Induction of Epithelial-Mesenchymal Transition Program in Cultured Epithelial Cells Derived from Oral Mucosa of Adult Albino Rat (Histological and Immunohistochemical Study)

Abstract

Introduction : The origin of mesenchymal cells participating in tissue repair following pathological process (fibrosis) are poorly understood. EMT represents an important source of these cells. The identification of the signaling pathways involved in transition of epithelial to mesenchymal phenotype help to understand the plasticity of cellular phenotypes and the possible therapeutic interventions. Aim of the work : This work aimed to induce EMT in different cell lines in order to study the morphological and immunohistochemical changes associated with this process. Materials and Methods: Ten female albino rats were used in this study to provide a source for epithelial cells of oral mucosa. In addition, A549 human lung carcinoma cell line was used for EMT induction. Cultured Cells used in the study were classified into two groups. Group (I), oral mucosa group, which was subdivided into three subgroups: Subgroup (Ia) included cells of primary culture of oral mucosa. Subgroup (Ib) included subcultured cells of oral mucosa. Subgroup (Ic) included subcultured cells of oral mucosa after EMT induction. Group (II), A549 human lung carcinoma cell line group, which further subdivided into two subgroups Subgroup (IIa) included cells of A549 human lung carcinoma cell line before EMT induction. Subgroup (IIb) included cells of A549 human lung carcinoma cell line after EMT induction. Morphologic and immunohistochemical changes were examined using phase contrast microscope. -iv- Results : Subcultured oral mucosa cells (group I) before EMT induction revealed polygonal cells with minimal intercellular spaces (ICS). They showed positive immunoreaction for E- cadherin and negative for vimentin. After EMT induction, the cells were spindle shaped with appearance of stress fibers in the cytoplasm. These cells showed negative immunoreaction for E cadherin and positive immunoreaction for vimentin. Subcultured cells of carcinoma cell line (group II) before EMT induction, showed polygonal cells with minute surface projections. They showed positive immunoreaction for E cadherin and negative immunoreaction for vimentin. After EMT induction, all the cells were spindle shaped. They showed strong positive immunoreaction for vimentin and negative immunoreaction for E cadherin. Conclusion: Epithelial Mesenchymal Transition (EMT) program can be induced in different types of cell lines, oral mucosa and A549 human lung carcinoma cell line. It was found that EMT induction was more prominent in A549 human lung carcinoma cell line. Activation of EMT programs can provide new insights to the plasticity of cellular phenotypes and possible therapeutic interventions. Keywords: EMT, oral mucosa, A549 human lung carcinoma cell line.