Mesenchymal stem cells loaded with paclitaxel-poly(lactic- co -glycolic acid) nanoparticles for glioma-targeting therapy.

Background: Mesenchymal stem cells (MSCs) possess inherent tropism towards tumor cells, and so have attracted increased attention as targeted-therapy vehicles for glioma treatment.

Purpose: The objective of this study was to demonstrate the injection of MSCs loaded with paclitaxel (Ptx)-encapsulated poly(d,l-lactide- co -glycolide) (PLGA) nanoparticles (NPs) for orthotopic glioma therapy in rats.

Methods: Ptx-PLGA NP-loaded MSC was obtained by incubating MSCs with Ptx-PLGA NPs. The drug transfer and cytotoxicity of Ptx-PLGA NP-loaded MSC against tumor cells were investigated in the transwell system. Biodistribution and antitumor activity was evaluated in the orthotopic glioma rats after contralateral injection.

Results: The optimal dose of MSC-loaded Ptx-PLGA NPs (1 pg/cell Ptx) had little effect on MSC-migration capacity, cell cycle, or multilineage-differentiation potential. Compared with Ptx-primed MSCs, Ptx-PLGA NP-primed MSCs had enhanced sustained Ptx release in the form of free Ptx and Ptx NPs. Ptx transfer from MSCs to glioma cells could induce tumor cell death in vitro. As for distribution in vivo, NP-loaded fluorescent MSCs were tracked throughout the tumor mass for 2 days after therapeutic injection. Survival was significantly longer after contralateral implantation of Ptx-PLGA NP-loaded MSCs than those injected with Ptx-primed MSCs or Ptx-PLGA NPs alone.

Conclusion: Based on timing and sufficient Ptx transfer from the MSCs to the tumor cells, Ptx-PLGA NP-loaded MSC is effective for glioma treatment. Incorporation of chemotherapeutic drug-loaded NPs into MSCs is a promising strategy for tumor-targeted therapy.