A study of 131iodine-labeling of histamine-indomethacin: its in vivo therapeutic effect and anti-tumor mechanisms in Lewis-bearing lung cancer

BACKGROUND In our research,we study the effect of 131iodine-labeled histamine-indomethacin (131I-His-IN). We focus on its in vivo therapeutic effect and anti-tumor mechanisms in Lewis-bearing lung cancer. METHODS 131I-His-IN was administered by garage to the mice. At different timepoints, we made autoradiography (ARG) slices to observe the distribution of 131I-His-IN in the cellular, and the sliced samples underwent hematoxylin and eosin (HE) staining for observation of tumor necrosis. Before treatment, the groups of mice underwent 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography-computed tomography (PET-CT) scans ,and they were then given physiologic saline, iodine 131 (131I), indomethacin (IN), Histamine-indomethacin (His-IN), and 131I-His-IN, respectively, three times daily for seven days. Seven days later, all the mice underwent 18F-FDG PET-CT scans again. We calculated the maximum standard uptake value (SUVmax) of the region of interest (ROI) and tumor inhibition rate at the same time. RESULTS In ARG groups, black silver particle was concentrated in the nucleus and cytoplasm. 131I-His-IN mainly concentrated in tumor tissues. At 8 hours after 131I-His-IN, the radioactivity uptake in tumor tissue was higher than in other organs (F=3.46, P<0.05). For the 18F-FDG PET-CT imaging, the tumor tissuses SUVmax of the ROI was lower compared to other groups after the treatment with 131I-His-IN. The tumor inhibitory rate (54.8%) in 131I-His-IN group was higher than in other groups, too. In the 131I-His-IN group the vascular endothelial growth factor (VEGF) decreased gradually compared to other groups. The tumor tissue necrotized obviously in 131I-His-IN group. CONCLUSIONS Through these animal experiments, we found 131I-His-IN could inhibit the Lewis lung cancer cells. 131I-His-IN focused at the cell nucleus and cytoplasm. It could reduce VEGF and increase tumor inhibitory rate. At the same time, 18F-FDG PET-CT scan could be used for a curative effect and monitoring of disease prognosis.