Combined Fiber Modifications Both to Target αvβ6 and Detarget the Coxsackievirus-Adenovirus Receptor Improve Virus Toxicity Profiles In Vivo but Fail to Improve Antitumoral Efficacy Relative to Adenovirus Serotype 5
Combined Fiber Modifications Both to Target αvβ6 and Detarget the Coxsackievirus-Adenovirus Receptor Improve Virus Toxicity Profiles In Vivo but Fail to Improve Antitumoral Efficacy Relative to Adenovirus Serotype 5
复制标题
DOI：
10.1089/hum.2011.218
复制
发表时间：
2012-09-01
影响因子：
4.2
通讯作者：
Hart, Ian R.
中科院分区：
文献类型：
--
作者：
Coughlan, Lynda;Vallath, Sabari;Hart, Ian R.
在全身递送后实现高效的肿瘤靶向是溶瘤基因治疗师面临的相当大的挑战。有效的重靶向应该与改善体内安全性、降低肝毒性、最小化脱靶相互作用以及改善抗肿瘤效力和功效的努力相结合。我们先前描述了腺病毒血清型5（Ad 5）成功地重靶向α（v）β（6），α（v）β（6）是一种在许多人类癌中高度过表达的整合素。在这项研究中，我们通过引入突变进一步修饰了该构建体，这些突变可以消除柯萨奇病毒-腺病毒受体（CAR）与因子IX（FIX）/C4 b结合蛋白（C4 BP）的结合和推定的相互作用。我们已经发现，所得载体Ad 5 - 477 d/TAYT（A20）显示出期望的体内安全性特征。该载体不凝集人红细胞，静脉内递送后不能引起血小板减少症，具有促炎细胞因子的有限诱导，并且当与Ad 5-EGFP（WT）相比时导致低水平毒性（天冬氨酸转氨酶/丙氨酸转氨酶）。此外，其在枯否细胞中的蓄积减少（1小时），并在随后的时间点（24和96小时）限制肝细胞转导。亲本载体Ad 5-EGFP（A20）也显示出许多这些期望的特性。由于两种A20修饰载体的安全性得到改善，我们在抗肿瘤疗效研究中将剂量从2 × 10（10）个病毒颗粒增加到4 × 10（10）个病毒颗粒。与Ad 5-EGFP（WT）相比，我们观察到在早期时间点（96小时）降低肿瘤生长百分比的改善，尽管增加剂量并没有有益地影响治疗结果。实验完成后，我们在所有A20处理组的肿瘤中检测到E1 A染色增加，并且我们确定E1 A表达主要位于α（v）β（+）（6）肿瘤细胞内。然而，尽管明显有效的肿瘤转导，这并没有导致增强的抗肿瘤功效，因为病毒未能有效地传播到整个肿瘤块，可能是由于物理肿瘤内的限制。这凸显了在开发此类载体用于未来癌症基因治疗应用之前需要克服的剩余挑战。
Achieving high-efficiency tumor targeting after systemic delivery is a considerable challenge facing oncolytic gene therapists. Efficient retargeting should be combined with efforts to improve in vivo safety, reduce hepatotoxicity, minimize off-target interactions, and improve antitumoral potency and efficacy. We previously described the successful retargeting of adenovirus serotype 5 (Ad5) to alpha(v)beta(6), an integrin that is highly overexpressed in numerous human carcinomas. In this study, we have further modified this construct by introducing mutations that ablate coxsackievirus-adenovirus receptor (CAR) binding and putative interactions with factor IX (FIX)/C4b-binding protein (C4BP). We have found that the resulting vector, Ad5-477d/TAYT(A20), displays a desirable in vivo safety profile. This vector does not agglutinate human erythrocytes, fails to cause thrombocytopenia after intravenous delivery, has limited induction of proinflammatory cytokines, and results in low-level toxicity (aspartate aminotransferase/alanine aminotransferase) when compared with Ad5-EGFP(WT). Furthermore, it has reduced accumulation in Kupffer cells (1 hr) and limited hepatocyte transduction at later time points (24 and 96 hr). The parental vector, Ad5-EGFP(A20), also displayed many of these desirable properties. As a result of the improved safety profile of both A20-modified vectors, we escalated the dose from 2 x 10(10) to 4 x 10(10) viral particles in an antitumoral efficacy study. We observed improvements in reducing percent tumor growth at early time points (96 hr) when compared with Ad5-EGFP(WT), although increasing the dose did not affect the therapeutic outcome beneficially. On completion of the experiment, we detected increased E1A staining in the tumors of all A20-treated groups and we determined that E1A expression was localized largely within alpha(v)beta(+)(6) tumor cells. However, in spite of apparently efficient tumor transduction, this did not result in enhanced antitumoral efficacy as the virus failed to disseminate effectively throughout the tumor mass, presumably due to physical intratumoral restrictions. This highlights a remaining challenge that needs to be overcome before such vectors can be developed for future cancer gene therapy applications.