Figure 4.

Cytotoxicity of Z-hTRAIL and hTRAIL in colorectal tumor cells. (A) Receptor expression (PDGFRβ, DR4, and DR5) and protein binding of LS174T, COLO205, and HCT116 tumor cells. To detect the receptor, cells were incubated with antibody against PDGFRβ, DR4, or DR5 followed by flow cytometry. To examine the protein binding, cells were incubated with FAM-labeled Z-hTRAIL or hTRAIL prior to flow cytometry. (B) Cytotoxicity of Z-hTRAIL and hTRAIL. Cells (1-2×10⁴ cells/well) were incubated with different concentration of Z-hTRAIL or hTRAIL overnight. PBS was used as the control. The surviving cells were measured using CCK-8.