Abstract: 【Objective】 To study the expression of Robos in T24 cells and the influence in human bladder transitional epithelial carcinoma T24 cell proliferation when Robo gene was silenced. 【Methods】 The experiment was divided into two groups:control group(without carrier) and interference group(with composite carrier). (1)Immunohistochemistry

immunofluorescence and Western blot was performed to investigate whether Robos expressed in T24 cells cultured in vitro

and determined the types of this expression. (2)T24 cells were transferred by RNAi technique through seeking the gene silent sites and constructing a proper expression vector. Immunofluorescence was carried out to confirm the results of interference and Western blot was performed to detect the changes of expression of Robos. Survival rate was evaluated by MTT method. 【Results】 (1)Immunohistochemistry and immunofluorescence showed that the expression subtypes of T24 cells were Robo1 and Robo4 with no statistically significant(P = 0.363 and P = 0.241)

and none of the subtypes is expressed in normal transitional epithelial cancer cells. Western blot confirmed this result(P = 0.205). (2) RNAi technique efficiently silenced the expressions of Robo1 and Robo4 in T24

especially Robo1

almost was completely inhibited (immunofluorescence P = 0.002

Western blot P = 0.0001). Survival rate of Robo1-interfered group

had significant difference (P = 0.012 and P = 0.02) with control group and Robo4 group

decreased obviously as showed by MTT method. 【Conclusion】 Protein receptors Robo1 and Robo4 were demonstrated exist in T24 cells and the expression of Robo1 and survival rate of T24 cells decreased obviously after Robo gene was silenced