@article {Shi1458, author = {Shuo Shi and Min Zhang and Rui Guo and Ying Miao and Biao Li}, title = {bone marrow derived mesenchymal stem cells mediated dual gene therapy for glioblastoma}, volume = {57}, number = {supplement 2}, pages = {1458--1458}, year = {2016}, publisher = {Society of Nuclear Medicine}, abstract = {1458Objectives Major barriers to effective lentivirus-based gene therapy for glioblastoma include induction of an immune response, tumor-specific targeting of vectors, blood-brain barrier and blood-tumor barrier. The use of bone mesenchymal stem cells (BMSC) as systemic delivery vehicles for therapeutic genes has been proposed as a result of their combined ability to home in on the tumor site and evade the host immune response. This study is aimed at investigating the potential of a dual-gene lentiviral vector (Lv-TIE-2-K5-Egr1-NIS) transduced BMSC as a therapeutic approach in glioblastoma (luciferase gene transduced U87 xenografts). The lentiviral vector contains: 1) kringle 5 (K5) of human plasminogen, anangiogenesis inhibitor, driven by the promoter of TIE-2 gene that overexpressed in the tumor endothelial cells; 2) human sodium iodide symporter (NIS) gene, driven by a radiation-activated gene promoter (Egr1). Noninvasive 125I micro-SPECT imaging and optical imaging will be used to assess the treatment response dynamically.Methods We constructed a lentiviral vector (Lv-TIE-2-K5-Egr1-NIS) and stably transfected it into BMSC to create BMSC-K5-NIS cells. The expression of NIS protein induced by 188Re and K5 protein was detected by Western blot, 188Reuptake mediated by NIS gene was measured in vitro. Luciferase gene transduced U87 xenografts were established in nude mice; 1{\texttimes}105 BMSC-K5-NIS cells were injected intravenously every 3 days, totally 3 times. 125I micro-SPECT/CT imaging was used to detect the distribution and survival time of BMSC-K5-NIS after transplantation; the therapeutic effects of 188Re combined with K5 on U87-luciferase xenografts were assessed by measuring luciferase activity using in vivo optical imaging system and immunohistochemical staining of the excised tumors.Results Western blotting confirmed that BMSC-K5-NIS expressed high levels of K5 and NIS protein. In vitro study showed that BMSC-K5-NIS could take up and accumulate 188Re, 188Re radiation could induce more expression of NIS protein driven by Egr1 promoter. In vivo study showed that 125I uptake could be detected by micro-SPECT/CT in intracranial U87-luciferase xenografts after 6 days of BMSC-K5-NIS transplantation and could not be detected after 24 days transplantation. 2 days after radiation by 37MBq 125I, more 125I (1.73 MBq/mm3) could be detected in U87-luciferase xenografts compared with before (0.94 MBq/mm3). Three cycles of systemic BMSC-K5-NIS followed by 188Re application resulted in a significant delay in U87-luciferase xenografts growth (mean {\textpm} SEM, 10.76 {\textpm} 3.65 ({\texttimes}107) p/sec/cm2/sr vs. 120 {\textpm} 6.82 ({\texttimes}107) p/sec/cm2/sr in controls) detected by in vivo optical imaging. At the end of 188Re therapy, U87-luciferase xenograft cells expressed lower levels of CD31-positive vessels.Conclusions Our results demonstrate tumor-specific accumulation and therapeutic efficacy of 188Re after BMSC-mediated NIS gene and K5 gene delivery in U87-luciferase tumors, opening the prospect of a new adjuvant therapeutical option for glioblastoma using BMSC as gene delivery vehicles. Figure legends: A: The NIS expression and function. a-b: Protein expression after 188Re radiation detected by Western blot in vitro; c: The absorption of 125I before and after 125I injection. B: Optimal imaging and miscro-SPECT/CT imaging in vivo. a: Luciferase optical imaging of U87-luciferase xenograft; b: 125I miscro-SPECT/CT imaging after 6 days of BMSC-K5-NIS transplantation; c: The biodistribution of transplanted BMSC-K5-NIS in vivo. C: The immunofluorescence of transplanted BMSC-EGFP-NIS in U87 xenograft. D: The luciferase activity of U87 xenograft by optimal imaging in vivo. a: The experimental group; b: The control group.}, issn = {0161-5505}, URL = {https://jnm.snmjournals.org/content/57/supplement_2/1458}, eprint = {https://jnm.snmjournals.org/content}, journal = {Journal of Nuclear Medicine} }