title: A hypoxia-regulated adeno-associated virus vector for cancer-specific gene therapy.
abstract: The presence of hypoxic cells in human brain tumors is an important factor leading to resistance to radiation therapy. However, this physiological difference between normal tissues and tumors also provides the potential for designing cancer-specific gene therapy. We compared the increase of gene expression under anoxia (<0.01% oxygen) produced by 3, 6, and 9 copies of hypoxia-responsive elements (HRE) from the erythropoietin gene (Epo), which are activated through the transcriptional complex hypoxia-inducible factor 1 (HIF-1). Under anoxic conditions, nine copies of HRE (9XHRE) yielded 27- to 37-fold of increased gene expression in U-251 MG and U-87 MG human brain tumor cell lines. Under the less hypoxic conditions of 0.3% and 1% oxygen, gene activation by 9XHRE increased expression 11- to 18-fold in these cell lines. To generate a recombinant adeno-associated virus (rAAV) in which the transgene can be regulated by hypoxia, we inserted the DNA fragment containing 9XHRE and the LacZ reporter gene into an AAV vector. Under anoxic conditions, this vector produced 79- to 110-fold increase in gene expression. We believe this hypoxia-regulated rAAV vector will provide a useful delivery vehicle for cancer-specific gene therapy.
authors.affiliation: Brain Tumor Research Center of the Department of Neurological Surgery.
authors.forename: H
authors.initials: H
authors.lastname: Ruan
authors.forename: H
authors.initials: H
authors.lastname: Su
authors.forename: L
authors.initials: L
authors.lastname: Hu
authors.forename: K R
authors.initials: KR
authors.lastname: Lamborn
authors.forename: Y W
authors.initials: YW
authors.lastname: Kan
authors.forename: D F
authors.initials: DF
authors.lastname: Deen
mesh_terms: D000256:Adenoviridae / Q000235:genetics; D015153:Blotting, Western; D001932:Brain Neoplasms / Q000378:metabolism* / Q000628:therapy; D004268:DNA-Binding Proteins / Q000378:metabolism*; D018628:Gene Dosage; D015972:Gene Expression Regulation, Neoplastic; D017930:Genes, Reporter; D015316:Genetic Therapy; D005822:Genetic Vectors; D005909:Glioblastoma / Q000378:metabolism* / Q000628:therapy; D006801:Humans; D002534:Hypoxia, Brain / Q000378:metabolism*; D051793:Hypoxia-Inducible Factor 1; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D007763:Lac Operon / Q000235:genetics; D009687:Nuclear Proteins / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism; D010957:Plasmids; D011401:Promoter Regions, Genetic; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis*; D014157:Transcription Factors; D015533:Transcriptional Activation; D014162:Transfection; D014407:Tumor Cells, Cultured; D001616:beta-Galactosidase / Q000378:metabolism
chemical_list: D004268:DNA-Binding Proteins; C497442:HIF1A protein, human; D051793:Hypoxia-Inducible Factor 1; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; D014157:Transcription Factors; D001616:beta-Galactosidase; D010100:Oxygen