The Research Institute for Children, Children's Hospital, New Orleans, LA 70118, USA.
Int J Oncol. 2016 Jan;48(1):173-80. doi: 10.3892/ijo.2015.3223. Epub 2015 Oct 30.
Accurate detection of neuroendocrine (NE) tumors is critically important for better prognosis and treatment outcomes in patients. To demonstrate the efficacy of using an adenoviral vector for the detection of NE tumors, we have constructed a pair of adenoviral vectors which, in combination, can conditionally replicate and release Gaussia luciferase into the circulation after infecting the NE tumors. The expression of these two vectors is regulated upstream by an INSM1-promoter (insulinoma-associated-1) that is specifically active in NE tumors and developing NE tissues, but silenced in normal adult tissues. In order to retain the tumor-specificity of the INSM1 promoter, we have modified the promoter using the core insulator sequence from the chicken β-globin HS4 insulator and the neuronal restrictive silencing element (NRSE). This modified INSM1-promoter can retain NE tumor specificity in an adenoviral construct while driving a mutated adenovirus E1A gene (∆24E1A), the Metridia, or Gaussia luciferase gene. The in vitro cell line and mouse xenograft human tumor studies revealed the NE specificity of the INSM1-promoter in NE lung cancer, neuroblastoma, medulloblastoma, retinoblastoma, and insulinoma. When we combined the INSM1-promoter driven Gaussia luciferase with ∆24E1A, the co-infected NE tumor secreted higher levels of Gaussia luciferase as compared to the INSM1p-Gaussia virus alone. In a mouse subcutaneous xenograft tumor model, the combination viruses secreted detectable level of Gaussia luciferase after infecting an INSM1-positive NE lung tumor for ≥12 days. Therefore, the INSM1-promoter specific conditional replicating adenovirus represents a sensitive diagnostic tool to aid clinicians in the detection of NE tumors.
准确检测神经内分泌 (NE) 肿瘤对于改善患者预后和治疗效果至关重要。为了证明使用腺病毒载体检测 NE 肿瘤的疗效，我们构建了一对腺病毒载体，这对载体在感染 NE 肿瘤后可以条件性复制并将 Gaussia 荧光素酶释放到循环中。这两个载体的表达由 INSM1 启动子（胰岛素瘤相关蛋白-1）调节，该启动子在 NE 肿瘤和发育中的 NE 组织中特异性活跃，但在正常成年组织中沉默。为了保留 INSM1 启动子的肿瘤特异性，我们使用鸡β-球蛋白 HS4 绝缘子和神经元限制沉默元件（NRSE）的核心绝缘子序列对启动子进行了修饰。这种修饰后的 INSM1 启动子可以在腺病毒构建体中保留 NE 肿瘤特异性，同时驱动突变的腺病毒 E1A 基因（∆24E1A）、Metridia 或 Gaussia 荧光素酶基因。体外细胞系和小鼠异种移植人类肿瘤研究揭示了 INSM1 启动子在 NE 肺癌、神经母细胞瘤、髓母细胞瘤、视网膜母细胞瘤和胰岛素瘤中的 NE 特异性。当我们将 INSM1 启动子驱动的 Gaussia 荧光素酶与 ∆24E1A 结合使用时，共感染的 NE 肿瘤分泌的 Gaussia 荧光素酶水平高于单独使用 INSM1p-Gaussia 病毒时的水平。在小鼠皮下异种移植肿瘤模型中，当感染 INSM1 阳性的 NE 肺肿瘤≥12 天后，组合病毒会分泌可检测水平的 Gaussia 荧光素酶。因此，INSM1 启动子特异性条件复制腺病毒代表了一种敏感的诊断工具，可以帮助临床医生检测 NE 肿瘤。
