Fig. 2

Downregulation of NEU1 in bladder cancer cells. a Enzymatic activities of total sialidases in five cell lines as shown were quantitatively analyzed based on fluorescence intensity, and presented as mean ± SD from triplicate experiments. **, P = 0.001–0.005. ***, P < 0.001. b Expression of NEU1 in HCV29, KK47 and YTS-1 by SILAC analysis. Cells were cultured in SILAC-labeled RPMI 1640 with 10% dialyzed FBS containing “light” (K0R0), “medium” (K4R6), or “heavy” (K8R10) Lys and Arg as described previously [36], and subjected to LC-MS/MS analysis. Specific peptides of NEU1 in the three cell lines were annotated. c Data on NEU1 in HCV29, KK47, YTS-1, T24, and J82 cells from Western blotting (left) and relative integrated optical density (IOD) were quantified using the Image J software program, and presented as mean ± SD from triplicate experiments (right). d Sialic acids in the five cell lines stained by Cy3-labeled lectins SNA or MAL-II (red) and merged with DAPI (blue), or by immunofluorescence staining with anti-NEU1 antibody (green) and merged with DAPI (blue). scale bar: 50 μm