Characterization of cysteine protease inhibitors with antineoplastic activity by in silico and cell-based assays coupled with chemical analyses

Abstract

The drug discovery process is time-consuming and often leads to dead ends. This is especially true for the study of bioactive substance for cancer diseases, in which new therapeutic approaches are eagerly needed. Cathepsin inhibitors are described in the literature as potential novel antineoplastic compounds, inhibiting the migration and invasion of cancer cells. In this work, it is devised an integrated strategy combining in silico, synthesis and in vitro studies for dipeptidyl nitriles along with their peptoid derivatives against a set of cancer cell lines. The computational work will map a set of cathepsins (L, B, and S) and their inhibitors using molecular interaction fields coupled with chemometric analyses to define the physicochemical properties that are important for potency and selectivity. These in silico studies will guide the synthesis of a set of forty compounds, following by the characterization and bioassays. All tests are going to be based on pancreatic (MIA PaCa-2 and BxPC-3), liver (HepG2), prostate (DU145 and PC-3) and breast (MDA-MB-231) cancer cells, including non-tumorigenic cell lines to quantify the selectivity. The cytostatic activity in two and three-dimensional cell cultures is expected for these compounds according to our initial studies. Hence, a myriad of phenotypic studies involving the cell cycle arrest, inhibition of migration and colony formation should be evaluated along with combined therapy using known antineoplastic drugs. The mechanistic study comprises the analysis of the metabolism of the selective cysteine protease substrate Z-FR-MCA and profiling of distinct cysteine proteases using Western blot. Bioanalytical methods applying HPLC-MS techniques will provide the pharmacokinetics parameters related to compound permeability and stability to be coupled with the pharmacological response. These results altogether provide a glimpse for the complex chemical-biological interface in a drug discovery effort. (AU)