Figure 3.

Cellular uptake of Cy5-labeled SN38/m and (SN38 + DACHPt)/m in CD18/HPAF cells as a function of incubation time at 37 °C as investigated by flow cytometry and expressed in (A) % gated cells and (B) mean fluorescence intensity (MFI). (C) Representative confocal images of the uptake at 60 min post-treatment with micelles and magnified images of the boxed areas (red). White, Cy5; blue, DAPI. Scale bars represent 20 µm. (D) Effect of endocytosis inhibitors on the uptake of drug-loaded micelles. Cells were pretreated with corresponding inhibitors or at 4°C for 30 minutes followed by adding Cy5-labeled SN38/m or (SN38 + DACHPt)/m at concentration of 40 µM based on SN38 equivalents and incubated for another 60 min. The relative cell uptake (%) represents the uptake of micelles by cells treated with endocytic inhibitors normalized by the uptake by nontreated ones. Data presented as mean ± SD (n = 3). Statistical comparisons between the control group (no inhibitor) and the corresponding inhibitor group were determined by Student t-test (*p < 0.05, **p < 0.01, ^#p < 0.001, ^##p < 0.0001).