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Gene therapy against an experimental glioma using adeno-associated virus vectors
1Department of Neurosurgery, Nagoya University School of Medicine, Japan.
Abstract:
The efficacy of gene therapy for glioma was examined using adeno-associated virus (AAV)-based vectors to deliver genes to experimental tumors in mice. Stereotactic injection of 2 x 10(5) U-251SP human glioma cells into the brains of nude mice produced tumors of 19.06 +/- 1.79 mm2 17 days after injection. Employing a high titer preparation of AAV vector containing the gene for beta-galactosidase (AAV-lacZ), dose-dependent transduction of U-251SP cells was seen in vitro. When 1.6 x 10(10) AAV-lacZ particles were directly injected into tumors in vivo, 30-40% of the cells along the needle track expressed beta-galactosidase. Transduction of U-251SP cells in vitro with an AAV vector containing a bicistronic gene encoding both herpes simplex thymidine kinase and human interleukin-2 (AAV-tk-IRES-IL2) rendered them sensitive to the cytocidal effects of ganciclovir (GCV) and IL-2 was produced in a dose-dependent manner. Cocultures of AAV-tk-IRES-IL2 transduced cells and nontransduced cells proved highly sensitive to GCV indicating the contribution of the bystander effect. Stereotactic delivery of 6 x 10(10) AAV-tk-IRES-IL2 particles into day 7 tumors in nude mice followed by administration of GCV for 6 days, resulted in a 35-fold reduction in the mean volume of tumors compared with controls. Normal brains did not suffer from any toxic effect of the administration of AAV-tk-IRES-IL2 and GCV. These results indicate that high titer AAV vector treatment may be safe and effective for in vivo gene therapy of human brain tumors.
Insights
Gene therapy using adeno-associated virus (AAV) vectors shows promise for treating glioma. This study demonstrated AAV vector safety and efficacy in reducing human brain tumor volume in mice.
Area of Science:
- * Neuro-oncology
- * Gene Therapy
- * Viral Vector Technology
Background:
- * Gliomas are aggressive brain tumors with limited treatment options.
- * Gene therapy offers a potential new therapeutic strategy.
- * Adeno-associated virus (AAV) vectors are being explored for targeted gene delivery.
Purpose of the Study:
- * To evaluate the efficacy and safety of AAV-based gene therapy for glioma.
- * To assess gene transduction efficiency in glioma cells in vitro and in vivo.
- * To determine the therapeutic effect of AAV-mediated delivery of herpes simplex thymidine kinase and interleukin-2 in combination with ganciclovir.
Main Methods:
- * Establishment of human glioma xenografts (U-251SP) in nude mice.
- * In vitro and in vivo transduction of glioma cells using AAV vectors carrying beta-galactosidase (AAV-lacZ) or a bicistronic gene (AAV-tk-IRES-IL2).
- * Stereotactic injection of AAV vectors into tumors, followed by ganciclovir (GCV) administration and tumor volume measurement.
Main Results:
- * AAV-lacZ demonstrated dose-dependent transduction of glioma cells in vitro and in vivo.
- * AAV-tk-IRES-IL2 transduction sensitized glioma cells to GCV, with a significant bystander effect observed.
- * Treatment with AAV-tk-IRES-IL2 and GCV resulted in a 35-fold reduction in tumor volume without observable toxicity in normal brain tissue.
Conclusions:
- * High-titer AAV vectors can effectively transduce glioma cells in vivo.
- * AAV-mediated gene therapy combined with GCV shows significant anti-tumor activity against gliomas.
- * This approach appears safe and holds potential for clinical application in human brain tumor treatment.