EDIL3 regulates gastric cancer cell migration, invasion and epithelial-mesenchymal transition via TGF-β1/XIST/miR-137 feedback loop

BACKGROUND: Human gastric cancer is a serious disease with high mortality rate all over the world. The one of difficulties in effective therapy of gastric cancer is metastasis. It has been reported that lncRNAs and miRNAs are involved in cancer metastasis. So, exploration of new molecular mechanism underlying gastric cancer metastasis involving in network of lncRNAs/miRNAs/effector proteins is important and meaningful for guiding the treatment of gastric cancer. METHODS: MTT assay, flow cytometric analysis and colony formation assay were performed to evaluate AGS or MKN-45 cell proliferation, cycle distribution and colony formation, and RT-qPCR was used to examine the expressive abundances of EDIL3, XIST and miR-137. EDIL3 and epithelial-mesenchymal transition (EMT) related proteins were detected by western blot and migration and invasion were measured by transwell analysis. Meanwhile, dual-luciferase reporter assay was used to confirm XIST binding to miR-137, and miR-137 binding to EDIL3. AGS cells were used to establish the xenograft tumor model to verify the role of EDIL3 in tumorigenesis in nude mice. RESULTS: Expression levels of EDIL3 were increased in gastric cancer tissues and cell lines. Downregulation of EDIL3 or XIST and overexpression of miR-137 inhibited proliferation, migration, invasion and EMT in AGS and MKN-45 cells. XIST could specifically bind to miR-137, and EDIL3 was a target gene of miR-137. Moreover, TGF-β1 stimulated XIST expression, inhibited miR-137 expression and induced migration, invasion and EMT. We also found that overexpression of EDIL3 elevated levels of TGF-β1 and induced migration, invasion and EMT, which were reversed by TGF-β1 inhibition. EDIL3 knockdown suppressed migration, invasion and EMT, which were reversed by XIST. Overexpression of miR-137 inhibited proliferation, migration, invasion and EMT, which were reversed by EDIL3 overexpression. CONCLUSIONS: EDIL3 regulates gastric cancer cell migration, invasion and EMT, which is involved in the regulation of TGF-β1/XIST/miR-137 feedback loop, and EDIL3 knockdown inhibits tumor growth in nude mice. These findings indicate that the EDIL3 mediated molecular feedback loop may be developed as drug targets for the gastric carcinoma treatment.