Ulasov Ilya V, Rivera Angel A, Han Yu, Curiel David T, Zhu Zeng B, Lesniak Maciej S
Division of Neurosurgery, The University of Chicago, Chicago, Illinois 60637, USA.
J Neurosurg. 2007 Sep;107(3):617-27. doi: 10.3171/JNS-07/09/0617.
Gene therapy protocols for malignant gliomas utilize adenoviral vectors that rely almost exclusively on the adenovirus serotype 5 (Ad5) backbone. The authors have previously shown that chimeric vectors that bind to the Ad3 receptor, or CD46, increase the transduction efficiency of malignant brain tumors. In light of the debate regarding the efficacy of CD46 compared with CD80/CD86 in binding Ad3 virions, the authors now examine the expression and transduction efficiency of Ad5/3 chimeras that bind via CD80/CD86.
The authors first analyzed CD80/CD86 expression in glioma cell lines. They then used three replication-defective vectors containing a luciferase reporter gene: Ad5/3 (containing the tail and shaft domain of Ad5 and the knob domain of Ad3); Ad3/5 (containing the tail of Ad5, shaft of Ad3, and knob of Ad5); and Ad3/3 (containing the tail of Ad5, shaft of Ad3, and knob of Ad3). These vectors were analyzed both in vitro and in vivo against malignant glioma cells. To examine further the effect of Ad5/3 fiber modification, the authors created an oncolytic vector, conditionally replicative Ad5/3 (CRAd5/3).
The Ad5/3 vector showed a 10- to 100-fold enhanced transduction efficiency of malignant glioma compared with replication-defective wild-type adenovirus (reAd5) (p < 0.05). Moreover the use of Ad5/3 reduced transgene expression by more than 90% in normal human brain cells compared with reAd5. Finally, the use of CRAd5/3 inhibited tumor cell proliferation by 43% more than replication-competent wild-type virus in vitro (p < 0.05).
The results of this study demonstrate that the Ad5/3 vector offers superior transduction efficiency and low toxicity in the setting of brain tumors, and therefore represents a potential new approach to gene therapy for malignant gliomas.
恶性胶质瘤的基因治疗方案使用的腺病毒载体几乎完全依赖腺病毒5型（Ad5）骨架。作者先前已表明，与Ad3受体或CD46结合的嵌合载体可提高恶性脑肿瘤的转导效率。鉴于在结合Ad3病毒粒子方面，CD46与CD80/CD86功效的争论，作者现在研究通过CD80/CD86结合的Ad5/3嵌合体的表达及转导效率。
作者首先分析了胶质瘤细胞系中CD80/CD86的表达。然后他们使用了三种含有荧光素酶报告基因的复制缺陷型载体：Ad5/3（包含Ad5的尾部和杆部结构域以及Ad3的头部结构域）；Ad3/5（包含Ad5的尾部、Ad3的杆部以及Ad5的头部）；以及Ad3/3（包含Ad5的尾部、Ad3的杆部以及Ad3的头部）。这些载体在体外和体内针对恶性胶质瘤细胞进行了分析。为进一步研究Ad5/3纤维修饰的效果，作者构建了一种溶瘤载体，即条件性复制型Ad5/3（CRAd5/3）。
与复制缺陷型野生型腺病毒（reAd5）相比，Ad5/3载体对恶性胶质瘤的转导效率提高了10至100倍（p < 0.05）。此外，与reAd5相比，Ad5/3在正常人脑细胞中转基因表达降低了90%以上。最后，在体外，使用CRAd5/3比有复制能力的野生型病毒抑制肿瘤细胞增殖多43%（p < 0.05）。
本研究结果表明，Ad5/3载体在脑肿瘤治疗中具有卓越的转导效率和低毒性，因此代表了一种潜在的恶性胶质瘤基因治疗新方法。
