Fig. 4

RhoA, but not Src, medicates EGFR expression by CD24 in SGC-7901 cells. a SGC-7901 and BGC-823 cells were treated with 20 μM PP2. 30 min later, and total protein extracts from cells were analyzed by Western blotting assays for CD24 and EGFR expression. b SGC-7901 cells were transfected with control siRNA or siCD24, and the activity of RhoA was measured. RhoA-GTP bands were quantified and normalized against RhoA level (graph on the right). Asterisk P < 0.05 in the siCD24 cells relative to siRNA control cells. c SGC-7901 cells were transfected with control siRNA or siRhoA, and the expressions of RhoA and EGFR were measured. EGFR bands were quantified and normalized against GAPDH (graph on the right). Asterisk P < 0.05 in the siCD24 cells relative to siRNA control cells. d SGC-7901 cells were transfected with GFP-tagged empty vector or RhoA-V14 plasmids, and the total cellular proteins were extracted and analyzed for expression of EGFR by Western blotting assays. Asterisk P < 0.05 in the CD24 overexpressing cells relative to control cells