EFFECT OF PROCATHEPSIN-D AND ITS ACTIVATION PEPTIDE ON PROSTATE-CANCER CELLS

Cathepsin D, a lysosomal aspartic proteinase, is secreted in the form of enzymatically inactive precursor in some cancer cells. This precurs or, called procathepsin D, was found to exhibit growth factor activity toward breast cancer cell lines and this activity was later shown to be mediated by its activation peptide. In the present investigation we have used human procathepsin D and a synthetic 44 amino acid peptide corresponding to the activation peptide of procathepsin D to test its growth factor activity for human prostate cancer-derived cell lines PC 3, DU145 and LNCaP. We have tested the level of proliferation of these cell lines depending on the presence of either procathepsin or activa tion peptide in the medium. In parallel, we have also measured the tim e dependency of this growth and established the optimal dose of activa tion peptide. These findings represent the first experimental data sho wing the direct effects of procathepsin D on prostate cancer cells. (C ) 1998 Elsevier Science Ireland Ltd. All rights reserved.