Tumor-specific gene expression using regulatory elements of the glucose transporter isoform 1 gene

Abstract

In order to achieve tumor-specific targeting of adeno-associated virus (AAV)-mediated gene expression, the promoter of the glucose transporter isoform 1 (GLUT1) gene was cloned upstream of the enhanced green fluorescence protein (EGFP) and the herpes simplex virus thymidine kinase (HSVtk) gene. FACS analysis performed at 48 h after transient infection with rAAV/cytomegalovirus (CMV)egfp viral particles revealed an increase of fluorescence in all the cell lines tested. However, EGFP expression under control of the GLUT1 promoter element (rAAV/GTI-1.3egfp) was limited to the tumor cells and oncogene-transformed cells. Evidence for phosphorylation of the HSVtk substrates ganciclovir (GCV) and 125 I-deoxycytidine was found in all transfected tumor cell lines compared to noninfected controls (HCT116: 111%; MH3924A: 130%; HaCaT-RT3: 257% increase), but not in HaCaT and HUVEC cells. Furthermore, tumor cells and the oncogene-transformed (ras) cell line HaCaT-RT3 showed a GCV-induced reduction in cell number (HCT116: À71%; MH3924A: À43% and HaCaT-RT3: À31%). No statistically relevant cytotoxic effect was observed in HaCaT (6% decrease) and HUVEC cells (2% decrease). Furthermore, a reduction of 3 H-thymidine incorporation into the DNA was seen after treatment with GCV (HCT116: 38%; MH3924A: 33% and HaCaT-RT3: 37% decrease). In a therapy study of HSVtkexpressing tumors with GCV, we achieved total tumor remission.

Transcriptional targeting of gene expression in breast cancer by the promoters of protein regulator of cytokinesis 1 and ribonuclease reductase 2

“…Previously, several cancer-specific promoters including the TERT (Gu et al, 2000;Gu and Fang, 2003), the synthetic hTERT promoter , tandem hypoxia-responsive elements (HRE) with the enhancerless SV40 promoter (Ruan et al, 2001), the alpha-fetoprotein promoter (Su et al, 1996), calcitonin gene regulatory sequence (Jiang et al, 2001) and the glucose transporter isoform 1 promoter (Sieger et al, 2004) have been identified and examined for cancer-specific expression. We tested the TERT promoter as naked plasmids in MCF7 and MDA-MB-231 cells, but the result showed weaker activation than those of both PRC1 and RRM2 promoters in the same transfection condition (Figure 3).…”

Evaluation of Firefly Luciferase Bioluminescence Mediated Photodynamic Toxicity in Cancer Cells

“…Genes can be selectively delivered to tumors and their metastases with a range of vehicles (e.g., transferrin-coated polyethyleneimine complexes [13], genetically altered, Bretargetedâ denoviruses that express tumor-targeting protein sequences within their knobs, or bispecific antibodies that target antigens both on the tumor and on the delivery virus). Tumor-specific gene expression can be driven by tissue-or tumor-specific promoters, such as the PSA promoter in prostate carcinoma [14], the Chromogranin A promoter in neuroendocrine tumors [15], or the glut1 promoter, which is specific for many neoplastic tissues [16]. Weak tissue specific promoters can be amplified by using strategies such as the two-step transcriptional activation, or the CreYLoxP system [17,18].…”

Molecular Imaging of Tumor Metabolism and Apoptosis

“…The increase in GLUT1 transcription can be used for imaging or therapy by cloning a reporter gene or a therapeutic gene such as suicide genes downstream of the GLUT1 promoter/enhancer elements (Haberkorn et al 2002. Examples are the herpes simplex virus thymidine kinase (HSVtk) gene or the sodium iodide symporter, where adeno associated virus or retroviral vectors have been used to transfect tumor cells and to measure the uptake of specific substrates or to treat animals with genetically modified tumors (Sieger et al 2003(Sieger et al , 2004. In these studies, reporter gene expression (green fluorescent protein, HSVtk or sodium iodide symporter) was specific for tumor cells or cells with expression of an activated ras oncogene (Fig.…”