Han Z Q, Assenberg M, Liu B L, Wang Y B, Simpson G, Thomas S, Coffin R S
Biovex Ltd., 70 Milton Park, Abingdon, Oxon OX14 4RX, UK.
J Gene Med. 2007 Feb;9(2):99-106. doi: 10.1002/jgm.999.
Tumour necrosis factor alpha (TNFalpha) therapy is a promising anti-cancer treatment when combined with radiotherapy due to its potent radio sensitising effects, but systemic toxicity has limited its clinical use. Previously, non-replicative adenovirus vectors have been used to deliver TNFalpha directly to the tumour, including under the control of a radiation sensitive promoter. Here, we have used an ICP34.5 deleted, oncolytic herpes simplex virus (HSV) for delivery to increase expression levels and spread through the tumour, and the use of the US11 true late HSV promoter to limit expression to where the virus replicates, i.e. selectively in tumour tissue.
TNFalpha expression under the CMV or US11 promoter was compared on cell lines CT26, BHK and Fadu. To further compare the activities of the promoters, expression of human TNFalpha was analysed in the presence and absence of acyclovir--an inhibitor of viral DNA replication and on HSV/ICP34.5- non-permissive cell line 3T6. The in vivo efficacy and toxicity of TNFalpha viruses were compared using A20 double flank tumour model in Balb/C mice and Fadu tumour model in nude mice.
The results demonstrated that the US11 promoter significantly reduced and delayed TNFalpha expression as compared to use of the CMV promoter, especially in non-permissive cells or in the presence of acyclovir. Despite the reduced and more selective expression levels, US11 driven TNFalpha showed improved anti-tumour effects compared to CMV driven TNFalpha, and without the toxic side effects.
This approach is therefore beneficial in increasing localised TNFalpha expression as compared to the use of non-replicative approaches, and combines the effects of TNFalpha with oncolytic virus replication which is expected to further enhance the efficacy of radiotherapy in a combined treatment approach.
肿瘤坏死因子α（TNFα）疗法与放疗联合使用时，因其强大的放射增敏作用而成为一种有前景的抗癌治疗方法，但全身毒性限制了其临床应用。此前，非复制性腺病毒载体已被用于将TNFα直接递送至肿瘤，包括在辐射敏感启动子的控制下。在此，我们使用了一种缺失ICP34.5的溶瘤单纯疱疹病毒（HSV）进行递送，以提高表达水平并在肿瘤中扩散，并使用US11真正的HSV晚期启动子将表达限制在病毒复制的部位，即在肿瘤组织中选择性表达。
比较了CMV或US11启动子控制下TNFα在CT26、BHK和Fadu细胞系中的表达。为了进一步比较启动子的活性，在有和没有阿昔洛韦（一种病毒DNA复制抑制剂）的情况下，以及在HSV/ICP34.5非允许细胞系3T6中分析了人TNFα的表达。使用Balb/C小鼠的A20双侧肿瘤模型和裸鼠的Fadu肿瘤模型比较了TNFα病毒的体内疗效和毒性。
结果表明，与使用CMV启动子相比，US11启动子显著降低并延迟了TNFα的表达，尤其是在非允许细胞中或存在阿昔洛韦的情况下。尽管表达水平降低且更具选择性，但与CMV驱动的TNFα相比，US11驱动的TNFα显示出更好的抗肿瘤效果，且没有毒副作用。
因此，与使用非复制方法相比，这种方法有利于增加局部TNFα的表达，并将TNFα的作用与溶瘤病毒复制相结合，有望在联合治疗方法中进一步提高放疗的疗效。
