FIGURE 3.

Overexpression of TRAILR4 interferes with TRAIL-induced cell death. A, cytofluorometric analysis of TRAIL receptor cell surface expression in HeLa cells. B, cell surface expression of TRAILR4 in HeLa R4 cells, which express TRAILR4 at a level comparable to TRAILR1. C, HeLa R4+ cells show a significantly stronger expression of TRAILR4. D, HeLa (squares), HeLa R4 (circles), or HeLa R4+ (triangles) cells were treated with serial dilutions of antibody-cross-linked sTRAIL (TRAIL) in combination with 0.5 μg/ml cycloheximide. After 24 h cell viability was determined by crystal violet staining. Shown are mean values ± S.D. calculated from nine independent experiments each performed in triplicate. Significance was tested using two-way analysis of variance in combination with Bonferroni post-test. ***, p < 0.001 was considered significant.