Preclinical Development Dual Combination Therapy Targeting DR5 and EMMPRIN in Pancreatic Adenocarcinoma

The goal of the study was to assess the efficacy of combined extracellular matrix metalloprotease inducer (EMMPRIN)and death receptor 5 (DR5)-targeted therapy for pancreatic adenocarcinoma in orthotopic mouse models with multimodal imaging. Cytotoxicity of anti-EMMPRIN antibody and anti-DR5 antibody (TRA-8) in MIA PaCa-2 and PANC-1 cell lines was measured by ATPlite assay in vitro. The distributions of Cy5.5-labeled TRA-8 and Cy3-labeled anti-EMMPRIN antibody in the 2 cell lines were analyzed by fluorescence imaging in vitro. Groups 1 to 12 of severe combined immunodeficient mice bearing orthotopic MIA PaCa-2 (groups 1–8) or PANC-1 (groups 9–12) tumors were used for in vivo studies. Dynamic contrastenhanced–MRIwas applied in group 1 (untreated) or group 2 (anti-EMMPRIN antibody). The tumor uptake of Tc-99m-labeled TRA-8wasmeasured in group 3 (untreated) and group 4 (anti-EMMPRIN antibody). Positron emission tomography/computed tomography imaging with F-FDGwas applied in groups 5 to 12. Groups 5 to 8 (or groups 9 to 12) were untreated or treated with anti-EMMPRIN antibody, TRA-8, and combination, respectively. TRA-8 showed high killing efficacy for bothMIAPaCa-2 and PANC-1 cells in vitro, but additional anti-EMMPRIN treatment did not improve the cytotoxicity. Cy5.5–TRA-8 formed cellular caps in both the cell lines, whereas themaximum signal intensitywas correlatedwith TRA-8 cytotoxicity. Anti-EMMPRIN therapy significantly enhanced the tumordelivery of theMRcontrast agent, but not Tc-99m–TRA-8. Tumor growthwas significantly suppressed by the combination therapy, and the additive effect of the combination was shown in both MIA PaCa-2 and PANC-1 tumor models. Mol Cancer Ther; 11(2); 405–15. 2011 AACR.