Bystander effect-mediated gene therapy of gliomas using genetically engineered neural stem cells

Abstract

Since neural stem cells (NSCs) have the ability to migrate toward a tumor mass, genetically engineered NSCs were used for the treatment of gliomas. We first evaluated the ''bystander effect'' between NSCs transduced with the herpes simplex virus-thymidine kinase (HSVtk) gene (NSCtk) and C6 rat glioma cells under both in vitro and in vivo conditions. A potent bystander effect was observed in co-culture experiments of NSCtk and C6 cells. In the intracranial co-implantation experiments in athymic nude mice and Sprague-Dawley rats, the animals co-implanted with NSCtk and C6 cells and treated with ganciclovir (GCV) showed no intracranial tumors and survived more than 100 days, while those treated with physiological saline (PS) died of tumor progression. We next injected NSCtk cells into the pre-existing C6 tumor in rats and treated them with GCV or PS. The tumor volume was serially measured by magnetic resonance imaging. The tumor disappeared in six out of nine rats in the NSCtk/GCV group, while all the rats treated with PS died of tumor progression by day 21. The results indicate the feasibility of a novel gene therapy strategy for gliomas through a bystander effect generated by intratumoral injection of NSCtk cells and systemic GCV administration.

The anti-glioma effect of suicide gene therapy using BMSC expressing HSV/TK combined with overexpression of Cx43 in glioma cells

“…7,8,[16][17][18] However, clinical trials for glioma using this treatment have failed. [19][20][21][22] One of the major reasons may be due to the delivery manner of HSV-TK into glioma cells located only in the direct vicinity of the injection site, but fail to transduce infiltrating tumor cells or distant tumor areas that eventually serve as the reservoirs for tumor recurrence. In this study, we used BMSCs as HSV-TK gene vector that show an innate tumor-homing capability.…”

“…Similar results were reported by several groups showing that a bystander effect is the main mechanism of HSV-TK/GCV therapy mediated by stem cells in glioma. Li et al 22 showed a potent bystander effect between NSC-TK and C6 cells, and complete tumor eradication was obtained by NSC-TK therapy when the same number of NSC-TK and the tumor cells were intracranially implanted. Uhl et al 23 reported that the admixture of HSV-TK-transduced NSC to U87 MG and LN-18 human malignant glioma cell lines at ratios of 1:10 or 1:1 eliminated more than 50 or 90% of glioma cells in the presence of GCV (25 mM).…”

Novel Treatment Strategies for Malignant Gliomas Using Neural Stem Cells

“…56 -58 Coinjection of these cells with malignant glioma cells followed by systemic ganciclovir treatment results in prolonged survival and significant inhibition of tumor growth. 56 This newer system may be more effective in inhibiting tumor progression and growth than the earlier suicide gene systems; however, such a NSC-based treatment strategy has yet to be tested in a clinical trial. Notably, both the CD-5-FC and the HSV-tk-ganciclovir systems show a bystander effect, wherein tumor cells not carrying the suicide genes are also killed, which amplifies the antitumor activity in the suicide gene therapy systems.…”

p27 modulates tropism of mesenchymal stem cells toward brain tumors

“…all following experiments were performed according to the rules of animal Experimentation and the Guide for the care and use of laboratory animals of the hamamatsu university School of medicine. p27 -/-and p27 +/+ C57BL/6 mice (8 weeks old) were sacrificed with ether, and the marrow tissue was obtained from the femurs and tibias as previously described (21). a single-cell suspension was obtained by gently aspirating the tissue several times using the same needle and syringe in 5 ml murine mSc Growth Medium (MMSCGM; StemCell Technologies Inc., British columbia, canada), washed one time with 10 ml fresh mmScGm and passed through a 70-µm nylon strainer (Falcon, Becton Dickinson Labware, Franklin lakes, NJ, uSa).…”

“…to compare the in vivo migratory capacity and tropism of p27 -/-and p27 +/+ mScs toward glioma, we injected 2x10 4 c6 rat glioma cells into one side of the mouse brain hemisphere and 1x10 5 Brdu-labeled mScs into the opposite hemisphere. the method of cell implantation was the same as described previously (21). Briefly, 10 BALB/c nude mice (6 weeks old, Nippon SLC, Hamamatsu, Japan) were anesthetized with 0.4 ml/100 g equithesin and placed in a stereotaxic apparatus (Narishige Scientific Instrument Lab., Tokyo, Japan).…”