Msctrail(University College, London)

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) triggers apoptosis of cancer cells and, when used in combination with other anticancer drugs, is regarded as an effective strategy for anticancer treatment. In this study, we investigated the efficacy of combination treatment with TRAIL-secreting human mesenchymal stem cells (MSC-TRAIL) and compound C, an AMP-activated protein kinase (AMPK inhibitor), on glioblastoma.

The anticancer effect using MSC-TRAIL and compound C on glioma was evaluated in vitro and on in vivo models.

Combination treatment of MSC-TRAIL and compound C increased apoptosis by enhancing expression of B-cell lymphoma 2 (BCL2)-associated X protein (BAX) and reducing that of anti-apoptotic proteins cellular FLICE-inhibitory protein (FLIP), X-linked inhibitor of apoptosis (XIAP), and BCL2 in glioma. In addition, MSC-TRAIL and compound C combination increased caspase-3 cleavage and apoptotic cells in a mouse glioma model compared with the group treated with the agents alone.

Our results suggest that MSC-TRAIL and compound C are a novel combination for treatment of glioma.

Since the tumor-oriented homing capacity of mesenchymal stem cells (MSCs) was discovered, MSCs have attracted great interest in the research field of cancer therapy mainly focused on their use as carries for anticancer agents. Differing from DNA-based vectors, the use of mRNA-based antituor gene delivery benefits from readily transfection and mutagenesis-free. However, it is essential to verify if mRNA transfection interferes with MSCs' tropism and their antitumor properties. TRAIL- and PTEN-mRNAs were synthesized and studied in an in vitro model of MSC-mediated indirect co-culture with DBTRG human glioma cells. The expression of TRAIL and PTEN in transfected MSCs was verified by immunoblotting analysis, and the migration ability of MSCs after anticancer gene transfection was demonstrated using transwell co-cultures. The viability of DBTRG cells was determined with bioluminescence, live/dead staining and real time cell analyzer. An in vivo model of DBTRG cell-derived xenografted tumors was used to verify the antitumor effects of TRAIL- and PTEN-engineered MSCs. With regard to the effect of mRNA transfection on MSCs' migration toward glioma cells, an enhanced migration rate was observed with MSCs transfected with all tested mRNAs compared to non-transfected MSCs (p<0.05). TRAIL- and PTEN-mRNA-induced cytotoxicity of DBTRG glioma cells was proportionally correlated with the ratio of conditioned medium from transfected MSCs. A synergistic action of TRAIL and PTEN was demonstrated in the current co-culture model. The immunoblotting analysis revealed the apoptotic nature of the cells death in the present study. The growth of the xenografted tumors was significantly inhibited by the application of MSCPTEN or MSCTRAIL/PTEN on day 14 and MSCTRAIL on day 28 (p<0.05). The results suggested that anticancer gene-bearing mRNAs synthesized in vitro are capable of being applied for MSC-mediated anticancer modality. This study provides an experimental base for further clinical anticancer studies using synthesized mRNAs.