Regulation of plasminogen activation, matrix metalloproteinases and urokinase-type plasminogen activator-mediated extracellular matrix degradation in human osteosarcoma cell line MG63 by interleukin-1 alpha

Plasmin-mediated extracellular proteolysis has been implicated in the degradation of bone in normal and pathological conditions. Normal and malignant osteoblasts can produce both tissue-type plasminogen activator (t- PA) and urokinase-type plasminogen activator (u-PA). We have used the osteosarcoma cell line MG63 to address the question of...

Protein and messenger RNA levels of plasminogen activators and inhibitors analyzed in 22 human tumor cell lines

In 22 human tumor cell lines the regulation of production of plasminogen activators urokinase (u-PA) and tissue-type (u-PA) and their inhibitors PAI-1 and PAI-2 was studied. These four components may determine the net plasminogen activator activity, which is often associated with tumor development and metastatic processes. The amount of specific...

Apoptin induces apoptosis in human transformed and malignant cells but not in normal cells

The chicken anemia virus protein apoptin induces a p53-independent, Bcl- 2-insensitive type of apoptosis in various human tumor cells. Here, we show that, in vitro, apoptin fails to induce programmed cell death in normal lymphoid, dermal, epidermal, endothelial, and smooth-muscle cells. However, when normal cells are transformed they become...

Mitogenic effects of urokinase on melanoma cells are independent of high affinity binding to the urokinase receptor

The structural and functional properties of the urokinase-type plasminogen activator (u-PA) that are involved in the mitogenic effect of this proteolytic enzyme on human melanoma cells M14 and IF6 and the role of the u-PA receptor (u-PAR) in transducing this signal were analyzed. Native u- PA purified from urine induced a mitogenic response in...