Super-enhancer-associated LINC00963 promotes epithelial-mesenchymal transition in gastric cancer

Abstract

Abstract Background In clinical practice, gastric cancer (GC) is a common malignancy with high morbidity. Accumulating research has revealed that lncRNAs are involved in the development and metastasis of tumor tissues in multiple cancers. As reported, LINC00963, a typical lncRNA is aberrantly expressed in gastric cancer. However, the underlying mechanisms of super-enhancers mediating remain unclear. Materials and methods The GC cell line enhancer-super-enhancer data were downloaded and analyzed from the NCBI database (GSE75595). Combined RT-qPCR and Sanger sequencing were employed to identify three variants of LINC00963 in gastric cell lines and peripheral blood samples from gastric cancer patients. The gene expression was detected through RT-qPCR, and their encoded protein expression levels were mesured by western blot. Transwell assayswere applied to assess the cell invasion and migration, while the apoptosis rate was tested by flow cytometry. A xenograft model was applied to simulate the tumor development process, during which the effect of LINC00963 on promoting tumorigenesis were investigated. Results Analysis of the GC cell line enhancer-super-enhancer data revealed a high expression of LINC00963 driven by super-enhancer. The variant 1 and variant 2 of LINC00963 exhibited high expression in GC cell line and the peripheral blood of gastric cancers. After down-regulated variant 1 of LINC00963, the results showed a significant increase in cell apoptosis rate. LINC00963 expression in GC cell line reduced upon exposure to a low dose of the bromodomain and extra-terminal inhibitor, JQ1, which resulted in a decrease of the protein levels of β-catenin and ZEB1. As a result, the protein expression levels of several marker proteins related to epithelial-mesenchymal transition (EMT), such as Vimentin, N-cadherin and Snail were observed to decrease, which may lead to an inhibition on GC cells metastasis, thereby suppressing tumor growth. Conclusion This study demonstrated that the Super-enhancer-associated LINC00963 is via a Wnt/β-catenin pathway that promotes EMT and tumor metastasis in gastric cancer.