Figure 7
Effect of recombinant pigment epithelium-derived factor on tamoxifen sensitivity in MCF-7:5C, MCF-7, and BT474 xenografts. (a) MCF-7:5C cells were bilaterally injected into the mammary fat pads of ovariectomized athymic mice (n = 32), and after tumors reached a mean cross-sectional area of 0.2 cm2 groups of eight mice were randomly assigned to the following treatments: PBS (control), recombinant pigment epithelium-derived factor (rPEDF), tamoxifen (TAM), or rPEDF + TAM. TAM was given orally by gavage at 1.5 mg/day and rPEDF was given via intraperitoneal injection at 4 mg/kg every other day for 21 days. (b) MCF-7 cells were bilaterally injected into the mammary fat pads of ovariectomized mice (n = 32), and after tumors reached a mean cross-sectional area of 0.32 cm2 groups of eight mice were randomly assigned to the following treatments: PBS (control), rPEDF, TAM, or rPEDF + TAM as described in Materials and methods. (c) BT474 cells were bilaterally injected into the mammary fat pads of ovariectomized mice (n = 32), and after tumors reached a mean cross-sectional area of 0.3 cm2 groups of eight mice were randomly assigned to the following treatments: PBS (control), rPEDF, TAM, or rPEDF + TAM. Mean cross-sectional tumor area was measured every 5 days with vernier calipers. Cross-sectional areas were calculated by multiplying the length (l) by the width (w) and by π and dividing the product by 4 (that is, lwπ/4). (d) Western blot analysis of MCF-7:5C tumors following treatment with rPEDF, tamoxifen, or rPEDF and tamoxifen. Tumors were generated as described in 7a and the lysates were preprepared as described in Materials and Methods. Blots were probed with the indicated antibodies.