Fig. 3

CCKBR mediated suppressive effects of gastrin on ER⁺ BC cells. a ER⁺ MCF-7, as well as T-47D and ER⁻ MDA-MB-231 BC cells were treated with gastrin (10^− 7 M) for 7 d. CCK-8 assay results demonstrated that gastrin inhibited proliferation of MCF-7 (a) and T-47D (b), but not MDA-MB-231 (c) cells. (b-c) Knockdown of CCKBR by CCKBR-targeted siRNA blocked the effects of gastrin on ER⁺ BC cells. (a) Expression of CCKBR in MCF-7 and T-47D cells transfected with CCKBR-targeted siRNA for 48 h. (b) Gray density analysis demonstrated about two-thirds of CCKBR were downregulated in MCF-7 and T-47D cells (*P < 0.01). (c) CCK-8 assay results demonstrated that knockdown of CCKBR blocked the inhibitory effects of gastrin on MCF-7 and T-47D cells (*P < 0.05). d MCF-7 BC tumors grew much slower in animals treated with gastrin. (a) Growth curves of MCF-7 tumors in control and experimental mice (*P < 0.01). (b) The panel shows tumors removed from mice 12-d post-gastrin treatment (control, N = 6; gastrin treatment, N = 6). (c) Weight of tumors removed from mice 12-d post-gastrin treatment (control, N = 6; gastrin treatment, N = 6; *P < 0.05)