表达大肠杆菌胞嘧啶脱胺酶(CD)基因的重组腺病毒AdCD体外转染小鼠黑色素瘤细胞B16F10,结果显示转染了CD基因的B16F10细胞对5-氟胞嘧啶(5FC)的敏感性显著提高.将经AdCD/5FC系统处理的B16F10细胞上清倍比稀释后.加至野生型B16F10细胞中,发现当上清仅占6.25%时即可对野生型B16F10细胞发挥明显的杀伤作用,提示AdCD/5FC介导的旁观者效应可能是通过5FC经CD酶代谢产生的毒性产物扩散而实现的.本实验还观察了CD基因体内转染后的杀伤效果,荷瘤小鼠经注射AdCD并连续10天给予5FC治疗后,与PBS、对照病毒AdLacZ/5FC治疗小鼠比较,小鼠肿瘤生长明显受到抑制,小鼠存活期明显延长.

Escherichia coli cytosine deaminase ( CD) gene was transfected into murine B16F10 melanoma cells by recombinant adenovirus AdCD in vitro . The tumor cells infected with AdCD were more sensitive to 5-fluorocytosine (5FC) than cells infected with a control adenovirus AdLacZ. The supernatant from B16F10 cells treated with AdCD/5FC was transferred to uninfected cells, and we found that only 6. 25 % of the supernatant could significantly inhibit the growth of wild type B16F10 cells. When AdCD was directly injected into established subcutaneous B16F10 tumors in mice followed by intraperitoneal injection of 5FC for 10 days, a significant reduction in tumor size and prolongation of survival period were observed. These studies not only explored the cytotoxic effects of AdCD/5FC on B16F10 melanoma cells in vitro and in vivo but also elucidated the mechanisms of its bvstander effect.

R-5

自然科学基金(39600181)资助