Figure 7.

Irradiated senescence-enriched human glioblastoma cell populations secrete factors that can attenuate vaccinia virus growth. (A) Experimental outline: human U87 and ED501 glioblastoma cell lines were either non-irradiated (0 Gy) or treated with a radiation dose of 10 Gy. Then 7 days later, culture medium was replaced, and conditioned for 48 h. Fresh radiation-naïve glioblastoma cell lines were cultured in this conditioned medium during subsequent virus growth assays. Lysates were harvested immediately after infection (0 h) and 72 h post-infection, then titered in duplicate by plaque assay to assess virus yield. (B) Graphs showing fold change in virus yield of oncolytic ∆F4L∆J2R or wild-type (WT) vaccinia viruses 72 h post-infection in fresh radiation-naïve glioblastoma cells cultured using conditioned medium from either non-irradiated (0 Gy) or 10 Gy treated glioblastoma cells (the cell type infected was matched to the cell type used to condition the media). Cells were infected with 0.03 PFU per cell. Data information: data represent three independent experiments, mean ± SEM is shown. Graphs show fold change relative to lysates taken at t = 0. Significance determined by unpaired t-test (* = p < 0.05).