BINDING OF A RADIOLABELED TUMOR SELECTIVE GNRH ANALOG TO PC-3 HUMAN PROSTATE-CANCER CELLS AND THE INDUCTION OF APOPTOSIS

The human prostate cancer cell line PC-3 was treated with 0.1-1.0-10.0 mu g/ml of TH-332, a tumor selective GnRH analog. The treatment resul ted in a dose dependent decrease in cell number, due to an increase of apoptotic cells and a parallel decrease of mitosis. H-3-labeled TH-33 2 was also applied to PC-3 cell culture as a one hour treatment. High dose (100.0 mu g/ml) of the labeled peptide resulted in a heavy labeli ng of the whole cell including the nucleus, whereas after 10.0 mu g/ml only the cell surface was labeled. These findings suggest an indirect evidence of GnRH receptors in the PC-3 cells and contribute to the be tter understanding of the mode of action of peptide hormones on tumor cells.