Abstract:

Objective To discuss the targeting relationship between microRNA-214-3p （miR-214-3p） and enhancer of zeste homolog 2 （EZH2）， and to clarify its effects on the proliferation， invasion， and apoptosis of ovarian cancer SKOV3 cells. Methods The human ovarian cancer SKOV3 cells were divided into control group， mimics negative control （NC） group， miR-214-3p mimics group， miR-214-3p mimics+overexpression NC （OE-NC） group， and miR-214-3p mimics+overexpression EZH2 （OE-EZH2） group. Real-time fluorescence quantitative PCR （RT-qPCR） method was used to detect the expression levels of miR-214-3p and EZH2 mRNA in the cells in various groups； Western blotting method was used to detect the expression levels of EZH2 protein in the cells in various groups. Reporter plasmids containing wild-type （WT） or mutant-type （MT） EZH2 were constructed and co-transfected with miR-214-3p mimics or NC into the 293T cells， and the dual-luciferase reporter gene assay was used to detect the luciferase activities of the cells in various groups. Cell counting kit-8 （CCK-8） method was used to detect the activities of the cells in various groups； Transwell chamber assay was used to detect the numbers of invasion cells in various groups； flow cytometry was used to detect the apoptotic rates and cell cycle distribution of the cells in various groups. Results Compared with control group and mimics NC group， the expression level of miR-214-3p in the cells in miR-214-3p mimics group was significantly increased （P<0.05）， and the expression levels of EZH2 mRNA and protein were significantly decreased （P<0.05）. Compared with miR-214-3p mimics group， the expression level of miR-214-3p in the cells in miR-214-3p mimics+OE-EZH2 group was significantly decreased （P<0.05）， and the expression levels of EZH2 mRNA and protein were significantly increased （P<0.05）. Compared with pGL3-EZH2-WT+NC group， the luciferase activity in the cells in pGL3-EZH2-WT+miR-214-3p mimics group was significantly decreased （P<0.05）. Compared with control group and mimics NC group， the activity of the cells in miR-214-3p mimics group was significantly decreased （P<0.05）， the number of invasion cells was significantly decreased （P<0.05）， the apoptotic rate was significantly increased （P<0.05）， and the percentage of the cells at G₁ phase was significantly increased （P<0.05）. Compared with miR-214-3p mimics group， the activity of the cells in miR-214-3p mimics+OE-EZH2 group was significantly increased （P<0.05）， the number of invasion cells was significantly increased （P<0.05）， and the apoptotic rate was significantly decreased （P<0.05）. Conclusion miR-214-3p can down-regulate EZH2 expression by targeting it， thereby inhibiting the proliferation and invasion abilities and promoting the apoptosis of ovarian cancer SKOV3 cells. Overexpression of EZH2 can antagonize the tumor-suppressive effect of miR-214-3p， further confirming the targeting regulatory relationship between them.

Key words: MicroRNA-214-3p, Enhancer of zeste homolog 2, Ovarian neoplasm, Cell proliferation, Cell invasion, Cell migration