Transoriptional Tayiting of herpes simplex virus for cell-specific replication

我们开发了一种病毒介导的肿瘤治疗策略，在这种策略中，单纯疱疹病毒(HSV)的复制和相关的细胞毒性被一种重要的即刻早期基因的调控表达限制在特定的细胞类型。构建了单纯疱疹病毒载体G92A，其生长受限于表达白蛋白的分裂细胞。G92a在HSV-1 ICP4缺失突变体D120的胸苷激酶(Tk)基因内含有白蛋白增强子/启动子-ICP4转基因。此外，它还含有ICP4转基因上游的E.coliLacZ基因，受tk启动子的控制。因此，在更昔洛韦(tk-)存在的情况下，G92a斑块与X-Gal(LacZ+)染色。在体外，G92A在3个白蛋白表达的人肝癌细胞系中复制良好，并摧毁它们，而在8个非白蛋白表达的人肿瘤细胞系中不复制。这种细胞特异性在体内是保守的，单次接种G92A可显著抑制已建立的皮下肝癌肿瘤的生长，而对非白蛋白表达的肿瘤的生长没有影响。肝内接种G92a的小鼠，在野生型HSV致死率为100%的情况下，没有表现出疾病症状。这些研究表明，将生产性、裂解性感染限制在特定的细胞类型上是可行的。包含其他细胞特异性调节区的HSV载体应该可以靶向各种类型的肿瘤。

We have developed a strategy for viral-mediated tumor therapy, where herpes simplex virus (HSV) replication and associated cytotoxicity are limited to a specific cell-type by the regulated expression of an essential immediate-early gene. A HSV vector, G92A,was constructed whose growth is restricted to albumin-expressing, dividing cells. G92A contains an albumin enhancer/promoter-ICP4 transgene within the thymidine kinase (tk) gene of the HSV-1 ICP4 deletion mutant d120. In addition, it contains the E.coli LacZ gene upstream of the ICP4 transgene, under control of the tk promoter. Therefore, G92A plaques stain bule with X-gal (lacZ+) in the presence of gancilovir (tk-). In Vitro, G92A replicates well in 3 human hepatoma (albumin-expressing) cell lines, destroying them, and not in 8 non-albumin-expressing human tumor cell lines. This cell-specificity was conserved in vivo, where the growth of established subcutaeous hepatoma tumors was significantly inhibited by a single inoculation of G92A,whereas, there was no effect on the growth of non-albumin expressing tumors. Mice inoculated intrahepatically with G92A,at doese that were 100% lethal with wild-type HSV,exhibited no symptoms of disease. These studies demonstrate the feasibility of confining a productive, lytic infection to defined cell types. HSV vectors containing other cell-specific regulatory regions should confer targeting to a variety of tumor types.