METHODS: LNCaP cells were cultured with or without GA under normoxic or hypoxic conditions. Cell viability was examined in response to dihydrotestosterone (DHT). Luciferase reporter gene assay was used to measure androgen response element (ARE)- and hypoxia response element (HRE)-mediated transcriptional activities. Western blot was used to analyze the protein levels of androgen receptor (AR), hypoxia-inducible factor-1alpha (HIF-1alpha) and Hsp90. RESULTS: The DHT-dependent growth and ARE-mediated transcriptional activities of LNCaP cells were depressed under hypoxic conditions. However, these effects were recovered after incubation with GA. In contrast, hypoxia-induced HRE-mediated transcriptional activity, which was dose-dependently increased by DHT, was suppressed by GA. The expression of AR, HIF-1alpha and Hsp90 proteins were decreased under hypoxic conditions by adding GA. CONCLUSIONS: Geldanamycin increases the androgen response regardless of AR protein in hormone-dependent prostate cancer cells under hypoxic conditions.
OBJECTIVES: To investigate the androgen response of hormone-dependent prostate cancer cells under hypoxia and to examine the effect of geldanamycin (GA), a heat shock protein 90 (Hsp90)-specific inhibitor, on the androgen response. METHODS: LNCaP cells were cultured with or without GA under normoxic or hypoxic conditions. Cell viability was examined in response to dihydrotestosterone (DHT). Luciferase reporter gene assay was used to measure androgen response element (ARE)- and hypoxia response element (HRE)-mediated transcriptional activities. Western blot was used to analyze the protein levels of androgen receptor (AR), hypoxia-inducible factor-1alpha (HIF-1alpha) and Hsp90. RESULTS: The DHT-dependent growth and ARE-mediated transcriptional activities of LNCaP cells were depressed under hypoxic conditions. However, these effects were recovered after incubation with GA. In contrast, hypoxia-induced HRE-mediated transcriptional activity, which was dose-dependently increased by DHT, was suppressed by GA. The expression of AR, HIF-1alpha and Hsp90 proteins were decreased under hypoxic conditions by adding GA. CONCLUSIONS:Geldanamycin increases the androgen response regardless of AR protein in hormone-dependent prostate cancer cells under hypoxic conditions.