Overexpression of E2F-1 leads to bax-independent cell death in human glioma cells.
Gliomas are highly resistant to any kind of treatment. Multiple genetic abnormalities exist in gliomas indicating that effective gene therapy should be directed towards replacement of multiple rather than single genes. Bax is a protein of the Bcl-2 family that promotes apoptosis and functions as a tumor suppressor gene. The E2F family of transcription factors plays a pivotal role in the regulation of cell-cycle and cell-death related genes in gliomas. We examined the therapeutic potential of the simultaneous transfer of Bax and E2F molecules (1, 2 or 4) to gliomas. We used first generation E1A-deleted adenoviral vectors to transduce the E2Fs and Bax cDNAs. The recombinant adenoviral vector encoding bax uses the inducible Cre-loxP system to transduce the protein expression. Western blot analysis and immunofluorescence assays demonstrated high level of expression of the exogenous proteins. Trypan blue cell viability assays and flow cytometric cell-cycle analysis demonstrated an additive effect of these molecules to induce cell death via apoptosis. Western blot analysis showed that the ectopic expression of E2F-1 decreased the level of expression of Bax. These results indicate that E2F-1 and Bax have an additive anti-glioma effect when expressed simultaneously at high levels. Our data also suggest that Bax is not involved in the E2F-1-mediated apoptosis.
Mitlianga
Paraskevi G
PG
Department of Neuro-Oncology, University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA. pmitliag@cc.uoi.gr
Gomez-Manzano
Candelaria
C
Kyritsis
Athanassios P
AP
Fueyo
Juan
J
D000256:Adenoviridae / Q000235:genetics; D017209:Apoptosis; D018797:Cell Cycle Proteins; D002470:Cell Survival; D004268:DNA-Binding Proteins; D050684:E2F Transcription Factors; D050687:E2F1 Transcription Factor; D015316:Genetic Therapy; D005910:Glioma / Q000737:chemistry / Q000473:pathology / Q000628:therapy*; D006801:Humans; D011518:Proto-Oncogene Proteins / Q000032:analysis / Q000235:genetics* / Q000502:physiology; D019253:Proto-Oncogene Proteins c-bcl-2; D014157:Transcription Factors / Q000032:analysis / Q000235:genetics* / Q000502:physiology; D014407:Tumor Cells, Cultured; D051028:bcl-2-Associated X Protein
C494826:BAX protein, human; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D050684:E2F Transcription Factors; D050687:E2F1 Transcription Factor; C493753:E2F1 protein, human; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D014157:Transcription Factors; D051028:bcl-2-Associated X Protein