Figure 7. BLT2 inhibition suppresses metastasis of MDA-MB-231 cells in vivo.

(A and B) MDA-MB-231 cells treated for 24 h with LY255283 (10 µM) or DMSO were injected into the tail vein of nude mice, which were subsequently injected intraperitoneally with DMSO (control) or LY255283 (2.5 mg/kg) at 3 and 5 days after cell injection. Mice were killed 10 weeks after cell injection, and the lungs were removed and subjected to histological analysis (A). Arrowheads indicate metastatic nodules. Scale bars, 5 mm (upper panels) and 200 µm (lower panels). The number of metastatic nodules in the lungs was also counted (B); data are means±SD of values from four mice of each group. *P<0.05. (C and D) MDA-MB-231 cells pretreated for 24 h with LY255283 (10 µM) or DMSO were implanted into the mammary fat pad of nude mice, and the animals were then injected intraperitoneally with LY255283 (2.5 mg/kg) or DMSO (control) three times at 5-day intervals. The mice were killed 14 weeks after cell implantation, and lung sections were stained with H&E for analysis of metastatic nodules (C). Scale bars, 200 µm. The number of metastatic nodules in the lung was also counted (D). Data are representative of results obtained with three mice per group. *P<0.05.