Fig. 3.

5-HT-induced MDA-MB-231 cell invasion was linked to 5-HT₇ receptor-dependent Gαs and Gβγ signaling. a The invasivenesses of MDA-MB-231 cells were determined after cells were pretreated with gallein or DDA alone, or a combination of both, for 1 h prior to 5-HT treatment. *P < 0.05 vs. vehicle-treated controls. ^# P < 0.05 vs. 5-HT-treated cells. ^$ P < 0.05 vs. 5-HT- and DDA-treated cells. &P < 0.05 vs. 5-HT- and gallein-treated cells. b Cells were treated with 5-HT or forskolin and cAMP levels were measured. *P < 0.05 vs. vehicle-treated controls. c Protein extracts from MDA-MB-231 cells treated with 5-HT alone or 5-HT plus gallein were analyzed for the activation of Gβγ-downstream signaling by western blotting. d 5-HT-induced MDA-MB-231 cell invasion was examined in the presence of various inhibitors, that is, AZM-475271 (AZM), wortmannin (Wort), tricirbine, rapamycin (Rapa), SB203580, U0126, and PD98059, at the indicated concentrations. *P < 0.05 vs. vehicle-treated controls. ^# P < 0.05 vs. 5-HT-treated cells. e Cells were treated with gallein, wortmannin, or DDA, and basal levels of TPH1 and MMP-9 were analyzed by western blotting. *P < 0.05 vs. vehicle-treated controls