In vivo radioiodide imaging and treatment of pancreatic cancer xenografts after MUC1 promoter-driven expression of the human sodium-iodide symporter.
ABSTRACT Mucin 1 (MUC1) is a transmembrane glycoprotein that is overexpressed in many tumor types, including breast, pancreatic, and ovarian cancer. The aim of this study was to create a construct containing sodium-iodide symporter (NIS) under the control of the 0.8-kb MUC1 promoter to infect pancreatic cancer cells both in vitro and in vivo, to investigate the potential for radioiodide imaging and ablation of this disease.
We amplified the 797-bp MUC1 promoter by two-step nested PCR. Subsequently, a replication-deficient adenoviral construct was created containing the MUC1 promoter followed by the human NIS gene. Iodide uptake assays and immunofluorescence were used to confirm NIS expression and function. Pancreatic cancer xenografts in mice were infected with Ad/MUC1/NIS and then imaged and treated using radioiodide.
A 23- and 15.5-fold increase in iodide uptake was observed in Ad/MUC1/NIS-infected MUC1-positive Capan-2 and SW1990 cells with no significant increase observed in MUC1-negative Hela cells or in cells infected with the control virus. The in vivo study showed a clear image of Ad/MUC1/NIS-infected tumor xenografts using (125)I. Administration of a therapeutic dose of (131)I resulted in a regression in size to 76 +/- 15% of their original volume, whereas control tumors continued to increase in size to >200% of their original volume.
These results show that the 0.8-kb MUC1 promoter was successfully used to drive human NIS-targeted expression in pancreatic cancer cells, and Ad/MUC1/NIS-mediated radiotherapy can make pancreatic cancer xenografts in mice shrinking. This could potentially have applications for both imaging and therapy in other MUC1-positive tumors.
Article: Insertion of the human sodium iodide symporter to facilitate deep tissue imaging does not alter oncolytic or replication capability of a novel vaccinia virus.[show abstract] [hide abstract]
ABSTRACT: Oncolytic viruses show promise for treating cancer. However, to assess therapeutic efficacy and potential toxicity, a noninvasive imaging modality is needed. This study aimed to determine if insertion of the human sodium iodide symporter (hNIS) cDNA as a marker for non-invasive imaging of virotherapy alters the replication and oncolytic capability of a novel vaccinia virus, GLV-1h153. GLV-1h153 was modified from parental vaccinia virus GLV-1h68 to carry hNIS via homologous recombination. GLV-1h153 was tested against human pancreatic cancer cell line PANC-1 for replication via viral plaque assays and flow cytometry. Expression and transportation of hNIS in infected cells was evaluated using Westernblot and immunofluorescence. Intracellular uptake of radioiodide was assessed using radiouptake assays. Viral cytotoxicity and tumor regression of treated PANC-1tumor xenografts in nude mice was also determined. Finally, tumor radiouptake in xenografts was assessed via positron emission tomography (PET) utilizing carrier-free 124I radiotracer. GLV-1h153 infected, replicated within, and killed PANC-1 cells as efficiently as GLV-1h68. GLV-1h153 provided dose-dependent levels of hNIS expression in infected cells. Immunofluorescence detected transport of the protein to the cell membrane prior to cell lysis, enhancing hNIS-specific radiouptake (P < 0.001). In vivo, GLV-1h153 was as safe and effective as GLV-1h68 in regressing pancreatic cancer xenografts (P < 0.001). Finally, intratumoral injection of GLV-1h153 facilitated imaging of virus replication in tumors via 124I-PET. Insertion of the hNIS gene does not hinder replication or oncolytic capability of GLV-1h153, rendering this novel virus a promising new candidate for the noninvasive imaging and tracking of oncolytic viral therapy.Journal of Translational Medicine 03/2011; 9:36. · 3.41 Impact Factor