Abstract： Objective:To examine the expression of long-chain non-coding RNA (lncRNA) FLJ37505 in bladder cancer tissues and cell lines, and to analyze the molecular mechanism of FLJ37505 to inhibit the proliferation and migration of bladder cancer cells.Methods:Quantitative Real-time PCR(qPCR) was used to analyze the relative expression of FLJ37505 in 63 cases of bladder cancer tissues and bladder cancer cell lines (T24, J82, 5637, BIU-87 and UM-UC-3). The bladder cancer cell lines with the least expression of FLJ37505 were divided into control group (transfected with blank plasmid) and FLJ37505 group (transfected with a plasmid carrying the FLJ37505 sequence) according to random number method. MTS assay and scratch assay were used to detect the effect of up-regulation of FLJ37505 expression on cell proliferation and migration. Bioinformatics predicts the target gene of FLJ37505. The dual luciferase reporter system detects the binding of FLJ37505 to the target gene. qPCR and Western blot were used to detect the effect of FLJ37505 on the expression of target gene.Results:Compared with adjacent tissues, FLJ37505 expression was lower in bladder cancer tissue [(4.90±0.79) vs (0.89±0.28), P<0.05]. Compared with human normal bladder tubular epithelial cells, the expression of FLJ37505 was lower in bladder cancer cell lines ( P<0.05), and FLJ37505 has the lowest expression in UM-UC-3 cells ( P<0.01). Compared with the control group, the expression of FLJ37505 in UM-UC-3 cells of FLJ37505 group was higher [(0.79±0.04) vs (9.92±1.17), P<0.01]. Compared with the control group, the proliferation ability of UM-UC-3 cells in FLJ37505 group was inhibited ( P<0.05), and the cell migration ability was also inhibited ( P<0.01). Bioinformatics showed that the target gene of FLJ37505 is miR-203a-3p, and the target gene of miR-203a-3p is inositol polyphosphate 4-phosphatase typeⅡ (INPP4B). The dual luciferase reporter gene system showed that FLJ37505 could complement the miR-203a-3p ( P<0.01), and miR-203a-3p could complement the INPP4B mRNA ( P<0.01). Compared with the control group, the expression of miR-203a-3p was lower [(1.00±0.05) vs (0.20±0.02), P<0.01], the expression of INPP4B in mRNA and protein levels of UM-UC-3 cells in FLJ37505 group was significantly increased (all P<0.01). Conclusions:The expression of FLJ37505 was significantly decreased in bladder cell carcinoma and bladder cancer cells. Up-regulation of FLJ37505 significantly inhibits the proliferation and migration of bladder cell carcinoma UM-UC-3 cells, and the mechanism might be up-regulating the expression of the INPP4B gene by adsorbing miR-203a-3p.