The Effect And Mechanism Of MiR-1236-3p On Migration And Invasion Of High-Grade Serous Ovarian Carcinoma

Background and objectives:Ovarian cancer is a kind of common gynecological malignance. Although ovarian cancer accounts for a very small percentage of all cancers in women, it is the main cause of death among gynecological malignancies. The high mortality has been ascribed to the absence of special clinical symptoms in early stages of ovarian cancer. Epithelial ovarian cancer (EOC), particularly high-grade serous ovarian carcinoma (HG-SOC), is the main cause of death among gynecological malignancies.MicroRNAs (miRNAs) are a class of small non-coding RNAs that negatively modulate gene expression. MiRNAs play important roles in numerous biological processes, such as cell cycle, differentiation, proliferation, apoptosis and angiogenesis. The relationship between miRNAs and cancer was first discovered in chronic lymphocytic leukemia. Since then, numerous miRNAs have been found abnormally expressed in many types of cancers including ovarian cancer. Genes was modulated by miRNA by the way of complementary base-pairing reactions. One miRNA could regulate many genes, and one Genes could also been modulated by many miRNAs. The sequence of miR-1236-3p is5’-ccucuuccccuugucucuccag-3’. There are few reports about miR-1236-3p. So far, we have known that miR-1236-3p involved in the regulation of VEGFR-3and TLR4.ZEB1is one of transcriptional factors of Epithelial-mesenchymal transition (EMT). EMT is known as a key regulatory mechanism of migration and invasion in many types of cancers including ovarian cancer. EMT is a morphological change where cells switch from a cobblestone-like appearance to a spindle-like morphology. During the process of EMT, cells lose epithelial adhesion molecules (such as E-cadherin) and acquire mesenchymal markers (such as N-cadherin), with increased migration and invasion.So far no study has demonstrated that miR-1236-3p could influence the migration and invasion of ovarian cancer cells. The purpose of this research is to examine the expression of miR-1236-3p between HG-SOC and normal fallopian tube tissue and the relationship between miR-1236-3p and migration and invasion of ovarian cancer cells.Methods: (1) Validation of miR-1236-3p expression in HG-SOC and normal fallopian tube tissue:We designed the primer of miR-1236-3p and used RT-PCR to examine the expression of miR-1236-3p in tissue.(2) Migration and invasion assays:We examined the migration and invasion abilities of ovarian cancer cells (A2780and SKOV3) that transfected with miR-1236-3p mimics or inhibitors.(3) Dual-luciferase reporter assay:It was used to verify the relationship between miR-1236-3p and ZEB1.(4) Western blot and RT-PCR:The ovarian cancer cell lines (A2780and SKOV3) were transfected with miR-1236-3p mimics and inhibitors. After48h, the transfected cells were harvested and tested by Western blot and RT-PCR. We also detected the expression of ZEB1between HG-SOC and normal fallopian tube tissue.Results:(1) The expression of miR-1236-3p in HG-SOC was lower than that in normal fallopian tube tissue.(2) Functional experiments showed that miR-1236-3p could significantly influence the metastasis and morphology of ovarian cancer cells.(3) The result of dual-luciferase reporter assay demonstrated that miR-1236-3p could bind to the3’UTR of ZEB1mRNA, and functions as a negative regulator of ZEB1.(4) Manipulation of miR-1236-3p modulates ZEB1expression and influences expression of its downstream genes E-cadherin and N-cadherin at both the mRNA and protein levels.(5) We found an inverse relationship between miR-1236-3p and ZEB1expression in the HG-SOC tissue samples.Conclusion:(1) MiR-1236-3p functions as a tumor suppressor gene in HG-SOC, and its expression is negatively correlated with the expression of ZEB1. (2) Mir-1236-3p modulates migration and invasion of ovarian cancer cells by targeting ZEB1.