Effects of SVV-001 on primary cultured tumor cells and preformed neurospheres derived from GBM xenograft models. (A) Killing of primary cultured GBM xenograft tumor cells by SVV-001. Cell viability was estimated using CCK-8 assay by measuring the absorbance at 460 nm after the cells were exposed to SVV-001 ranging from 0 to 25 vp/cell for 72 h. **P < .01 compared with the untreated control. (B) Infection of preformed GBM neurospheres with SVV-GFP. Representative images (left panel) and flow cytometry (FCM) quantitative analysis (right panel) of viable GFP+ cells (right lower quadrant) as well as dead GFP+ cells (right upper quadrant) in neurospheres derived from IC-1406GBM 48 h post incubation with SVV-GFP, ranging from 0 to 2000 vp/cell. (C) Graphs showing the time-course analysis of SVV-GFP infection in the permissive models (ICb-1227AA, IC-1406GBM, IC-2305GBM, and IC-1621GBM) as examined through FCM analysis of GFP+ cells (*P < .05, **P < .01). By day 7, the GFP+ cells in ICb-1227AA and IC-2305GBM became undetectable. No GFP expression was detected in the resistant model IC-1128GBM.