Development of peptide conjugated Superparamagnetic Iron Oxide (SPIO) Nanoparticles for Targeted MR Imaging and Therapy of Pancreatic Cancer

Development of multifunctional nanoparticles that selectively target to human tumors for in vivo tumor imaging as well as inhibition of tumor growth holds a great promise for improving survival rate of cancer patients. In this study, we have engineered peptide conjugated superparamagnetic iron oxide (SPIO) nanoparticles targeting to urokinase plasminogen activator receptor (uPAR) or a single chain antibody to epidermal growth factor receptor (ScFvEGFR), which are highly expressed in human pancreatic cancer tissues. We demonstrated that the SPIO nanoparticles bind to and are internalized by pancreatic cancer cells in vitro, resulting a significant shortened T2 detected by MRI scan and positive Prussian blue staining in the tumor cells. Furthermore, the targeted-SPIO nanoparticles markedly inhibited the growth of pancreatic cancer cells in vitro. Using an orthotopic human pancreatic cancer xenograft model in nude mice, in vivo MRI demonstrated that systemic delivery of the targeted SPIO nanoparticles leads to accumulation of the IO nanoparticles in intra-pancreatic tumors causing a significant signal drop in those areas. Examination of tissue distribution of the target-IO nanoparticles by Prussian blue staining of frozen tissue sections showed high levels of iron staining in pancreatic cancer lesions but not in adjacent normal pancreas. Normal liver and spleen also displayed high levels of iron staining, while normal lung tissue had a low level of iron staining. Both kidney and heart tissues lacked iron staining. Therefore, those multifunctional nanoparticles have potential for the development of tumortargeted imaging probes and drug delivery particles for the detection and treatment of pancreatic cancer.