Knockdown of LINC01694 inhibits growth of gallbladder cancer cells via miR-340-5p/Sox4

Purpose: The indispensable role of long non-coding RNAs (lncRNAs) in tumorigenesis has been increasingly reported. In the present study, LINC01694 was found to regulate the proliferation, invasion, as well as apoptosis in gallbladder cancer (GBC) cells through sponging miR-340-5p. Methods: LINC01694 level in GBC cells was quantified by quantitative real-time polymerase chain reaction (qRT-PCR). The proliferation, invasion, and apoptosis were determined by Cell Counting Kit-8 (CCK-8), Transwell, and flow cytometry, respectively. The expression of Sry-related high-mobility group box 4 (Sox4) was detected by Western blot (WB). The interaction between LINC01694 and miR-340-5p was measured by dual-luciferase reporter (DLR) assay, RNA immunoprecipitation (RIP) test, and RNA pull-down. Tumor formation was examined by in vivo experiment. Results: qRT-PCR illustrated that cancerous tissues had higher LINC01694 than normal tissues. Survival analysis demonstrated that the prognosis of patients with high LINC01694 was significantly poorer than those with low LINC01694. Down-regulation of LINC01694 slowed down the proliferation and invasion in GBC cells and accelerated the apoptosis. DLR assay indicated that LINC01694 elevated Sox4 expression by regulating miR-340-5p. LINC01694 functioned as miR-340-5p sponge to inhibit Sox4 expression. Conclusion: LINC01694 level is elevated in GBC by regulating miR-340-5p/Sox4 axis, which indicates the poor prognosis of the patients.