Functional and structural uncoupling of the angiogenic and enzymatic inhibitory activity of TIMPs : loop 6 of TIMP-2 is a novel inhibitor of angiogenesis

Tissue inhibitors of metalloproteinases (TIMPs) regulate tumor growth, progression and angiogenesis in a variety of experimental cancer models and in human malignancies. However, numerous studies have revealed important differences between TIMP family members in their ability to inhibit angiogenic processes in vitro and angiogenesis in vivo despite their universal ability to inhibit matrix metalloproteinase (MMP) activity. To address these differences, structure-function studies were conducted to identify and characterize the anti-angiogenic domains of TIMP-2, the endogenous MMP inhibitor that uniquely inhibits capillary endothelial cell (EC) proliferation and angiogenesis in vivo. Only the carboxy-terminal domain of TIMP-2 (T2C) and not the MMP-inhibitory N-terminal domain (T2N), inhibited capillary EC proliferation. Although both T2N and T2C inhibited embryonic angiogenesis, only T2C potently inhibited mitogen-stimulated angiogenesis. These findings demonstrate that TIMP-2 possesses two distinct types of anti-angiogenic activities which can be uncoupled from each other. The anti-proliferative activity of T2C was further mapped to the 24-amino acid peptide, Loop 6, which proved to be a potent inhibitor of both embryonic and nitogen-stimulated angiogenesis in vivo. Initial studies into the mechanism(s) by which Loop 6 inhibits angiogenesis revealed that the anti-proliferative effects of Loop 6 are due, at least in part, to the inhibition of cell cycle progression and not to the induction of apoptosis. This inhibition was associated with increased levels of cell cycle inhibitor p27. Although Loop 6 did not compete with bFGF for binding to its receptor,

Department dc:contributor.department

Massachusetts Institute of Technology. Biological Engineering Division.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2004

Author dc:creator

• Fernández, Cecilia A., 1969-

Advisor dc:contributor.advisor

• Robert S. Langer and Marsha A. Moses.

• Biological Engineering Division.

Statement dc:rights

• MIT theses are protected by copyright. They may be viewed, downloaded, or printed from this source but further reproduction or distribution in any format is prohibited without written permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/31110

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/31110