Abstract. The purpose of the present study was to analyze the crucial role of microRNAs (miRNAs/miRs) involved in the proliferation and migration of colorectal cancer (CRC) and to investigate their underlying mechanisms. The present study discusses the expression and function of miR-552 in CRC. The expression level of miR-552 in CRC cells and tissues was observed, and it was suggested that the high expression of miR-552 accelerated the proliferation and migration of CRC cells in vitro. Notably, a result of the present study was that the cell fate determination factor Dachshund family transcription factor 1 (DACH1) was identified as a direct target of miR-552. Suppressing miR-552 expression in CRC cells increased endogenous DACH1 mRNA and protein levels, which was negatively correlated with miR-552. DACH1 performs an important role in the development of a number of neoplasms, and has the ability to regulate the Wnt/β-catenin signaling pathway as a novel predictive and diagnostic biomarker. Accordingly, it was concluded that miR-552 exerted a tumor-promoting role in CRC development by targeting DACH1, which may contribute to the increase in the rates of CRC proliferation and migration. miR-552 may serve as a potential diagnostic and prognostic biomarker for CRC.
IntroductionColorectal cancer (CRC) has one of the highest cure rates of all types of malignant tumors (1), however remains ranked as the fourth leading cause of cancer-associated mortality in the world (2). In previous years, the morbidity and mortality rates of CRC have significantly increased due to an ageing population, and with changes in eating habits and lifestyles (3). The development of distant metastasis is a major cause of cancer-associated mortalities in CRC patients (4). Overwhelming evidence has demonstrated that aberrant expression of microRNA (miRNA/miR) contributes to CRC development by affecting the expression of the genes that regulate cancer progression (5).miRNAs, endogenous small non-coding regulatory RNAs measuring 18-25 nucleotides long (6), usually regulate gene expression in a number of tumor-associated signaling pathways at the post-transcriptional level, including the Wnt/β-catenin signaling pathway (7). As miRNAs tend to be localized to fragile chromosomal regions (8), they have the ability to adjust the levels of their corresponding mRNAs, and serve critical roles in the physiological and pathological processes of tumor development, which are a novel aspect of cancer studies. Previous evidence has demonstrated that miRNAs are involved in a number of biological processes, including proliferation, differentiation, migration, angiogenesis and protein splitting (9-11). miRNAs also serve as tumor promoter genes or tumor suppressor genes by negatively regulating their targets. These data suggest a possibility that miRNA is a novel focus for examining the current diagnosis and treatment of tumors.Previously, several studies revealed that miR-124 results in a decrease in the proliferation ability of CRC cells by targeting ribose-phosp...