Fig. 5.
A) siRNAs against CXCL12 markedly down-regulated the expression of CXCL12 mRNA in HCC95 cells, which expressed the highest levels of CXCL12 among all lung cancer cell lines in this study. NT: treatment with medium alone; Oligo: treatment with Oligofectamine reagent alone. HCC95 cells were transfected with 100 nM siRNAs against either CXCL12 (CXCL12-1 and CXCL12-2) or Tax. After 72 h, cells were harvested and quantitative real-time RT-PCR was performed. siRNA-mediated CXCL12 knockdown inhibited cellular proliferation and migration as evaluated by (B) MTT assay, (C) colony formation assay and (D) migration assay in HCC95 cells but not in HI299 cells, in which CXCL12 was undetectable. The MTT assay was performed in replicates of 8 at 4 days after transfection of siRNAs. Columns represent the mean ± SD (bars). Cells were also replated for the colony formation assay in liquid culture at 48 h post-transfection. and surviving colonies were stained with methylene blue 14 days later. Columns represent the mean ±SD (bars) obtained from three independent experiments. For the migration assay, 105 cells/well of the 12-blind-well chemotaxis chamber were loaded after 48 h of siRNA transfection. Columns represent, the mean ± SD (bars) of three independent experiments. Treatment with medium alone was set at 100%. *, P<0.001.