Fig. 6.

Effect of silencing of CXCR4 and HuR on invasion and migration of MDA-MB-231 cells. (A) Invasiveness of MDA-MB-231 cells as a result of CXCR4 knockdown. MDA-MB-231 cells were transfected with 50nM CXCR4 siRNA or control siRNA and cotransfected with 0.25 μg of luciferase expression constructs for 48h then reseeded in serum-free media in the upper matrigel invasion chambers. CXCL12 or 0.1% bovine serum albumin (BSA) (as a control) was used as the chemoattractant in the lower chambers. Luciferase was measured after 24h. Data represent mean ± standard error of the mean of three independent experiments, **P < 0.005 (Student’s t-test). (B) MDA-MB-231 cells ability to migrate toward CXCL12 as a result of CXCR4 silencing. Cells were transfected with CXCR4 siRNA or control siRNA for 24h and reseeded in serum-free medium in the upper chambers of a migration chamber plate. CXCL12 (10nM) or 0.1% BSA alone was added to the lower chamber and luminescence was measured after 24h. Data are from one experiment representative of two independent experiments, ***P < 0.0001 (Student’s t-test). (C) Effect of HuR knockdown on CXCR4-mediated invasion. MDA-MB-231 cells were transfected with HuR siRNA or control siRNA and reseeded in serum-free media in the upper chambers of a matrigel invasion plate as in A. Data are from one experiment representative of three independent experiments, *P < 0.05 (Student’s t-test). (D) Effect of HuR knockdown on CXCR4-mediated migration. MDA-MB-231 cells were transfected with HuR siRNA or control siRNA and reseeded in serum-free media in the upper chambers of a migration chamber plate. CXCL12 or 0.1% BSA alone was added to the lower chamber, and luminescence was measured after 24h. Data are from one experiment representative of two independent experiments, **P < 0.01 (Student’s t-test).