Blue Light Inhibits Proliferation of Metastatic Cancer Cells by Regulating Translational Initiation: A Synergistic Property with Anticancer Drugs.

The aim of this study was to examine the inhibitory effect of blue light (BL) on the proliferation of metastatic cancer cells and synergistic properties with chemo-drugs. BL significantly inhibited the proliferation of B cell lymphoma (A20 and RAMOS) cells in a dose-dependent manner. Anti-proliferative effect of BL irradiation was identified to be associated with the inhibition of proliferating-cell nuclear antigen expression and cell cycle by decreasing S-phase cells. Consistent with its inhibitory effects, BL irradiation at 20 J/cm2 daily for 10 days inhibited metastasis of cancer cells which were distributed and invaded to other organs including bone marrow, liver, kidney, etc., and induced paraplegia, thereby leading to an increased survival rate of tumor-bearing mice. Anti-proliferative activity of BL was expanded in solid tumor cells including pancreatic carcinoma (Mia PaCa-2, PANC-1), lung carcinoma A549 and colorectal carcinoma HCT116 cells. Additionally, combination with chemo-drugs such as 5-FU and gemcitabine resulted in an increase in the anti-proliferative activity after BL irradiation accompanied by regulating mRNA translational process via inhibition of p70S6K, 4EBP-1 and eIF4E phosphorylation during cellular proliferation. These results indicate the anti-metastatic and photo-biogoverning abilities of BL irradiation as a potent therapeutic potential for repressing the progression of tumor cells.

Effect of Ursodeoxycholic Acid on the Biodistribution and Excretion of Technetium-99m Radiopharmaceuticals in Rat: A Potential Image Quality Enhancer.

PURPOSE: This study aimed to investigate the effect of ursodeoxycholic acid (UDCA) on the biodistribution and excretion of technetium-99m (Tc-99m)-labeled radiopharmaceuticals. MATERIALS AND METHODS: Tc-99m hydroxy-methylene-diphosphonate (HDP), Tc-99m pertechnetate, and Tc-99m dimercaptosuccinic acid (DMSA) were injected via the tail vein of rats. After 30 min, the control group was administered saline, and the UDCA group was given UDCA orally. Scintigraphy images were acquired after 30 min and 1, 2, 3, and 4 h. Radioactivity and rate of change were compared. Tc-99m mercaptoacetyltriglycine (MAG3) imaging was also performed. RESULTS: In image analysis of Tc-99m HDP, radioactivity of the buttock was lower in the UDCA group at 4 h. Rates of change in the buttock were significantly different at 3 h-30 min and 4 h-30 min, and buttock radioactivity in the UDCA group had decreased more. In analysis of Tc-99m pertechnetate, radioactivity of the buttock was higher in the control group. Rates of change in the thyroid gland and buttock were different at 1 h-30 min, 3 h-30 min, and 4 h-30 min, with radioactivity in the UDCA group decreasing more. In the analysis of Tc-99m DMSA, while the radioactivity of the kidneys in the control group showed little decrease at 1 h-30 min, that in the UDCA group increased. In the analysis of Tc-99m MAG3 images, radioactivity and radioactivity/total body radioactivity (TBA) values for the kidneys were higher in the UDCA group at 2 min. At 5 and 10 min, radioactivity/TBA values for soft tissue in the UDCA group were lower than those in the control group. CONCLUSION: This study demonstrated that administration of UDCA increases renal excretion and soft tissue clearance of radiopharmaceuticals. This investigation could contribute to the broadening of applications of UDCA.

Rodent Leukocyte Isolation and Radiolabeling for Inflammation Imaging Study.

PURPOSE: The objective of this study was to describe to develop methods of rodent leukocyte isolation and radiolabeling for in vivo inflammation imaging. METHODS: Thigh muscle inflammation was induced by injection of collagenase. Blood was collected from the jugular vein and separated by Histopaque. The collected cells were incubated in a 37 °C CO2 incubator for 1~2 h. After incubation, 99mTc-HMPAO and 18F-FDG were used to treat leukocytes followed by incubation for 30 min. 99mTc-HMPAO and 18F-FDG labeled autologous leukocytes were injected into the tail veins of rats. The images were then acquired at various time points. Image-based lesion to normal muscle ratio was compared. RESULTS: After Histopaque separation, the proportion of lymphocytes was higher than that of other cell types. After CO2 incubation, the collected leukocytes were viable, while room temperature exposed leukocytes without CO2 incubation were non-viable. Granulocytes, especially, were more quickly influenced by various conditions than the mononuclear cells. Labeling efficiencies of 99mTc-HMPAO and 18F-FDG were 4.00 ± 2.06 and 1.8%, respectively. 99mTc-HMPAO- and 18F-FDG-labeled leukocytes targeted well the inflamed lesion. 99mTc-HMPAO-labeled leukocytes, but not 18F-FDG-labeled leukocytes, were found in the abdomen activity. CONCLUSION: Inflamed lesions of rats were well visualized using autologous radiolabeled leukocytes. This method might provide good information for understanding inflammatory diseases.