TGF-beta1 and TGF-beta2 strongly enhance the secretion of plasminogen activator inhibitor-1 and matrix metalloproteinase-9 of the human prostate cancer cell line PC-3.
BACKGROUND
Recently it was demonstrated that transforming growth factor beta 2 (TGF-beta 2) is the predominant TGF-beta isoform in the human prostate. However, with the human prostatic cancer cells PC-3 mostly effects of TGF-beta 1 were investigated. This study aimed to analyze the effects of TGF-beta 2 on its own secretion, on the secretion of plasminogen activator inhibitor-1 (PAI-1), and the matrix metalloproteinases (MMP)-2 and MMP-9 in comparison to stimulations with TGF-beta 1.


METHODS
PC-3 cells were cultured with and without TGF-beta 1 and TGF-beta 2 to analyze autostimulation and their effects on protein secretion. ELISAs for TGF-beta 1, TGF-beta 2, TGF-beta 3, PAI-1, MMP-2 and MMP-9 were used to analyze protein levels in the supernatant. Cell proliferation was determined with a proliferation assay.


RESULTS
A dose-dependent and significant suppression of cell proliferation with TGF-beta 1 (p < 0.05) and TGF-beta 2 (p < 0.05) was observed. PC-3 cells secrete higher amounts of total TGF-beta 2 compared to total TGF-beta 1. Only for TGF-beta 2, we found the active isoform. In contrast, the secretion of TGF-beta 3 was not detectable. Additionally, we observed a strong and significant increase in the secretion of MMP-9 and PAI-1 after stimulations with TGF-beta 1 and TGF-beta 2, respectively. However, no protein levels of MMP-2 were detectable.


CONCLUSIONS
Our experiments revealed that TGF-beta 2 is the predominant TGF-beta isoform in PC-3 cells. Furthermore, a strong effect of TGF-beta 1 and TGF-beta 2 on the secretion of MMP-9 and PAI-1 was found. Thus, PC-3 cells not only secrete TGF-beta 1 and TGF-beta 2 but also respond to stimulations with the TGF-beta isoforms. The interesting observation that only TGF-beta 2 is activated points to different mechanisms of proteolytic activation of the diverse TGF-beta isoforms.
Konrad
Lutz
L
Department of Urology, Medical Faculty, 35033 Marburg, Germany. Lutz.Konrad@gyn.med.uni-giessen.de
Scheiber
Jonas A
JA
Schwarz
Lena
L
Schrader
Andres J
AJ
Hofmann
Rainer
R
D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D017395:Plasminogen Activator Inhibitor 1 / Q000378:metabolism*; D011471:Prostatic Neoplasms / Q000378:metabolism; D053773:Transforming Growth Factor beta1 / Q000378:metabolism* / Q000494:pharmacology*; D053781:Transforming Growth Factor beta2 / Q000378:metabolism* / Q000494:pharmacology*
D017395:Plasminogen Activator Inhibitor 1; D053773:Transforming Growth Factor beta1; D053781:Transforming Growth Factor beta2; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9