Fig. 4

Combined treatment of GSCs with conditioned medium derived from NDV-infected UC-MSCs and radiation exerts a synergistic cytotoxic effect on GSCs. The HF2355 GSCs were infected with NDV and irradiated (3 Gy) (a). The self-renewal of the cells was determined after 10 days of treatment. HF2355 GSCs were irradiated in the presence or absence of conditioned medium derived from NDV-infected UC-MSCS (b, c). Cell death was determined after 3 days using LDH (b) or caspase 3/7 (c) assays. The role of TRAIL in the increased sensitization to radiation was examined in the HF2359 GSCs. The addition of a neutralizing anti-TRAIL antibody (5 μg/ml) prior to NDV infection and γ-irradiation abrogated the increased cytotoxic effect of the infected UC-MSCs conditioned medium and that of the combined effects of γ-radiation and the conditioned medium. Cell death was measured using LDH assay and data are presented as relative cell death (d). The results are presented as the means ± SE and represent three different experiments. ^* p < 0.001; ^** p < 0.01. (^*Control vs. infected cells; radiation + CM of NDV-infected UC-MSCs vs. radiation or NDV alone; control vs. anti-TRAIL antibody; ^**GSCs treated with UC-MSC CM and NDV infected GSCs vs. untreated cells). MSC mesenchymal stromal cells cell, NDV Newcastle disease virus, TRAIL TNF-related apoptosis-inducing ligand, UC umbilical cord