Chimeric tumor suppressor 1, a p53-derived chimeric tumor suppressor gene, kills p53 mutant and p53 wild-type glioma cells in synergy with irradiation and CD95 ligand.
Adenoviral chimeric tumor suppressor 1 (CTS1) gene transfer was evaluated as a novel approach of somatic gene therapy for malignant glioma. CTS1 is an artificial p53-based gene designed to resist various pathways of p53 inactivation. Here, we report that an adenovirus encoding CTS1 (Ad-CTS1) induces growth arrest and loss of viability in all glioma cell lines examined, in the absence of specific cell cycle changes. In contrast, an adenovirus encoding wild-type p53 (Ad-p53) does not consistently induce apoptosis in the same cell lines. Electron microscopic analysis of Ad-CTS1-infected glioma cells reveals complex cytoplasmic pathology and delayed apoptotic changes. Ad-CTS1 induces prominent activation of various p53 target genes, including p21 and MDM-2, but has no relevant effects on BCL-2 family protein expression. Although Ad-CTS1 strongly enhances CD95 expression at the cell surface, endogenous CD95/CD95 ligand interactions do not mediate CTS1-induced cell death. This is because Ad-CTS1 promotes neither caspase activation nor mitochondrial cytochrome c release and because the caspase inhibitors, z-val-Ala-DL-Asp-fluoromethylketone (zVAD)-fmk or z-Ile-Glu-Thr-Asp- fluoromethylketone (z-IETD)-fmk, do not block CTS1-induced cell death. Ad-CTS1 synergizes with radiotherapy and CD95 ligand in killing glioma cells. In summary, Ad-CTS1 induces an unusual type of cell death that appears to be independent of BCL-2 family proteins, cytochrome c release, and caspases. CTS1 gene transfer is a promising strategy of somatic gene therapy for malignant glioma.
Naumann
U
U
Laboratory of Molecular Neuro-Oncology, Department of Neurology, Institute of Pathology, University of Tübingen Medical School, Hoppe-Seyler-Strasse 3, 72076 Tübingen, Germany.
Kügler
S
S
Wolburg
H
H
Wick
W
W
Rascher
G
G
Schulz
J B
JB
Conseiller
E
E
Bähr
M
M
Weller
M
M
D000260:Adenoviruses, Human / Q000235:genetics; D000970:Antineoplastic Agents / Q000494:pharmacology; D020169:Caspases / Q000502:physiology; D002455:Cell Division / Q000187:drug effects / Q000235:genetics / Q000528:radiation effects; D002470:Cell Survival / Q000187:drug effects / Q000235:genetics / Q000528:radiation effects; D003131:Combined Modality Therapy; D003574:Cytochrome c Group / Q000378:metabolism; D053222:Fas Ligand Protein; D016158:Genes, p53 / Q000235:genetics*; D015316:Genetic Therapy / Q000379:methods*; D005910:Glioma / Q000235:genetics / Q000532:radiotherapy / Q000628:therapy*; D006801:Humans; D008562:Membrane Glycoproteins / Q000235:genetics / Q000502:physiology*; D008928:Mitochondria / Q000378:metabolism; D009154:Mutation; D011993:Recombinant Fusion Proteins / Q000235:genetics*; D014162:Transfection; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000502:physiology; D019014:fas Receptor / Q000502:physiology
D000970:Antineoplastic Agents; D003574:Cytochrome c Group; C505661:FASLG protein, human; D053222:Fas Ligand Protein; D008562:Membrane Glycoproteins; D011993:Recombinant Fusion Proteins; D016159:Tumor Suppressor Protein p53; D019014:fas Receptor; D020169:Caspases