MEDI0641 induces G2/M cell cycle arrest and induces apoptosis. (A) Western blot showing the endogenous expression of 5T4 oncofetal antigen in a panel of HNSCC cell lines. (B) Graphs of SRB assays in UM-SCC-11B and UM-SCC-22B cells depicting optical density at 565 nm normalized to IgG1-PBD control over increasing concentrations of MEDI0641 at 24, 48, 72, and 96 hours. (C) Modfit depictions of cell cycle changes in UM-SCC-11B and UM-SCC-22B cells following treatment with 521 ng/mL and 686 ng/mL, respectively, of either IgG1-PBD control or MEDI0641 at 72 hours. Graphs depicting triplicate analyses of the changes in cell cycle and apoptosis in UM-SCC-11Bs and UM-SCC-22Bs at 24, 48, and 72 hours. *p<0.05, **p<0.005. (D) Representative images (200x) of TUNEL staining for apoptosis in PDX-SCC-M11 tissue samples treated with a single dose of 1 mg/kg MEDI0641 or control 1 mg/kg IgG1-PBD 7 days prior to euthanasia. Inserts are at 400x magnification. Pictures were taken of five fields per tumor in three tumors per group. A graph depicting TUNEL-positive cells per field in the control IgG1-PBD and MEDI0641 treatment groups.