Novel chimeric gene promoters responsive to hypoxia and ionizing radiation

• Published in: Gene therapy Vol. 9; no. 20; pp. 1403 - 1411
• Main Authors: GRECO, O, MARPLES, B, DACHS, G. U, WILLIAMS, K. J, PATTERSON, A. V, SCOTT, S. D
• Format: Journal Article
• Language: English
• Published: Basingstoke Nature Publishing Group 01.10.2002
• Subjects: Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Animals; Applied cell therapy and gene therapy; Biological and medical sciences; Biotechnology; Bladder cancer; Carcinoma; Enhancers; Enzyme Precursors - genetics; Erythropoietin; Expression vectors; Female; Fundamental and applied biological sciences. Psychology; Gene Expression; Gene therapy; Genetic Engineering; Genetic Therapy - methods; Health. Pharmaceutical industry; Horseradish peroxidase; Hypoxia; Hypoxia - genetics; Indoleacetic acid; Industrial applications and implications. Economical aspects; Ionizing radiation; Kinases; Mammary gland; Mammary Neoplasms, Animal - radiotherapy; Mammary Neoplasms, Animal - therapy; Medical sciences; Phosphoglycerate kinase; Phosphoglycerate kinase 1; Promoter Regions, Genetic; Promoters; Radiation therapy; Radiotherapy - methods; Regulatory sequences; Suicide; Suicide genes; Transfusions. Complications. Transfusion reactions. Cell and gene therapy; Tumor Cells, Cultured; Tumor microenvironment; Tumors; Urinary Bladder Neoplasms - radiotherapy; Urinary Bladder Neoplasms - therapy; Vascular endothelial growth factor; Cationic complex; GDEPT; Transcription promoter; CArG element; HRP/IAA; Genetic transfer; Plasmid; Ionizing radiation; Reporter gene; Cell line; radiotherapy; Hypoxia; Regulatory sequence; HRE; Gene therapy
• ISSN: 0969-7128; 1476-5462
• DOI: 10.1038/sj.gt.3301823

Despite being an adverse prognostic factor in radiotherapy, hypoxia represents a physiological difference that can be exploited for selective cancer gene therapy. In this study gene therapy vectors responsive to both hypoxia and ionizing radiation (IR) were developed. Gene expression was regulated by novel, synthetic promoters containing hypoxia responsive elements (HREs) from the erythropoietin (Epo), the phosphoglycerate kinase 1 (PGK1) and the vascular endothelial growth factor (VEGF) genes, and IR-responsive CArG elements from the early growth response (Egr) 1 gene. All chimeric promoters could be activated by hypoxia and/or IR-treatment, and selectively control marker gene expression in human T24 bladder carcinoma and MCF-7 mammary carcinoma cells. Importantly, enhancers containing combinations of HREs and CArG elements were able to respond to both triggering treatments, with the Epo HRE/CArG combination proving to be the most responsive and robust. The Epo HRE/CArG enhancer could effectively control a suicide gene therapy strategy by selectively sensitizing hypoxic and/or irradiated cells expressing the enzyme horseradish peroxidase (HRP) to the prodrug indole-3-acetic acid (IAA). These data indicate that the use of such chimeric promoters may effectively regulate therapeutic gene expression within the tumor microenvironment in gene therapy strategies aimed at addressing the problem of hypoxia in radiotherapy.