Figure 2.

Macrophage-dependent NOS expression is required for controlling lung metastases. WT and NOS2^−/− mice were treated as indicated. (A and B) Black bars indicate mice that were treated with L-NAME for the duration of the experiment. (C and D) For clodronate studies, mice received either saline control liposomes (white bars) or macrophage-depleting clodronate (black bars) as detailed in the Materials and methods. (E and F) Black bars indicate results using NOS2^−/− mice. (A, C, and E) On day 22, mice were euthanized and the primary tumor was dissected and measured. Lungs from these treated mice were collected on the same day and fixed in Bouin’s solution. (B, D, and F) The number of lung metastases was counted under a dissecting microscope. In A–D, the pooled results from two experiments are shown and in E and F, the results from one experiment are shown. The error bars indicate the standard error of the means for each treatment group. Each experiment consisted of 10 mice/treatment group. *, P < 0.05; **, P < 0.005 for the indicated comparisons.