Solid tumor cell lines take up NE and P3. Cell lines representing solid tumors were incubated with (A) NE (10 μg/mL) or (B) P3 (10 μg/mL) and then permeabilized and stained with anti-NE or anti-P3 antibodies. Data represent mean ± SEM fold increase in NE or P3 uptake vs. unpulsed cells from triplicate wells from 2 independent experiments. MDA-MB-231, breast carcinoma; MIA PaCa-2, pancreatic carcinoma; Mel 624 and Mel 526, melanoma; OVCAR3, ovarian adenocarcinoma; SW-620, colon adenocarcinoma.