Novel Schiff base copper complexes of quinoline-2 carboxaldehyde as proteasome inhibitors in human prostate cancer cells

We report the synthesis of novel 1: 1 Schiff base copper complexes of quinoline-2-carboxaldehyde showing dose-dependent, antiproliferative, and proapoptotic activity in PC-3 and LNCaP prostate cancer cells. We found that quinoline thiosemicarbazone 2 (FPA-137) was the most potent and inhibited proteosome activity in intact human prostate cancer PC-3 and LNCaP cells (IC50 of 4 and 3.2 mu M, respectively) compared to clioquinol and pyrrolidine dithiocarbamate (IC50 of 10 and 20 mu M), supporting the novelty of 2.