Chung R Y, Saeki Y, Chiocca E A
Molecular Neuro-Oncology Laboratories, Neurosurgical Service, Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA.
J Virol. 1999 Sep;73(9):7556-64. doi: 10.1128/JVI.73.9.7556-7564.1999.
Deletion of the gamma34.5 gene coding for virulence markedly reduces cytotoxicity mediated by herpes simplex virus type 1 (HSV-1) (J. M. Markert et al., Neurosurgery 32:597-603, 1993; N. S. Markovitz et al. , J. Virol. 71:5560-5569, 1997). To target lytic virulence to tumors, we have created a novel HSV-1 mutant, designated Myb34.5. This viral mutant is characterized by a deletion of the gene for infected cell polypeptide 6 (ICP6; also known as UL39 or ribonucleotide reductase) and of the two endogenous copies of the gamma34.5 gene (RL1) and by reintroduction of one copy of gamma34.5 under control of the E2F-responsive, cellular B-myb promoter. On direct intracerebral inoculation in BALB/c mice, the 50% lethal dose (LD(50)) for Myb34.5 was 2.7 x 10(7) PFU while that for HSVs with mutations in the gamma34.5 gene could not be technically achieved with available viral stocks and it was estimated as >1 x 10(7) PFU. The LD(50) for an HSV with a single defect in ICP6 function was 1.3 x 10(6) PFU. Conversely, Myb34.5's oncolytic efficacy against a variety of human glioma cells in culture and in vivo was enhanced compared to that of HSVs with gamma34.5 mutations, and in fact, it was comparable to that of the wild-type F strain and of viral mutants that possess a wild-type gamma34.5 gene. The characteristic shutoff of host protein synthesis, occurring after infection of human SK-N-SH neuroblastoma cells by gamma34.5 mutant viruses (J. Chou and B. Roizman, Proc. Natl. Acad. Sci. USA 89:3266-3270, 1992), was not present after infection with Myb34.5. There was an increase of almost 3 logarithmic units in the production of progeny virus in arrested fibroblasts compared to that in cycling fibroblasts infected with Myb34.5. These results suggest that transcriptional regulation of gamma34.5 by cell cycle-regulated promoters can be used to target HSV-1 virulence toward tumors while maintaining the desirable neuroattenuated phenotype of a gamma34.5 mutant.
编码毒力的γ34.5基因的缺失显著降低了1型单纯疱疹病毒（HSV-1）介导的细胞毒性（J.M.马克特等人，《神经外科》32:597 - 603，1993；N.S.马尔科维茨等人，《病毒学杂志》71:5560 - 5569，1997）。为了将裂解性毒力靶向肿瘤，我们构建了一种新型的HSV-1突变体，命名为Myb34.5。这种病毒突变体的特征是感染细胞多肽6（ICP6；也称为UL39或核糖核苷酸还原酶）基因以及γ34.5基因（RL1）的两个内源性拷贝缺失，并在E2F应答的细胞B-myb启动子控制下重新引入一个γ34.5拷贝。在BALB/c小鼠中直接脑内接种时，Myb34.5的50%致死剂量（LD(50)）为2.7×10(7) PFU，而对于γ34.5基因突变的HSV，用现有的病毒毒株在技术上无法达到其LD(50)，估计>1×10(7) PFU。ICP6功能有单一缺陷的HSV的LD(50)为1.3×10(6) PFU。相反，与γ34.5基因突变的HSV相比，Myb34.5在体外培养和体内对多种人胶质瘤细胞的溶瘤效力增强，实际上，它与野生型F株以及具有野生型γ34.5基因的病毒突变体相当。γ34.5突变病毒感染人SK-N-SH神经母细胞瘤细胞后出现的宿主蛋白合成特征性关闭（J.周和B.罗伊兹曼，《美国国家科学院院刊》89:3266 - 3270，1992），在Myb34.5感染后未出现。与感染Myb34.5的循环成纤维细胞相比，静止成纤维细胞中子代病毒产量增加了近3个对数单位。这些结果表明，通过细胞周期调控启动子对γ34.5进行转录调控可用于将HSV-1毒力靶向肿瘤，同时维持γ34.5突变体所需的神经减毒表型。
