Fig. 4
Gaussia luciferase (hGluc) is active in murine blood and the signal is elevated in tumor-bearing mice. a Frozen sections of lungs of tumor-bearing mice sacrificed 10 days after Dil-labeled hGluc-MSC administration were stained with DAPI and then imaged by fluorescence microscopy. MSCs (red) were observed to home to tumor niche (dense blue). Scale bar: 100 μm. b Five weeks after Fluc-tdT-231 were seeded intravenously into NSG mice, 106 hGluc-MSCs were administered systemically into both tumor-free and tumor-bearing mice. Then murine blood was harvested and hGluc activity was measured at different time points (6, 24, and 48 hours and 7 and 10 days after MSC infusion) with IVIS Lumina immediately after substrate was added. hGluc activity measured at different time points was quantified and normalized to the time point of 6 hours. The inset graph shows that the hGluc activity in blood between tumor-bearing and tumor-free mice is significantly different from 48 hours after MSC infusion. Error bar: mean ± standard error of the mean. *P <0.05. Exposure time = 30 s. n=4 in each group. DAPI 4',6-Diamidino-2-phenylindole, MSC mesenchymal stem cell