Abstract: Objective　To elucidate the molecular mechanism and potential therapeutic targets of bladder cancer and explore the regulatory mechanism of MALAT1-miR-30a-5p-SOX4 axis in bladder cancer. Methods　Quantitative real-time PCR (RT-PCR) was used to detect the expressions of mir-30a-5p, MALAT1 and SOX4 in bladder cancer cells. Luciferase reporter assay was used to verify the biological relationship between mir-30a-5p and SOX4.The biological functions of mir-30a-5p and SOX4 in T24 cells were studied by in vitro experiments, including the detection of cell proliferation by CCK-8 method, cell invasion by Transwell and cell migration by wound healing method. Western blot was used to detect protein expression. Results 　In bladder cancer cells, MALAT1 expression was up-regulated and mir-30a-5p expression was down-regulated (P<0.01). Sh-MALAT1 inhibited the proliferation, invasion and migration of T24 cells. Further studies showed that MALAT1 can directly interact with mir-30a-5p, and SOX4 is the target of miR-30a-5p, and SOX4 can be down-regulated by over-expression mir-30a-5p.　Conclusions　MALAT1 knockout can relieve the inhibition of mir-30a-5p by MALAT1 and thus inhibiting SOX4. MALAT1 may regulate the proliferation, invasion and metastasis of bladder cancer by regulating the mir-30a/SOX4 pathway.

Key words: Bladder cancer, 　MALAT1, 　miR-30a, 　SOX4