The Experimental Study Of Stem Cell Fusion Induced Epithelial-Mesenchymal Transition

Objective:Multiple factors involved in the process of tumor metastasis, epithelial to mesenchymal transition (EMT) is one of the factors. The role of cell fusion in EMT is worthy of attention. In this study we cultured immortalized human gastric mucosal epithelial cell line (GES-1) and the fusion cells between GES-1and cord matrix-derived mesenchymal stem cells (CM-MSCs) to investigate the possibility of epithelial to mesenchymal transition induced by cell fusion.Methods:GES-1, CM-MSCs and fusion cells were cultured and the morphology and growth characteristics were observed. The migration and invasive ability were compared with the unfused parental cells by scratch and transwell migration assay. The proliferation capacity of fusion cells were monitored by MTT assay. Expression of E-cadherin, N-cadherin and Vimentin in three cells were detected by immunocytochemistry. The mRNA transcription level of EMT related genes, Twist and Slug, were determined by real-time quantitative PCR.Results:The shape of fusion cells were oval, showed greater heterogeneity in size, shape and nuclei. Increased nuclei to cytoplasmic ratio were observed. The proliferation, migration and invasion ability of the fused cells were increased. The scores about staining intensity for expression of N-cadherin and Vimentin in fusion cells were4.067±1.387and5.067±1.907, while GES-1were2.333±1.234and2.067±0.961. The expression of N-cadherin and Vimentin in the fusion cells were significantly higher than that in GES-1(P<0.05). The mRNA expression of Twist and Slug in fusion cells were0.0122±0.0060and0065±0.0022, while GES-1were0.0013±0.0007and0.0010±0.0003. The expression of EMT related genes Twist and Slug in fusion cells were higher than GES-1(P<0.05).Conclusion:The resulting fusion cells were morphological different from typical MSCs and GES-1cells. The growth, migration and invasion ability of the fusion cells were increased. Compared to GES-1, the level of interstitial marker protein N-cadherin and Vimentin expressed in fusion cells were increased, and the mRNA expression of EMT related genes Twist and Slug in fusion cells were also increased, indicating that fusion between MSCs and epithelial cells can result in EMT and induce epithelial cells malignant transformation. Stem cell fusion may be one of the machanisms of tumor development and progression.