Figure 3.

Metastatic explants have a higher baseline activation of mTOR based on phosphorylation levels of pAkt(473), pmTOR(4885), and p4E-BP1. Metastasis of explant no. 15 (from a bone lesion) is inhibited by sirolimus but demonstrates reduced sensitivity to sirolimus compared to the parental line. (A-D) Western blot analysis of metastatic explants: no. 15, bone metastasis, and no. 7, liver metastasis. The bar graphs describe fold increase of protein expression over the parental C666-1 line. (E) Growth curves of multiple independent metastases from mice injected with the metastatic C666-1 subclone, no. 15, treated with sirolimus (blue, n = 3) or placebo (red, n = 6) beginning the day following tumor injection. The x-axis indicates days after sirolimus treatment was started.