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: Naoki Mizutani, Minami Inoue, Yukari Omori, Hiromi Ito, Keiko Tamiya-Koizumi, Akira Takagi, Tetsuhito Kojima, Mitsuhiro Nakamura, Soichiro Iwaki, Masahiro Nakatochi, Motoshi Suzuki, Yoshinori Nozawa, Takashi Murate
• Journal: Journal of biochemistry (J Biochem) Vol. 158 Issue 4 Pg. 309-19 (Oct 2015) ISSN: 1756-2651 [Electronic] England
• PMID: 25888580 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © The Authors 2015. Published by Oxford University Press on behalf of the Japanese Biochemical Society. All rights reserved.

Chemical References

• Androgen Antagonists
• Androgens
• Antineoplastic Agents
• Neoplasm Proteins
• Proteasome Inhibitors
• Recombinant Proteins
• Endopeptidases
• USP2 protein, human
• Ubiquitin Thiolesterase
• Proteasome Endopeptidase Complex
• ASAH1 protein, human
• Acid Ceramidase

Topics

• Acid Ceramidase (antagonists & inhibitors, genetics, metabolism)
• Androgen Antagonists (pharmacology)
• Androgens (pharmacology)
• Antineoplastic Agents (pharmacology)
• Breast Neoplasms (drug therapy, enzymology, metabolism)
• Cell Line, Tumor
• Endopeptidases (chemistry, genetics, metabolism)
• Enzyme Induction (drug effects)
• Enzyme Stability (drug effects)
• Female
• Gene Expression Regulation, Neoplastic (drug effects)
• Humans
• Lung Neoplasms (drug therapy, enzymology, metabolism)
• Male
• Neoplasm Proteins (antagonists & inhibitors, genetics, metabolism)
• Promoter Regions, Genetic (drug effects)
• Prostatic Neoplasms (drug therapy, enzymology, metabolism)
• Prostatic Neoplasms, Castration-Resistant (drug therapy, enzymology, metabolism)
• Proteasome Endopeptidase Complex (drug effects, metabolism)
• Proteasome Inhibitors (pharmacology)
• RNA Interference
• Recombinant Proteins (chemistry, metabolism)
• Ubiquitin Thiolesterase