title: Induction of cell differentiation activates transcription of the Sarco/Endoplasmic Reticulum calcium-ATPase 3 gene (ATP2A3) in gastric and colon cancer cells.
abstract: The Sarco/Endoplasmic Reticulum Ca2+-ATPases (SERCAs), pump Ca2+into the endoplasmic reticulum lumen modulating cytosolic Ca2+concentrations to regulate various cellular processes including cell growth. Previous studies have reported a downregulation of SERCA3 protein expression in gastric and colon cancer cell lines and showed that in vitro cell differentiation increases its expression. However, little is known about the transcriptional mechanisms and transcription factors that regulate SERCA3 expression in epithelial cancer cells. In this work, we demonstrate that SERCA3 mRNA is upregulated up to 45-fold in two epithelial cancer cell lines, KATO-III and Caco-2, induced to differentiate with histone deacetylase inhibitors (HDACi) and by cell confluence, respectively. To evaluate the transcriptional elements responding to the differentiation stimuli, we cloned the human ATP2A3 promoter, generated deletion constructs and transfected them into KATO-III cells. Basal and differentiation responsive DNA elements were located by functional analysis within the first -135 bp of the promoter region. Using site-directed mutagenesis and DNA-protein binding assays we found that Sp1, Sp3, and Klf-4 transcription factors bind to ATP2A3 proximal promoter elements and regulate basal gene expression. We showed that these factors participated in the increase of ATP2A3 expression during cancer cell differentiation. This study provides evidence for the first time that Sp1, Sp3, and Klf-4 transcriptionally modulate the expression of SERCA3 during induction of epithelial cancer cell differentiation. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Department of Biochemistry, School of Medicine, National Autonomous University of Mexico, Mexico City, Mexico.
authors.forename: Lucía
authors.initials: L
authors.lastname: Flores-Peredo
authors.affiliation: Department of Biochemistry, School of Medicine, National Autonomous University of Mexico, Mexico City, Mexico.
authors.forename: Gabriela
authors.initials: G
authors.lastname: Rodríguez
authors.affiliation: Department of Biochemistry, School of Medicine, National Autonomous University of Mexico, Mexico City, Mexico.
authors.forename: Angel
authors.initials: A
authors.lastname: Zarain-Herzberg
mesh_terms: D001483:Base Sequence; D018938:Caco-2 Cells; D002454:Cell Differentiation; D045744:Cell Line, Tumor; D003106:Colon / Q000378:metabolism; D003110:Colonic Neoplasms / Q000235:genetics* / Q000378:metabolism; D005753:Gastric Mucosa / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D000090062:Kruppel-Like Factor 4; D051741:Kruppel-Like Transcription Factors / Q000378:metabolism; D011401:Promoter Regions, Genetic; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases / Q000235:genetics*; D016329:Sp1 Transcription Factor / Q000378:metabolism; D051705:Sp3 Transcription Factor / Q000378:metabolism; D013274:Stomach Neoplasms / Q000235:genetics* / Q000378:metabolism; D015533:Transcriptional Activation
chemical_list: C000715467:KLF4 protein, human; D000090062:Kruppel-Like Factor 4; D051741:Kruppel-Like Transcription Factors; C497121:SP3 protein, human; D016329:Sp1 Transcription Factor; C108209:SP1 protein, human; D051705:Sp3 Transcription Factor; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; C506949:ATP2A3 protein, human
keywords: SERCA; calcium ATPase; cancer biology; cell differentiation; gene expression; transcriptional regulation