Abstract
BackgroundTumor necrosis factor-related apoptosis-inducing ligand (TRAIL) functions as a cytokine to selectively kill various cancer cells without toxicity to most normal cells. Numerous studies have demonstrated the potential use of recombinant soluble TRAIL as a cancer therapeutic agent. We have showed previous administration of a recombinant adeno-associated virus (rAAV) vector expressing soluble TRAIL results in an efficient suppression of human tumor growth in nude mice. In the present study, we introduced Tet-On gene expression system into the rAAV vector to control the soluble TRAIL expression and evaluate the efficiency of the system in cancer gene therapy.MethodsControllability of the Tet-On system was determined by luciferase activity assay, and Western blotting and enzyme-linked immunoabsorbent assay. Cell viability was determined by MTT assay. The breast cancer xenograft animal model was established and recombinant virus was administrated through tail vein injection to evaluate the tumoricidal activity.ResultsThe expression of soluble TRAIL could be strictly controlled by the Tet-On system in both normal and cancer cells. Transduction of human cancer cell lines with rAAV-TRE-TRAIL&rAAV-Tet-On under the presence of inducer doxycycline resulted in a considerable cell death by apoptosis. Intravenous injection of the recombinant virus efficiently suppressed the growth of human breast carcinoma in nude mice when activated by doxycycline.ConclusionThese data suggest that rAAV-mediated soluble TRAIL expression under the control of the Tet-On system is a promising strategy for breast cancer therapy.
Highlights
Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) functions as a cytokine to selectively kill various cancer cells without toxicity to most normal cells
Controllable expression of target gene driven by tet-on system To evaluate a controllable gene expression of the target gene driven by the Tet-On system, HEK293T/17 cells were first transduced with the recombinant virus rAAVTRE-Luc&associated virus (AAV)-Tet-On at 2 × 105 genome particles (Gps) per cell.The relative light units representing luciferase activity in the cell lysate were detected
This result was confirmed in the cells transduced with AAV-tetracycline responsive element (TRE)-enhanced green fluorescent protein (EGFP)&AAV-Tet-On (Figure 1B), in which GFP expression driven by TRE and observed by fluorescence microscopy was as strong as that driven by CAG in AAV-CAG-EGFP [17]
Summary
Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) functions as a cytokine to selectively kill various cancer cells without toxicity to most normal cells. Numerous studies have demonstrated the potential use of recombinant soluble TRAIL as a cancer therapeutic agent. We have showed previous administration of a recombinant adeno-associated virus (rAAV) vector expressing soluble TRAIL results in an efficient suppression of human tumor growth in nude mice. We introduced Tet-On gene expression system into the rAAV vector to control the soluble TRAIL expression and evaluate the efficiency of the system in cancer gene therapy. Our previous study showed that administration of the recombinant adeno-associated virus (rAAV) vector expressing soluble TRAIL (sTRAIL) results in efficient suppression. One of the key points in successfully implementing gene therapy or biological therapy in the clinical setting is to be able to regulate the targeted gene expression strictly and consistently as and when it is needed
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
