Effect of angiostatic steroid with or without glucocorticoid activity on metastasis.

The effect of angiostatic steroids on pulmonary metastasis was investigated using mice treated with such a steroid before or after intravenous inoculation with Lewis lung carcinoma; cortisone acetate and tetrahydro S, of which the former possesses glucocorticoid activity, and the latter lacks it, were used as the angiostatic steroids. In the presence of heparin, both types of steroids prevented angiogenesis in chick embryo and also pulmonary metastasis in mice when the administration started after cell lodgement. On the other hand, one-shot cortisone treatment before cell inoculation increased the weight of lung colonies to twice that seen in the controls, while tetrahydro S pretreatment did not enhance metastasis. These results revealed that both angiostatic steroids with and without glucocorticoid activity in the presence of heparin inhibited tumor growth in the lungs, and further indicated that cortisone acetate affected the steps of metastasis after the invasion of tumor cells into the blood stream until angiogenesis in the secondary foci, and consequently promoted metastasis, whereas tetrahydro S (which has no glucocorticoid activity) did not affect the steps before angiogenesis. It was thus indicated that the inhibitory effect of angiostatic steroids against tumor growth due to an anti-angiogenic activity was not dependent at all on the metastasis promotion by these steroids having glucocorticoid activity.