LncRNA MT1JP plays a protective role in intrahepatic cholangiocarcinoma by regulating miR-18a-5p/FBP1 axis

Background Cholangiocarcinoma is a common malignant tumor of digestive system. LncRNA metallothionein 1 J, pseudogene (MT1JP) has been reported to play tumor-suppressing roles in multiple cancers. However, its effect on cholangiocarcinoma has not been evaluated. Methods The expression of MT1JP in intrahepatic cholangiocarcinoma specimens and paired para-carcinoma tissues were detected by real-time PCR. The overexpression plasmid and siRNA of MT1JP were transfected into intrahepatic cholangiocarcinoma cells to change the expression levels of MT1JP. CCK-8, flow cytometry and transwell assays were performed to measure proliferation, cell cycle transition, apoptosis, migration and invasion. Dual-luciferase reporter assay, real-time PCR and western blot were carried out to screen the miRNA bound by MT1JP. In addition, xenograft experiment was used to determine the tumorigenesis of cholangiocarcinoma cells in nude mice. Results MT1JP was downregulated in intrahepatic cholangiocarcinoma specimens, and its expression was related with TNM stage and lymph node metastasis. Overexpression of MT1JP inhibited proliferation, cell cycle transition, migration and invasion, and induced apoptosis in intrahepatic cholangiocarcinoma cells. The knockdown of MT1JP led to opposite results. MT1JP bound to miR-18a-5p to facilitate the expression of fructose-1,6-bisphosphatase 1 (FBP1). MiR-18a-5p was increased in intrahepatic cholangiocarcinoma samples, and its expression was negatively correlated with that of MT1JP. In addition, MT1JP also suppressed tumorigenesis in nude mice. Conclusions MT1JP alleviated proliferation, migration and invasion, and induced apoptosis in cholangiocarcinoma cells by regulating miR-18a-5p/FBP1 axis. These findings may provide novel insights for clinical diagnosis and treatment of cholangiocarcinoma.