Transforming growth factor-beta regulates mammary carcinoma cell survival and interaction with the adjacent microenvironment.
Transforming growth factor (TGF)-beta signaling has been associated with early tumor suppression and late tumor progression; however, many of the mechanisms that mediate these processes are not known. Using Cre/LoxP technology, with the whey acidic protein promoter driving transgenic expression of Cre recombinase (WAP-Cre), we have now ablated the type II TGF-beta receptor (T beta RII) expression specifically within mouse mammary alveolar progenitors. Transgenic expression of the polyoma virus middle T antigen, under control of the mouse mammary tumor virus enhancer/promoter, was used to produce mammary tumors in the absence or presence of Cre (T beta RII((fl/fl);PY) and T beta RII((fl/fl);PY;WC), respectively). The loss of TGF-beta signaling significantly decreased tumor latency and increased the rate of pulmonary metastasis. The loss of TGF-beta signaling was significantly correlated with increased tumor size and enhanced carcinoma cell survival. In addition, we observed significant differences in stromal fibrovascular abundance and composition accompanied by increased recruitment of F4/80(+) cell populations in T beta RII((fl/fl);PY;WC) mice when compared with T beta RII((fl/fl);PY) controls. The recruitment of F4/80(+) cells correlated with increased expression of known inflammatory genes including Cxcl1, Cxcl5, and Ptgs2 (cyclooxygenase-2). Notably, we also identified an enriched K5(+) dNp63(+) cell population in primary T beta RII((fl/fl);PY;WC) tumors and corresponding pulmonary metastases, suggesting that loss of TGF-beta signaling in this subset of carcinoma cells can contribute to metastasis. Together, our current results indicate that loss of TGF-beta signaling in mammary alveolar progenitors may affect tumor initiation, progression, and metastasis through regulation of both intrinsic cell signaling and adjacent stromal-epithelial interactions in vivo.
Bierie
Brian
B
Department of Cancer Biology, Vanderbilt University, Nashville, TN 37232-6838, USA.
Stover
Daniel G
DG
Abel
Ty W
TW
Chytil
Anna
A
Gorska
Agnieszka E
AE
Aakre
Mary
M
Forrester
Elizabeth
E
Yang
Li
L
Wagner
Kay-Uwe
KU
Moses
Harold L
HL
D000818:Animals; D001854:Bone Marrow Cells / Q000378:metabolism / Q000473:pathology; D047688:Breast Cyst / Q000378:metabolism / Q000473:pathology; D002454:Cell Differentiation / Q000502:physiology; D002470:Cell Survival / Q000502:physiology; D018450:Disease Progression; D006965:Hyperplasia / Q000378:metabolism / Q000473:pathology; D008175:Lung Neoplasms / Q000378:metabolism / Q000556:secondary; D008325:Mammary Neoplasms, Experimental / Q000378:metabolism* / Q000473:pathology*; D051379:Mice; D014411:Neoplastic Stem Cells / Q000378:metabolism / Q000473:pathology; D011230:Precancerous Conditions / Q000378:metabolism / Q000473:pathology; D017346:Protein Serine-Threonine Kinases / Q000172:deficiency / Q000378:metabolism; D000077294:Receptor, Transforming Growth Factor-beta Type II; D018125:Receptors, Transforming Growth Factor beta / Q000172:deficiency / Q000378:metabolism; D015398:Signal Transduction; D017154:Stromal Cells / Q000378:metabolism / Q000473:pathology; D016212:Transforming Growth Factor beta / Q000378:metabolism*
D018125:Receptors, Transforming Growth Factor beta; D016212:Transforming Growth Factor beta; D017346:Protein Serine-Threonine Kinases; D000077294:Receptor, Transforming Growth Factor-beta Type II