ABCC1 expression and transporter function in MPNST-derived cell lines NF94.3 and NF96.2. Immunofluorescent staining for ABCC1 (green) and S100 (red) with DAPI (blue) nuclear stain as indicated in NF94.3 (A) and NF96.2 (B). Scale bar = 10 μm. C) Relative cell content following 5 days of growth in doxorubicin-containing media with and without 100 μM verapamil in NF94.3 cells. Average doxorubicin EC50 0.81 μg/ml, versus 0.34 μg/ml in the presence of verapamil (*p = 0.025, n = 5). D) NF96.2 cells; average doxorubicin EC50 0.44 μg/ml, versus 0.22 μg/ml in the presence of verapamil (n.s. p = 0.16, n = 5). E) No growth inhibition with verapamil alone at concentrations 125 μM and lower. Dotted line indicates 100 μM verapamil concentration used in (C, D). F) Quantitative real-time PCR for ABCC family transporter transcript levels. G) Doxorubicin EC50 values for benign neurofibroma-derived cell lines as compared to MPNST-derived cell lines. H) Growth inhibition curves for a representative experiment with molecular-guided therapy predicted drugs. Data is graphed as percentage untreated control per drug concentration.