Identification of the Anti-angiogenic Site within Vascular Basement Membrane-derived Tumstatin

• Published in: The Journal of biological chemistry Vol. 276; no. 18; pp. 15240 - 15248
• Main Authors: Maeshima, Yohei, Manfredi, Mark, Reimer, Corinne, Holthaus, Kathryn A., Hopfer, Helmut, Chandamuri, Babi R., Kharbanda, Surender, Kalluri, Raghu
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 04.05.2001; American Society for Biochemistry and Molecular Biology
• Subjects: Angiogenesis Inhibitors - chemistry; Angiogenesis Inhibitors - isolation & purification; Animals; Autoantigens - chemistry; Autoantigens - genetics; Autoantigens - isolation & purification; Basement Membrane - chemistry; Caspase 3; Caspases - metabolism; Cattle; Cell Division; Cell Line; Collagen - chemistry; Collagen - genetics; Collagen - isolation & purification; Collagen Type IV; Endothelium, Vascular - chemistry; Endothelium, Vascular - cytology; Endothelium, Vascular - metabolism; Humans; Mice; Recombinant Proteins - chemistry; Recombinant Proteins - genetics
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M007764200

Components of vascular basement membrane are involved in regulating angiogenesis. Recently, tumstatin (the NC1 domain of α3 chain of type IV collagen) was identified as possessing anti-angiogenic activity. In the present study, the anti-angiogenic activity of tumstatin was localized to the putative 54–132-amino acid Tum-5 domain, and the activity mediated by αvβ3 integrin interaction in an RGD-independent manner. The recombinant Tum-5 produced inEscherichia coli and Pichia Pastorisspecifically inhibited proliferation and caused apoptosis of endothelial cells with no significant effect on nonendothelial cells. Tum-5 also inhibited tube formation of endothelial cells on Matrigel and induced G1 endothelial cell cycle arrest. Moreover, anti-angiogenic effect of Tum-5 was also examined in vivousing both a Matrigel plug assay in C57BL/6 mice and human prostate cancer (PC-3) xenografts in nude mice. The in vivo results demonstrate that Tum-5 at 1 mg/kg significantly inhibited growth of PC-3 tumors in association with a decrease in CD31 positive vasculature. These in vivo studies also show that, at molar equivalents, human Tum-5 is at least 10-fold more active than human endostatin. In addition, these studies for the first time suggest that through the action of endogenous inhibitors, αvβ3 integrin may also function as a negative regulator of angiogenesis. Taken together, these findings demonstrate that Tum-5, a domain derived from tumstatin, is an effective inhibitor of tumor-associated angiogenesis and a promising candidate for the treatment of cancer.