[Inhibitory effects of HSV-tk/GCV system mediated by recombinant adeno-associated virus 2 on rabbit lens epithelial cells].
OBJECTIVE
To study the inhibitory effects of recombinant adeno-associated virus 2 (rAAV2)-mediated herpes simplex virus thymidine kinase/ganciclovir (HSV-tk/GCV) system on the rabbit lens epithelial cells (N/N1003A) in vitro and to investigate the mechanism of cell death.


METHODS
After N/N1003A cells had been transfected with rAAV2-EGFP, expression of enhanced green fluorescent protein (EGFP) were observed by inverted fluorescent microscope and the transfection efficiency was detected by flow cytometry. N/N1003A cells were infected by recombinant virus rAAV2/HSV-tk as the treated group, and the uninfected N/N1003A cells were used as the controls. The dose- and time-dependent efficiency and bystander effect of HSV-tk/GCV system on the cells were studied by MTT assay. Apoptosis and necrosis were observed by phase contrast microscope, electron microscope and Hoechst33258 stain. Apoptotic cell rate and cell cycle were detected by flow cytometry.


RESULTS
rAAV2 vector encoding EGFP gene could be transfected into N/N1003A cells stably and efficiently. The effects of GCV on these two groups were dose-dependent (F = 13.076. 239, P < 0.001). The difference of percentages of survival cells between the study group and the control group at various doses of GCV was statistically significant (F = 53,47.119, P < 0.001). The 50% of the inhibitory concentration (IC50) of GCV in the study group was 2 mg/L and was 524 mg/L in the control group. The killing efficiency of GCV increased with the prolongation of time and showed significant bystander effect. Cell apoptosis and necrosis were observed in N/N1003A-tk cells transfected by GCV, and the percentage of apoptotic cells was significantly higher than that of the control group (t = 3.83, P < 0.01). The percentages of N/N1003A-tk cells in the S phase of the cell cycle was significantly higher than that of the control group (t = 3.55, P < 0.01). Whereas the percentages of the G0/ G1 phase in GCV treated cells was significantly lower than that of the control group ( t = 4.29, P < 0.01).


CONCLUSIONS
GCV can kill efficiently the N/N1003A cells infected by recombinant virus rAAV2/HSV-tk, and there is strong bystander effect. Recombinant adeno-associated virus-mediated HSV-tk/GCV suicide gene system may provide an effective approach for the treatment of lens posterior capsular opacification.
Ding
Zhi-Xiang
ZX
Department of Ophthalmology, Xiangya Hospital, Central South University, Changsha 410008, China.
Tan
Qian
Q
Liu
Shuang-Zhen
SZ
Yang
Jing
J
Li
Zhong-Qing
ZQ
Liu
Dan
D
Hu
Mei
M
D000818:Animals; D002470:Cell Survival; D002478:Cells, Cultured; D000229:Dependovirus / Q000235:genetics*; D004847:Epithelial Cells; D015774:Ganciclovir / Q000494:pharmacology*; D041722:Genes, Transgenic, Suicide; D005822:Genetic Vectors; D007908:Lens, Crystalline / Q000166:cytology*; D011817:Rabbits; D018139:Simplexvirus / Q000201:enzymology; D013937:Thymidine Kinase; D014162:Transfection
D013937:Thymidine Kinase; D015774:Ganciclovir