Figure 3.

VPA Enhances HSV^GM-CSF-Induced Cytotoxicity, Viral Replication, and Transgene Expression

(A) Melanoma cell lines were seeded and treated with VPA (0, 1, and 2 mM) for 24 h prior to addition of HSV^GM-CSF at concentrations ranging from 0 to 1 PFUs/cell. Cells were left for a further 48 h, and cell viability was determined by MTT assay. The graph shows the average cell viability for at least five independent experiments ± SEM. (B) VPA-treated melanoma cells were treated with HSV^GM-CSF for 24 h, and GM-CSF production was determined by ELISA. The graph shows the mean + SEM (n = 6). (C) MEL888 or A375 cells were treated with 0.05 PFUs/cell HSV^GM-CSF alone, 1 mM VPA for 24 h prior to 0.05 PFUs/cell HSV^GM-CSF, or 1 mM VPA and 0.05 PFUs/cell HSV^GM-CSF simultaneously. Cells were left for 24 h, and the fold increase in HSV^GM-CSF replication was determined by plaque assay. The graph shows the mean + SEM (n = 4). Statistical significance is denoted by *p < 0.05, **p < 0.01, p*** < 0.005, and ****p < 0.0001.