Research On The Construction Of Iron Oxide Nanoparticles Modified Mesenchymal Stem Cells Based Carriers And Its Targeted Therapy Against Glioma

Objective: To construct tumor-targeting delivery system based on iron oxide nanoparticles-modified mesenchymal stem cells(MSCs)for efficient suicide gene transfection,improved gap junctional intercellular communication(GJIC)between MSCs and tumor cells,and efficient transfer of cytotoxic drugs to tumor cells.Ultimately,to achieve highly effective and selective killing of glioma cells,providing a novel strategy based on modified stem cells for glioma treatments.Methods: 1.A non-viral gene transfection system with modern ferrimagnetic iron oxide nanoparticles(MFIONs)as the core was applied to genetically engineer MSCs with plasmid DNA(p DNA)encoding herpes virus thymidine kinase(HSV-tk).The in vitro suicide effect was evaluated and the best suicide condition was explored through cell viability of MSCs engineered with HSV-tk suicide gene(MSCs-tk).2.The in vitro bystander effect was evaluated by total cell viability of MSCs-tk and co-cultured C6 glioma cells or cell viability of C6 glioma cells.3.The Cx43 expression level of MFIONs-modified MSCs and the GJIC between MSCs and C6 glioma cells was evaluated to investigate the relationship between bystander effect and MFIONs-induced Cx43 overexpression.4.The in vitro and in vivo glioma tropism of MFIONs-modified MSCs was evaluated by in vitro migration assays and in vivo fluorescence labeling technology.5.Therapeutic effect of the delivery system based on MFIONs-modified MSCs for suicide gene therapy was evaluated through in vivo treatment assays,and the safety of this delivery system was preliminarily checked.Results: 1.Highly efficient genetically engineering of MSCs was achieved through the non-viral gene transfection system based on MFIONs,which showed no obvious cytotoxicity at proper concentration.The MSCs-tk engineered by gene transfection system based on MFIONs showed the highest suicide effect in vitro and the best condition was treatment with 200 μg/m L Ganciclovir(GCV)solution for 5 days.2.The MSCs-tk engineered by gene transfection system based on MFIONs showed the best bystander effect in vitro.In addition to high gene expression efficiency,it may also be related to the MFIONs-induced Cx43 over-expression of MSCs and improved GJIC between MSCs and C6 glioma cells.3.The in vitro migration assays showed the sufficient tumor tropism of MFIONs-modified MSCs to C6 glioma cells.The results of in vivo distribution investigation showed the improved homing of MFIONs-modified MSCs to glioma,which could even penetrate into the tumor tissues.4.The in vivo therapeutic evaluation results showed that the delivery system based on MFIONs-modified MSCs to carry HSV-tk suicide gene achieved highly efficient suicide gene therapeutic effects against glioma,which significantly promoted glioma cells apoptosis,inhibited glioma growth and prolonged the survive time of glioma-bearing rats.6.Preliminary safety evaluation results showed that suicide gene therapy based on this delivery system suggested no obvious toxicity to normal brain tissues and other important internal organs expect slight toxicity to lungs.Conclusion: In addition to efficient suicide gene engineering and expression of MSCs,the iron oxide nanoparticles have the potential to promote the drug delivery between MSCs and tumor cells through GJIC,enhancing the bystander effect of HSV-tk/GCV suicide gene therapy dramatically.Consequently,it is expected to be a potential avenue to modify stem cells for highly efficient tumor therapy.