1. Specific cytotoxicity of DTEGF13.
Specific cytotoxicity of DTEGF13. A, the ability of DTEGF13 to specifically kill EGFR- and IL-13R–expressing target cancer cells was tested using a protein synthesis inhibition assay. The effects of DTEGF13, DTIL13, and DTEGF were tested by incubating the cytotoxins with PC-3 prostate cancer cells. Protein synthesis of PC-3 cells was measured by [3H]leucine incorporation after 72 h. B, the specific cytotoxicity of DTEGF13 was assayed by measuring its effect on the proliferation of the EGFR− and IL-13R− Daudi lymphoma cell line. [3H]Thymidine uptake was used to measure cell proliferation. Points, mean of triplicate samples; bars, SD. IC50 is the concentration of cytotoxin that inhibits 50% of the percent control activity. C, to test the importance of both EGF and IL-13 in the activity of DTEGF13, blocking assays were conducted in which antibodies were mixed with cytotoxin and then added to cells. Proliferation assays were then conducted. About 50 μg/mL of antibody (α-EGF, α-IL-13, or α-Ly5.2, a negative control antibody recognizing murine CD45) were used to block 0.1 nmol/L DTEGF13 activity. Protein synthesis of PC-3 cells was measured by [3H]leucine incorporation. D, the proliferation of DU-145 human prostate cancer cells incubated with DTEGF13, DTEGF, DTIL13, or DT2222 (negative control) was measured by [3H]thymidine incorporation 72 h after cytotoxin exposure.
Brad J. Stish et al. Clin Cancer Res 2007;13:
©2007 by American Association for Cancer Research