title: ROS mediates 4HPR-induced posttranscriptional expression of the Gadd153 gene.
abstract: All-trans-N-(4-hydroxyphenyl)retinamide (4HPR) is a synthetic retinoid that can induce apoptosis in many cancer cell lines. The cytotoxicity of 4HPR is dependent on the production of ROS but the underlying reasons are not entirely certain. We have investigated the role of 4HPR-induced production of ROS in mediating the expression of the recently identified 4HPR-responsive gene Gadd153. In 4HPR-treated cells, the elevation of Gadd153 protein level was prevented by vitamin C, which had no effect on the activation of the Gadd153 gene promoter. The 4HPR-induced elevation of Gadd153 mRNA level persisted even after transcription was blocked with actinomycin D, but declined rapidly upon the addition of antioxidants to the transcription-arrested cells. The mRNA expressed from the full-length Gadd153 cDNA was degraded constitutively in cells in the absence but not in the presence of 4HPR. Such an inhibitory effect of 4HPR was abolished by antioxidants and by inhibitors of 12-lipoxygenase, baicalein (specific) and esculetin (panspecific). The inhibition of 4HPR-induced expression of Gadd153 protein by vitamin C was independent of intracellular proteasome activity and vitamin C had no effect on the intracellular decay of Gadd153 protein. Our data provide the first evidence that the posttranscriptional expression of the Gadd153 gene can be regulated by ROS produced by 4HPR.
authors.affiliation: Department of Biochemistry, Faculty of Medicine, University of Hong Kong, Pokfulam, Hong Kong, People's Republic of China.
authors.forename: Wai-Lung
authors.initials: WL
authors.lastname: Lai
authors.forename: Nai-Sum
authors.initials: NS
authors.lastname: Wong
mesh_terms: D000975:Antioxidants / Q000494:pharmacology; D001205:Ascorbic Acid / Q000494:pharmacology; D022762:CCAAT-Enhancer-Binding Proteins / Q000096:biosynthesis*; D003609:Dactinomycin / Q000494:pharmacology; D017313:Fenretinide / Q000494:pharmacology*; D044950:Flavanones / Q000494:pharmacology; D019073:HT29 Cells; D006367:HeLa Cells; D006801:Humans; D016859:Lipoxygenase Inhibitors / Q000494:pharmacology; D011401:Promoter Regions, Genetic / Q000187:drug effects; D012333:RNA, Messenger / Q000187:drug effects; D017382:Reactive Oxygen Species / Q000378:metabolism*; D051742:Transcription Factor CHOP; D014157:Transcription Factors / Q000096:biosynthesis*; D014158:Transcription, Genetic / Q000187:drug effects; D014468:Umbelliferones / Q000494:pharmacology
chemical_list: D000975:Antioxidants; D022762:CCAAT-Enhancer-Binding Proteins; C497249:DDIT3 protein, human; D044950:Flavanones; D016859:Lipoxygenase Inhibitors; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D014157:Transcription Factors; D014468:Umbelliferones; D051742:Transcription Factor CHOP; D017313:Fenretinide; D003609:Dactinomycin; C006680:baicalein; D001205:Ascorbic Acid; C007628:esculetin