Figure 5

MM-121 in combination with low-dose paclitaxel significantly inhibits in vivo tumor growth of trastuzumab-resistant breast cancer cells in a murine model. BT474-HR20 cells were subcutaneously injected into nude mice to establish tumor xenografts. The tumor-bearing mice (n = 5) received intraperitoneal injections of either PBS, or MM-121 (10 mg/kg), or paclitaxel (7.5 mg/kg) alone, or both MM-121 and paclitaxel as described in Methods. After six treatments the mice were euthanized at day 36 post injection of tumor cells, and all tumors were excised for histology and IHC analysis. (A) The graphs show the tumor growth curves. Bars represent SD. ^*P <0.04 versus control or MM-121; ^**P <0.05 versus MM-121 and P <0.005 versus paclitaxel; ^***P <0.04 versus paclitaxel; ^****P <0.05 versus control, P <0.008 versus MM-121, and P <0.02 versus paclitaxel; ^*****P = 0.005 versus control, P <0.004 versus MM-121, and P = 0.0006 versus paclitaxel. (B) Data show the representative tumors with H&E staining and IHC analysis of erbB2 and erbB3 receptors.