title: Identification of cis- and trans-acting elements regulating calretinin expression in mesothelioma cells.
abstract: Calretinin (CALB2) is a diagnostic marker for epithelioid mesothelioma. It is also a prognostic marker since patients with tumors expressing high calretinin levels have better overall survival. Silencing of calretinin decreases viability of epithelioid mesothelioma cells. Our aim was to elucidate mechanisms regulating calretinin expression in mesothelioma. Analysis of calretinin transcript and protein suggested a control at the mRNA level. Treatment with 5-aza-2'-deoxycytidine and analysis of TCGA data indicated that promoter methylation is not likely to be involved. Therefore, we investigated CALB2 promoter by analyzing ~1kb of genomic sequence surrounding the transcription start site (TSS) + 1 using promoter reporter assay. Deletion analysis of CALB2 proximal promoter showed that sequence spanning the -161/+80bp region sustained transcriptional activity. Site-directed analysis identified important cis-regulatory elements within this -161/+80bp CALB2 promoter. EMSA and ChIP assays confirmed binding of NRF-1 and E2F2 to the CALB2 promoter and siRNA knockdown of NRF-1 led to decreased expression of calretinin. Cell synchronization experiment showed that calretinin expression was cell cycle regulated with a peak of expression at G1/S phase. This study provides the first insight in the regulation of CALB2 expression in mesothelioma cells.
authors: Laboratory of Molecular Oncology, Clinic of Oncology, University Hospital Zürich, Zürich, Switzerland.
authors: Jelena
authors: J
authors: Kresoja-Rakic
authors: Laboratory of Molecular Oncology, Clinic of Oncology, University Hospital Zürich, Zürich, Switzerland.
authors: Esra
authors: E
authors: Kapaklikaya
authors: Laboratory of Molecular Oncology, Clinic of Oncology, University Hospital Zürich, Zürich, Switzerland.
authors: Gabriela
authors: G
authors: Ziltener
authors: Institute of Veterinary Biochemistry and Molecular Biology, University of Zürich, Zürich, Switzerland.
authors: Damian
authors: D
authors: Dalcher
authors: Institute of Veterinary Biochemistry and Molecular Biology, University of Zürich, Zürich, Switzerland.
authors: Raffaella
authors: R
authors: Santoro
authors: Departments of Epidemiology, Pharmacology and Toxicology and Community and Family Medicine, Geisel School of Medicine at Dartmouth, Hanover, NH, USA.
authors: Brock C
authors: BC
authors: Christensen
authors: Departments of Epidemiology, Pharmacology and Toxicology and Community and Family Medicine, Geisel School of Medicine at Dartmouth, Hanover, NH, USA.
authors: Kevin C
authors: KC
authors: Johnson
authors: Anatomy, Department of Medicine, University of Fribourg, Fribourg, Switzerland.
authors: Beat
authors: B
authors: Schwaller
authors: Division of Thoracic Surgery, University Hospital Zürich, Zürich, Switzerland.
authors: Walter
authors: W
authors: Weder
authors: Laboratory of Molecular Oncology, Clinic of Oncology, University Hospital Zürich, Zürich, Switzerland.
authors: Rolf A
authors: RA
authors: Stahel
authors: Laboratory of Molecular Oncology, Clinic of Oncology, University Hospital Zürich, Zürich, Switzerland.
authors: Emanuela
authors: E
authors: Felley-Bosco
mesh_terms: D001483:Base Sequence; D064032:Calbindin 2 / Q000235:genetics* / Q000378:metabolism; D002478:Cells, Cultured; D050703:E2F2 Transcription Factor / Q000235:genetics / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008654:Mesothelioma / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D051266:Nuclear Respiratory Factor 1 / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012045:Regulatory Sequences, Nucleic Acid
chemical_list: C576764:CALB2 protein, human; D064032:Calbindin 2; D050703:E2F2 Transcription Factor; C493761:E2F2 protein, human; C495633:NRF1 protein, human; D051266:Nuclear Respiratory Factor 1
keywords: NRF-1; calretinin; cell-cycle regulated expression; malignant pleural mesothelioma; promoter