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The use of suicide gene systems in vascular cells in vitro
Abstract:
To investigate the efficiency of suicide gene systems on vascular cells, HSV-tk/GCV and EC-CD/5-FC systems were established on vascular endothelial cells in vitro by retroviral transduction. Both modified cell lines were highly sensitive to prodrugs, the IC50 for GCV was less than 0.4 microM, and IC50 for 5-FC was less than 75 microM, while the parental endothelial cells were insensitive even at the highest concentrations of prodrugs in this experiment. Mixed cellular assay showed that significant bystander effect was exhibited in modified endothelial cells. When only 10% or 30% of the mixed cells were tk positive and exposed to 20 microM GCV for 6 days, more than 60% or 90% of the whole population was killed. Similar result was also found in CD positive cells. These results indicated that both HSV-tk/GCV and EC-CD/5-FC systems could efficiently suppress endothelial cell growth in vitro.
Insights
Two suicide gene systems, HSV-tk/GCV and EC-CD/5-FC, effectively suppressed vascular endothelial cell growth in vitro. These systems demonstrated significant bystander effects, killing both modified and unmodified cells when exposed to prodrugs.
Area of Science:
- Molecular Biology
- Cell Biology
- Gene Therapy
Background:
- Suicide gene therapy offers a potential strategy for targeted cell ablation.
- Vascular endothelial cells play critical roles in various physiological and pathological processes.
- Developing efficient suicide gene systems for vascular cells is crucial for therapeutic applications.
Purpose of the Study:
- To evaluate the efficacy of two suicide gene systems, herpes simplex virus-thymidine kinase/ganciclovir (HSV-tk/GCV) and engineered cytosine deaminase/5-fluorocytosine (EC-CD/5-FC), in suppressing vascular endothelial cell growth in vitro.
- To assess the bystander effect of these systems on unmodified cells.
Main Methods:
- Retroviral transduction was used to establish modified vascular endothelial cell lines expressing either HSV-tk or EC-CD.
- In vitro assays were performed to determine the sensitivity of modified and parental cells to prodrugs (GCV and 5-FC).
- Mixed cellular assays were conducted to evaluate the bystander effect by co-culturing modified and unmodified cells and exposing them to prodrugs.
Main Results:
- Both HSV-tk/GCV and EC-CD/5-FC modified cell lines exhibited high sensitivity to their respective prodrugs, with low IC50 values (GCV < 0.4 µM, 5-FC < 75 µM).
- Parental endothelial cells remained insensitive to high concentrations of prodrugs.
- Significant bystander effects were observed; for example, exposing mixed populations with 10% or 30% modified cells to GCV resulted in >60% or >90% cell death, respectively. Similar results were seen with the EC-CD/5-FC system.
Conclusions:
- The HSV-tk/GCV and EC-CD/5-FC suicide gene systems are highly efficient in suppressing vascular endothelial cell growth in vitro.
- The observed bystander effects suggest these systems can eliminate not only genetically modified cells but also neighboring unmodified cells, enhancing therapeutic potential.