RESUMO
BACKGROUND: Colorectal cancer (CRC) is one of the most common types of cancer worldwide. A number of dysregulated microRNAs (miRNAs) have been linked to CRC progression and treatment response and are thought to be promising prognostic biomarkers for this cancer. microRNA-330 (miR-330-5p) has been reported to inhibit cell proliferation through suppressing thymidylate synthase (TYMS). In the current study, miR-330-5p, TYMS, and their interactions were investigated to evaluate their therapeutic and diagnostic value for CRC treatment. METHODS: The expression levels of miR-330-5p and TYMS were evaluated in silico using TCGA datasets for CRC. Data validation was performed on a set of internal samples (100 pairs of CRC tumor specimens and adjacent non-cancerous samples) utilizing real-time PCR assay. The linkage between clinicopathological parameters and expression levels was also investigated. RESULTS: TCGA results indicated that miR-330-5p and TYMS were significantly upregulated and downregulated in the CRC, respectively. Real-time PCR results confirmed that the expression of miR-330-5p was significantly upregulated in tumor tissues relative to marginal tissues (P = 0.0005), whereas TYMS expression was significantly downregulated (P = 0.0001). The transcript level of miR-330-5p was associated with tumor stage and lymph node metastases. CONCLUSION: The microRNA-330 inhibited cell proliferation by suppressing thymidylate synthase (TYMS) in colorectal cancer. Therefore, suggesting that they are valuable factors for further studies of alternative treatment and diagnostic methods.