title: Prolyl-4-hydroxylase 3 (PHD3) expression is downregulated during epithelial-to-mesenchymal transition.
abstract: Prolyl-4-hydroxylation by the intracellular prolyl-4-hydroxylase enzymes (PHD1-3) serves as a master regulator of environmental oxygen sensing. The activity of these enzymes is tightly tied to tumorigenesis, as they regulate cell metabolism and angiogenesis through their control of hypoxia-inducible factor (HIF) stability. PHD3 specifically, is gaining attention for its broad function and rapidly accumulating array of non-HIF target proteins. Data from several recent studies suggest a role for PHD3 in the regulation of cell morphology and cell migration. In this study, we aimed to investigate this role by closely examining the relationship between PHD3 expression and epithelial-to-mesenchymal transition (EMT); a transcriptional program that plays a major role in controlling cell morphology and migratory capacity. Using human pancreatic ductal adenocarcinoma (PDA) cell lines and Madin-Darby Canine Kidney (MDCK) cells, we examined the correlation between several markers of EMT and PHD3 expression. We demonstrated that loss of PHD3 expression in PDA cell lines is highly correlated with a mesenchymal-like morphology and an increase in cell migratory capacity. We also found that induction of EMT in MDCK cells resulted in the specific downregulation of PHD3, whereas the expression of the other HIF-PHD enzymes was not affected. The results of this study clearly support a model by which the basal expression and hypoxic induction of PHD3 is suppressed by the EMT transcriptional program. This may be a novel mechanism by which migratory or metastasizing cells alter signaling through specific pathways that are sensitive to regulation by O2. The identification of downstream pathways that are affected by the suppression of PHD3 expression during EMT may provide important insight into the crosstalk between O2 and the migratory and metastatic potential of tumor cells.
authors.affiliation: Molecular and Cellular Biology Program, The University of Iowa, Iowa City, Iowa, United States of America ; Department of Radiation Oncology, The University of Iowa, Iowa City, Iowa, United States of America.
authors.forename: Trenton L
authors.initials: TL
authors.lastname: Place
authors.affiliation: Department of Molecular Physiology and Biophysics, The University of Iowa, Iowa City, Iowa, United States of America.
authors.forename: Jones T
authors.initials: JT
authors.lastname: Nauseef
authors.affiliation: Department of Anatomy and Cell Biology, The University of Iowa, Iowa City, Iowa, United States of America.
authors.forename: Maina K
authors.initials: MK
authors.lastname: Peterson
authors.affiliation: Department of Molecular Physiology and Biophysics, The University of Iowa, Iowa City, Iowa, United States of America.
authors.forename: Michael D
authors.initials: MD
authors.lastname: Henry
authors.affiliation: Department of Surgery, The University of Iowa, Iowa City, Iowa, United States of America.
authors.forename: James J
authors.initials: JJ
authors.lastname: Mezhir
authors.affiliation: Molecular and Cellular Biology Program, The University of Iowa, Iowa City, Iowa, United States of America ; Department of Radiation Oncology, The University of Iowa, Iowa City, Iowa, United States of America.
authors.forename: Frederick E
authors.initials: FE
authors.lastname: Domann
mesh_terms: D000818:Animals; D015820:Cadherins / Q000378:metabolism; D002448:Cell Adhesion; D045744:Cell Line, Tumor; D002465:Cell Movement; D004285:Dogs; D015536:Down-Regulation; D058750:Epithelial-Mesenchymal Transition / Q000235:genetics*; D015971:Gene Expression Regulation, Enzymologic; D055785:Gene Knockdown Techniques; D020868:Gene Silencing; D006801:Humans; D061985:Madin Darby Canine Kidney Cells; D009362:Neoplasm Metastasis; D064828:Prolyl Hydroxylases / Q000172:deficiency / Q000235:genetics* / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D015820:Cadherins; D064828:Prolyl Hydroxylases