Locoregional Delivery of Adenoviral Vectors

Journal of Nuclear Medicine

Maarten ter Horst¹  Peter A.E. Sillevis Smitt¹  Bertie H.C.G.M. de Leeuw¹  Eric Brouwer¹  Suzanne M. Verwijnen¹  Marion de Jong¹  Rob C. Hoeben¹ 

关键词: [^99mTc-N₄^0–1;    Asp⁰;    Tyr³]octreotate;    somatostatin receptor;    adenovirus;    glioma;    convection-enhanced delivery;   

DOI  :  

学科分类：医学（综合）

来源: Society of Nuclear Medicine

【 摘 要 】

The overall median survival of patients with a malignant glioma is <1 y. Because malignant gliomas rarely metastasize outside the skull, locoregional treatment strategies, such as gene therapy, are under investigation. Recently, convection-enhanced delivery (CED) has been presented as a method to improve delivery of large molecules. The goal of this study was to evaluate whether CED improves intratumoral delivery of adenoviral vectors and compare it with single injection (SI) and multiple injection (4×, MI). Methods: A replication-deficient adenoviral vector encoding the herpes simplex virus thymidine kinase (HSV-tk) and the human somatostatin receptor subtype 2 (sst2) was administered into nude mice bearing subcutaneous U87 xenografts. Tumors were injected with 1.5 × 109 plaque-forming units of Ad5.tk.sstr by CED, SI, or MI. Three days later, [99mTc-N40–1,Asp0,Tyr3]octreotate (99mTc-Demotate 2) was injected intravenously to monitor the virus-induced sst2 expression. γ-Camera imaging was performed for in vivo imaging, and the tumor uptake of 99mTc-Demotate 2 was determined by γ-counter. Furthermore, the tumor was sectioned and ex vivo autoradiography was performed. After decay of radioactivity, adjacent sections were submitted to in vitro autoradiography with 125I-DOTA-Tyr3-octreotate, which was used to calculate the transduced areas. Results: Transfected xenograft tissues showed high sst2 expression and were clearly visualized with a γ-camera. Accumulation of radioactivity was 2-fold higher in the tumors that were injected with MI compared with CED and SI (P = 0.01). CED and SI resulted in equal uptake of radioactivity in the tumors. The measured areas of transduction in ex vivo and in vitro autoradiographs showed a high concordance (r2 = 0.89, P < 0.0001). The maximum area of transfection was significantly larger after MI than after CED (P < 0.05) or SI (P = 0.05). Also, the measured volume of distribution was twice as high after administration of Ad5.tk.sstr by MI (56.6 mm3) compared with SI (25.3 mm3) or CED (26.4 mm3). Conclusion: CED does not increase adenoviral vector distribution in a glioma xenograft model compared with SI. Therefore, in the clinic MI is probably the most effective delivery method for the large adenoviral particle (70 nm) in malignant gliomas.

【 授权许可】

Unknown