Control of tumor growth in animals by infusion of an angiogenesis inhibitor.

Angiogenesis and tumor growth were inhibited in two different animal models by regional infusion of a partially purified cartilage extract. In rabbits bearing corneal implants of V2 carcinoma and receiving the inhibitor, vascular growth rates were < 3% of those in control animals receiving either Ringer's solution or bovine trypsin inhibitor (Trasylol). Subconjunctival B16 melanoma implants in mice receiving the inhibitor weight < 2.5% of implants in mice receiving Ringer's solution, Trasylol, or albumin. Histologic study of major organs and standard blood tests revealed no toxic effects in any of the animals. The inhibitor did not retard the growth of either tumor cell type in tissue culture at concentrations as high as 1 mg/ml. These results suggest that the cartilage factor does not interfere with the growth of the tumor cell population directly but that it prevents tumor growth by inhibiting angiogenesis.