The therapeutic potential of mesenchymal stem cells (MSCs) for various malignancies is currently under investigation due to their unique properties. However, many discrepancies regarding their anti-tumoral or pro-tumoral properties have raised uncertainty about their application for anti-cancer therapies. To investigate, if the anti-tumoral or pro-tumoral properties are subjective to the type of MSCs under different experimental conditions we set out these experiments. Three treatments namely cell lysates (CL), serum-free conditioned media and FBS conditioned media (FBSCM) from each of Wharton’s Jelly MSCs and Bone Marrow-MSCs were applied to evaluate the anti-tumoral or pro-tumoral effect on the glioma cells (U87MG). The functional analysis included; Morphological evaluation, proliferation and migration potential, cell cycle analysis, and apoptosis for glioma cells. The fibroblast cell line was added to investigate the stimulatory or inhibitory effect of treatments on the proliferation of the normal cell. We found that cell lysates induced a generalized inhibitory effect on the proliferation of the glioma cells and the fibroblasts from both types of MSCs. Similarly, both types of conditioned media from two types of MSCs exerted the same inhibitory effect on the proliferation of the glioma cells. However, the effect of two types of conditioned media on the proliferation of fibroblasts was stimulatory from BM-MSCs and variable from WJ-MSCs. Moreover, all three treatments exerted a likewise inhibitory effect on the migration potential of the glioma cells. Furthermore, we found that the cell cycle was arrested significantly at the G1 phase after treating cells with conditioned media which may have led to inhibit the proliferative and migratory abilities of the glioma cells (U87MG). We conclude that cell extracts of MSCs in the form of secretome can induce specific anti-tumoral properties in serum-free conditions for the glioma cells particularly the WJ-MSCs and the effect is mediated by the cell cycle arrest at the G1 phase.

Cancer stem cells (CSCs) use their stemness properties to perpetuate their lineage and survive chemotherapy. Currently cell-based and cell-free therapies are under investigation to develop novel anti-cancer treatment modalities. We designed this study to investigate how cell extracts of mesenchymal stem cells affect the growth of glioma stem cells in vitro . Gliospheres were generated from the U87MG cell line and treated with conditioned media of Wharton’s jelly and bone marrow mesenchymal stem cells. The effects were investigated at the functional and molecular levels. Our results showed that conditioned media from both types of mesenchymal stem cells changed the morphology of spheres and inhibited the proliferation, invasion, and self-renewal ability of glioma stem cells. At the molecular level, metabolism interruption at oxidative phosphorylation, cell cycle arrest, cell differentiation, and upregulation of the immune response were observed. Furthermore, this effect was mediated by the upregulation of the DKK1 gene inhibiting the Wnt pathway mediated by growth factor activity and downregulation of the KITLG gene activated by growth factor and cytokine activity, inhibiting multiple pathways. We conclude that different types of mesenchymal stem cells possess antitumor properties and their paracrine factors, in combination with anti-immune modalities, can provide practical therapeutic targets for glioblastoma treatment.

Abstract Background. Cancer stem cells (CSCs) use their stemness properties such as self renewal, toxicity, plasticity, and communication with the tumor microenvironment (TME) to perpetuate their lineage and survive chemotherapy. Learning how to interrupt the self renewal ability or modulate the interaction of CSCs with the TME signaling will dramatically improve therapeutic impact on patient’s remission. Anti-tumor properties of mesenchymal stem cells (MSCs) are currently under investigations and different approaches have been applied to gain beneficial effects However, different types of MSCs yielded different conflicting results. In order to investigate if different types of MSCs preconditioned in the same culture conditions can exert alike anti oncogenic effect on glioma stem cells, we planned this study. Methods. GSCs were isolated from U87 cell line by FACS cell sorter, characterized and established as gliospheres. Condition media from MSCs of Wharton Jelly (WJ-MSCs) and bone marrow (BM-MSCs) were harvested and used as treatments on glioshperes (3D) to investigate the effect on proliferation, invasion and self renewal properties of GSCs. Microarray analysis was used to determine the effect at molecular level. Specific human CSC gene arrays were applied to validate the findings of the microarray explicitly the pluripotency of the GSCs. Results. Our results from functional and molecular assays showed that condition media (CM) from both types of MSCs inhibited the metabolism by interrupting oxidative phosphorylation, arrested the cell cycle, induced cell differentiation, targeted the pluripotency and up-regulated the immune response in GSCs. Moreover , condition media from both types of MSCs significantly affected the same genes (KITLG and DKK1) causing a similar effect while using slightly different routes and signaling pathways signifying their individual effects.Conclusion.We conclude that mesenchymal stem cells possess antitumor properties and paracrine factors of mesenchymal stem cells in combination with anti-immune modalities can provide novel therapeutic targets for glioma treatment.