Image-guided, Tumor Stroma-targeted 131I Therapy of Hepatocellular Cancer After Systemic Mesenchymal Stem Cell-mediated NIS Gene Delivery
Authors: Kerstin Knoop, Marie Kolokythas, Kathrin Klutz, Michael J. Willhauck, Nathalie Wunderlich, Dan Draganovici, Christian Zach, Franz-Josef Gildehaus, Guido Böning, Burkhard Göke, Ernst Wagner, Peter J. Nelson, Christine Spitzweg
Journal: Molecular Therapy (2011)

Due to its dual role as reporter and therapy gene, the sodium iodide symporter (NIS) allows noninvasive imaging of functional NIS expression by 123I-scintigraphy or 124I-PET imaging before the application of a therapeutic dose of 131I. NIS expression provides a novel mechanism for the evaluation of mesenchymal stem cells (MSCs) as gene delivery vehicles for tumor therapy. In the current study, we stably transfected bone marrow–derived CD34− MSCs with NIS cDNA (NIS-MSC), which revealed high levels of functional NIS protein expression. In mixed populations of NIS-MSCs and hepatocellular cancer (HCC) cells, clonogenic assays showed a 55% reduction of HCC cell survival after 131I application. We then investigated body distribution of NIS-MSCs by 123I-scintigraphy and 124I-PET imaging following intravenous (i.v.) injection of NIS-MSCs in a HCC xenograft mouse model demonstrating active MSC recruitment into the tumor stroma which was confirmed by immunohistochemistry and ex vivo γ-counter analysis. Three cycles of systemic MSC-mediated NIS gene delivery followed by 131I application resulted in a significant delay in tumor growth. Our results demonstrate tumor-specific accumulation and therapeutic efficacy of radioiodine after MSC-mediated NIS gene delivery in HCC tumors, opening the prospect of NIS-mediated radionuclide therapy of metastatic cancer using MSCs as gene delivery vehicles. Due to its dual role as reporter and therapy gene, the sodium iodide symporter (NIS) allows noninvasive imaging of functional NIS expression by 123I-scintigraphy or 124I-PET imaging before the application of a therapeutic dose of 131I. NIS expression provides a novel mechanism for the evaluation of mesenchymal stem cells (MSCs) as gene delivery vehicles for tumor therapy. In the current study, we stably transfected bone marrow–derived CD34− MSCs with NIS cDNA (NIS-MSC), which revealed high levels of functional NIS protein expression. In mixed populations of NIS-MSCs and hepatocellular cancer (HCC) cells, clonogenic assays showed a 55% reduction of HCC cell survival after 131I application. We then investigated body distribution of NIS-MSCs by 123I-scintigraphy and 124I-PET imaging following intravenous (i.v.) injection of NIS-MSCs in a HCC xenograft mouse model demonstrating active MSC recruitment into the tumor stroma which was confirmed by immunohistochemistry and ex vivo γ-counter analysis. Three cycles of systemic MSC-mediated NIS gene delivery followed by 131I application resulted in a significant delay in tumor growth. Our results demonstrate tumor-specific accumulation and therapeutic efficacy of radioiodine after MSC-mediated NIS gene delivery in HCC tumors, opening the prospect of NIS-mediated radionuclide therapy of metastatic cancer using MSCs as gene delivery vehicles.