Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.73 (urokinase-type plasminogen activator)
 10,685 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

By primarily measuring changes in transcript and protein abundance, conventional genomics and proteomics methods may fail to detect significant posttranslational events that regulate protein activity and, ultimately, cell behavior. To address these limitations, activity-based proteomic technologies that measure dynamics in protein function on a global scale would be of particular value. Here, we describe the application of a chemical proteomics strategy to quantitatively compare enzyme activities across a panel of human breast and melanoma cancer cell lines. A global analysis of the activity, subcellular distribution, and glycosylation state for the serine hydrolase superfamily resulted in the identification of a cluster of proteases, lipases, and esterases that distinguished cancer lines based on tissue of origin. Strikingly, nearly all of these enzyme activities were down-regulated in the most invasive cancer lines examined, which instead up-regulated a distinct set of secreted and membrane-associated enzyme activities. These invasiveness-associated enzymes included urokinase, a secreted serine protease with a recognized role in tumor progression, and a membrane-associated hydrolase KIAA1363, for which no previous link to cancer had been made. Collectively, these results suggest that invasive cancer cells share discrete proteomic signatures that are more reflective of their biological phenotype than cellular heritage, highlighting that a common set of enzymes may support the progression of tumors from a variety of origins and thus represent attractive targets for the diagnosis and treatment of cancer.
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PMID:Enzyme activity profiles of the secreted and membrane proteome that depict cancer cell invasiveness. 1214 57

Entry of malignant cells into the vasculature (i.e. intravasation) requires proteolytic remodeling of the extracellular matrix so that tumor cells may pass through the local stroma and penetrate the vessel wall. The circulatory system then provides a means of transporting tumor cells to distant sites where they extravasate and establish metastatic lesions. This study utilizes activity-based protein profiling to compare the active serine hydrolase repertoire in high intravasating (HT-hi/diss) and low intravasating (HT-lo/diss) variants of the human fibrosarcoma HT-1080 cell line to determine which enzyme(s) play a role in intravasation. Activity-based protein profiling revealed multiple serine hydrolases with altered activity between HT-hi/diss and HT-lo/diss cells, with the largest difference being the activity of urokinase-type plasminogen activator (uPA). Levels of inactive uPA zymogen were similar between the two cell variants, but only HT-hi/diss conditioned medium contained active uPA, suggesting that uPA activation may contribute to the enhanced intravasation of HT-hi/diss cells. To analyze the role of uPA activity specifically in the process of intravasation, we grafted cells from the two HT-1080 variants onto the chorioallantoic membrane of chick embryos and measured levels of tumor cell intravasation in the distal chorioallantoic membrane using quantitative human-specific Alu PCR. Inhibition of uPA activity with natural (plasminogen activator inhibitor-1) or synthetic (amiloride) inhibitors diminished HT-hi/diss Matrigel invasion in vitro and intravasation and metastasis in vivo. Additionally, treatment of HT-lo/diss tumors with exogenous active uPA increased the number of intravasated cells in vivo. These results indicate that active uPA promotes tumor cell intravasation and that uPA activation appears to be a key step in tumor progression.
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PMID:Activity-based protein profiling implicates urokinase activation as a key step in human fibrosarcoma intravasation. 1661 36