Figure 2.

Roles of Virus Receptor and Apoptosis in EV-A71-Mediated Oncolysis

(A) Surface expression of EV-A71 receptor SCARB2 on human glioma cell lines and normal glial cells was quantified by flow cytometry. Representative histograms show the measured fluorescence of cells incubated with an isotype control antibody (red curves) or anti-SCARB2 antibody (blue curves). (B and C) U87 glioma cells were treated with SCARB2-specific siRNA or control siRNA. Representative immunoblot analysis of cells harvested 48 h after siRNA transfection (B). beta-actin served as a loading control. SCARB2 expression was measured by flow cytometry (C). Data are presented as the SCARB2 expression ratio relative to that in mock cells. (D and E) U87 glioma cells transfected with siRNA were infected with EV-A71 (MOI = 1) and assessed by a TCID50 assay (D) or an LDH assay (E) at 24 h postinfection. (F) U87 cells were infected with EV-A71 BrCr at an MOI of 2 for 24 h. Representative results showed that the early apoptotic population was identified as the Annexin V-FITC⁺/PI⁻ cells. (G) Representative immunoblot analysis of cellular lysate of EV-A71-infected U87 cells. Full-length PARP (116 kDa) and an apoptotic cleavage product of PARP (89 kDa) were detected. (H) U87 cells treated with the pan-caspase inhibitor z-VAD-fmk were exposed to EV-A71. Virus-induced oncolysis was assessed by an LDH assay. Bars represent the mean ± the standard deviations of three independent experiments. ∗∗p < 0.01, ∗∗∗p < 0.001.