Evidence indicate that the miR-298 dysregulation might associate with colorectal cancer (CRC) development. Herein, we evaluated the effect of miR-298 dysregulation on colon cancer invasiveness. First, metabolic activity, cell cycle progression, apoptosis, and invasion of miR-298 overexpressed/knocked out colon cancer cells were examined and combined with their transcriptome analysis data for better visualization of miR-298 intracellular signaling networks. Interaction between miR-298 and its target was evaluated with luciferase assay and validated using western blot analysis. The proportion of abnormal miR-298 level was investigated in tumor samples, matched normal adjacent tissues, and plasmas of 100 CRC patients, and also compared with 100 normal plasma samples. TheMann-Whitney U test was performed to assess miR-298 differences among the studied groups, and the correlation between miR-298 and the risk of CRC was shown by univariate and multivariate logistic regression. The data indicate that miR-298 overexpression promoted proliferation and metastasis in CRC cells via targeting phosphatase and tensin homolog. Comparative analysis of CRC tumors, normal adjacent tissues, and plasmas indicated a significant miR-298 upregulation in tumors and plasmas (1.72-fold and 1.65fold, respectively; p < .001). Also, the aberrant level of miR-298 contributed with CRC tumor differentiation, TNM stage and lymph node metastasis (p < .001), and independently associated with poor survival of CRC patients (p < .029; hazard ratio: 1.292; 95% confidence interval: 0.339-2.184). Collectively, these data showed that abnormal level of miR-298 correlated with cancer development and through that lowered the overall survival rate of CRC patients. Therefore, miR-298 could be considered as a therapeutic target for CRC. K E Y W O R D S colorectal cancer, invasion, metastasis, microRNA-298, PTEN

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