Evaluation of MiR-720 Prognostic Significance in Patients with Colorectal Cancer

Aberrant expression of miR-720 had been reported in several cancers. However, the expression level and prognostic value of miR-720 in colorectal cancer (CRC) had not been addressed. In our study, we detected the expression level of miR-720 in 96 CRC tissues to evaluate its clinicopathological characteristics in colorectal cancer. Kaplan-Meier survival curve was performed to evaluate the prognostic role of miR-720 in patients with CRC. Furthermore, in vitro, we transfected the miR-720 mimics or inhibitors into the corresponding CRC cell lines and evaluated the effects on the abilities of cell growth, colony formation, migration, wound healing, and invasion in CRC cells. Our data showed that miR-720 level was significantly upregulated in CRC tissues than that in corresponding normal-appearing tissues (NATs) (p < 0.05), and high miR-720 correlated with the tumor size (p = 0.014), tumor-node-metastasis (TNM) stage (p = 0.040), lymphatic metastasis (p = 0.008), and distant metastasis (p = 0.016), which led to a poorer 5-year overall survival rate in CRC patients (p < 0.05). Our experiments in vitro also confirmed that miR-720 could promote the cell growth (p < 0.05), abilities of colony formation (p < 0.05), wound healing (p < 0.05), migration (p < 0.05), and invasion of CRC cells (p < 0.05). We identified StarD13 gene as a putative target of miR-720 in colorectal cancer by bioinformatics analysis, and subsequent dual luciferase activity and Western blot assay further certified that miR-720 might specifically target the StarD13 3'-untranslated region (UTR) at the 795 region (p < 0.05). miR-720 might act as a promoting factor in the development of CRC and could be a prognostic indicator in the prognosis of CRC. Downregulation of miR-720 might be considered to be a potentially important molecular treatment strategy for early stage CRC patients.