Mammary Neoplasia in Mouse Mammary Tumor Virus-Transforming Growth Factor α Transgenic Mice

Author(s):  
Robert J. Coffey ◽  
Peter J. Dempsey
1996 ◽  
Vol 16 (10) ◽  
pp. 5726-5736 ◽  
Author(s):  
W J Muller ◽  
C L Arteaga ◽  
S K Muthuswamy ◽  
P M Siegel ◽  
M A Webster ◽  
...  

Transgenic mice expressing either the neu proto-oncogene or transforming growth factor (TGF-alpha) in the mammary epithelium develop spontaneous focal mammary tumors that occur after a long latency. Since the epidermal growth factor receptor (EGFR) and Neu are capable of forming heterodimers that are responsive to EGFR ligands such as TGF-alpha, we examined whether coexpression of TGF-alpha and Neu in mammary epithelium could cooperate to accelerate the onset of mammary tumors. To test this hypothesis, we interbred separate transgenic strains harboring either a mouse mammary tumor virus/TGF-alpha or a mouse mammary tumor virus/neu transgene to generate bitransgenic mice that coexpress TGF-alpha and neu in the mammary epithelium. Female mice coexpressing TGF-alpha and neu developed multifocal mammary tumors which arose after a significantly shorter latency period than either parental strain alone. The development of these mammary tumors was correlated with the tyrosine phosphorylation of Neu and the recruitment of c-Src to the Neu complex. Immunoprecipitation and immunoblot analyses with EGFR- and Neu-specific antisera, however, failed to detect physical complexes of these two receptors. Taken together, these observations suggest that Neu and TGF-alpha cooperate in mammary tumorigenesis through a mechanism involving Neu and EGFR transactivation.


2004 ◽  
Vol 78 (5) ◽  
pp. 2201-2211 ◽  
Author(s):  
Koldo Aurrekoetxea-Hernández ◽  
Elena Buetti

ABSTRACT Tissue-specific transcription is advantageously investigated by using viral promoters, which are selected for compact regulatory elements. Mouse mammary tumor virus (MMTV) has adapted to specialized cell types and targets initially B lymphocytes. We previously showed that, in B-cell lines, glucocorticoid-induced MMTV transcription requires an ETS family factor, GA-binding protein (GABP), bound in tandem to the MMTV DNA next to the glucocorticoid receptor (GR). We now report that transforming growth factor β (TGF-β) superinduces this response up to 10-fold through binding of its effectors, Smads, between the GABP-binding motifs. The basal level was unaffected. The TGF-β-glucocorticoid cooperation also depended on GR and GABP binding, was transferable to another promoter, and occurred both with transiently transfected and with integrated templates. Smad3 associated in vitro with GR, with GABPα (via the MH2 domain), and with GABPβ, Smad4 only with GABPα. Interactions of Smad3 with GABP (when coexpressed or endogenous to B cells) were shown by coprecipitation and by mammalian two-hybrid assay. This composite DNA element integrates three signaling pathways deriving from TGF-β, glucocorticoid hormones, and a unique ETS factor, and may allow MMTV to exploit factors from the milk. It may as well indicate novel possibilities for cellular regulatory networks.


2006 ◽  
Vol 168 (4) ◽  
pp. 1365-1374 ◽  
Author(s):  
Lisa M. Arendt ◽  
Teresa A. Rose-Hellekant ◽  
Eric P. Sandgren ◽  
Linda A. Schuler

2006 ◽  
Vol 169 (5) ◽  
pp. 1821-1832 ◽  
Author(s):  
Teresa A. Rose-Hellekant ◽  
Kristin M. Wentworth ◽  
Sarah Nikolai ◽  
Donald W. Kundel ◽  
Eric P. Sandgren

1988 ◽  
Vol 8 (1) ◽  
pp. 473-479
Author(s):  
T A Stewart ◽  
P G Hollingshead ◽  
S L Pitts

Transcription initiated within the mouse mammary tumor virus (MTV) long terminal repeat (LTR) is regulated by glucocorticoids, androgens, and estrogen. However, expression of the virus in vivo and transcription of MTV LTR fusion genes in transgenic mice are not readily interpretable solely in terms of the influence of these hormones. To investigate whether there is a regulatory role for sequences within the LTR but outside the region known to be responsible for glucocorticoid induction, we have produced transgenic mice carrying genes in which various regions of the LTR have been linked to the human growth hormone gene. Analysis of expression of the fusion genes in these transgenic mice has demonstrated that the 5' end of the LTR can profoundly influence transcription initiated within the MTV LTR.


2001 ◽  
Vol 281 (5) ◽  
pp. L1088-L1094 ◽  
Author(s):  
William D. Hardie ◽  
Alyssa Piljan-Gentle ◽  
Michelle R. Dunlavy ◽  
Machiko Ikegami ◽  
Thomas R. Korfhagen

Transgenic mice overexpressing human transforming growth factor-α (TGF-α) develop emphysema and fibrosis during postnatal alveologenesis. To assess dose-related pulmonary alterations, four distinct transgenic lines expressing different amounts of TGF-α in the distal lung under control of the surfactant protein C (SP-C) promoter were characterized. Mean lung homogenate TGF-α levels ranged from 388 ± 40 pg/ml in the lowest expressing line to 1,247 ± 33 pg/ml in the highest expressing line. Histological assessment demonstrated progressive alveolar airspace size changes that were more severe in the higher expressing TGF-α lines. Pleural and parenchymal fibrosis were only detected in the highest expressing line ( line 28), and increasing terminal airspace area was associated with increasing TGF-α expression. Hysteresis on pressure-volume curves was significantly reduced in line 28 mice compared with other lines of mice. There were no differences in bronchoalveolar lavage fluid cell count or differential that would indicate any evidence of lung inflammation among all transgenic lines. Proliferating cells were increased in line 28 without alterations of numbers of type II cells. We conclude that TGF-α lung remodeling in transgenic mice is dose dependent and is independent of pulmonary inflammation.


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