hTPO和hNIS共转染胶质瘤细胞U251介导放射性碘摄取的研究

目的 将人甲状腺过氧化物酶（hTPO）基因及人钠/碘同向转运体（hNIS）基因共转入胶质瘤细胞系U251后,研究其摄碘能力的变化.方法 克隆、重组、包装并扩增纯化得到重组腺病毒（AdTPO）,测定病毒滴度,Western-Blotting检测重组腺病毒的表达.使用脂质体转染法将hNIS基因转染入人胶质瘤细胞系U251中,经过G418硫酸盐筛选获得稳定表达hNIS的细胞系（hNIS-U251）,为hNIS-U251组;使用重组腺病毒将hTPO基因转导入hNIS-U251中,使胶质瘤细胞获得hTPO基因（AdTPO-hNIS-U251）,为AdTPO-hNIS-U251组;未转入hTPO和hNIS的细胞为对照组（U251）.然后进行3组稳定表达细胞系体外摄125I实验及体外125I外流实验.3组间两两比较用q检验（Newman-Keuls法）.结果 AdTPO-hNIS-U251细胞、hNIS-U251细胞和U251细胞所摄取125I分别为（74 647.53±3605.88）、（55 769.96±4353.26）和（507.67±57.69）计数/min,3组间差异有统计学意义（F=836.17,P＜0.01）.AdTPO-hNIS-U251组较对照组（U251）摄125I能力增高约147倍（q=55.64,P＜0.01）,hNIS-U251组较对照组（U251）摄碘能力增高约110倍（q=41.47,P＜0.01）.AdTPO-hNIS-U251组较hNIS-U251组高约1.3倍（q=14.17,P＜0.01）.在体外125I外流实验中证实AdTPO-hNIS-U251组125I外流减慢,其有效半衰期延长至13 min.结论 将hTPO和hNIS基因共转染至胶质瘤细胞系U251后,能有效提高U251的摄碘能力.

125I uptake in U251 glioma cell co-transfected with the human sodium/iodide symporter and the human thyroperoxidase

Objective To investigate the iodide uptake by U251 glioma cell lines which were transfered with both human sodium/iodide symporter (hNIS) and human thyroperoxidase (hTPO) genes. Methods Recombinant adenosine virus AdTPO was constructed through cloning, recombination, packaging and amplifying. The viral titers were calculated after purification. The protein expression of AdTPO was tested by Western-Blotting and the recombinant plasmids PcDNA3. 1/hNIS were constructed. After hNIS gene was transfected into human glioma cell lines U251 through liposome, the cell lines with stable hNIS expression (hNIS-U251) selected by G418 antibiotics were defined as hNIS-U251 group. Then, hTPO was transducted into hNIS-U251 with adenosine virus (AdTPO-hNIS-U251 group). U251 cells with no plasmid were used as the control group (U251). Cultured cells from each group were studied for 125I uptake as well as 125I efflux rate. Student-Newman-Keuls in multiple range test was used. Results AdTPO-hNIS-U2.51 with stable expression was successfully established by transfecting hNIS and hTPO genes into human glioma cell lines. The 125I uptake by AdTPO-hNIS-U251, hNIS-U251 and U251 cell lines was (74 647.53 ±3605.88), (55 769.96 ±4353.26) and ( 507.67 ± 57.69 ) counts/min, respectively ( F = 836. 17, P ＜ 0.05 ). The uptake compacity by AdTPO-hNIS-U251 was 147 fold higher than that by U251 (q =55.64, P＜0.01 ) and 1.3 fold higher that by hNIS-U251 (q = 14. 17, P ＜0.01 ). 125I efflux rate was prolonged in AdTPO-hNIS-U251 group and its effective half time was 13 min. Conclusion Enhanced 125I uptake by the human glioma cell lines can be achieved with combined transfection of hNIS and hTPO genes.