Fig. 3
Mesenchymal stem cells home to tumor site and persist longer than in healthy mice. a Five weeks after eGFP-231 were seeded intravenously into NSG mice, 106 Fluc-tdT-MSCs were administered systemically into both tumor-free (top) and tumor-bearing (bottom) mice. Then mice were injected intraperitoneally with D-Luciferin (150 mg/kg in Dulbecco’s phosphate-buffered saline), and in vivo Fluc activity was measured at different time points (2, 6, 24, and 48 hours and 7 and 10 days after MSC infusion) by using an IVIS Lumina to begin data acquisition 10 minutes after substrate administration (exposure time = 60 s; n=4 in each group). MSCs were cleared out faster in tumor-free mice. Color scale: minimum = 6.50×104, maximum = 7.50×105. Frozen sections of lungs of b tumor-free mice and c eGFP-231 tumor-bearing mice sacrificed 10 days after Fluc-tdT-MSC infusion were stained with anti-eGFP (green) and anti-Fluc (red) antibodies. MSCs were observed to home to tumor niche. Scale bar: 50 μm. d Fluc activity measured at different time points was quantified and normalized to the time point of 2 hours. Error bar: mean ± standard error of the mean. *P <0.05. n=4 in each group. eGFP enhanced green fluorescent protein, Fluc firefly luciferase, MSC mesenchymal stem cell, NSG nonobese diabetic/severe combined immunodeficiency gamma, tdT tdTomato red fluorescent protein