title: 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 replication-deficient 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+) 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(+)-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.
authors.affiliation: Center for Molecular Imaging Research, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA. kshah@helix.mgh.harvard.edu
authors.forename: Khalid
authors.initials: K
authors.lastname: Shah
authors.forename: Yi
authors.initials: Y
authors.lastname: Tang
authors.forename: Xandra
authors.initials: X
authors.lastname: Breakefield
authors.forename: Ralph
authors.initials: R
authors.lastname: Weissleder
mesh_terms: D000818:Animals; D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins; D002470:Cell Survival; D017690:Cell Transplantation; D003199:Computer Systems; D017930:Genes, Reporter; D005822:Genetic Vectors; D005910:Glioma / Q000473:pathology*; D049452:Green Fluorescent Proteins; D018259:Herpesvirus 1, Human / Q000235:genetics; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008156:Luciferases / Q000235:genetics; D008163:Luminescent Measurements; D008164:Luminescent Proteins / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000378:metabolism* / Q000627:therapeutic use*; D051379:Mice; D008819:Mice, Nude; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D053221:TNF-Related Apoptosis-Inducing Ligand; D013997:Time Factors; D014183:Transplantation, Heterologous; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism* / Q000627:therapeutic use*
chemical_list: D051017:Apoptosis Regulatory Proteins; D008164:Luminescent Proteins; D008562:Membrane Glycoproteins; D011993:Recombinant Fusion Proteins; D053221:TNF-Related Apoptosis-Inducing Ligand; C505653:TNFSF10 protein, human; C505654:Tnfsf10 protein, mouse; D014409:Tumor Necrosis Factor-alpha; D049452:Green Fluorescent Proteins; D008156:Luciferases