Assessment of Non-Coding RNAs (miR-506 and circRNA 000284) and their Target Gene SNAIL-2 in Breast Tumors: Implications for Prognosis and a Possible Circulating Biomarker

Abstract

Breast cancer is the most common malignancy among women, and early diagnosis and targeted therapy have garnered significant attention. Non-coding RNAs have emerged as potential diagnostic, prognostic, and treatment biomarkers for breast cancer. This study aimed to evaluate the expression of non-coding RNAs, specifically miR-506 and circular RNA 000284, and their target gene SNAIL-2 in breast tumors compared to normal controls. The study also focused on clinicopathological characteristics, and plasma was monitored for expression of circ0000284 to identify a possible accessible cancer-related marker. Using the SYBR-Green Real-time PCR technique, total RNA was extracted from 80 breast tumors and normal adjacent tissues, and circ0000284, miR-506, and SNAIL2 expression were analyzed. The results showed overexpression, down-regulation, and up-regulation of circRNA 000284, miR-506, and SNAIL-2 gene, respectively. These expression changes were associated with advanced stages of the disease and lymph nodal involvement, which are signs of a poor prognosis. Additionally, a positive direct correlation was observed between circRNA000284 expression in tumors and plasma. Moreover, it was discovered that circ-0000284 sponged miR-506, causing up-regulation of SNAIL-2 as its mRNA target. The upregulation of SNAIL-2 as an epithelial-mesenchymal-transition (EMT)factor leads to poor prognosis in breast cancer and is epigenetically regulated by miR-506 and circRNA 000284. Therefore, the overexpression of circRNA000284 in plasma could be considered an indicator of lymph nodal involvement and advanced stages of cancer, and nominated as a poor prognostic biomarker for future considerations.

Keywords

• breast cancer
• circRNA000284
• miR-506
• noncoding RNAs
• prognostic biomarker