Figure 4. Treatment of GEP-NEN cell lines with siomycin A.

In three independent experiments, BON A., QGP-1 B., KRJ-1 C. and LCC-18 D. cells were treated with increasing concentrations (1μM, 2μM, 5μM) of siomycin A and (0.1μM,1μM, 5μM) everolimus for 24, 48 and 72 hours and analyzed by colorimetric proliferation assays (graphs in percent of internal DMSO controls). Siomycin A significantly inhibits GEP-NEN cell proliferation (p=0.000) and was superior to everolimus treatment in all cell lines. Antiproliferative effects could be shown for concentration ≥1μM in BON, KRJ 1, LCC 18 and ≥2μM for QGP-1 cells in relation to DMSO internal controls and were verified in a linear regression analysis. KRJ-1 cells showed a strong variance in the response due to intercellular clustering effects. Nevertheless these changes were highly significant (p=0.000). Representative data of one experiment is shown. Dotted lines indicate 100% and 10% of control.