Figure 5

dNSurR9-C84A in combination with TNF-α upregulates the expression of caspase-8 activity. (A) dNSurR9-C84A does not induce caspase-8 activity in 3D cultured DU145 cells. Cells were treated with PBS, R9-GST and dNSurR9-C84A for 6 to 12 h and the activity of caspase-8 measured. (B) dNSurR9-C84A potentiates the upregulation of caspase-8 in response to TNF-α. 3D-cultures of cells were treated with PBS, TNF-α, dNSurR9-C84A and the combination of dNSurR9-C84A and TNF-α for 6 and 12 h. The activity of caspase-8 was measured. A statistically significant difference in the caspase-8 activity of cells treated with the combination of dNSurR9-C84A and TNF-α versus TNF-α alone is denoted as "*". *p < 0.05. (C) 3D-cultures of DU145 cells were treated with PBS, TNF-α, dNSurR9-C84A, and the combination of dNSurR9-C84A and TNF-α in the presence or absence of the caspase-8 specific inhibitor Z-IETD-FMK for 36 h. Cell viability was assessed by the MTT assay. A statistically significant difference in the caspase-8 activity of cells treated with the combination of dNSurR9-C84A, TNF-α, and Z-IETD-FMK versus the combination of dNSurR9-C84A and TNF-α is denoted as "*".*p < 0.05.