Inhibition of CHST11 expression and P-selectin binding to MDA-MB-231 cells by CHST11 siRNA. MDA-MB-231 cells were treated with three different siRNAs for the CHST11 gene. RNA was harvested after 48 hours and gene expression was assayed at the mRNA level (A). GAPDH was used as the house keeping gene to normalize mRNA-based expression data using the delta delta CT method. CHST11 mRNA levels are shown relative to mRNA level in cells treated with transfection agent only (vehicle). Data were log transformed and subjected to one way ANOVA with post-hocTukey's analysis. B) Binding of anti-CS-A (2H6 mAb) (top) and P-selectin (bottom) was tested at Day 6 post siRNA transfection. Binding of secondary antibodies only serves as control. Binding of anti-CS-A 2H6 mAb and recombinant human P-selectin to vehicle-treated and siRNA-treated MDA-MB-231 cells with the three siRNAs is shown. Mean fluorescent intensities of three independent experiments were log transformed and analyzed by ANOVA and post-hoc comparison. Treatment with CHST11 siRNA #31 significantly reduced mean fluorescent intensities for anti-CS-A 2H6 mAb (P ≤ 0.015) and P-selectin (P ≤ 0.001) binding, as compared with vehicle-treated cells.