title: The ectopic expression of Snail in MDBK cells does not induce epithelial-mesenchymal transition.
abstract: Epithelial-mesenchymal transition (EMT), a key process in the tumor metastatic cascade, is characterized by the loss of cell-cell junctions and cell polarity, as well as by the acquisition of migratory and invasive properties. However, the precise molecular events that initiate this complex EMT process are poorly understood. Snail expression induces EMT in Madin-Darby canine kidney (MDCK) cells and the human epidermoid carcinoma cell line, A431. Snail is a zinc finger transcription factor and triggers EMT by suppressing E-cadherin expression. In the present study, to broaden our knowledge of Snail‑induced EMT, we generated stable Snail transfectants using Madin-Darby bovine kidney (MDBK) cells. Contrary to the MDCK or A431 cells examined in our previous studies, the MDBK cells transfected with the Snail construct maintained an epithelial morphology and showed no sign of reduced cell-cell adhesiveness compared to the control cells. Consistent with these observations, the downregulation of epithelial marker proteins, e.g. E-cadherin and desmoglein, and the upregulation of mesenchymal marker proteins, e.g., N-cadherin and fibronectin, were not detected. Furthermore, the E-cadherin promoter was not methylated. Therefore, in the MDBK cells, the ectopic expression of Snail failed to induce EMT. As previously demonstrated, in MDCK cells, Snail expression is accompanied by the increased expression of other EMT-inducing transcription factors, e.g., Slug and zinc finger E-box-binding homeobox 1 (ZEB1). However, the MDBK cells transfected with the Snail construct did not exhibit an increased expression of these factors. Thus, it is possible that the failure to upregulate other EMT-related transcription factors may explain the lack of Snail-mediated induction of EMT in MDBK cells.
authors.affiliation: Department of Biochemistry and Molecular Biology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544, Japan.
authors.forename: Genya
authors.initials: G
authors.lastname: Izawa
authors.affiliation: Department of Biochemistry and Molecular Biology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544, Japan.
authors.forename: Wakako
authors.initials: W
authors.lastname: Kobayashi
authors.affiliation: Department of Biochemistry and Molecular Biology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544, Japan.
authors.forename: Misako
authors.initials: M
authors.lastname: Haraguchi
authors.affiliation: Department of Sport and Physical Education, Faculty of Physical Education, Kokushikan University, Tama-shi, Tokyo 206-8515, Japan.
authors.forename: Akiharu
authors.initials: A
authors.lastname: Sudo
authors.affiliation: Department of Biochemistry and Molecular Biology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Ozawa
mesh_terms: D000818:Animals; D015820:Cadherins / Q000096:biosynthesis* / Q000235:genetics; D002417:Cattle; D002448:Cell Adhesion / Q000502:physiology; D002449:Cell Aggregation / Q000502:physiology*; D002460:Cell Line; D019175:DNA Methylation; D051182:Desmogleins / Q000096:biosynthesis; D004285:Dogs; D058750:Epithelial-Mesenchymal Transition / Q000502:physiology*; D015972:Gene Expression Regulation, Neoplastic; D018398:Homeodomain Proteins / Q000096:biosynthesis*; D061985:Madin Darby Canine Kidney Cells; D011401:Promoter Regions, Genetic / Q000235:genetics; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors / Q000096:biosynthesis*; D016335:Zinc Fingers / Q000502:physiology
chemical_list: D015820:Cadherins; D051182:Desmogleins; D018398:Homeodomain Proteins; C000604407:SNAI1 protein, human; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors