title: Distinct promoters, subjected to epigenetic regulation, drive the expression of two clusterin mRNAs in prostate cancer cells.
abstract: The human clusterin (CLU) gene codes for several mRNAs characterized by different sequences at their 5' end. We investigated the expression of two CLU mRNAs, called CLU 1 and CLU 2, in immortalized (PNT1a) and tumorigenic (PC3 and DU145) prostate epithelial cells, as well as in normal fetal fibroblasts (WI38) following the administration of the epigenetic drugs 5-aza-2'-deoxycytidine (AZDC) and trichostatin A (TSA) given either as single or combined treatment (AZDC-TSA). Our experimental evidences show that: a) CLU 1 is the most abundant transcript variant. b) CLU 2 is expressed at a low level in normal fibroblasts and virtually absent in prostate cancer cells. c) CLU 1, and to a greater extent CLU 2 expression, increased by AZDC-TSA treatment in prostate cancer cells. d) Both CLU 1 and CLU 2 encode for secreted CLU. e) P2, a novel promoter that overlaps the CLU 2 Transcription Start Site (TSS), drives CLU 2 expression. f) A CpG island, methylated in prostate cancer cells and not in normal fibroblasts, is responsible for long-term heritable regulation of CLU 1 expression. g) ChIP assay of histone tail modifications at CLU promoters (P1 and P2) shows that treatment of prostate cancer cells with AZDC-TSA causes enrichment of Histone3(Lys9)acetylated (H3K9ac) and reduction of Histone3(Lys27)trimethylated (H3K27me3), inducing active transcription of both CLU variants. In conclusion, we show for the first time that the expression of CLU 2 mRNA is driven by a novel promoter, P2, whose activity responds to epigenetic drugs treatment through changes in histone modifications.
authors.affiliation: Department of Biomedicine, Biotechnology and Translational Research, University of Parma, Via Volturno 39/a, 43126 Parma, Italy.
authors.forename: Martina
authors.initials: M
authors.lastname: Bonacini
authors.affiliation: Department of Biomedicine, Biotechnology and Translational Research, University of Parma, Via Volturno 39/a, 43126 Parma, Italy.
authors.forename: Mariangela
authors.initials: M
authors.lastname: Coletta
authors.affiliation: Department of Biomedicine, Biotechnology and Translational Research, University of Parma, Via Volturno 39/a, 43126 Parma, Italy; Centre for Molecular and Translational Oncology (COMT), University of Parma, Parco Area delle Scienze 11/a, 43124 Parma, Italy; National Institute of Biostructure and Biosystems (INBB), Viale Medaglie d'Oro 305, 00136 Rome, Italy.
authors.forename: Ileana
authors.initials: I
authors.lastname: Ramazzina
authors.affiliation: Department of Biomedicine, Biotechnology and Translational Research, University of Parma, Via Volturno 39/a, 43126 Parma, Italy; Centre for Molecular and Translational Oncology (COMT), University of Parma, Parco Area delle Scienze 11/a, 43124 Parma, Italy; National Institute of Biostructure and Biosystems (INBB), Viale Medaglie d'Oro 305, 00136 Rome, Italy.
authors.forename: Valeria
authors.initials: V
authors.lastname: Naponelli
authors.affiliation: Department of Biomedicine, Biotechnology and Translational Research, University of Parma, Via Volturno 39/a, 43126 Parma, Italy.
authors.forename: Alice
authors.initials: A
authors.lastname: Modernelli
authors.affiliation: Department of Biomedical Sciences, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Via Campi 287, 41125 Modena, Italy.
authors.forename: Pierpaola
authors.initials: P
authors.lastname: Davalli
authors.affiliation: Department of Biomedicine, Biotechnology and Translational Research, University of Parma, Via Volturno 39/a, 43126 Parma, Italy; Centre for Molecular and Translational Oncology (COMT), University of Parma, Parco Area delle Scienze 11/a, 43124 Parma, Italy; National Institute of Biostructure and Biosystems (INBB), Viale Medaglie d'Oro 305, 00136 Rome, Italy. Electronic address: saverio.bettuzzi@unipr.it.
authors.forename: Saverio
authors.initials: S
authors.lastname: Bettuzzi
authors.affiliation: Department of Biomedicine, Biotechnology and Translational Research, University of Parma, Via Volturno 39/a, 43126 Parma, Italy; Centre for Molecular and Translational Oncology (COMT), University of Parma, Parco Area delle Scienze 11/a, 43124 Parma, Italy; National Institute of Biostructure and Biosystems (INBB), Viale Medaglie d'Oro 305, 00136 Rome, Italy.
authors.forename: Federica
authors.initials: F
authors.lastname: Rizzi
mesh_terms: D045744:Cell Line, Tumor; D051152:Clusterin / Q000096:biosynthesis*; D018899:CpG Islands / Q000235:genetics; D019175:DNA Methylation / Q000235:genetics; D044127:Epigenesis, Genetic; D015972:Gene Expression Regulation, Neoplastic; D006657:Histones / Q000378:metabolism; D006801:Humans; D008297:Male; D011401:Promoter Regions, Genetic; D011471:Prostatic Neoplasms / Q000235:genetics* / Q000473:pathology; D012333:RNA, Messenger / Q000096:biosynthesis*
chemical_list: D051152:Clusterin; D006657:Histones; D012333:RNA, Messenger
keywords: Alternative promoter; Clusterin; Epigenetic regulation; Prostate cancer