Real-time imaging of TRAIL-induced apoptosis of glioma tumors in vivo

Abstract

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has been shown to induce apoptosis in neoplastic cells. While many previous studies have been performed in cell culture, the delivery and efficiency of TRAIL variants in vivo is less well established. Using dual substrate/ reporter bioluminescence imaging (Fluc: firefly luciferase -luciferin and Rluc: Renilla luciferase -coelenterazine), we tested the efficacy of TRAIL using replicationdeficient herpes simplex virus (HSV) type 1 amplicon vectors in gliomas. The cDNA for complete TRAIL and the extracellular domain of TRAIL (aa 114-281) were cloned into HSV amplicons and packaged into helper virus-free vectors. Both forms of TRAIL induced similar degrees of apoptosis in human glioma cells (Gli36) in culture within 24 h of infection with TRAIL amplicon vectors. Growth of tumors stably transfected with Fluc (Gli36fluc þ ) was readily monitored in vivo by bioluminescence imaging following luciferin administration. HSV amplicon vectors bearing the genes for TRAIL and Rluc injected directly into Gli36fluc þ -expressing subcutaneous gliomas revealed peak Rluc activity 36 h after intratumoral injection as determined by coelenterazine injection followed by imaging. TRAIL-treated gliomas regressed in size over a period of 4 weeks as compared to the mock-injected gliomas. These results show the efficacy of vector delivered TRAIL in treating tumors in vivo and offer a unique way to monitor both gene delivery and efficacy of TRAIL-induced apoptosis in tumors in vivo in real time by dual enzyme substrate (Rluc/Fluc) imaging.

Assessment of therapeutic efficacy and fate of engineered human mesenchymal stem cells for cancer therapy

“…As opposed to systemic delivery of therapeutic agents, MSCs have the advantages of offering a continuous and concentrated local delivery of secretable therapeutic molecules like TRAIL, thus reducing the non-selective targeting, and allowing higher treatment efficiency and potency for a longer time period. A number of previous studies by others and ourselves (4,13,14,44,45) have shown that in vivo bioluminescence imaging of tumor cells enables rapid, noninvasive measurement of tumor load before, during, and after treatment of mice with highly malignant intracranial tumors. Despite the advantages and convenience of bioluminescence imaging for monitoring tumor growth, there are some disadvantages that should be taken into account while assessing the fate of tumors in vivo.…”

Application and Prospects of Molecular Imaging

“…료의 효과를 정략적으로 분석하거나 [10] 줄기세포(stem cell) 치료 후 이식편의 생존율(graft Survival)을 분석 [11] 하는 등의 실험에 유용하게 사용될 수 있다. 세포에 삽입된 루시페라제가 루시페린을 만나서 방출하는 빛 의 양(photon counts)이 세포의 수에 비례한다 [12] .…”

Stem cells tropism for malignant gliomas

“…Taking advantage of the efficient tumor targeting capabilities, investigators have used genetically engineered NSCs to disseminating tumors. Genetically modified NSCs from different sources have been shown to exhibit the same gliomatropic effect in gliomabearing models and effectively to reduce tumor bulk and prolong host survival [13][14][15][16][17][18][19] .…”

“…This behavior of NSCs has been exploited as a tumor targeting strategy for glioma gene therapy [11][12][13][14][15][16][17][18][19] . Recently, it has been suggested that mesenchymal stem cells (MSCs) may represent an alternative source of NSCs for regeneration [20,21] .…”