Investigation of miR-133a, miR-637 and miR-944 genes expression and their relationship with PI3K/AKT signaling in women with breast cancer

Background: MicroRNA (miRNA) is a regulatory molecule capable of positively or negatively regulating signaling pathways and furthermore assumes a part tumorigenesis and various aspects of cancer. The purpose of this study is to investigate the expression level of miR-133a, miR-637 and miR-944 genes in serum and tumor tissue and their relationship with the expression level of phosphatidylinositol-3-kinase (PI3K (and protein kinase-B (AKT) genes and proteins and its clinical significance in breast cancer. Methods: : The expression of miR-133a, miR-637, miR-944, PI3K and AKT genes in tumor tissues and tumor margins tissues of 40 patients with breast cancer, as well as the serum levels of miR-133a, miR-637 and miR-944 in these patients and 40 healthy groups were examined by quantitative real-time PCR (qRT-PCR). PI3K and AKT proteins expression in tumor tissue and tumor margins tissues were detected by immunohistochemistry (IHC). Results: The expression levels of miR-133a and miR-637 in the tumor tissue and serum of patients were lower than the tumor margin tissue and serum of the healthy group, respectively. Also, the expression level of miR-944 in the tumor tissue was lower than in the tumor margin tissue, but its expression increased in the serum of cancer patients compared to the healthy group. The expression of miR-637 was correlated with tumor location, tumor size, and Her2 receptors, as well as the expression of miR-944 with tumor location and family history. PI3K and AKT mRNA and protein levels were higher in tumor tissues compared to tumor margin tissue ( p <0.05). Conclusion: The results of our study show that miR-637 has a better diagnostic value in breast cancer than miR-133a and miR-944.