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Pancreatic ductal adenocarcinoma (PDAC) is a highly fatal metastatic disease associated with robust activation of the coagulation and fibrinolytic systems. However, the potential contribution of the primary fibrinolytic protease plasminogen to PDAC disease progression has remained largely undefined. Mice bearing C57Bl/6‐derived KPC (KRasG12D, TRP53R172H) tumors displayed evidence of plasmin activity in the form of high plasmin–antiplasmin complexes and high plasmin generation potential relative to mice without tumors. Notably, plasminogen‐deficient mice (Plg‐) had significantly diminished KPC tumor growth in subcutaneous and orthotopic implantation models. Moreover, the metastatic potential of KPC cells was significantly diminished in Plg‐ mice, which was linked to reduced early adhesion and/or survival of KPC tumor cells. The reduction in primary orthotopic KPC tumor growth in Plg‐ mice was associated with increased apoptosis, reduced accumulation of pro‐tumor immune cells, and increased local proinflammatory cytokine production. Elimination of fibrin(ogen), the primary proteolytic target of plasmin, did not alter KPC primary tumor growth and resulted in only a modest reduction in metastatic potential. In contrast, deficiencies in the plasminogen receptors Plg‐RKT or S100A10 in tumor cells significantly reduced tumor growth. Plg‐RKT reduction in tumor cells, but not reduced S100A10, suppressed metastatic potential in a manner that mimicked plasminogen deficiency. Finally, tumor growth was also reduced in NSG mice subcutaneously or orthotopically implanted with patient‐derived PDAC tumor cells in which circulating plasminogen was pharmacologically reduced. Collectively, these studies suggest that plasminogen promotes PDAC tumor growth and metastatic potential, in part through engaging plasminogen receptors on tumor cells. [ABSTRACT FROM AUTHOR]

The plasminogen receptor, Plg-RKT, is a unique cell surface receptor that is broadly expressed in cells and tissues throughout the body. Plg-RKT localizes plasminogen on cell surfaces and promotes its activation to the broad-spectrum serine protease, plasmin. In this study, we show that overexpression of Plg-RKT protects mice from high fat diet (HFD)-induced adipose and metabolic dysfunction. During the first 10 weeks on the HFD, the body weights of mice that overexpressed Plg-RKT (Plg-RKT-OEX) were lower than those of control mice (CagRosaPlgRKT). After 10 weeks on the HFD, CagRosaPlgRKT and Plg-RKT-OEX mice had similar body weights. However, Plg-RKT-OEX mice showed a more metabolically favourable body composition phenotype. Plg-RKT-OEX mice also showed improved glucose tolerance and increased insulin sensitivity. We found that the improved metabolic functions of Plg-RKT-OEX mice were mechanistically associated with increased energy expenditure and activity, decreased proinflammatory adipose macrophages and decreased inflammation, elevated brown fat thermogenesis, and higher expression of adipose PPARγ and adiponectin. These findings suggest that Plg-RKT signalling promotes healthy adipose function via multiple mechanisms to defend against obesity-associated adverse metabolic phenotypes. [ABSTRACT FROM AUTHOR]

The plasminogen activation system regulates the activity of the serine protease, plasmin. The role of plasminogen receptors in cancer progression is being increasingly appreciated as key players in modulation of the tumor microenvironment. The interaction of plasminogen with cells to promote plasminogen activation requires the presence of proteins exposing C-terminal lysines on the cell surface. Plg-RKT is a structurally unique plasminogen receptor because it is an integral membrane protein that is synthesized with and binds plasminogen via a C-terminal lysine exposed on the cell surface. Here, we have investigated the expression of Plg-RKT in human breast tumors and human breast cancer cell lines. Breast cancer progression tissue microarrays were probed with anti-Plg-RKT mAB and we found that Plg-RKT is widely expressed in human breast tumors, that its expression is increased in tumors that have spread to draining lymph nodes and distant organs, and that Plg-RKT expression is most pronounced in hormone receptor (HR)-positive tumors. Plg-RKT was detected by Western blotting in human breast cancer cell lines. By flow cytometry, Plg-RKT cell surface expression was highest on the most aggressive tumor cell line. Future studies are warranted to address the functions of Plg-RKT in breast cancer. [ABSTRACT FROM AUTHOR]

Patients who have pheochromocytomas may be carriers of multiple endocrine neoplasia type 2 (MEN-2) or von Hippel-Lindau disease and should be screened for these diseases. Also, patients with MEN-2 or von Hippel-Lindau disease should be tested for asymptomatic pheochromocytomas. A pheochromocytoma is a usually benign tumor of the adrenal gland. MEN-2 and von Hippel-Lindau disease are hereditary syndromes characterized by an increased risk of multiple tumors or cancer. Among 82 patients with pheochromocytomas, 23% were found to be carriers of either MEN-2 or von Hippel-Lindau disease. The pheochromocytoma patients who were carriers were younger on average than those who were not. Among 79 known carriers of either tumor syndrome, 46% were found to have pheochromocytomas. Most of those with pheochromocytomas had no symptoms. Screening for pheochromocytomas should include both biochemical tests and radiologic imaging.