Shirin Eyvazi - Department of Biotechnology, School of Advanced Technologies in Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Vahideh Tarhriz - Molecular Medicine Research Center, Tabriz University of Medical Sciences, Tabriz, Iran

Introduction & Aim: MicroRNAs (miRNAs) are small endogenous non-coding single-stranded RNA molecules which, regulates gene transcription in animal cells by binding to a target mRNA. Depending on the identity of the target, miRNAs may act as oncogenic and tumor suppressor factors. The aim of this study is determination of the role of miR-191 in MCF7 breast cancer cell line. Methods MiR-191 was cloned in pCMV-MIR vector. The vector was transfected into MCF7 cell line using lipofectamine 2000. After 48 h, the expression of miR-191 was verified by qRT-PCR. Doxorubicin was used to induction of apoptosis. For detection of apoptosis, the transfected and untransfected cells were stained with the Annexin-V-FLUOS Staining Kit. Results: PCR and restriction analyses confirmed the cloning of the mir-191 in the vector. The transfection was confirmed by PCR analysis. qRT-PCR result showed that miR-191 was overexpressed in MCF7 cell line. Apoptosis test confirmed the inhibition of apoptosis in the transfected cells. Conclusion; Here, we showed that overexpression of miR-191 inhibits apoptosis in MCF7 breast cancer cell line. Since the apoptosis-mediated cancer cell death is the base of the most treatment strategies, therefore, identification of miRNAs involved in the regulation of apoptosis holds immense importance.