Modulation of cyclophilin gene expression by N-4-(hydroxyphenyl)retinamide: Association with reactive oxygen species generation and apoptosis

✍ Scribed by Stephen D. Hursting; Jian-cheng Shen; Xiao-Ya Sun; Thomas T.Y. Wang; James M. Phang; Susan N. Perkins

• Publisher: John Wiley and Sons
• Year: 2002
• Tongue: English
• Weight: 510 KB
• Volume: 33
• Category: Article
• ISSN: 0899-1987
• DOI: 10.1002/mc.10020

✦ Synopsis

Abstract

To explore the mechanisms underlying the pro‐apoptotic effects of the synthetic retinoid N‐4‐(hydroxyphenyl)retinamide (4‐HPR) on LNCaP human prostate cancer cells, we used the differential display–polymerase chain reaction (DD‐PCR) technique to identify 4‐HPR–responsive genes. RNA extracted from LNCaP cells that had been treated for 24 h with 4‐HPR at a dose (2.5 μM) optimal for apoptosis induction was used for DD‐PCR analysis using random primers. A differentially expressed 115 bp fragment was cloned and sequenced and then identified in GenBank as having a high degree of homology with several members of the cyclophilin gene family. Northern blot analyses using specific probes for cyclophilin A, cyclophilin D, and the cloned 115‐bp fragment were performed on RNA extracted from LNCaP cells and MCF‐7 human breast cancer cells treated with 4‐HPR, N‐acetylcysteine (NAC, an anti‐oxidant), 4‐HPR plus NAC, cyclosporin A, R‐1881 (a synthetic androgen), dehydroepiandrosterone, all‐trans retinoic acid, or prednisone. 4‐HPR downregulated the transcript detected by the 115‐bp fragment. Expression patterns detected by the 115‐bp fragment and cyclophilin D probes were identical in response to each treatment; none of these treatments affected cyclophilin A expression. Furthermore, expression of mRNA transcripts detected by the 115‐bp fragment and cyclophilin D probes correlated with the generation of reactive oxygen species (ROS), as detected by measurement of 2,7‐dichlorofluorescein oxidation. Therefore, members of the cyclophilin gene family, such as cyclophilin D (a component of the mitochondrial permeability transition pore previously linked with oxidative stress and apoptosis), may play a role in the ROS‐mediated apoptotic effects of 4‐HPR. Published 2002 Wiley‐Liss, Inc.