title: Identification and functional characterization of glioma-specific promoters and their application in suicide gene therapy.
abstract: Suicide gene therapy has been shown to be effective in inducing tumor regression. In this study, a human brain tumor-specific promoter was identified and used to develop transcriptionally targeted gene therapy. We searched for genes with brain tumor-specific expression. By in silico and reverse-transcription polymerase chain reaction screening, MAGE-A3 and SSX4 were found to be expressed in a tumor-specific manner. SSX4 gene promoter activity was high in human brain tumor cells but not in normal human astrocyte cells, whereas the MAGE-A3 promoter showed activity in both tumor and normal cells. A retrovirus vector carrying a suicide gene, the herpes simplex virus thymidine kinase gene controlled by the SSX4 promoter, was constructed to evaluate the efficacy of the promoter in tumor-specific gene therapy. Glioma and human telomerase catalytic subunit-immortalized fibroblast BJ-5ta cell lines transduced with retrovirus vectors were assayed for killing activity by ganciclovir. Glioma cell lines were effectively killed by ganciclovir in a concentration-dependent manner, whereas BJ-5ta cells were not. By contrast, MAGE-A3 promoter failed to induce cytotoxicity in a brain tumor-specific manner. In addition, mouse glioma RSV-M cells transduced with retrovirus vector also showed suppressed tumor formation activity in syngeneic mice in response to ganciclovir administration. Therefore, the SSX4 promoter is a candidate for brain tumor-specific gene therapy and supports the efficacy and safety of suicide gene therapy for malignant brain tumors.
authors.affiliation: Department of Neurosurgery, Kochi Medical School, Nankoku, Kochi, Japan.
authors.forename: Toshio
authors.initials: T
authors.lastname: Yawata
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Maeda
authors.forename: Makiko
authors.initials: M
authors.lastname: Okiku
authors.forename: Eri
authors.initials: E
authors.lastname: Ishida
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Ikenaka
authors.forename: Keiji
authors.initials: K
authors.lastname: Shimizu
mesh_terms: D000818:Animals; D000951:Antigens, Neoplasm / Q000096:biosynthesis / Q000235:genetics*; D001932:Brain Neoplasms / Q000235:genetics* / Q000628:therapy; D045744:Cell Line, Tumor; D041722:Genes, Transgenic, Suicide / Q000235:genetics*; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors; D005910:Glioma / Q000235:genetics* / Q000628:therapy; D006801:Humans; D007150:Immunohistochemistry; D051379:Mice; D009363:Neoplasm Proteins / Q000096:biosynthesis / Q000235:genetics*; D011401:Promoter Regions, Genetic; D012097:Repressor Proteins / Q000096:biosynthesis / Q000235:genetics*; D012190:Retroviridae / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014161:Transduction, Genetic; D023041:Xenograft Model Antitumor Assays
chemical_list: D000951:Antigens, Neoplasm; C072013:MAGEA3 protein, human; D009363:Neoplasm Proteins; D012097:Repressor Proteins; C093962:synovial sarcoma X breakpoint proteins