MiR-205Down-regulates PEG3in Endometrial Cancer Celllines

Background And Objectives:Endometrial carcinoma is the most common gynecologic malignancy in western countries and the second gynecologic cancer in China.MicroRNAs (miRNA) are small non-coding RNAs which function as negative regulators of gene expression by blocking the translation or decreasing the stability of mRNAs. It has been shown that miRNAs form a complex named miRNAs-containing ribonucleo-protein particles to the complementary site in the3’-untranslated region(3-UTR) of the target mRNA. If it is partially matched or completely matched, translation blockage or mRNA degradation will happen to the target gene. MiRNA is highly conserved in biological evolution, and it is involved in one third of gene expression in human vital movement, like cell proliferation, apoptosis, immunity and neuroendocrine. MicroRNAs are reported to involve in many human cancers, and they served as either oncogenes or tumor suppressor genes. MiRNAs are initially found in chronic lymphocytic leukemia (CLL), which showed that down-expression of miR-15a and miR-16-1caused the13q14deletion. Now, it has been found in many other carcinomas and the expression files were detected followed. MiRNAs are considered to be oncogenes in some tumors but tumor suppressor genes in the others. One miRNA had different expression level in different cancers.Human miR-205is located in the second intron of LOC642587in chromosome1. Our previous study clearly demonstrated that miR-205is up-regulated in endometrial carcinoma.PEG-3(paternally expressed gene3) is an imprinted gene that expresses primarily during embryogenesis, as well as in adult ovary, testis, muscle, and brain. PEG-3invovles in parenting and sexual behaviors, regulates growth and apoptosis, and exhibits tumor suppressor activity in glioma cell line. The down-expression of PEG-3in giloma cells promotes proliferations by inhibiting WNT/β-catenin pathways.β-catenin is a kind of multifunction protein in cytoplasma. And it is known to play the most important role in WNT pathway. The accumulation of β-catenin can incur the expression of the genes in downstream. C-myc is a kind of downstream gene in the Wnt/β-catenin pathway and overexpressed in many kinds of human malignant tumors. So far, there is no report about PEG3in endometrial cancer.This study is aim to explore the differences of expression level between the endometrial cancer tissues and normal endometrial tissue. And further more, the relationship between micro-205and PEG3(Paternally Expressed Gene3) in endometrial cancer celllines.Methods:(1).Immunohistochemical to detect the different expression of PEG3in normal endometrial tissue and endometrioid endometrial carcinoma tsues.(2).Three diffenrent differtiation kinds of endometrial cancer celllines were chosen which were highly expressed miR-205than normal endometrial cellline confirmed by RT-PCR.(3).Then, CCK8, flow cytometry anlyasis were used to detect the cell proliferation and apoptosis after the miR-205eleveted by miR-205mimics.(4).Western blot, RT-PCR, and dual luciferase assay are used to explore the target relationship between micro-205and PEG3.Results:(1) Immunohistometrical to detect the different expression of PEG3in normal endometrial tissue and endometrioid endometrial carcinoma tsues.(2) Three diffirent differtiation kinds of endometrial cancer celllines were chosen which were highly expressed miR-205than normal endometrial cellline confirmed by RT-PCR.(3) Then, CCK8, flow cytometry anlyasis were used to detect the cell proliferation and apoptosis after the miR-205eleveted by miR-205mimics.(4) Western blot, RT-PCR, and dual luciferase assay are used to explore the target relationship between micro-205and PEG3.Conclusion:(1).PEG3act as an tumor suppressor gene in endometrial cancer. And in different stage of the cancer, the PEG3expression level are consequently different.(2)MiR-205directly target PEG3by acting on the3’UTR of PEG3mRNA.