FIGURE 2.

Validation of CCL5 as an effector of the S-SMase/ceramide pathway. MCF7 breast carcinoma cells lines stably expressing V5-LacZ, V5-aSMase^WT, and V5-aSMase^S508A were treated with vehicle (PBS) or IL-1β (2.5 ng/ml) for 18 h. A, cell-free conditioned medium was collected, and CCL5 protein levels were determined by ELISA. B, CCL5 mRNA levels were determined by RT-PCR in response to 18 h PBS (Ctl) or IL-1β (2.5 ng/ml) and were normalized to β-actin (see “Experimental Procedures”) (n ≥ 3; two-way ANOVA with Bonferroni post-test; *, p < 0.05; **, p < 0.01; ***, p < 0.001 versus LacZ; #, p < 0.05 versus untreated).