Kramm C M, Rainov N G, Sena-Esteves M, Chase M, Pechan P A, Chiocca E A, Breakefield X O
Neuroscience Center, Massachusetts General Hospital, Boston 02129, USA.
Hum Gene Ther. 1996 Feb 10;7(3):291-300. doi: 10.1089/hum.1996.7.3-291.
The present study investigated the ability of a recombinant herpes simplex virus type 1 (HSV) vector to deliver genes into disseminated brain tumor foci through intrathecal injection of the vector. The animal model was designed to simulate brain tumors with cerebrospinal fluid (CSF) metastases, which are found especially in the pediatric population. 9L gliosarcoma cells were injected both into the right frontal lobe and in through the cisterna magna of adult rats. The HSV vector, hrR3, was inoculated intrathecally 5 days later. This vector is defective in the gene for ribonucleotide reductase, and, therefore, replicates preferentially in dividing cells; it retains an intact HSV-thymidine kinase gene (HSV-tk). Two days after injection of the vector, immunohistochemical staining for HSV thymidine kinase (HSV-TK) revealed expression in frontal tumors, as well as in leptomeningeal tumor foci along the entire neuroaxis. HSV-TK-immunopositive cells were most frequent in small tumors contacting the CSF pathways. Frontal lobe tumors showed the highest density of HSV-TK-immunopositive cells around their periphery with little expression in central parts. Some paraventricular neurons temporarily showed HSV-TK-immunolabeling at this early time point. The number of HSV-TK-immunopositive tumor cells markedly decreased 5 days after injection of the HSV vector. In all animals, some toxicity was observed in the first 2-4 days after virus injection with extensive leptomeningeal inflammation. In conclusion, intrathecal application of HSV vectors can mediate widespread transfer of the therapeutic HSV-tk gene into disseminated tumors throughout the brain and CSF pathways. Although there was marked toxicity associated with intrathecal injection of this vector, this mode of gene delivery offers a promising approach for treatment of CSF-metastases in conjunction with development of less toxic vectors.
本研究调查了重组1型单纯疱疹病毒（HSV）载体通过鞘内注射将基因传递至播散性脑肿瘤病灶的能力。该动物模型旨在模拟伴有脑脊液（CSF）转移的脑肿瘤，这种情况尤其多见于儿童群体。将9L胶质肉瘤细胞注射到成年大鼠的右额叶和小脑延髓池。5天后经鞘内接种HSV载体hrR3。该载体的核糖核苷酸还原酶基因有缺陷，因此优先在分裂细胞中复制；它保留了完整的HSV胸苷激酶基因（HSV-tk）。注射载体两天后，HSV胸苷激酶（HSV-TK）的免疫组织化学染色显示在额叶肿瘤以及沿整个神经轴的软脑膜肿瘤病灶中有表达。HSV-TK免疫阳性细胞在与CSF通路接触的小肿瘤中最为常见。额叶肿瘤在其周边显示出最高密度的HSV-TK免疫阳性细胞，而中央部分表达较少。在这个早期时间点，一些脑室旁神经元暂时显示出HSV-TK免疫标记。注射HSV载体5天后，HSV-TK免疫阳性肿瘤细胞数量明显减少。在所有动物中，在病毒注射后的头2 - 4天观察到一些毒性，伴有广泛的软脑膜炎。总之，鞘内应用HSV载体可介导治疗性HSV-tk基因广泛转移至全脑和CSF通路中的播散性肿瘤。尽管鞘内注射该载体存在明显毒性，但这种基因传递方式为结合开发毒性较小的载体治疗CSF转移提供了一种有前景的方法。
