The influence of Fluosol-DA on the occurrence of lung metastases in Lewis lung carcinoma and B16 melanoma.

The development of lung metastases from subcutaneously implanted tumors or the development of lung nodules from intravenously injected tumor cells are model systems for metastases formation. Animals bearing subcutaneous Lewis lung tumors (50-100 mm3) were treated with a single dose of Fluosol-DA followed by 1 h of breathing carbogen or maintenance in air. Their lungs were examined for metastases 25 or 40 days after tumor cell implantation. Treatment with Fluosol-DA and carbogen or air breathing reduced by almost 4-fold the number of lung metastases seen. The addition of Fluosol-DA with air or carbogen breathing to treatment of the tumor-bearing limb with 20 Gy reduced the number of lung metastases by 2-fold compared to radiation treatment alone. If Fluosol-DA was administered immediately before or up to 3 days prior to an intravenous challenge with Lewis lung tumor cells, there was a 2- to 3-fold reduction in the number of lung nodules formed. Fluosol-DA administered immediately before or up to 4 days prior to B16 melanoma cells caused a 2- to 3-fold reduction in the number of lung nodules observed. The vascular endothelial cell monolayer adhesion assay was used to test the effects of prior exposure to Fluosol-DA on the attachment of radiolabelled B16 melanoma cells in vitro. There was a trend toward increasing attachment of B16 cells to the endothelial monolayer with prior exposure to increasing concentrations of Fluosol-DA; however, this difference did not reach statistical significance.