Evaluation of SIRT1-Regulating miRNAs in Breast Cancer: miR-9, miR-34a, and miR-132 Expression Analysis

Objectives: Breast cancer is one of the most common malignancy for women and one of the most common causes of cancer related deaths for women. Genetic factors and family history play major roles in its etiology. For a possible genetic treatment genetic pathway should be illuminated. Materials and methods: Three miRNAs known to be involved in the regulation of SIRT1 were selected for review in this study. These were miRNA-34a, miRNA-9 and miRNA-132 miRNAs. The miRNeasy Mini Kit was used to isolate total RNA from both cancer tissues and normal breast tissues in patients with breast cancer who underwent mastectomy for treatment. Expression levels of miRNAs were measured and normalized with U6 gene. Results: After measurment of expression levels, normalizing with U6 gene and statistical analysis, we found that there was no statistically significant difference between breast cancer tissues and normal breast tissues. Conclusion: Limited number of studies reported that the levels of all three micro RNAs were found to be lower in breast cancer tissues than in normal breast tissue. In this study, no statistically significant difference was found between normal breast tissue and breast cancer tissues in terms of levels of these micro RNAs for all three micro RNAs. The existence of conflicting and incomplete information about the SIRT1 enzyme did not surprise us with a result that is not compatible with the literature. Further studies are needed to clearly elucidate the mechanisms of SIRT1 and its regulating micro-RNAs. In the studies to be done, the determination of the microRNA levels simultaneously with SIRT1’s own expression levels can be enlightening on this issue.