Figure 7
FTY720 reduces breast tumor growth and enhances anticancer effectiveness of TAM in ERα-negative 4T1 syngeneic xenografts. 4T1 cells were surgically implanted into the second mammary fat pads under direct vision. Tumor-bearing mice were randomized into five groups 2 days after implantation and then treated with vehicle, FTY720 (1 mg/kg), TAM (25 mg/kg), FTY720 plus TAM or SAHA (intraperitoneal (i.p.) 20 mg/kg) plus TAM by gavage daily till day 15 (n=8). (a) Tumor volumes were measured daily. (Insert) Tumor volumes on day 15. (b) Representative tumors. *P<0.01, #P<0.05 compared with vehicle. (c, d) Immunohistochemical staining of tumor sections for TUNEL (c) and ERα (d). Scale bar: 20 μm. Quantifications of TUNEL-positive cells and ERα intensity are shown. *P<0.05 compared with vehicle or TAM. (e) HDAC activity in nuclear extracts of tumors was determined and expressed as arbitrary fluorescence units. (f) Expression of ERα in the tumors was analyzed by quantitative real-time PCR (QPCR) and normalized to Gapdh. (g) Nuclear extract proteins were analyzed by western blotting with the indicated antibodies. Histone H3 was used as loading control. Data are mean±s.e.m. *P<0.01 compared with vehicle or TAM.
