Ulasov Ilya V, Rivera Angel A, Nettelbeck Dirk M, Rivera Lisa B, Mathis J Michael, Sonabend Adam M, Tyler Matthew, Wang Ming, Douglas Joanne T, Lesniak Maciej S
Division of Neurosurgery, The University of Chicago, Chicago, IL 60637, USA.
Int J Oncol. 2007 Nov;31(5):1177-85.
Targeting gene expression to cancer cells remains a challenge for the development of gene and viral therapy for gliomas. Recent studies have highlighted transcriptional targeting as one of the possible solutions to overcome this limitation. In this context, melanoma associated antigens (MAAs) are usually over-expressed in brain tumors in comparison to normal brain tissue. For this reason, we investigated the use of the tyrosinase promoter as a transcriptional element to target oncolytic therapy for gliomas. Tyrosinase mRNA expression was evaluated by qRT-PCR in normal human brain tissue as well as in human glioma specimens. We found that this gene was significantly over-expressed in glioma cell lines and in primary glioma samples. Tyrosinase expression correlated with the grade of the tumor (p-value range: 0.05-0.001). Furthermore, transfection of several cell cultures with human and mouse tyrosinase promoters driving a luciferase reporter gene confirmed the activity of this promoter in mouse and human cells. To evaluate whether tyrosinase-activated conditionally replicative adenoviruses (CRAds) could induce toxicity in glioma cells, two vectors (Ad h/m and Ad24TYR) were tested in a mouse glioma model. C57BL/6 mice underwent intracranial injection of tumor cell line GL261. Survival was used to evaluate efficacy of the tested vectors. Mice receiving 1 x 10(9) MOI of Ad h/m and Ad24TYR following intracranial tumor implants had a median survival of 46+/-3 days (p<0.05); in contrast, those treated with medium had a median survival of 31+/-2 days. These results suggest that injection of tyrosinase CRAds leads to prolongation of survival in mice with experimental brain tumors. The tyrosinase promoter stands as a proof of principle of the potential use of MAA over-expression patterns for targeting novel anti-glioma therapies.
将基因表达靶向癌细胞仍然是胶质瘤基因治疗和病毒治疗发展面临的一项挑战。最近的研究强调转录靶向是克服这一限制的可能解决方案之一。在这种情况下,与正常脑组织相比,黑色素瘤相关抗原(MAA)通常在脑肿瘤中过度表达。因此,我们研究了使用酪氨酸酶启动子作为转录元件来靶向胶质瘤的溶瘤治疗。通过qRT-PCR评估正常人类脑组织以及人类胶质瘤标本中酪氨酸酶mRNA的表达。我们发现该基因在胶质瘤细胞系和原发性胶质瘤样本中显著过度表达。酪氨酸酶表达与肿瘤分级相关(p值范围:0.05 - 0.001)。此外,用驱动荧光素酶报告基因的人和小鼠酪氨酸酶启动子转染几种细胞培养物,证实了该启动子在小鼠和人类细胞中的活性。为了评估酪氨酸酶激活的条件性复制腺病毒(CRAd)是否能在胶质瘤细胞中诱导毒性,在小鼠胶质瘤模型中测试了两种载体(Ad h/m和Ad24TYR)。C57BL/6小鼠接受颅内注射肿瘤细胞系GL261。用生存情况来评估测试载体的疗效。颅内植入肿瘤后接受1×10⁹ MOI的Ad h/m和Ad24TYR的小鼠中位生存期为46±3天(p<0.05);相比之下,接受培养基治疗的小鼠中位生存期为31±2天。这些结果表明,注射酪氨酸酶CRAd可延长实验性脑肿瘤小鼠的生存期。酪氨酸酶启动子证明了利用MAA过度表达模式靶向新型抗胶质瘤治疗的潜在原理。