Inhibition of human epithelial ovarian cancer cell growth in vitro by somatostatin analog RC-160

In th is study, we investigated the effects of somatostatin analog RC-160 o n the growth of the OV-1063 human epithelial ovarian cancer cell line in vi tro. RC-160 inhibited cell proliferation, as measured by cell number, and [ H-3]thymidine incorporation into DNA at 10(-9)-10(-5) M. In OV-1063 cells, I-125-labeled RC-160 was bound to one class of specific, saturable binding sites with high affinity (K-d = 0.2 +/- 0.03 nM) and low capacity (5,500 bi nding sites per cell). I-125-labeled RC-160 could be displaced by unlabeled RC-160, Ligand binding was dependent on time and temperature. Receptor int ernalization assay showed that the ligand-receptor complex was internalized at 37 degreesC, which indicates the presence of biologically active somato statin receptors on OV-1063 cells. These results suggest that somatostatin analog RC-160 can suppress the growth of OV-1063 human epithelial ovarian c ancer cells by a direct action and that the inhibitory effect of somatostat in analog is mediated through the high-affinity somatostatin receptors, Cop yright (C) 2000 S. Karger AG, Basel.