Regulation of plasminogen activator activity in transitional carcinoma cell lines by wound site growth factors.

Abstract

The effect of two growth factors ellicited in response to surgical woundings (transforming growth factor alpha [TGF alpha] and beta 1) on the regulation of cellular plasminogen activator activity (PAA) in human transitional carcinoma cell lines, with differing baseline PAA (253J--high; 647V--low), was studied. mRNA transcript levels of PA regulatory proteins in both cell lines were responsive to TGF alpha and TGF beta 1. However, both the magnitude and nature of the response differed markedly between the two lines. TGF alpha increased uPA transcript levels in both cell lines in a dose-dependent fashion. In the case of uPA receptor, exogenous TGF alpha concentrations which increased receptor levels over fivefold in the 253J line had no effect on this transcript in the 647V line. This differential responsiveness was even more pronounced for TGF beta 1. TGF beta 1 appeared to increase uPA transcript in the 253J line in a dose dependent manner while decreasing transcript levels in the 647V line. uPAr mRNA in 253J cells increased over a 19-fold range in response to TGF beta 1 while this same transcript was decreased 14-fold in 647V cells. The most pronounced effect of TGF beta 1 was seen on PAI1 transcript levels in the 253J line. This transcript increased in a concentration dependent fashion from non-detectable levels. These findings demonstrate that growth factors ellicited by surgical wounding may alter the biology of neoplastic cells. Both the growth factor milieu, and intrinsic cellular regulatory mechanism, appear important in determing net PAA in transitional carcinoma cell lines.