Gfp-Expressing Vascularization of Gelfoam® as a Rapid in Vivo Assay of Angiogenesis Stimulators and Inhibitors

orthotopically transplanted MIA PaCa2 human pancreatic cancer expressing RFP was also visualized by dual-color imaging. Gemcitabine significantly decreased the mean nascent blood vessel density in the tumor as well as decreased tumor volume. These results demonstrated for the first time that gemcitabine is an inhibitor of angiogenesis as well as tumor growth in pancreatic cancer (13). Angiogenesis of liver metastasis of the XPA-1-RFP human pancreatic cancer in the ND-GFP transgenic nude mice was visualized by dualcolor fluorescence imaging. ND-GFP was highly expressed in proliferating endothelial cells and nascent blood vessels in the growing liver metastasis. The density of nascent blood vessels in the liver metastasis was readily quantitated by ND-GFP expression. Gemcitabine significantly decreased the mean nascent blood vessel density in the liver metastases (14). In the present study, we developed a very convenient imageable in vivo angiogenesis assay after transplantation of Gelfoam® (Pharmacia & Upjohn Company, Kalamazoo, MI, USA) in the ND-GFP mice. We demonstrate that the Gelfoam is rapidly vascularized with GFP-expressing vessels in the presence of an angiogenesis stimulator. Antiangiogenesis agents inhibit this process. Thus, this rapid and simple new in vivo assay can rapidly identify angiogenesis