Adenovirus mediated transfer of p53, GM-CSF and B7-1 suppresses growth and enhances immunogenicity of glioma cells.

Objectives: Malignant gliomas are good targets for gene therapy because they have been proven incurable with conventional treatments. However, malignant gliomas are genetically and physiologically highly heterogeneous, and current gene therapy interventions have been designed to target only a few variations of this kind of disease. Hence, we developed a combined gene therapy approach using a recombinant adenovirus carrying human wild-type p53 (WT-p53), granulocyte-macrophage colony-stimulating factor (GM-CSF) and B7-1 genes (designated BB-102) to combat the disease.

Methods: Human malignant glioma cells U251 and U87 were transduced with BB-102. Expression of WT-p53, GM-CSF and B7-1 genes were determined by Western blot, enzyme linked immunosorbent assay and flow cytometric analysis, respectively. Growth rates were determined by serial cell counts. Apoptosis was detected by flow cytometric analysis. Proliferation of autologous peripheral blood lymphocytes (PBLs) and cytotoxicity against primary glioma cells were assessed by cell proliferation and cytotoxicity assay kits, respectively.

Results: By the transduction of BB-102, high expression levels of the three exogenesis genes were detected in glioma cells. Cell growth was inhibited and apoptosis was induced. Significant proliferation of autologous PBLs and specific cytotoxicity against primary glioma cells were also induced by the infection of BB-102 in vitro, with the effect being more evident than that of Ad-p53.

Conclusion: These results suggest that glioma cell vaccination co-transferred with p53, GM-CSF and B7-1 genes may be a feasible and effective immunotherapeutic approach in glioma treatments.