Enhanced jun gene expression is an early genomic response to transforming growth factor beta stimulation

1989 ◽  
Vol 9 (3) ◽  
pp. 1255-1262
Author(s):  
L Pertovaara ◽  
L Sistonen ◽  
T J Bos ◽  
P K Vogt ◽  
J Keski-Oja ◽  
...  

Transforming growth factor beta (TGF beta) is a multifunctional polypeptide that regulates proliferation, differentiation, and other functions of many cell types. The pathway of TGF beta signal transduction in cells is unknown. We report here that an early effect of TGF beta is an enhancement of the expression of two genes encoding serum- and phorbol ester tumor promoter-regulated transcription factors: the junB gene and the c-jun proto-oncogene, respectively. This stimulation was observed in human lung adenocarcinoma A549 cells which were growth inhibited by TGF beta, AKR-2B mouse embryo fibroblasts which were growth stimulated by TGF beta, and K562 human erythroleukemia cells, which were not appreciably affected in their growth by TGF beta. The increase in jun mRNA occurred with picomolar TGF beta concentrations within 1 h of TGF beta stimulation, reached a peak between 1 and 5 h in different cells, and declined gradually to base-line levels. This mRNA response was followed by a large increase in the biosynthesis of the c-jun protein (AP-1), as shown by metabolic labeling and immunoprecipitation analysis. However, differential and cell type-specific regulation appeared to determine the timing and magnitude of the response of each jun gene in a given cell. In AKR-2B and NIH 3T3 cells, only junB was induced by TGF beta, evidently in a protein synthesis-independent fashion. The junB response to TGF beta was maintained in c-Ha-ras and neu oncogene-transformed cells. Thus, one of the earliest genomic responses to TGF beta may involve nuclear signal transduction and amplification by the junB and c-jun transcription factors in concert with c-fos, which is also induced. The differential activation of the jun genes may explain some of the pleiotropic effects of TGF beta.

1989 ◽  
Vol 9 (3) ◽  
pp. 1255-1262 ◽  
Author(s):  
L Pertovaara ◽  
L Sistonen ◽  
T J Bos ◽  
P K Vogt ◽  
J Keski-Oja ◽  
...  

Transforming growth factor beta (TGF beta) is a multifunctional polypeptide that regulates proliferation, differentiation, and other functions of many cell types. The pathway of TGF beta signal transduction in cells is unknown. We report here that an early effect of TGF beta is an enhancement of the expression of two genes encoding serum- and phorbol ester tumor promoter-regulated transcription factors: the junB gene and the c-jun proto-oncogene, respectively. This stimulation was observed in human lung adenocarcinoma A549 cells which were growth inhibited by TGF beta, AKR-2B mouse embryo fibroblasts which were growth stimulated by TGF beta, and K562 human erythroleukemia cells, which were not appreciably affected in their growth by TGF beta. The increase in jun mRNA occurred with picomolar TGF beta concentrations within 1 h of TGF beta stimulation, reached a peak between 1 and 5 h in different cells, and declined gradually to base-line levels. This mRNA response was followed by a large increase in the biosynthesis of the c-jun protein (AP-1), as shown by metabolic labeling and immunoprecipitation analysis. However, differential and cell type-specific regulation appeared to determine the timing and magnitude of the response of each jun gene in a given cell. In AKR-2B and NIH 3T3 cells, only junB was induced by TGF beta, evidently in a protein synthesis-independent fashion. The junB response to TGF beta was maintained in c-Ha-ras and neu oncogene-transformed cells. Thus, one of the earliest genomic responses to TGF beta may involve nuclear signal transduction and amplification by the junB and c-jun transcription factors in concert with c-fos, which is also induced. The differential activation of the jun genes may explain some of the pleiotropic effects of TGF beta.


1988 ◽  
Vol 106 (2) ◽  
pp. 451-459 ◽  
Author(s):  
J Keski-Oja ◽  
F Blasi ◽  
EB Leof ◽  
HL Moses

Transforming growth factor-beta (TGF beta) is a regulator of cellular proliferation which can alter the proteolytic activity of cultured cells by enhancing the secretion of endothelial type plasminogen activator inhibitor and affecting the secretion of plasminogen activators (PAs) in cultured fibroblastic cells. We used the TGF beta-responsive malignant human lung adenocarcinoma cell line A549 to study the relationships between the known TGF beta-induced growth inhibition and the effects of TGF beta on the secretion of PA activity by A549 cells. PA activity was quantitated by caseinolysis assays, and characterized by urokinase mRNA analysis, immunoprecipitation, and zymography assays. PA-inhibitor production was observed in autoradiograms of SDS-polyacrylamide gels and reverse zymography assays. It was found that TGF beta enhanced the production of PA activity by these cells, in accordance with an enhancement of urokinase mRNA levels. A concomitant stimulation of type 1 PA-inhibitor production was also observed in A549 cells in response to TGF beta. In contrast to the observations of A549 cells, TGF beta caused a decrease in the expression of both urokinase and the tissue-type PA mRNA in human embryonic WI-38 lung fibroblasts indicating opposite regulation of the expression of PAs in these cells. The results suggest that TGF beta may play a role in the regulation of the invasive, proteolytically active phenotype of certain lung carcinoma cells.


1990 ◽  
Vol 265 (2) ◽  
pp. 1089-1093 ◽  
Author(s):  
P Kondaiah ◽  
M J Sands ◽  
J M Smith ◽  
A Fields ◽  
A B Roberts ◽  
...  

1988 ◽  
Vol 8 (5) ◽  
pp. 2229-2232 ◽  
Author(s):  
A M Brunner ◽  
L E Gentry ◽  
J A Cooper ◽  
A F Purchio

Analyses of cDNA clones coding for simian type 1 transforming growth factor beta (TGF-beta 1) suggest that there are three potential sites for N-linked glycosylation located in the amino terminus of the precursor region. Analysis of [3H]glucosamine-labeled serum-free supernatants from a line of Chinese hamster ovary cells which secrete high levels of recombinant TGF-beta 1 indicate that the TGF-beta 1 precursor, but not the mature form, is glycosylated. Digestion with neuraminidase resulted in a shift in migration of the two TGF-beta 1 precursor bands, which suggests that they contain sialic acid residues. Endoglycosidase H had no noticeable effect. Treatment with N-glycanase produced two faster-migrating sharp bands, the largest of which had a molecular weight of 39 kilodaltons. TGF-beta 1-specific transcripts produced by SP6 polymerase programmed the synthesis of a 42-kilodalton polypeptide which, we suggest, is the unmodified protein backbone of the precursor. Labeling with 32Pi showed that the TGF-beta 1 precursor was phosphorylated in the amino portion of the molecule.


1991 ◽  
Vol 173 (3) ◽  
pp. 589-597 ◽  
Author(s):  
G Poli ◽  
A L Kinter ◽  
J S Justement ◽  
P Bressler ◽  
J H Kehrl ◽  
...  

The pleiotropic immunoregulatory cytokine transforming growth factor beta (TGF-beta) potently suppresses production of the human immunodeficiency virus (HIV), the causative agent of the acquired immunodeficiency syndrome, in the chronically infected promonocytic cell line U1. TGF-beta significantly (50-90%) inhibited HIV reverse transcriptase production and synthesis of viral proteins in U1 cells stimulated with phorbol myristate acetate (PMA) or interleukin 6 (IL-6). Furthermore, TGF-beta suppressed PMA induction of HIV transcription in U1 cells. In contrast, TGF-beta did not significantly affect the expression of HIV induced by tumor necrosis factor alpha (TNF-alpha). These suppressive effects were not mediated via the induction of interferon alpha (IFN-alpha). TGF-beta also suppressed HIV replication in primary monocyte-derived macrophages infected in vitro, both in the absence of exogenous cytokines and in IL-6-stimulated cultures. In contrast, no significant effects of TGF-beta were observed in either a chronically infected T cell line (ACH-2) or in primary T cell blasts infected in vitro. Therefore, TGF-beta may play a potentially important role as a negative regulator of HIV expression in infected monocytes or tissue macrophages in infected individuals.


1991 ◽  
Vol 11 (10) ◽  
pp. 4952-4958
Author(s):  
A Zentella ◽  
F M Weis ◽  
D A Ralph ◽  
M Laiho ◽  
J Massagué

The growth-suppressive function of the retinoblastoma susceptibility gene product, RB, has been implicated in the mediation of growth inhibition and negative regulation of certain proliferation related genes by transforming growth factor-beta 1 (TGF-beta 1). Early gene responses to TGF-beta 1 were examined in order to determine their dependence on the cell cycle and on the growth-suppressive function of RB. TGF-beta 1, which rapidly elevates the steady-state level of junB and PAI-1 mRNAs and decreases that of c-myc mRNA, induces these responses in S-phase populations of Mv1Lu lung epithelial cells containing RB in a phosphorylated state. Since in this state RB is presumed to lack growth-suppressive activity, the response to TGF-beta 1 was also examined in DU145 human prostate carcinoma cells whose mutant RB product lacks growth-suppressive function. In these cells, TGF-beta 1 also decreases c-myc expression at the transcription initiation level. These results suggests that the c-myc, junB, and PAI-1 responses to TGF-beta 1 are not restricted to the G1 phase of the cell cycle and that down-regulation of c-myc expression by TGF-beta 1 can occur through a mechanism independent from the growth-suppressive function of RB.


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