Glioma regression in vitro and in vivo by a suicide combined treatment
Vega García-Escudero1, Ricardo Gargini, Marta Izquierdo
1Department of Molecular Biology, Centro de Biología Molecular Severo Ochoa, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain.
Abstract:
We present here a suicide therapy against malignant gliomas based on the transfer to tumor cells of a gene encoding a beta-glucosidase, linamarase (lis), which in the presence of the innocuous substrate linamarin (lin) produces cyanide, blocking the mitochondrial respiratory chain. Dog glioma cells carrying the lis gene are thus sensitive to lin (IC(50) of 250 microg/mL at 48 hours) and cell death is accompanied by mitochondrial fission and ATP depletion. The combination of lis/lin with an otherwise nontoxic level of glucose oxidase (GO) enhances the therapeutic potential (IC(50) of 50 microg/mL at 48 hours). GO produces hydrogen peroxide, inducing oxidative damage and increasing cellular stress. We show here the antitumoral effect of the lis/lin/GO therapy in a canine glioma cell line and in a xenograft glioma model in nude mice. The synergic combination causes mitochondrial membrane depolarization and phosphatidylserine externalization and accelerates death by 48 hours. The lethal process is caspase independent; poly(ADP-ribose) polymerase 1 is not implicated; and there is no apoptosis-inducing factor translocation to the nucleus. The combined system induces autophagic cell death that can be rescued by 3-methyladenine and is characterized by the presence of double-membrane vesicles and punctate LC-3 pattern.
Insights
This study introduces a novel suicide therapy for malignant gliomas using linamarase (lis) gene transfer to produce cyanide, enhanced by glucose oxidase (GO). This combination effectively targets glioma cells, offering a promising new cancer treatment strategy.
Area of Science:
- Oncology
- Molecular Biology
- Biochemistry
Background:
- Malignant gliomas are aggressive brain tumors with limited treatment options.
- Gene therapy offers a potential strategy for targeted cancer treatment.
- Cyanide production via enzyme-substrate interaction can induce cell death.
Purpose of the Study:
- To develop and evaluate a novel suicide gene therapy for malignant gliomas.
- To investigate the synergistic effects of linamarase/linamarin and glucose oxidase in glioma treatment.
- To elucidate the mechanism of cell death induced by this combined therapy.
Main Methods:
- Gene transfer of linamarase (lis) into dog glioma cells.
- Treatment with linamarin (lin) substrate and glucose oxidase (GO).
- Assessment of cell viability, mitochondrial function, and cell death pathways in vitro and in vivo.
Main Results:
- The lis/lin system effectively killed glioma cells by blocking mitochondrial respiration and depleting ATP.
- Combining lis/lin with GO significantly enhanced therapeutic efficacy and accelerated cell death.
- The therapy induced autophagic cell death, independent of caspase activation or apoptosis.
Conclusions:
- The lis/lin/GO suicide gene therapy demonstrates significant antitumoral effects against malignant gliomas.
- This combination therapy represents a promising strategy for glioma treatment, inducing targeted autophagic cell death.
- Further research into this gene therapy approach could lead to new clinical applications for brain cancer.