Conditional expression of the tumor suppressor p16 in a heterotopic glioblastoma model results in loss of pRB expression.

Details

Serval ID
serval:BIB_1DC041FA059B
Type
Article: article from journal or magazin.
Collection
Publications
Title
Conditional expression of the tumor suppressor p16 in a heterotopic glioblastoma model results in loss of pRB expression.
Journal
Journal of Neuro-Oncology
Author(s)
Simon M., Simon C., Köster G., Hans V.H., Schramm J.
ISSN
0167-594X (Print)
ISSN-L
0167-594X
Publication state
Published
Issued date
2002
Volume
60
Number
1
Pages
1-12
Language
english
Notes
Publication types: Journal Article ; Research Support, Non-U.S. Gov'tPublication Status: ppublish
Abstract
We have expressed the tumor suppressor p16 under the control of a tetracycline-sensitive promoter in two human glioblastoma cell lines which do not contain endogenous p16. Ectopic p16 expression led to a stable but reversible G1 phase cell cycle arrest, reduced the growth of both cell lines in cell culture, and almost abolished their in vitro tumorigenicity. U-87MG-tTA-p16 glioblastoma cells consistently formed tumors after subcutaneous injection into the flanks of nude mice. p16 expression in these tumors was strictly dependent on the presence or absence of tetracycline in the drinking water. Ectopic p16 reduced the tumor take rate (in vivo tumorigenicity) of U-87MG-tTA-p16 cells from 18/20 (90%) to 5 tumors/12 (42%) tumor cell injections. p16 positive and negative tumors differed with respect to their Ki67 labeling indices (34 +/- 4% vs. 52 +/- 6% , P < 0.001, student's t-test). These data are consistent with an in vitro and in vivo glioma suppressor role for p16. Interestingly, we observed a secondary reduction of pRB expression in tumors (and cell cultures) exposed to p16 for > or = 10 (6) days. pRB is p16's major downstream target. Hence, this finding might explain, why p16 expression neither significantly affected the morphology nor led to a reduction of size or growth rate of the tumors. Loss of pRB following p16 expression might severely limit the potential benefit of p16 gene therapy for glioblastoma.
Keywords
Animals, Cell Cycle/genetics, Cell Division/genetics, Fungal Proteins, Genes, p16/physiology, Glioblastoma/genetics, Glioblastoma/metabolism, Humans, Mice, Mice, Nude, Neoplasm Transplantation, Serine Endopeptidases/biosynthesis, Tetracycline, Transfection, Tumor Cells, Cultured
Pubmed
Web of science
Create date
21/01/2013 15:11
Last modification date
03/03/2018 14:34
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