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Cell-specific targeting of a thymidine kinase/ganciclovir gene therapy system using a recombinant Sindbis virus
1Department of Pathology and Kaplan Cancer Center, New York University Medical Center, New York 10016, USA.
Abstract:
Transfer of the herpes simplex virus type I thymidine kinase (HSV-TK) gene into tumor cells using virus-based vectors in conjunction with ganciclovir (GCV) exposure provides a potential gene therapy strategy for the treatment of cancer. The possibility of using a novel targetable Sindbis virus expression vector containing the HSV-TK gene was examined. Baby hamster kidney (BHK) cells and several human tumor cells infected with a Sindbis virus containing the HSV-TK gene showed strong expression of HSV-TK protein. Cells transduced with the HSV-TK gene exhibited increased TK activity, ranging from 3- to 20-fold over an average baseline level. The human HeLa-CD4+ cells infected with recombinant Sindbis virus containing the HSV-TK gene were sensitive to low concentrations of GCV (0.1-1 microg/ml) and the 50% growth inhibitory concentration (IC50) was 0.6 microg/ml. We also demonstrated applications of cell type-specific Sindbis virus-mediated antigen-antibody targeting of the HSV-TK/GCV system in vitro. Sindbis virus containing the HSV-TK gene packaged in a helper virus displaying the IgG-binding domain of protein A on its envelope could infect various tumor cell lines in the presence of specific antibodies that recognize antigens on their surfaces. HSV-TK-transduced tumor cell lines exhibited sensitivity to GCV. Our data suggest the potential for targeted gene therapy of the HSV-TK/GCV system using a cell type-specific recombinant Sindbis virus vector-antibody system.
Insights
This study explores using Sindbis virus to deliver the herpes simplex virus type I thymidine kinase (HSV-TK) gene for cancer gene therapy. The engineered virus effectively targeted tumor cells, making them sensitive to ganciclovir (GCV) treatment.
Area of Science:
- Oncolytic Virotherapy
- Molecular Therapy
- Gene Therapy
Background:
- The herpes simplex virus type I thymidine kinase (HSV-TK) gene combined with ganciclovir (GCV) is a promising cancer gene therapy strategy.
- Virus-based vectors are crucial for delivering therapeutic genes to tumor cells.
Purpose of the Study:
- To evaluate a novel, targetable Sindbis virus expression vector carrying the HSV-TK gene for cancer treatment.
- To assess the efficacy of cell type-specific targeting using Sindbis virus for the HSV-TK/GCV system.
Main Methods:
- Infection of baby hamster kidney (BHK) and human tumor cell lines with Sindbis virus expressing HSV-TK.
- Measurement of thymidine kinase (TK) activity in transduced cells.
- Assessment of tumor cell sensitivity to ganciclovir (GCV) post-transduction.
- Demonstration of targeted infection using antibody-mediated targeting of Sindbis virus.
Main Results:
- Sindbis virus efficiently expressed HSV-TK protein in various tumor cells, increasing TK activity significantly (3- to 20-fold).
- Transduced human HeLa-CD4+ cells showed high sensitivity to GCV, with a 50% growth inhibitory concentration (IC50) of 0.6 microg/ml.
- A targeted system using Sindbis virus, antibody targeting, and HSV-TK/GCV demonstrated effective in vitro infection and GCV sensitivity in tumor cell lines.
Conclusions:
- Recombinant Sindbis virus vectors effectively deliver the HSV-TK gene to tumor cells, enhancing their sensitivity to ganciclovir.
- Cell type-specific targeting via antibody-mediated Sindbis virus vectors offers a potential strategy for localized cancer gene therapy.