LncRNA XIST promotes metastasis in ESCC by sponging miR-34a to regulate ZEB1 Expression

Abstract Objective LncRNA X-inactive specific transcript (XIST) is the master regulator of transcriptional silencing of X chromosome. We will study the mechanism that XIST regulates the metastasis of ESCC by regulating ZEB1. Materials and Methods We chose KYSE150 cell line to knock down XIST. CCK-8 was used to detect the proliferation and transwell was used to detect the migration and invasion ability. The esophageal cancer xenograft nude mouse model was established to study the effect of XIST in vivo. Luciferase reporter assays were performed to determine whether miR-34a inhibits activity of the luciferase reporter gene by binding to the predicted target sites of XIST and ZEB1. We detected the expression levels of XIST and ZEB1 in 66 paired ESCC and adjacent non-tumor tissues. Correlations between XIST and ZEB1 in tumor tissues and patient characteristics were assessed using the χ2 statistical test. Results Knockdown of XIST inhibits the proliferation, migration and invasion of ESCC cells. Knockdown of XIST reduced the expression level of ZEB1, and increased the expression levels of E-cadherin and miR-34a. Down-regulation the expression of miR-34a while knocking down of XIST restored the reduction in cell proliferation, migration and invasion ability caused by knocking down of XIST. The luciferase reporter assays indicated that miR-34a directly binds to the predicted target site of XIST and ZEB1. Both the expression levels of XIST (2.69 ± 1.71 VS 1.84 ± 1.67) and ZEB1 (3.24 ± 2.79 VS 1.06 ± 1.31) were significantly higher in tumor tissues than in adjacent tissues. The relative level of XIST in ESCC tissues was positive correlation with ZEB1. Overexpression of XIST and ZEB1 were associated with postoperative metastasis and shorter OS. Conclusion Overexpression of XIST promotes metastasis and indicates a poor prognosis in ESCC. The XIST/miR-34a/ZEB1 axis can be used as a therapeutic target and prognostic biomarker of ESCC.