Abstract: [Abstract] Objective To investigate the effect of CD44 targeted RNA interference (RNAi) on the growth and Metastasis of human bladder carcinoma EJ cells. Methods We transfected bladder cancer cell line EJ with well-designed CD44 siRNA. Flow cytometry and western blot analysis were used to assess the CD44 immuno- bounding to the monoclonal antibody KMP1. Wound healing assay and Boyden chamber were used to investigate the change of shCD44－EJ cell’s migration. Proliferation of cells was measured using a [3H]-thymidine incorporation assay. Results CD44 knockdown extremely decreased KMP1 staining signal compared with the EJ cells transfected by pSuper-puro empty vector control，Both flow cytometry and western blot analysis revealed a remarkable decrease of CD44 expression in shCD44－EJ cells，but not in pSuper-puro vector transfected cells. CD44 silencing also significantly inhibited cell migration through wound healing assay. The modified Boyden chamber assay showed similar results also. Conclusions CD44 silencing can effectively decrease EJ cells immuno- bounding to the monoclonal antibody KMP1 and inhibit the migration and the proliferation of EJ cells in vitro.

Key words: bladder carcinoma, EJ cells, CD44, RNA interference