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24 results on '"Ostrow, Peter T."'

13. Increased expression of TGF-β1 reduces tumor growth of human U-87 Glioblastoma Cells in vivo.

Author

Jen-Jung Pan, Wei-Jen Chang, Barone, Tara A., Plunkett, Robert J., Ostrow, Peter T., and Greenberg, Steven J.

Subjects
TRANSFORMING growth factors-beta, GLIOMAS, TUMOR growth, TUMORS, TRANSFORMING growth factors
Abstract

The role that transforming growth factor β1 (TGF-β1) plays in influencing growth of glioma cells is somewhat controversial. To further understand the potential growth-regulatory effects of TGF-β1,we constructed an animal astroglial tumor model by injecting either wild-type or virally transduced human U-87 glioblastoma cells into nude rat brains. Wild type U-87 cells produced very low amounts of TGF-β1 and were highly tumorigenic. In contrast, U-87 cells transduced to express high levels of TGF-β1 showed reduced tumor size in vivo, in a dose-dependent manner. This reduction in tumor size was not due to either decreased vascularity or increased apoptosis. To test whether TGF-β1 overproduction inhibited tumor growth through an autocrine mechanism, the highest TGF-β1 producing cells were then double transduced with a vector expressing the kinase-truncated type II TGF-β receptor. Cells expressing high levels of truncated TGF-β receptor were less sensitive to TGF-β1 mediated growth inhibition in vitro and produced more aggressive tumors in vivo. The data suggest that the degree of tumorigenicity of the U-87 high-grade glioblastoma cell line may be associated with correspondingly low level of production of TGF-β1. These results also would tend to support the possibility that TGF-β1 may be useful in treating some high-grade gliomas. [ABSTRACT FROM AUTHOR]

Published
2006
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14. CT Atlas of the Dog Brain.

Author

Kaufman, Howard H., Cohen, Gerald, Glass, T. Franklin, Huchton, John D., Pruessner, Janice L., Ostrow, Peter T., Andia-Waltenbaugh, Ana-Marie, and Dujovny, Manuel

Published
1981
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24. Correlation of Endothelin-1 and Transforming Growth Factor {beta}1 with Malignancy and Vascularity in Human Gliomas

Author

Stiles, Jeffrey D., Ostrow, Peter T., Balos, Lucia L., Greenberg, Steven J., Plunkett, Robert, Grand, Walter, and Heffner, Reid R.

Abstract

Because the prominent neovascularization characteristic of high grade primary brain tumors is composed mostly of vascular smooth muscle cells (VSMC), we studied the expression of the potent smooth muscle mitogen endothelin-1 (ET-1) and one of its secretagogues, transforming growth factor β1 (TGF-β1) in a series of astrocytic tumors. TGF-β1 is also of interest due to its known activity as an angiogenic factor. Using immunohistochemical methods, we examined 30 surgical cases: 10 glioblastoma multiforme, 10 anaplastic astrocytomas, and 10 low-grade astrocytomas. Using a monoclonal antibody to TGF-β1 and a polyclonal antibody to ET-1, we detected both growth factors in all cases of glioblastoma examined. In cases of anaplastic astrocytoma, 4 tumors were positive for both factors; 2 contained only ET-1; 2 contained only TGF-β1; and 2 exhibited no tumor cell immunoreacdvity for either factor. In low-grade astrocytoma, 4 of 10 tumors showed weak ET-1 immunoreactivity; 2 of those contained TGF-β1 immunopositive tumor astrocytes; 6 tumors were negative for both factors. In all tumors that expressed both factors, serial sections showed that regions of ET-1 immunopositivity also tended to be positive for TGF-β1. Endothelial cells within all tumors were positive for ET-1. ET-1 and TGF-β1 are present in human astrocytomas and their expression correlates with tumor vascularity and malignancy. These results suggest roles for both ET-1 and TGF-β1 in the growth and progressive angiogenesis of the human glioma.

Published
1997
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