To study the combined potential of wild-type p53 gene transfer and administration of cisplatin for the treatment of glioblastoma multiforme, the authors used the 9L rat glioblastoma cell line, which expresses a mutant p53.
Stable expression of wild-type p53 in 9L cells was achieved by transfection of the cells with a wild-type p53-expressing plasmid (pCEP4p53). The resultant cell line, 9LpCEP4p53, was found to be more sensitive to cisplatin treatment in vitro than control (9LpCEP4) cells. The in vitro growth rates of control cells and wild-type p53-modified cells were similar in the absence of cisplatin. Fischer 344 rats were implanted intracerebrally with 9LpCEP4p53 cells and intraperitoneally administered 4 mg/kg cisplatin weekly for 7 weeks. These animals survived significantly longer than animals that were implanted with 9LpCEP4p53 cells but were given no cisplatin treatment. In contrast, concurrent cisplatin treatment provided no benefit for animals implanted with 9LpCEP4 cells. Tumors that developed in animals that had been implanted with 9LpCEP4p53 cells and treated with cisplatin had lost expression of wild-type p53, indicating a correlation between expression of wild-type p53 and cisplatin sensitivity in vivo.
The findings of this study suggest that p53-based gene therapy in combination with cisplatin-based chemotherapy may be superior to single-modality treatment in dealing with glioblastoma multiforme.
"The C6 rat glioma cell line (ATCC CCL-107, p53wt/wt [35,36], p16INK4A-/- , p19ARF-/- ) was grown in Dulbecco's Modified Eagle Medium (DMEM, Gibco-BRL, Rockville, MD, USA) with 10% fetal bovine serum (FBS) (CultiLab, Campinas, SP, Brazil). "
[Show abstract][Hide abstract] ABSTRACT: Background
The p16INK4A gene product halts cell proliferation by preventing phosphorylation of the Rb protein. The p16INK4a gene is often deleted in human glioblastoma multiforme, contributing to unchecked Rb phosphorylation and rapid cell division. We show here that transduction of the human p16INK4a cDNA using the pCL retroviral system is an efficient means of stopping the proliferation of the rat-derrived glioma cell line, C6, both in tissue culture and in an animal model. C6 cells were transduced with pCL retrovirus encoding the p16INK4a, p53, or Rb genes. These cells were analyzed by a colony formation assay. Expression of p16INK4a was confirmed by immunohistochemistry and Western blot analysis. The altered morphology of the p16-expressing cells was further characterized by the senescence-associated β-galactosidase assay. C6 cells infected ex vivo were implanted by stereotaxic injection in order to assess tumor formation.
The p16INK4a gene arrested C6 cells more efficiently than either p53 or Rb. Continued studies with the p16INK4a gene revealed that a large portion of infected cells expressed the p16INK4a protein and the morphology of these cells was altered. The enlarged, flat, and bi-polar shape indicated a senescence-like state, confirmed by the senescence-associated β-galactosidase assay. The animal model revealed that cells infected with the pCLp16 virus did not form tumors.
Our results show that retrovirus mediated transfer of p16INK4a halts glioma formation in a rat model. These results corroborate the idea that retrovirus-mediated transfer of the p16INK4a gene may be an effective means to arrest human glioma and glioblastoma.
Cancer Cell International 05/2002; 2(1):2. DOI:10.1186/1475-2867-2-2 · 2.77 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Cancer still represents a disease of high incidence and is therefore one major target for gene therapy approaches. Gene therapy
for cancer implies that ideally selective tumor cell killing or inhibition of tumor cell growth can be achieved using nucleic
acids (DNA and RNA) as the therapeutic agent. Therefore, the majority of cancer gene therapy strategies introduce foreign
genes into tumor cells which aim at the immunological recognition and destruction, the direct killing of the target cells
or the interference with tumor growth. To achieve this goal for gene therapy of cancer, a broad variety of therapeutic genes
are currently under investigation in preclinical and in clinical studies. These genes are of very different origin and of
different mechanisms of action, such as human cytokine genes, genes coding for immunstimulatory molecules/antigens, genes
encoding bacterial or viral prodrug-activating enzymes (suicide genes), tumor suppressor genes, or multidrug resistance genes.
[Show abstract][Hide abstract] ABSTRACT: Gliomas are the most common tumors originating in the brain. Most gliomas are malignant. They are the cause of death in almost
all patients who harbor them. Even tumors that are originally relatively benign histologically, usually evolve into more malignant
tumors and prove life-threatening. Current treatments for malignant gliomas include surgery,radiotherapy, chemotherapy, and
immunotherapy, either singly or in combination. Transient control is possible in many cases, yet recurrence is the rule.Possible
reasons for tumor recurrence include failure to extirpate all infiltrating tumor cells, tumor resistance to chemotherapy and
radiotherapy, and decreased immune response in the brain.
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