Inhibition of glioma cells in vitro and in vivo using a recombinant adenoviral vector containing an astrocyte-specific promoter

Abstract

Gene therapy using the herpes simplex virus thymidine kinase (HSV-TK) gene in combination with the drug ganciclovir (GCV) is a promising approach for the treatment of cancer-inducing gliomas, a tumor with a poor prognosis. In an attempt to limit the toxic effects on normal tissues, we constructed a recombinant adenoviral vector, Adgfa2TK, in which the HSV-TK gene is driven by the promoter for the gene encoding glial fibrillary acidic protein, an intermediate filament protein expressed primarily in astrocytes. Infection by Adgfa2TK of a glial cell line (C6) and a non-glial cell line (MDA-MB-231) revealed markedly increased expression of HSV-TK in glial cells as determined by Western blot. In comparison, high HSV-TK protein levels were produced in both cell lines after infection with a control virus, AdCMVTK, in which the constitutive cytomegalovirus viral promoter was used to direct HSV-TK expression. Infection of two glial cell lines (C6, U251) and two non-glial cell lines (HepG2, MDA-MB-231) with Adgfa2TK followed by GCV treatment revealed high toxicity in glial cell lines (50% growth inhibitory concentration: Ͻ2 g/mL of GCV) with little or no toxicity (50% growth inhibitory concentration: Ͼ75 g/mL) in the non-glial cell lines. In vivo, injection of Adgfa2TK into C6 tumors grown in nude mice followed by intraperitoneal GCV treatment significantly repressed tumor growth compared with the controls. Adgfa2TK may be useful for directing expression of the HSV-TK gene to gliomas.

Targeted-simultaneous expression of Gas1 and p53 using a bicistronic adenoviral vector in gliomas

“…56 Transcriptional regulation of transgene expression has been extensively used to express therapeutic transgenes in gliomas using the GFAP promoter. 10,11,18,[57][58][59] Reaching the goals of targeted gene expression will greatly increase the specificity and safety of gene therapy, thus getting us closer to the fulfillment of the expectations generated by this new branch of molecular medicine.…”

“…15 Previously, we and other groups have shown that a 2.2 kilobases (kb) fragment of the human glial fibrillary acidic protein (GFAP) promoter (gfa2) is sufficient to regulate the targeted expression of different transgenes in astrocytes, glioma cell lines and primary astrocyte cultures. 11,[16][17][18] Importantly, glial-specificity transcription of the gfa2 promoter was preserved, independently of the gene transfer method employed 11,[19][20][21] and the gfa2 promoter has been used to study the role of glial cells in neurogenesis using transgenic mice. 22 In this study, we examined the effect of different adenoviral systems to target specifically the expression of both gas1 and p53 transgenes to glioma cells.…”

Fluoxetine promotes gliogenesis during neural differentiation in mouse embryonic stem cells

“…A 1.6-kb promoter element of the mouse GFAP gene, which is reported to have astrocyte-specific transcription activity (Brenner et al, 1994;Vandier et al, 2000), was amplified by PCR from a commercially available vector containing the mouse GFAP promoter pDRIVE5s-mGFAP (InvivoGen, San Diego, CA). A 0.5-kb promoter element from the cytomegalovirus (CMV) gene was amplified by PCR from the pEGFP-C1 vector (Takara Bio).…”

Expression in UVW glioma cells of the noradrenaline transporter gene, driven by the telomerase RNA promoter, induces active uptake of [131I]MIBG and clonogenic cell kill

“…In some cases toxicity and therefore loss of some normal tissue may be acceptable, for example loss of normal prostate cells as a result of utilization of the prostate-speci®c antigen (PSA) promoter. However in many tumours such as brain malignancies, toxicity to normal tissue by utilization of currently available brain speci®c promoters such as glia ®brillary acidic protein (GFAP) promoter to drive expression of toxic transgenes, would result in unacceptable levels of normal tissue toxicity (Vandier et al, 1998, Eng, 1985. These limitations may ultimately be overcome by introduction of additional levels of speci®city to the tissue speci®c promoter elements such as coupling tissue speci®c transcription with cell cycle regulation (Nettelbeck et al, 1999) or coupling to other factors speci®c to the physiology of tumours rather than normal cells (Brown and Graccia, 1998).…”