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The ectopic expression of Snail in MDBK cells does not induce epithelial-mesenchymal transition.

Izawa G, Kobayashi W, Haraguchi M, Sudo A, Ozawa M - Int. J. Mol. Med. (2015)

Bottom Line: 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.Therefore, in the MDBK cells, the ectopic expression of Snail failed to induce EMT.However, the MDBK cells transfected with the Snail construct did not exhibit an increased expression of these factors.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry and Molecular Biology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544, Japan.

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.

No MeSH data available.


Related in: MedlinePlus

Madin-Darby bovine kidney (MDBK) cells ectopically expressing Snail protein display characteristics of the epithelial phenotype. (A) Both the control MDBK cells transfected with an empty vector containing a neomycin resistance gene (neo) and MDBK cells transfected with an expression vector encoding HA-tagged Snail protein (Snail) displayed typical epithelial cell morphology. (B) Immunofluorescence staining with an anti-HA antibody revealed the protein expression of Snail in the nucleus, which was co-stained with DAPI. (C) Cell aggregation assays revealed that the cells ectopically expressing Snail protein had similar adhesive properties as the control (neo) cells; furthermore, the observed cell-cell adhesion was calcium-dependent, indicating that it was mediated by cadherins. Scale bars, 20 µm.
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f1-ijmm-36-01-0166: Madin-Darby bovine kidney (MDBK) cells ectopically expressing Snail protein display characteristics of the epithelial phenotype. (A) Both the control MDBK cells transfected with an empty vector containing a neomycin resistance gene (neo) and MDBK cells transfected with an expression vector encoding HA-tagged Snail protein (Snail) displayed typical epithelial cell morphology. (B) Immunofluorescence staining with an anti-HA antibody revealed the protein expression of Snail in the nucleus, which was co-stained with DAPI. (C) Cell aggregation assays revealed that the cells ectopically expressing Snail protein had similar adhesive properties as the control (neo) cells; furthermore, the observed cell-cell adhesion was calcium-dependent, indicating that it was mediated by cadherins. Scale bars, 20 µm.

Mentions: MDBK cells, a cell line derived from bovine kidney, display epithelial properties, including a brickstone morphology. We introduced a control empty vector containing a neomycin resistance gene or an expression vector encoding HA-tagged Snail protein into the MDBK cells and isolated stable transfectants, designated as neo or Snail cells, respectively. The Snail cells retained the same epithelial morphology as the control neo cells (Fig. 1), despite the clear nuclear localization of Snail protein, as revealed by staining with an anti-HA antibody (Fig. 1B). Thus, contrary to our previous experiments with MDCK or A431 cells (28,29), the ectopic expression of Snail did not induce morphological changes that were characteristic of EMT.


The ectopic expression of Snail in MDBK cells does not induce epithelial-mesenchymal transition.

Izawa G, Kobayashi W, Haraguchi M, Sudo A, Ozawa M - Int. J. Mol. Med. (2015)

Madin-Darby bovine kidney (MDBK) cells ectopically expressing Snail protein display characteristics of the epithelial phenotype. (A) Both the control MDBK cells transfected with an empty vector containing a neomycin resistance gene (neo) and MDBK cells transfected with an expression vector encoding HA-tagged Snail protein (Snail) displayed typical epithelial cell morphology. (B) Immunofluorescence staining with an anti-HA antibody revealed the protein expression of Snail in the nucleus, which was co-stained with DAPI. (C) Cell aggregation assays revealed that the cells ectopically expressing Snail protein had similar adhesive properties as the control (neo) cells; furthermore, the observed cell-cell adhesion was calcium-dependent, indicating that it was mediated by cadherins. Scale bars, 20 µm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4494602&req=5

f1-ijmm-36-01-0166: Madin-Darby bovine kidney (MDBK) cells ectopically expressing Snail protein display characteristics of the epithelial phenotype. (A) Both the control MDBK cells transfected with an empty vector containing a neomycin resistance gene (neo) and MDBK cells transfected with an expression vector encoding HA-tagged Snail protein (Snail) displayed typical epithelial cell morphology. (B) Immunofluorescence staining with an anti-HA antibody revealed the protein expression of Snail in the nucleus, which was co-stained with DAPI. (C) Cell aggregation assays revealed that the cells ectopically expressing Snail protein had similar adhesive properties as the control (neo) cells; furthermore, the observed cell-cell adhesion was calcium-dependent, indicating that it was mediated by cadherins. Scale bars, 20 µm.
Mentions: MDBK cells, a cell line derived from bovine kidney, display epithelial properties, including a brickstone morphology. We introduced a control empty vector containing a neomycin resistance gene or an expression vector encoding HA-tagged Snail protein into the MDBK cells and isolated stable transfectants, designated as neo or Snail cells, respectively. The Snail cells retained the same epithelial morphology as the control neo cells (Fig. 1), despite the clear nuclear localization of Snail protein, as revealed by staining with an anti-HA antibody (Fig. 1B). Thus, contrary to our previous experiments with MDCK or A431 cells (28,29), the ectopic expression of Snail did not induce morphological changes that were characteristic of EMT.

Bottom Line: 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.Therefore, in the MDBK cells, the ectopic expression of Snail failed to induce EMT.However, the MDBK cells transfected with the Snail construct did not exhibit an increased expression of these factors.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry and Molecular Biology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544, Japan.

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.

No MeSH data available.


Related in: MedlinePlus