THE EFFECT OF AMILORIDE ON THE METASTATIC PROPERTIES OF PROSTATE-CANCER IN THE DUNNING RAT MODEL

Most deaths from cancer result from the metastatic spread of the disea se. The antidiuretic amiloride has been shown to inhibit tumor growth and metastasis in several tumor systems. The object of these studies w as to examine the effect on the in vitro and in vivo tumor growth and metastasis in the MatLyLu subline of the Dunning model of rat prostate cancer. In vitro, amiloride was found to have cytotoxic effects only at high concentrations, with an IC,, of 100 mu g/ml. In vitro analysis of the ability of amiloride to inhibit invasion of MLL cells demonstr ated that this drug was ineffective at all concentrations examined. In vivo, amiloride did not inhibit tumor growth or metastases developmen t. Our studies demonstrate that amiloride does not have activity in th is model of prostate cancer and suggest it may not be an appropriate t herapy for the treatment of prostate cancer.