Figure 3.

A. HNSCC cell lines were treated with OncoVEX^GFP or OncoVEX^GALV/CD at varying MOI, and cell viability was assessed over a time course by LDH assay. Viral dose-dependent cytotoxicity was noted for all cell lines. SCC15 was most susceptible to viral cytotoxicity, followed by QLL1, QLL2, and SCC25. All cell lines showed significant cytotoxicity by 5 days after exposure to either virus at MOI 0.1, although SCC25 was the least sensitive (Figure 3). At a low viral dose of MOI 0.01, >70% of the most sensitive SCC15 cells were dead by 6 days. OncoVEX^GFP and OncoVEX^GALV/CD exhibited similar cytotoxicity profiles. B. Crystal violet staining of cells treated with virus by day 6 qualitatively confirms the quantitative results from the LDH assays. The OncoVEX^GALV/CD clearly induced a syncytial phenotype in QLL2 cells, creating multinucleated giant cells in contrast to the OncoVEX^GFP virus. However, the identical cytotoxicity curves between these two viruses for all four HNSCC cell lines (A) demonstrate that GALV expression did not yield an additional cytotoxic benefit at these conditions.