Introduction of mutant p53 into a wild-type p53-expressing glioma cell line confers sensitivity to Ad-p53-induced apoptosis.
Transient expression of the tumor suppressor gene p53 via adenoviral-mediated gene transfer induces apoptosis in glioma cells expressing mutant p53, while causing cell cycle arrest in cells with wild-type p53. To determine whether a change in p53 status of a wild-type p53-expressing cell line such as U-87 MG would alter its apoptotic resistant phenotype in response to Ad-p53 infection, we generated cell lines U-87-175.4 and U-87-175.13 via retroviral-mediated gene transfer of the p53 (175H) mutant into the U-87 MG parental line. Control cell lines U-87-Lux.6 and U-87-Lux.8 were also generated and express the reporter gene luciferase. Both U-87-175.4 and U-87-175.13, but not control cell lines, exhibited morphology characteristic of apoptosis after Ad-p53 infection. Furthermore, expression of other p53 mutants (248W, 273H) in U-87 MG also sensitized cells to Ad-p53-induced apoptosis. Apoptosis was confirmed by TUNEL and cell cycle analysis. Several p53 response genes were examined in cells infected with Ad-p53, and among these, BCL2, p21WAF1/CIP1, CPP32/caspase 3, and PARP showed differences in expression between U87-175 and U87-Lux cell lines. Taken together, our data demonstrate that the introduction of p53 mutants in U-87 MG promotes an apoptotic response in association with adenoviral-mediated wild-type p53 gene transfer. These results underscore the importance of glioma p53 genotype for predicting tumor response to p53-based gene therapy.
Cerrato
J A
JA
Department of Neuro-Oncology, University of Texas M.D. Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX 77030, USA.
Yung
W K
WK
Liu
T J
TJ
D000256:Adenoviridae / Q000235:genetics*; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology; D020169:Caspases / Q000378:metabolism; D015870:Gene Expression / Q000502:physiology; D005814:Genes, Viral; D016158:Genes, p53 / Q000235:genetics*; D005910:Glioma / Q000235:genetics*; D009154:Mutation; D012680:Sensitivity and Specificity; D014407:Tumor Cells, Cultured / Q000821:virology
D020169:Caspases