Figure 2

Spontaneous metastasis xenograft model of human melanoma. (A) Kaplan-Meier overall-survival analysis (OS) for scid mice with subcutaneously injected MeWo cells revealed significantly prolonged OS in mice inoculated with MeWo CEACAM1 kd 1 against MeWo Luc inoculated animals (p < 0.001). (B) Tumor weight at the time of death was not significantly different between the two groups (p = 0.164; n = 11 Luc group and n = 12 CEACAM kd group). (C) Immunohistochemical staining of paraffin embedded tumor tissue (xenograft MeWo tumors in scid mice) for CEACAM1 demonstrated the stability of the CEACAM1 knockdown in the subcutaneous tumors: High CEACAM1 was detected in the MeWo Luc tumors (left panel) whereas little to no CEACAM1 (in red) could be shown in the MeWo CEACAM1 kd tumors (right panel). scale bar: 100 µm. (D) Knockdown of CEACAM1 significantly decreases metastasis (adj. for survival time and tumor weight; p = 0.016; n = 11 Luc group and n = 10 CEACAM kd group). (E) CEACAM1 knockdown does not significantly alter the number of circulating tumor cells in the blood of scid mice (p = 0.756, n = 10 each group). Quantification of circulating (human) tumor cells in the blood of scid mice inoculated with MeWo CEACAM1 kd (orange) compared with controls (MeWo Luc, teal) by quantitative real-time PCR.