In vivo evaluation of tumor uptake and bio-distribution of 99mTc-labeled 1-thio-β-D-glucose and 5-thio-D-glucose in mice model

Background: To investigate the capacity of Tc-99m-labeled 1-thio-beta-D-glucose (1-TG) and 5-thio-D-glucose (5-TG) to act as a marker for glucose consumption in tumor cells in vivo as well as to evaluate the biodistribution of 1-TG and 5-TG. We investigated the biodistribution, including tumor uptake, of 1-TG and 5-TG at various time points after injection (0.5, 2 and 4 h) in human colorectal carcinoma (HCT-116) and human lung adenocarcinoma (A549) xenograft bearing nude mice (N = 4 per tracer and time point). Results: Ex vivo biodistribution studies revealed a moderate uptake with a maximum tumor-to-muscle ratio of 4.22 +/- 2.7 and 2.2 +/- 1.3 (HCT-116) and of 3.2 +/- 1.1 and 4.1 +/- 1.3 (A549) for 1-TG and 5-TG, respectively, with a peak at 4 h for 1-TG and 5-TG. Biodistribution revealed a significantly higher uptake compared to blood in kidneys (12.18 +/- 8.77 and 12.69 +/- 8.93%ID/g at 30 min) and liver (2.6 +/- 2.8%ID/g) for 1-TG and in the lung (7.24 +/- 4.1%ID/g), liver (6.38 +/- 2.94%ID/g), and kidneys (4.71 +/- 1.97 and 4.81 +/- 1.91%ID/g) for 5-TG. Conclusions: 1-TG and 5-TG showed an insufficient tumor uptake with a moderate tumor-to-muscle ratio, not reaching the levels of commonly used tracer, for diagnostic use in human colorectal carcinoma and human lung adenocarcinoma xenograft model.