Metastatic behavior of human melanoma cell lines in nude mice correlates with urokinase-type plasminogen activator, its type-1 inhibitor, and urokinase-mediated matrix degradation.

Abstract

Abstract. Five out of six human melanoma cell lines tested were able to degrade in vitro a smooth muscle cell extracellular matrix in a plasmin-dependent way. In three of these five cell lines, this process was mediated by tissue-type plasminogen activator (t-PA) and in the other two cell lines by urokinase-type plasminogen activator (u-PA).All melanoma cell lines produced t-PA mRNA and protein, whereas only the two cell lines showing u-PAmediated matrix degradation produced u-PA mRNA and protein . These latter cell lines also produced plasminogen activator inhibitor type-1 (PAI-1) and type-2 (PAI-2) mRNA and protein . u-PA receptor (u-PA-R) mRNA and binding of radiolabeled u-PA was found in all melanoma cell lines. The metastatic capacity of these cell lines was studied in nude mice. All cell lines were able to develop primary tumors at the sub-RING metastasis, tumor cells must penetrate basement membranes and interstitial tissues, when they detach from the primary tumor and intravasate into the circulation, and later when they extravasate at the site formation of the secondary tumor. This means that these tumor cells should express the right panel and adequate levels of proteolytic enzymes to degrade the extracellular matrix (15,16,24,34,49,57) . In addition, these enzymes may have a function in the process of angiogenesis when endothelial cells grow invasively into the newly formed tumor and form new blood vessels (25,38) . The serine protease plasmin is one ofthe major enzymes believed to be involved in such proteolytic processes (15,16,24,42,43) . Plasmin has a broad substrate specificity and can digest most of the components of the extracellular matrix including the basement membrane, either directly or by activation of proenzymes of metalloproteinases, like type IV collagenase or interstitial collagenase (23,39,57) . Plasmin is formed by a conversion of the zymogen plasminogen, which is regulated by plasminogen activators. Two distinct plasminogen activators The two u-PA and PAM producing cell lines showed the highest frequency to form spontaneous lung metastases after subcutaneous inoculation, whereas five of the six cell lines formed lung colonies after intravenous inoculation .In conclusion, u-PA mediated matrix degradation in vitro and production of u-PA and PAI-1 by human melanoma cell lines correlated with their ability to form spontaneous lung metastasis in nude mice. No correlation was found with the ability to form lung colonies after intravenous injection. These findings suggest a role for u-PA and PAI-1 in a relatively early stage of melanoma metastasis.are known, the tissue-type (t-PA),' and the urokinase-type (u-PA) . The activity ofthe activators can be regulated by interactions with specific inhibitors, of which two have been described, type 1(PAI-1) and type 2 (PAI-2) (33, 53) . In addition, u-PA and its proenzyme, pro-u-PA, can be localized at cell surfaces by binding through their growth factor domain to a specific receptor (u-PAR) (2,8,12,41,51,55,56,62) .To study the role of plasminoge...

Vascular density in melanoma xenografts correlates with vascular permeability factor expression but not with metastatic potential

“…Previous studies have shown that BLM and MV3 differ from the other cell lines with respect to factors that influence the metastatic process. They show a strong adherence to extracellular matrix components laminin and collagen types I and IV (Danen et al, 1993, and have a high expression level of the extracellular protease urokinase-type plasminogen activator (uPA) and its inhibitor PAI-I (Quax et al, 1991;Van Muijen et al, 1995). The formation of experimental lung metastasis may be used as an indicator of the metastasizing capacities of a cell line.…”

Ultrasound and microbubble mediated drug delivery: Acoustic pressure as determinant for uptake via membrane pores or endocytosis

“…Human melanoma cells (BLM cells) [21], were grown in culture flasks in a humidified atmosphere with 5% CO 2 at 37°C. The culture medium was Dulbecco's Modified Eagle Medium with Nutrient Mixture F12 (Gibco, Merelbeke, Belgium), supplemented with 10% (v/v) fetal bovine serum (FBS) (Hyclone, Thermo Scientific, MA, USA), 20 U/ml penicillinstreptomycin (Gibco, Merelbeke, Belgium), 2 mM L-glutamine (Gibco, Merelbeke, Belgium) and 10 mM HEPES (4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid) (Sigma-Aldrich, Diegem, Belgium).…”

Contribution of plasminogen activators and their inhibitors to the survival prognosis of patients with Dukes' stage B and C colorectal cancer

“…The plasminogen activators and their inhibitors play a key role in the proteolytic cascade that is responsible for the breakdown of several components of the extracellular matrix, which surrounds the tumour cells. This process results in invasion and subsequently metastasis formation (Dan0 et al, 1985;Saksela, 1985;Vassalli et al, 1991;Ossowski et al, 1991;Quax et al, 1991;Hart, 1992;Schultz et al, 1992;Crowley et al, 1993;Duffy, 1993). We determined several components of the PA system in carcinomatous tissue and adjacent normal mucosa in a subgroup of 136 Dukes' stage B or C colorectal carcinoma patients, and evaluated their prognostic value for overall survival in comparison with several major clinicopathological parameters.…”

“…The activity of plasminogen activators is regulated by the plasminogen activator inhibitors PAI-I and PAI-2. In vitro experiments with human carcinoma cell lines have shown that invasion and metastasis are correlated with enhanced expression of u-PA, and that these processes could be inhibited by antibodies against u-PA and by blocking of the u-PA receptor (Ossowski et al, 1991;Quax et al 1991;Crowley, 1993).…”