Effects of Cyclosporine A on Experimental Hepatic Metastases of Mouse Colon-26 Tumour

Abstract

Cyclosporine A (CSA), an immunosuppressive agent with apparently selective effects on T lymphocytes and little myelotoxicity, was tested for its effects on hepatic metastases by inoculation of mouse colon-26 tumour cells into the portal vein in male CDF1 mice. CSA, given subcutaneously in daily doses of 10 – 50 mg/kg/day, for 22 days, significantly increased the incidence of hepatic nodules. This increase was positively correlated with the CSA dose. When 5-fluorouracil was injected at a dose of 15 mg/kg/day every other day after the inoculation of tumour cells a highly significant reduction in the incidence of metastases was seen (compared with the controls). This strong inhibitory effect of 5-fluorouracil on metastasis was almost completely suppressed when mice were treated with CSA concomitantly. The results suggest that CSA affects the host immune system, accelerating the production of hepatic metastases.