Selective ablation of human cancer cells by telomerase-specific adenoviral suicide gene therapy vectors expressing bacterial nitroreductase
Selective ablation of human cancer cells by telomerase-specific adenoviral suicide gene therapy vectors expressing bacterial nitroreductase
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DOI：
10.1038/sj.onc.1206168
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发表时间：
2003-01-23
期刊：
影响因子：
8
通讯作者：
Keith, WN
中科院分区：
文献类型：
--
作者：
Bilsland, AE;Anderson, CJ;Keith, WN
端粒酶的再活化维持端粒功能，并且被认为对大多数人类癌细胞的永生化至关重要。癌细胞中端粒酶表达的升高是高度特异性的：相对于正常细胞，癌细胞中RNA（hTR）和蛋白质（hTERT）组分的转录强烈上调。因此，端粒酶启动子可以通过在癌细胞而不是正常细胞中选择性地表达自杀基因而用于癌症基因治疗。自杀基因疗法的一个实例是细菌硝基还原酶（NTR）基因，其将前药CB 1954生物活化成活性细胞毒性烷化剂。我们描述了携带细菌NTR基因的腺病毒载体的构建，该基因在hTR或hTERT启动子的控制下。用腺病毒载体感染的正常细胞和癌细胞中NTR表达的Western印迹分析显示癌细胞特异性硝基还原酶表达。在一组7个癌细胞系中用腺病毒端粒酶-NTR构建体感染导致对前体药物CB 1954的致敏性高达18倍，这种效应在两个耐药卵巢细胞系中保留。重要的是，在四种正常细胞株中的任何一种中均未观察到任何启动子的致敏作用。最后，在子宫颈和卵巢异种移植模型中，在单次瘤内注射低剂量的载体，然后注射CB 1954后观察到有效的效果。
Reactivation of telomerase maintains telomere function and is considered critical to immortalization in most human cancer cells. Elevation of telomerase expression in cancer cells is highly specific: transcription of both RNA (hTR) and protein (hTERT) components is strongly upregulated in cancer cells relative to normal cells. Therefore, telomerase promoters may be useful in cancer gene therapy by selectively expressing suicide genes in cancer cells and not normal cells. One example of suicide gene therapy is the bacterial nitroreductase (NTR) gene, which bioactivates the prodrug CB1954 into an active cytotoxic alkylating agent. We describe construction of adenovirus vectors harbouring the bacterial NTR gene under control of the hTR or hTERT promoters. Western blot analysis of NTR expression in normal and cancer cells infected with adenoviral vectors showed cancer cell-specific nitroreductase expression. Infection with adenoviral telomerase-NTR constructs in a panel of seven cancer cell lines resulted in up to 18-fold sensitization to the prodrug CB1954, an effect that was retained in two drug-resistant ovarian lines. Importantly, no sensitization was observed with either promoter in any of the four normal cell strains. Finally, an efficacious effect was observed in cervical and ovarian xenograft models following single intratumoural injection with low doses of vector, followed by injection with CB1954.