Angiogenesis is required for tumor growth and metastasis, and inhibition of angiogenesis is a promising approach for anticancer therapy. Tie2 (a.k.a Tek) is an endothelium-specific receptor tyrosine kinase known to play a role in tumor angiogenesis. To explore the therapeutic potential of blocking the Tie2 pathway, an adenoviral vector was constructed to deliver a recombinant, soluble Tie2 receptor (AdExTek) capable of blocking Tie2 activation. Two days after i.v. injection of AdExTek, the plasma concentration of ExTek exceeded 1 mg/ml and was maintained for about 8 days. Administration of AdExTek to mice with two different well established primary tumors, a murine mammary carcinoma (4T1) or a murine melanoma (B16F10.9), significantly inhibited the growth rate of both tumors (64% and 47%, respectively). To study the effect of ExTek on tumor metastasis, both tumor cell lines were coinjected i.v. with either AdExTek or a control virus. Mice coinjected with control virus developed numerous large, well vascularized lung metastases. In contrast, mice coinjected with AdExTek virus developed few, if any, grossly apparent metastases, and histologic examination revealed only small avascular clusters of tumor cells. Administration of AdExTek also inhibited tumor metastasis when delivered at the time of surgical excision of primary tumors in a clinically relevant model of tumor metastasis. This study demonstrates the potential utility of gene therapy for systemic delivery of an antiangiogenic agent targeting an endothelium-specific receptor, Tie2.

Type

Conference paper

Publication Date

21/07/1998

Volume

95

Pages

8829 - 8834

Keywords

Adenoviridae, Angiopoietin-1, Angiopoietin-2, Animals, Endothelium, Vascular, Female, Genetic Therapy, Humans, Melanoma, Experimental, Membrane Glycoproteins, Mice, Mice, Inbred BALB C, Neoplasm Metastasis, Neovascularization, Pathologic, Phosphorylation, Proteins, Rats, Receptor Protein-Tyrosine Kinases, Receptor, TIE-2, Tumor Cells, Cultured