Effect of transforming growth factor-beta on plasminogen activator production of cultured human uveal melanoma cells.
OBJECTIVE
Human uveal melanoma cells have been shown to produce plasminogen activator (PA), an enzyme which can enhance tumor metastasis by promoting degradation of extracellular matrix. This study used cultured human uveal melanoma cells to determine whether the PA production of uveal melanoma cells could be modulated by transforming growth factor-beta2 (TGF-beta2), a mitogen present in the uvea.


METHODS
Five different cell lines of human uveal melanoma of differing cellular morphology (2 spindle, 2 epithelioid, 1 mixed) derived from tumors from different locations in the eye (3 choroidal, 1 ciliochoroidal, 1 orbital) were grown in serum-free media, in the presence or absence of TGF-beta2 (1ng/ml to 100ng/ml). After 24 hrs, the conditioned media were collected and quantitated for PA activity by measuring the radial diffusion in fibrin-agarose clot and for total PA concentration using an enzyme-linked immunoassay.


RESULTS
Among the cell lines studied, all produced PA. Cell lines derived from intraocular tumors secreted tissue-type PA (tPA), and TGF-beta2 stimulated tPA activity and secretion of cell lines containing epithelioid cells but had no effect on spindle cells. In contrast, tumor cells isolated from an orbital tumor secreted urokinase (uPA), activity and secretion of which was inhibited by TGF-beta2.


CONCLUSIONS
We conclude that cultured human uveal melanoma cells produce either tPA or uPA, and TGF-beta2 can have a variable effect on PA production of these cells.
Park
S S
SS
Department of Ophthalmology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75235-9057, USA.
Li
L
L
Korn
T S
TS
Mitra
M M
MM
Niederkorn
J Y
JY
D017077:Culture Media, Conditioned; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism; D006801:Humans; D008545:Melanoma / Q000378:metabolism*; D017395:Plasminogen Activator Inhibitor 1 / Q000096:biosynthesis; D010959:Tissue Plasminogen Activator / Q000096:biosynthesis*; D016212:Transforming Growth Factor beta / Q000494:pharmacology*; D014407:Tumor Cells, Cultured; D014568:Urokinase-Type Plasminogen Activator / Q000096:biosynthesis*; D014604:Uveal Neoplasms / Q000378:metabolism*
D017077:Culture Media, Conditioned; D017395:Plasminogen Activator Inhibitor 1; D016212:Transforming Growth Factor beta; D016222:Fibroblast Growth Factor 2; D010959:Tissue Plasminogen Activator; D014568:Urokinase-Type Plasminogen Activator