Remission of Invasive, Cancer Stem-Like Glioblastoma Xenografts Using Lentiviral Vector-Mediated Suicide Gene Therapy

Abstract

BackgroundGlioblastoma is the most frequent and most malignant primary brain tumor with a poor prognosis. The translation of therapeutic strategies for glioblastoma from the experimental phase into the clinic has been limited by insufficient animal models, which lack important features of human tumors. Lentiviral gene therapy is an attractive therapeutic option for human glioblastoma, which we validated in a clinically relevant animal model.Methodology/Principal FindingsWe used a rodent xenograft model that recapitulates the invasive and angiogenic features of human glioblastoma to analyze the transduction pattern and therapeutic efficacy of lentiviral pseudotyped vectors. Both, lymphocytic choriomeningitis virus glycoprotein (LCMV-GP) and vesicular stomatitis virus glycoprotein (VSV-G) pseudotyped lentiviral vectors very efficiently transduced human glioblastoma cells in vitro and in vivo. In contrast, pseudotyped gammaretroviral vectors, similar to those evaluated for clinical therapy of glioblastoma, showed inefficient gene transfer in vitro and in vivo. Both pseudotyped lentiviral vectors transduced cancer stem-like cells characterized by their CD133-, nestin- and SOX2-expression, the ability to form spheroids in neural stem cell medium and to express astrocytic and neuronal differentiation markers under serum conditions. In a therapeutic approach using the suicide gene herpes simplex virus thymidine kinase (HSV-1-tk) fused to eGFP, both lentiviral vectors mediated a complete remission of solid tumors as seen on MRI resulting in a highly significant survival benefit (p<0.001) compared to control groups. In all recurrent tumors, surviving eGFP-positive tumor cells were found, advocating prodrug application for several cycles to even enhance and prolong the therapeutic effect.Conclusions/SignificanceIn conclusion, lentiviral pseudotyped vectors are promising candidates for gene therapy of glioma in patients. The inefficient gene delivery by gammaretroviral vectors is in line with the results obtained in clinical therapy for GBM and thus confirms the high reproducibility of the invasive glioma animal model for translational research.

Cellular effects of oncolytic viral therapy on the glioblastoma microenvironment

“…25 Interestingly, we obtained similar transduction volumes using pseudotyped lentiviral vectors (LV) in a study where GBM xenografts were initiated from the same patient biopsy. 27 Lymphocytic choriomeningitis viruspseudotyped LV transduced 7.05±3.51 mm 3 volume of tumor tissue, whereas vesicular stomatitis virus-pseudotyped LV transduced 4.05±2.04 mm 3 tissue. When applied at the same total volume of concentrated stock as used with G207, both lentiviral vectors mediated tumor regression through thymidin-kinase-assisted suicide gene therapy.…”

Genome Editing Reveals Glioblastoma Addiction to MicroRNA-10b

“…Therapeutic gene editing using high viral titers applied locally to the surgical cavity may also prove to be effective for targeting infiltrating tumor cells. 26,27 An additional advantage of the locally applied lentivirus pseudotyped with the VSV-G glycoprotein is that its inactivation by human serum 28 would reduce systemic effects. Although the application of human lentiviral gene therapy is hampered by the risk of carcinogenesis by random proviral integration into the genome of normal somatic cells, future studies should determine whether this risk is acceptable for local GBM treatment, given the lack of efficacious drugs and poor life expectancy of patients with the disease.…”

Brain Tumor Treatment: 2017 Update

“…Combining HSV vector G47Δ with temozolomide increased sensitivity to temozolomide in killing BTSCs while sparing neurons and induced long-term remission in 4 of 8 treated xenograft-bearing mice (Kanai, Rabkin et al 2012). Lymphocytic choriomeningitis virus glycoprotein and vesicular stomatitis virus glycoprotein-pseudotyped lentiviral vectors were both able to efficiently infect glioblastoma BTSCs and carry the suicide gene HSV thymidine kinase fused to eGFP to mediate complete radiologic remission and significant survival benefit in rats bearing glioblastoma BTSC xenografts (Huszthy, Giroglou et al 2009). These studies suggest the therapeutic potential of oncolytic viruses against BTSCs; indeed, Delta-24-RGD is currently in phase 1 clinical testing for the treatment of patients with recurrent glioma (U.S. National Institutes of Health).…”