Selective Regulation of Epithelial-Mesenchymal Transition (EMT) Using Micro-RNAs in Breast Disease

다국어 초록 (Multilingual Abstract)

Most of breast cancer (BC) metastasis is caused by epithelial-mesenchymal transition (EMT) that invades other organs by changing their characteristics. A new research is required for real-time information, detection of EMT processes, and better treatment with focusing. As a small non-coding RNA molecules, microRNA (miRNA) is to degrade the target mRNA by destabilizing and suppressing the further processes of translation. Because this miRNA can bind binds through seed sites which have 2 to 8 nucleotides. Thus, one gene can be regulated by a variety of miRNAs. It is necessary to study the effect of miRNAs as new molecular mechanistic modulators in tumor progression and inflammation. In this study, I tried to find common miRNAs which are linked with the several tumor suppressor genes using big data mining and validation. I identified that miR-93-5p and miR-221-3p are associated with inflammation of breast epithelial cells. Induction of EMT in mammary epithelial cell (MCF-10A) was triggered by transforming growth factor beta (TGF-β1) treatment. In TGF-β-induced EMT processes, miR-93-5p and miR-221-3p were double checked as a common miRNAs which are elevated and linked to the degradation of five tumor suppressor genes. MiR-93-5p and miR-221-3p overexpression levels were elucidated by real-time PCR. When I verified the protein expression level of EMT markers including E-cadherin, N-cadherin, and fibronectin, the expression level of N-cadherin and fibronectin were significantly increased in EMT- induced MCF-10A. However, the level of E-cadherin was significantly reduced vice versa. Likewise, expression level of tumor suppressor gene Smad4 is significantly increased in EMT- induced MCF-10A. After that when I transfected with miR-93-5p and miR-221-3p anti-sense oligonucleotide (ASO), the reduced tumor suppressor Smad4 protein expression was recovered. Through this study, I can conclude that the data mined miRNA candidates which can regulate the five tumor suppressor genes were validation as a common miRNA in EMT-induced breast cancer progression.
Keywords: microRNA, big data mining, epithelial to mesenchymal transition (EMT), tumor suppressor gene, breast cancer prevention.

목차 (Table of Contents)

• Introduction 1
• Materials and methods 6
• 1. Big data mining 6
• 2. Validation through experimental methods 10
• Results 15
• Discussion 39
• References 42