CD自杀基因系统对胶质瘤细胞作用的实验研究

EXPERIMENTAL TREATMENT OF BRAIN TUMOR CELLS USING CD SUICIDE GENE

将含大肠杆菌胞嘧啶脱氨酶(EC-CD)基因的重组逆转录病毒感染大鼠神经胶质瘤细胞C6,获得稳定表达CD的克隆细胞C6/CD。CD可以将无毒性的原药5-氟胞嘧啶(5-FC)转化成高度细胞毒性物质5-氟尿嘧啶(5-FU)。生长抑制试验表明C6/CD细胞对5-FC高度敏感,IC_(50)为3μmol/L;5-FC对C6细胞基本无毒性,IC_(50)近6000μmol/L;而C6/CD和C 6细胞均对低浓度5-FU敏感,IC_(50)小于1μmol/L。混合细胞试验表明C6/CD细胞在5-FC存在下对C6细胞有旁杀伤效应。本工作在细胞水平建立了一个治疗神经胶质瘤的自杀基因系统,过去无人报道过。

A negative selection system for glio-ma gene therapy was established in vitro. C 6 rat glioma cells were infected with recombined retrovirus which contain Es-cherichia coli cytosine deaminase (EC-CD) gene. The enzyme CD can transform the non-toxic prodrug 5-Fluorocytosine (5-FC) to the highly cellular toxic compound 5-Fluorouracil (5-FU). The growth inhibition studies proved that CD-positive cells were highly sensitive to 5-FC, the IC50 about 3 μmol/L, compared with an IC50 of approximately 6000μmol/L in parental C 6 cells. Both CD-positive and negative cells were sensitive to 5-FU at very low concentration (IC50<1μmol/L). Mixed cellular assay showed CD-positive cells had 'bystander effect' on CD-negative cells when exposed to 5-FC. Our results demonstrate that EC-CD gene should be an efficient suicide gene for the treatment of glioma.