Yang Wen Qing, Senger Donna, Muzik Huong, Shi Zhong Qiao, Johnson Denise, Brasher Penny M A, Rewcastle N Barry, Hamilton Mark, Rutka Jim, Wolff Johannes, Wetmore Cynthia, Curran Tom, Lee Patrick W K, Forsyth Peter A
Department of Oncology, University of Calgary and Tom Baker Cancer Centre, Calgary, Alberta, T2N 4N2 Canada.
Cancer Res. 2003 Jun 15;63(12):3162-72.
Medulloblastoma (MB), the most common pediatric brain tumor, is a highly malignant disease with a 5-year survival rate of only 60%. Tumor cells invade surrounding tissue and disseminate through cerebral spinal fluid, making treatment difficult. Human reovirus type 3 exploits an activated Ras pathway in tumor cells to support productive infection as an oncolytic virus. Here, we examined the ability of human reovirus to kill MB cells lines and surgical specimens in vitro and inhibit tumor growth/metastases in vivo. Most human MB cell lines tested (five of seven = 71.4%), two MB cell lines derived from spontaneously arising tumors in Patched-1(+/-) mice (two of two = 100%) and three MB primary cultures derived from surgical specimens, were susceptible to reovirus infection. Reovirus was internalized and transcribed in both susceptible and resistant cell lines. However, viral protein synthesis was restricted to cell lines with higher levels of activated Ras, suggesting that Ras plays a critical role in reovirus oncolysis in MB. Using an in vivo Daoy orthotopic animal model, we found that a single i.t. injection of reovirus dramatically prolonged survival compared with controls (160 versus 70 days, respectively; P = 0.0003). Repeating this experiment with GFP-labeled Daoy cells and multiple i.t. administrations of reovirus, we again found prolonged survival and a dramatic reduction in spinal and leptomeningeal metastases (66.7% in control injections versus 0.0% in the live virus group). These data suggest that this oncolytic virus may be a potentially effective novel therapy against human MB. Its ability to reduce metastases to the spinal cord could allow a reduction in the dose/field of total neuroaxis cerebral-spinal radiotherapy currently used to treat/prevent cerebral spinal fluid dissemination.
髓母细胞瘤（MB）是最常见的儿童脑肿瘤，是一种高度恶性疾病，5年生存率仅为60%。肿瘤细胞侵袭周围组织并通过脑脊液扩散，使得治疗困难。3型人呼肠孤病毒利用肿瘤细胞中激活的Ras通路来支持其作为溶瘤病毒的有效感染。在此，我们研究了人呼肠孤病毒在体外杀死MB细胞系和手术标本以及在体内抑制肿瘤生长/转移的能力。大多数测试的人MB细胞系（7个中的5个 = 71.4%）、2个源自Patched-1(+/-)小鼠自发产生肿瘤的MB细胞系（2个中的2个 = 100%）以及3个源自手术标本的MB原代培养物，均对呼肠孤病毒感染敏感。呼肠孤病毒在敏感和耐药细胞系中均能内化和转录。然而，病毒蛋白合成仅限于具有较高激活Ras水平的细胞系，这表明Ras在MB的呼肠孤病毒溶瘤作用中起关键作用。使用体内Daoy原位动物模型，我们发现与对照组相比，单次经颅内注射呼肠孤病毒显著延长了生存期（分别为160天和70天；P = 0.0003）。用绿色荧光蛋白标记的Daoy细胞重复此实验并多次经颅内给予呼肠孤病毒，我们再次发现生存期延长且脊髓和软脑膜转移显著减少（对照注射组为66.7%，而活病毒组为0.0%）。这些数据表明，这种溶瘤病毒可能是一种针对人MB的潜在有效新疗法。其减少脊髓转移的能力可能允许降低目前用于治疗/预防脑脊液播散的全神经轴脑脊髓放疗的剂量/照射野。
