(A) Fluorescence confocal microscopy shows CLR1501 (5 µM) uptake in multiple cancer types, and less uptake in normal human fibroblasts at 24 hours. Scale bar, 10 µm. (B) Coculture of human prostate cancer (PC-3) cells and normal human fibroblasts. Cells were treated with the fluorescent analog CLR1501 (5 µM) for 24 hours and counterstained with the nuclear stain, Hoechst 33342. Scale bar, 10 µm. (C) Quantitative uptake and retention of 125I-CLR1404 in three cancer cell lines derived from patients and the corresponding patient-matched normal cell lines. Data are means ± SEM (n = 3 independent experiments with three biological replicates each). *P < 0.001, analysis of variance (ANOVA) with post hoc Tukey test.