Selective astrocytic transgene expression in vitro and in vivo from the GFAP promoter in a HSV RL1 null mutant vector – potential glioblastoma targeting

Abstract

Due to the lack of any effective therapy, novel approaches acidic protein (GFAP), an astrocyte specific protein. Two are currently being explored for the treatment of primary 1716 variants, 1774 and 1775, were constructed which brain tumours. It has previously been demonstrated that contain the GFAP-promoter element linked to the E. coli ␤-variants of HSV-1 which are deleted in the RL1 gene and galactosidase gene, inserted into the HSV-1 UL43 and fail to produce the virulence factor ICP34.5 are potential US5 loci, respectively. In primary cultures, human primary candidates for tumour therapy. The RL1 variant 1716 replitumour cell lines and established tumour cell lines in vitro, cates selectively within tumour cells and has the potential 1774 and 1775 gave high levels of expression of ␤-to deliver a therapeutic or tumour killing gene directly to galactosidase specifically in astrocytes. In vivo following the site of tumour growth. As many intracerebral tumours intracerebral inoculation, both viruses demonstrated high are glial and predominantly astrocytic in origin, we have levels of ␤-galactosidase expression predominantly in evaluated the ability of 1716 to deliver a reporter gene astrocytes. These results indicate that the GFAP promoter specifically to astrocytes in vivo and in vitro using a 2.2 kb element could be used for efficient and selective transgene fragment which controls expression of the glial fibrillary delivery to human gliomas.

Astrocytic expression of transgene in the rat brain mediated by baculovirus vectors containing an astrocyte-specific promoter

“…In the last several years, the specific cellular location of the GFAP protein in the CNS has encouraged the extensive use of a GFAP promoter to target transgene expression to cells of glial origin. 12 Up to now, the astrocyte specificity of transgene expression driven by the GFAP promoter has been reported after using adenovirus, 30 herpes simplex virus (HSV) 31 and lentivirus. 29,32 However, when using AAV carrying the GFAP promoter, most transduced brain cells appeared neuronal.…”

Delivery of GDNF by an E1,E3/E4 deleted adenoviral vector and driven by a GFAP promoter prevents dopaminergic neuron degeneration in a rat model of Parkinson's disease

“…Our interest was also to test the GFAP promoter for PD therapy since this promoter was described to direct specifically transgene expression in astrocytes. 24,25 In our cell cultures, GDNF protein was not synthesized by the mesencephalic cells infected with the recombinant GFAP-GDNF adenovirus, whereas this trophic factor was produced and secreted by the transduced astrocytes (Figure 1). Morelli et al 29 observed that only cultured neocortical neurons, infected with a recombinant defective adenovirus vector encoding FasL under the control of the neuronal-specific promoter NSE (RAd-NSE-FasL), released the cytotoxic Fas ligand into the culture supernatant.…”

“…Glial fibrillaly acidic protein, an intermediate filament protein, is expressed abundantly in astrocytes during development 28 of the CNS and in reactive astrocytes (astrogliosis) following CNS injury. 24,25 Reactive astrocytes, characterized by a significant increase in the GFAP intensity, cellular hypertrophy and increase in the density of GFAP immunoreactive Figure 8 TH immunostaining of the striatum, 4 weeks after viral treatment. On the intact side, the TH staining intensity was high throughout the striatum (a, b, right side).…”

“…[20][21][22][23] In addition, following brain injury, the glial fibrillary acidic protein (GFAP) gene is upregulated in reactive astrocytes. 24 We therefore used the promoter of the GFAP gene, whose expression in the CNS is restricted to astrocytes, 24,25 to drive GDNF gene expression. Restriction of GDNF expression to a specific cell type limits the side effects caused by the expression of this gene in surrounding cells, thus facilitating the long-term expression of the transgene.…”

Hypoxia Responsive Vectors Targeting Astrocytes in Glioma

“…Along with hypoxia regulated expression, tissue-specific expression may increase the possibilities to turn on genes in a regulated and tissue-specific manner. McKie EA (1998) used a GFAP promoter to target astrocytes for expression of transgenes as a potential treatment strategy for glioblastoma (McKie et al, 1998). Hypoxia could be used to switch on a foreign gene in glioma cells or in astrocytes.…”