In vivo antitumor effect of CDglyTK double suicide gene on C6 glioma cells / 中华神经医学杂志

ABSTRACT

Objective To observe the inhibitory effect of CDglyTK double suicide gene on the growth of C6 glioma in vivo. Methods Thirty 4- to 6-week-old male Balb/c nude mice with subcutaneous injection of C6 glioma cells were randomized into two groups for injections with 5x105 CFU of CDglyTK (treatment group) or 50 μL PBS (control group) for 5 consecutive days. RT-PCR was performed to examine the mRNA expression of the CDglyTK fusion gene in the tumor cells. All the mice received intraperitoneal injections of 5-FC (500 mg/kg) and GCV (60 mg/kg) for 7 days, and the tumor volume, weight and mice survival time were observed. The effect of CDglyTK gene transfer on the apoptosis of the C6 glioma cells was evaluated using flow cytometry. Results RT-PCR demonstrated effective expression of the fusion gene in C6 glioma cells. In the fourth week of tumor cell inoculation, the tumor in the control group grew to the volume of 20 mmx30 mm with occasional death of the mice, and in week 6, all the control mice died. In the treatment group, the tumors showed no obvious growth with a volume of around 5 mm, and some of tumors even disappeared; no death of the mice occurred at the end of the third month. By gross observation, the tumors in the control mice were large and red with rich blood supply, but those in the treatment group showed reduced volume. On day 21 following tumor cell inoculation, the weight of the tumors was significantly greater in the control group than in the treatment group (2.51±0.58 vs 0.35±0.26 g, P<0.05), and the growth inhibition rate was 86.1% in the latter group. Flow cytometry showed significantly higher apoptotic rate of the tumor cells in the treatment group than in the control group (34.41%±5.2% vs 2.92%±1.3%, P<0.05), and electron microscope demonstrated the formation of apoptotic bodies in the tumor cells in the former group. Conclusion Significant antitumor effects can be obtained with the CKglyTK fusion gene in combination with the two prodrugs.