MicroRNA-155 and FOXP3 jointly inhibit the migration and invasion of colorectal cancer cells by regulating ZEB2 expression

L.-P. Yang, Q. Lin, X.-L. Mu

Department of Clinical Laboratory, The Affiliated Yantai Yuhuangding Hospital of Qingdao University, Yantai, China. mxl105@163.com

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• Oncology

OBJECTIVE: The study aimed to explore whether microRNA-155 and FOXP3 could regulate invasive and migratory capacities of colorectal cancer (CRC) cells by mediating Zinc finger E-box binding homeobox 2 (ZEB2) expression.

MATERIALS AND METHODS: Dual-luciferase reporter gene assay was performed to detect the binding condition between microRNA-155, FOXP3, and ZEB2. Protein and mRNA levels of ZEB2 in CRC cells were detected after overexpression of microRNA-155 and FOXP3 by Western blot and quantitative Real Time-Polymerase Chain Reaction (qRT-PCR), respectively. In vitro experiments were conducted using HCT116 and SW620 cell lines. We first detected expression levels of microRNA-155, FOXP3, and ZEB2 in the normal colorectal epithelial cell line (NCM460) and CRC cell lines (HCT116 and SW620) by qRT-PCR. Protein expressions of ZEB2, E-cadherin, and vimentin in WT, LV-GFP, and LV-FOXP3 groups were detected. Wound healing assay and transwell assay were conducted to determine the regulatory effects of microRNA-155 and FOXP3 on invasive and migratory capacities of CRC cells, respectively.

RESULTS: Dual-luciferase reporter gene assay found that FOXP3 binds to the promoter and intron regions of ZEB2, and microRNA-155 binds to the 3’UTR region of wild-type ZEB2. Overexpression of FOXP3 downregulated mRNA and protein levels of ZEB2. ZEB2 was highly expressed, whereas microRNA-155 and FOXP3 were lowly expressed in HCT116 and SW620 cells than NCM460 cells. MicroRNA-155 overexpression upregulated E-cadherin and downregulated vimentin in CRC cells. Overexpression of FOXP3 and microRNA-155 inhibited invasive and migratory capacities of CRC cells.

CONCLUSIONS: MicroRNA-155 and FOXP3 can jointly regulate ZEB2 expression, thereby inhibiting the migration and invasion of colorectal cancer cells.

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