Abstract
BACKGROUND: Piwi-like RNA-mediated gene silencing 2 (PIWIL2) is a member of AGO/PIWI gene family, which is enriched in cancer stem cells (CSCs). The purpose of this research was to investigate the overexpression of PIWIL2 and its role in the induction of EMT and CSC properties in MCF7 breast cancer cell line. MATERIALS AND METHODS: MCF7 cells were transfected with the human gene PIWIL2 (Hili) under the control of CMV promoter utilizing the neon electroporation method. Subsequently, the selection was conducted using G418, and doubling time was calculated in the transformed and control cells. RT and real-time PCR were also performed to analyze the expression of epithelial and mesenchymal genes and those related to CSCs. RESULTS: According to the observations from this study, transfecting MCF7 cells with PIWIL2 triggered the conversion of epithelial cells to mesenchymal cells and induced the genes specific for breast CSCs, which was coincident with 9-h reduction in the doubling time of the transfected cells. Furthermore, the molecular analyses revealed a significant reduction in the expression of epithelial markers, while a significant increase was detected in the expression of mesenchymal genes and many CSC biomarkers. CONCLUSION: PIWIL2 protein acts as a master regulatory protein that is able to manipulate the transcription through specific signaling pathways, which allow the cells to gain stem cell-like properties.