Figure 6.

Knockdown of Ckb in the PyMT tumor epithelium or systemic cCr therapy decreases lung metastasis burden. (A) PyMT EV, sh59 KD or sh61 KD cells were injected into the tail vein of female FVB/Nj recipients. After 21 days, mice were euthanized and lungs were harvested for metastasis evaluation after lung inflation through the trachea with PBS. The number of metastases was compared across genotypes; the scatter plot shows the burden of individual lungs as the mean ± SEM. Corresponding H&E-stained images of lungs representative of the genotype mean are shown (400× magnification). Data are representative of two independent experiments. (B) EV PyMT cells were injected into the tail vein of female FVB/Nj recipients. The next day, treatment with either vehicle (saline, IP, daily) or cCr (1 g/kg in saline, IP, daily) was initiated. After 21 days, the mice were euthanized, and lungs were harvested after inflation with PBS. The total number of surface metastases was counted under a dissecting scope. Most of the mice treated with cCr (5 of 7) did not develop detectable metastases, although 2 mice in each cohort (2/8, saline and 2/7, cCr) developed fewer than 50 metastases. Only in the saline group did the majority of mice develop metastases throughout the lung, with >100 lesions present (5/8 mice; χ2 = 7.634, p = 0.022). Images of whole lungs photographed immediately post-dissection are shown. (C,D) Comparison of total metastases present per lung (C), or the number of macro-metastases per lung (D) when mice were treated with vehicle, or when cCr was administered at either day 1 (Day 1 cCr) or when cCr therapy began at day 7 after the tail vein injection (Day 7 cCr). All lungs were harvested at day 21 post-injection. (E) The mean bodyweight of the mice treated with saline (vehicle) or cCr from panels (C,D).