DIFFERENTIALLY REGULATED MIRNAS BY TWIST1 IN TRIPLE NEGATIVE BREAST CANCER CELLS

Objective: Breast cancer (BC) is the most common cancer in women and the second leading cause of cancer-related deaths. MicroRNAs (miRNAs) are short, non-coding RNA molecules that regulate gene expression post-transcriptionally and play a central role in the dysregulation of gene expression associated with carcinogenesis, cancer cell proliferation and metastasis. Twist1 is a transcription factor that binds to E-box motifs and controls the transcriptional activity of genes as a positive or negative regulator decisive in the cellular mechanisms. Accordingly, Twist1 also regulates the expression of miRNAs that are associated with cancer progression. In present study, we aimed to investigate the expressional changes of possible miRNAs directly regulated by Twist1 in triple negative breast cancer MDA-MB-231 cells. Materials and Methods: In this study, a total of 43 miRNA genes were evaluated that predicted might be associated with triple negative breast cancer. To determine the Twist1-targeted miRNA genes, endogenous high level Twist1 expression was suppressed through the antisense oligonucleotides in MDA-MB-231 TNBC cells. Differential miRNA expression levels were analyzed by real time PCR analysis in Twist1-suppressed cells compare to control. Results: Twist1 suppression leads to an increase in miR-1-1 and miR-210-3p expression, while a decrease in miR-193b-3p, miR-181b-5p, and miR-148a-3p expression. Conclusion: This study shows that the expression levels of certain miRNAs linked to invasion, metastasis, and apoptosis are controlled by Twist1 in triple negative breast cancer cells.