Proliferation and apoptosis of tumor β-cells treated with [Lys40(Ahx-DTPA-111In)NH
]-exendin-4 and/or vatalanib. (A) Treatment of mice with 1.1 MBq [Lys40(Ahx-DTPA-111In)NH2]-exendin-4, vatalanib, and the combination therapy induces a significant decrease in tumor cell proliferation (***p < 0.001, Newman-Keuls post-test). However, there is no significant difference between the three interventional groups. (B) In contrast, tumor cell apoptosis is significantly increased in the combined treatment group as compared to all the other groups (***p < 0.001, Newman-Keuls post-test). (C) Immunohistochemical staining for BrdU (proliferation, top row) and TUNEL (apoptosis, bottom row). Size bars, 100 μm.