Fig. 2
C2Am binds to dead cells in vitro. Flow cytometric analysis of MEDI3039-treated MDA-MB-231 (a) and Colo205 (b) cells shows three distinct populations (first and third plots, from left), which were gated based on their levels of UVA autofluorescence (NADH content) and plasma membrane integrity (Sytox R) as: viable (v%), apoptotic (a%) and necrotic (n%) cells. C2Am-AF750, a near infrared fluorophore-labeled derivative of C2Am labels (second and fourth plots) preferentially bound apoptotic (orange) and necrotic (red) cells, in comparison with viable (green) cells (c, d). Plots of C2Am-AF750 mean fluorescence intensity (MFI) ratios for necrotic/viable, apoptotic/viable and dead/viable MDA-MB-231 (e) and Colo205 (f) cells following treatment with MEDI3039 (mean ± SD, n = 3), error bars lie within the symbols when not shown. MEDI3039-treated MDA-MB-231 (g) and Colo205 (h) cells were incubated with 18F-C2Am at different concentrations (1–1000 nM) and the fraction of activity retained in the cell pellets (%) after three washes was measured. The signal-to-background ratio (SBR, black bars) of treated (grey bars) versus vehicle-treated (open bars, control) cells is also shown