Quantitative proteomic identification of novel, bioactive substrates of matrix metalloproteinase (MMP)-11 and system-wide identification of new proteases involved in breast cancer progression and metastasis
Zusammenfassung der Projektergebnisse
Breast cancer tumors produce enzymes called “proteases” that are thought to help cancer cells to grow, invade the bloodstream, move around the body and escape destruction by white blood cells. One particular important protease is matrix metalloproteinase 11 (MMP11) that is released from the stromal compartment of the tumor and has been strongly correlated with metastasis and thus poor prognosis for the patient. Since proteases cut tissue proteins also called “substrates” the key to understand their mechanism of action and to design new strategies for therapeutic intervention is the identification and characterization of these proteins. Therefore, we developed a new technology to identify substrates in complex biological samples termed TAILS that we applied to unravel novel substrate proteins cut by MMP11 in a cell based system. Among identified substrate candidates was Galectin-1, an important anti-inflammatory factor and inducer of cell death, that is known to be highly expressed in breast cancer tissue. Proteolytic processing of Galectin-1 by MMP11 might lead to functional inactivation and hence favor cancer cell survival, a hypothesis that will have to be confirmed in future experiments. To better understand the function of proteases and their contribution to tumor metastasis we also assessed expression of all known proteases and inhibitors in a murine breast cancer model. Thereby, we identified other members of the MMP family, MMP10 and 13, as being highly expressed by cancer cells in the most metastatic primary tumors. Again, we applied TAILS to define novel proteins cut by these cancer proteases and identified numerous substrates including members of the insulin-like growth factor binding proteins (IGFBPs). These proteins have been implicated in breast cancer development and progression, and the consequences of their cleavage is subject of further investigations. Finally, we performed TAILS analysis directly on normal and malignant mouse mammary tissues revealing many proteins that are only cleaved in aggressive tumors. Most importantly, we could verify Galectin-1 cleavage in vivo, and future studies will have to determine if MMP11 is the responsible protease.
Projektbezogene Publikationen (Auswahl)
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(2007). Protease research in the era of systems biology. Biol Chem 388:1159-1162
auf dem Keller, U., A. Doucet, and C. M. Overall
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(2008). Epithelialmesenchymal transition (EMT) is not sufficient for spontaneous murine breast cancer metastasis. Dev Dyn 237:2755-2768
Lou, Y., O. Preobrazhenska, U. auf dem Keller, M. Sutcliffe, L. Barclay, P. C. McDonald, C. Roskelley, C. M. Overall, and S. Dedhar
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(2008). Identification of Protease Substrates by Mass Spectrometry Approaches-2. The Cancer Degradome: Proteases and Cancer Biology 83
Prudova, A., U. auf dem Keller, and C. M. Overall
