Fig. 2
5-HT stimulated MDA-MB-231 cell invasion through 5-HT7 receptors. a MDA-MB-231 cells seeded in a Matrigel-coated transwell inserts were serum-starved and then treated with 5-HT for 18 h. Serum was used as a positive control to induce invasion. Invading cells were counted in five different fields per well, and results were averaged. The bar graphs represent the relative numbers of invading cells expressed as the means ± SEMs of three independent experiments. *P < 0.05 vs. vehicle-treated controls. b Cells were pretreated with LY310762 or SB269970 for 1 h prior to 5-HT (10 μM) treatment. *P < 0.05 vs. vehicle-treated controls. # P < 0.05 vs. 5-HT-treated cells. c-e MDA-MB-231 cells were transfected with two different sequences of siRNAs targeting either NT, 5-HT1D, or 5-HT7 receptor. The bar graphs represent mRNA and protein expression levels of TPH1, 5-HT1D, 5-HT7, and MMP-9, as determined by real time PCR (c) and western blot (d) *P < 0.05 vs. NT siRNA-transfected controls. e 5-HT-induced invasion ability was measured by invasion assay. *P < 0.05 vs. vehicle-treated controls. # P < 0.05 vs. cells treated with NT siRNA and 5-HT. f Serum-induced invasion was examined in MDA-MB-231 cells transfected with NT or two different sequences of TPH1 siRNA. *P < 0.05 vs. vehicle-treated controls. # P < 0.05 vs. NT siRNA-transfected cells