title: Increased acid ceramidase expression depends on upregulation of androgen-dependent deubiquitinases, USP2, in a human prostate cancer cell line, LNCaP.
abstract: Acid ceramidase (ACDase) metabolizes ceramide to sphingosine, leading to sphingosine 1-phosphate production. Reportedly, ACDase has been upregulated in prostate cancer. However, its regulatory mechanism remains unclear. LNCaP (androgen-sensitive prostate cancer cell line) but not PC3 and DU-145, (androgen-unresponsive cell lines) exhibited the highest ACDase protein. Among three cell lines, ASAH1 mRNA level was not correlated with ACDase protein expression, and the 5'-promoter activity did not show androgen dependency, suggesting the post-transcriptional regulation of ACDase in LNCaP cells. Based on these results, LNCaP was analysed further. Casodex, androgen receptor antagonist, and charcoal-stripped FCS (CS-FCS) decreased ACDase protein and activity, whereas dihydrotestosterone in CS-FCS culture increased ACDase protein and enzyme activity. MG132, a proteasome inhibitor, prevented the decrease of ACDase protein when cultured in CS-FCS, suggesting the involvement of ubiquitin/proteasome system. Reportedly, USP2, a deubiquitinase, plays an important role in LNCaP cells. USP2 siRNA decreased ACDase protein, whereas USP2 overexpression increased ACDase protein of LNCaP cells. However, SKP2, an ubiquitin E3 ligase known to be active in prostate cancer, did not affect androgen-dependent ACDase expression in LNCaP cells. Thus, ACDase regulation by androgen in androgen-sensitive LNCaP cells is mainly due to its prolonged protein half-life by androgen-stimulated USP2 expression.
authors.affiliation: Department of Pathophysiological Laboratory Science, Nagoya University Graduate School of Medicine, Nagoya 461-8673;
authors.forename: Naoki
authors.initials: N
authors.lastname: Mizutani
authors.affiliation: Department of Pathophysiological Laboratory Science, Nagoya University Graduate School of Medicine, Nagoya 461-8673;
authors.forename: Minami
authors.initials: M
authors.lastname: Inoue
authors.affiliation: Department of Pathophysiological Laboratory Science, Nagoya University Graduate School of Medicine, Nagoya 461-8673;
authors.forename: Yukari
authors.initials: Y
authors.lastname: Omori
authors.affiliation: Department of Pathophysiological Laboratory Science, Nagoya University Graduate School of Medicine, Nagoya 461-8673;
authors.forename: Hiromi
authors.initials: H
authors.lastname: Ito
authors.affiliation: Department of Pathophysiological Laboratory Science, Nagoya University Graduate School of Medicine, Nagoya 461-8673;
authors.forename: Keiko
authors.initials: K
authors.lastname: Tamiya-Koizumi
authors.affiliation: Department of Pathophysiological Laboratory Science, Nagoya University Graduate School of Medicine, Nagoya 461-8673;
authors.forename: Akira
authors.initials: A
authors.lastname: Takagi
authors.affiliation: Department of Pathophysiological Laboratory Science, Nagoya University Graduate School of Medicine, Nagoya 461-8673;
authors.forename: Tetsuhito
authors.initials: T
authors.lastname: Kojima
authors.affiliation: Department of Drug Information, Gifu Pharmaceutical University, Gifu 501-1196;
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Nakamura
authors.affiliation: Department of Molecular and Cellular Pathophysiology and Therapeutics, Graduate School of Pharmaceutical Science, Nagoya City University, Nagoya 467-8603;
authors.forename: Soichiro
authors.initials: S
authors.lastname: Iwaki
authors.affiliation: Bioinformatics Section, Center for Advanced Medicine and Clinical Research, Nagoya University Hospital, Nagoya 466-8550;
authors.forename: Masahiro
authors.initials: M
authors.lastname: Nakatochi
authors.affiliation: Division of Molecular Carcinogenesis, Nagoya University Graduate School of Medicine, Nagoya 466-8560; and.
authors.forename: Motoshi
authors.initials: M
authors.lastname: Suzuki
authors.affiliation: Department of Food and Health Science, Tokai Gakuin University, Kakamigahara 504-8511, Japan.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Nozawa
authors.affiliation: Department of Pathophysiological Laboratory Science, Nagoya University Graduate School of Medicine, Nagoya 461-8673; murate@met.nagoya-u.ac.jp.
authors.forename: Takashi
authors.initials: T
authors.lastname: Murate
mesh_terms: D055573:Acid Ceramidase / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D000726:Androgen Antagonists / Q000494:pharmacology; D000728:Androgens / Q000494:pharmacology; D000970:Antineoplastic Agents / Q000494:pharmacology; D001943:Breast Neoplasms / Q000188:drug therapy / Q000201:enzymology / Q000378:metabolism; D045744:Cell Line, Tumor; D010450:Endopeptidases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004790:Enzyme Induction / Q000187:drug effects; D004795:Enzyme Stability / Q000187:drug effects; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D008175:Lung Neoplasms / Q000188:drug therapy / Q000201:enzymology / Q000378:metabolism; D008297:Male; D009363:Neoplasm Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000187:drug effects; D011471:Prostatic Neoplasms / Q000188:drug therapy / Q000201:enzymology* / Q000378:metabolism; D064129:Prostatic Neoplasms, Castration-Resistant / Q000188:drug therapy / Q000201:enzymology / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex / Q000187:drug effects / Q000378:metabolism; D061988:Proteasome Inhibitors / Q000494:pharmacology; D034622:RNA Interference; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D043222:Ubiquitin Thiolesterase
chemical_list: D000726:Androgen Antagonists; D000728:Androgens; D000970:Antineoplastic Agents; D009363:Neoplasm Proteins; D061988:Proteasome Inhibitors; D011994:Recombinant Proteins; D010450:Endopeptidases; C108665:USP2 protein, human; D043222:Ubiquitin Thiolesterase; D046988:Proteasome Endopeptidase Complex; C526693:ASAH1 protein, human; D055573:Acid Ceramidase
keywords: acid ceramidase; androgen receptor; prostate cancer cell line; protein degradation; ubiquitin-specific protease 2