TNF-α induced epithelial mesenchymal transition increases stemness properties in renal cell carcinoma cells

Objective: Emerging evidence suggest that the acquisition of epithelial mesenchymal transition (EMT) and induction of cancer stem cell (CSC) or cancer stem-like cell phenotype are interrelated and contribute to tumor recurrence and drug resistance. The aim of this study is to shed light on the relationship between EMT and CSCs by using renal cell carcinoma (RCC) cell line, ACHN and 786-0. Methods: RCC cells were treated with 50 ng/ml of TNF-α for 14 days. To evaluate EMT, morphological changes were assessed by light microscopy. RT-PCR and Western blot for EMT-related markers. On TNF-α treated and untreated RCC cells, we performed stemness tests and stemness markers expression. Results: TNF-α treated ACHN cell lost its epithelial morphology assuming a fibroblast-like appearance. The same results were obtained for the 786-0 cells. RT-PCR and Western blot showed up-regulation of Vimentin and down-regulation of E-cadherin in TNF-α treated ACHN and 786-0 cells. Slug and ZEB1 mRNA transcripts were up-regulated in TNF-α treated RCC cells confirming EMT. This two cell line also showed overexpression of Oct4, Nanog, and Bmi-1, all genes of stemness. In addition, in TNF-α treated RCC cell, an increased tumorsphere-forming capacity was detectable. Conclusions: The induction of EMT by TNF-α exposure, in RCC cell results in the acquisition of mesenchymal profile and in the expression of stemness markers.