DESCRIPTION: The long-term goals of this research are to understand the molecular mechanisms of growth regulation and tumor progression in human gliomas. Recent data have suggested that TGF-a and the EGF receptor represent a major autocrine growth regulatory loop in human gliomas while VEGF could be the predominant angiogenic growth factor secreted by glioma cells. In the next five years it is planned to focus on the modulation of these three factors and receptor as a basis for future molecular therapy of malignant gliomas in the clinic. The hypotheses to be tested are: 1) amplification of and over-expression of EGFR/TGF-a and VEGF correlate with malignant progression from astrocytoma to glioblastoma, and 2) modulation of these factors will provide an inhibitory effect to the progression and growth of human glioblastoma. The specific aims are to 1) determine the expression and alteration of EGF-R, TGF-a, and VEGF in glioma and brain adjacent to tumor. This will be accomplished by PCR, in situ hybridization, and immunohistochemical methods. 2) Triple helix forming oligonucleotides will be designed to inhibit transcription through the promoter region of EGF-R and VEGF genes. Chemical modifications will also be applied to increase the binding efficiency and uptake of these oligonucleotides. 3) To modulate the expression of EGF-R and VEGF using these TFOs. Cells will be tested for growth inhibition, inhibition of transcription by PCR, RNA protection assay and Northern blot; protein synthesis will be determined by receptor binding, Western blot and immunokinase assays. In vivo activity will be determined with nude mice xenografts both subcutaneously and intracranially. 4) To modulate the activity of TGF-a by antisense oligonucleotides and antisense vectors. The biological activities of antisense TGF-a vectors and oligonucleotides will be further investigated. Any synergistic activity between antisense oligonucleotides and TFO's will also be focused upon.