¹Cell Genesys, Inc., 500 Forbes Boulevard, South San Francisco, California 94080, USA

Correspondence: Karin Jooss, Fax: (650) 266-3010. E-mail: karin.jooss@cellgenesys.com

Received 3 September 2003; Accepted 14 October 2003.

Abstract

Angiostatin is a potent endogenous inhibitor of angiogenesis and tumor growth in vivo. The therapeutic potential of adeno-associated viral (AAV) gene delivery of angiostatin in modulating tumor growth in vivo was evaluated. Sustained levels of angiostatin were detected in the sera of mice for up to 6 months after they received a single injection of AAV-angiostatin. AAV-mediated stable expression of angiostatin inhibited tumor burden in the highly aggressive B16F10 melanoma and Lewis lung carcinoma (LLC) models of experimental metastasis. Moreover, AAV-angiostatin prolonged survival in B16F10 and LLC tumor-bearing mice compared to control groups. Anti-tumor efficacy was consistently observed when angiostatin serum levels of 15–50 ng/ml were detected following gene transfer, but the effect was minimal when the levels were lower or higher than this range. The combination of AAV-angiostatin gene therapy with chemotherapy was also shown to extend marginally the survival of mice bearing preestablished human tumors; however, the effect was evident only within a narrow dose of circulating angiostatin. These studies demonstrate the feasibility of using AAV antiangiogenic gene therapy as a cancer treatment modality and suggest that the optimal anti-tumor efficacy of angiostatin following gene transfer may be limited to a narrow dose range.