Objective: Colorectal cancer (CRC) is one of the most frequent malignant tumors worldwide. Colon cancer and rectal cancer are two different malignant types, and it is important to distinguish these two cancers. However, the physiological function of microRNA-3174 (miR-3174) in rectal cancer remains unknown. Therefore, the aim of this study was to investigate the role of miR-3174 in rectal cancer progression and to explore the possible underlying mechanism.
Patients and methods: The relative expression level of miR-3174 in rectal cancer was evaluated by quantitative Real-time polymerase chain reaction (qRT-PCR). Cell counting kit-8 (CCK8) assay and colony formation assay were employed to detect the proliferation ability of cells. Flow cytometric analysis was used to detect cell cycle distribution and apoptotic cells. Bioinformatics analysis and dual luciferase reporter gene assay were employed to predict and verify the target genes of miR-3174, respectively. Meanwhile, the protein expression level of pterin-4 alpha-carbinolamine dehydratase 2 (PCBD2) normalized to glyceraldehyde 3-phosphate dehydrogenase (GAPDH) was assessed by Western blotting.
Results: The expression level of miR-3174 was significantly up-regulated in rectal cancer. CCK8 assay and colony formation assay suggested that miR-3174 markedly promoted the proliferation of rectal cancer cells. Subsequently, flow cytometric analysis demonstrated that over-expressed miR-3174 significantly accelerated cell cycle, whereas remarkably inhibited cell apoptosis. Public prediction websites and dual luciferase reporter gene assay further validated that PCBD2 was a direct down-stream target of miR-3174. Moreover, rescue assay confirmed that miR-3174 functioned as an oncogene in rectal cancer by regulating PCBD2.
Conclusions: Our study elucidated that miR-3174 functioned as an oncogene in rectal cancer by targeting PCBD2, which might bring new insights into the search for novel biomarkers and therapeutic strategies.