Design, in silico prioritization and biological profiling of apoptosis-inducing lactams amenable by the Castagnoli-Cushman reaction

Abstract

Five lactam chemotypes amenable by the Castagnoli-Cushman reaction of imines and cyclic anhydrides have been investigated for their ability to activate p53 tumor suppressing transcription factor thus induce apoptosis in p53⁺ cancer cells. A virtual library of 1.07 million chemically diverse compounds based on these scaffolds was subjected to in silico screening first. The compounds displaying high docking score were visually prioritized to identify the best-fitting compounds, i. e. the ones which adequately mimic the interactions of clinical candidate inhibitor Nutlin-3a. These 38 compounds were synthesized and tested for apoptosis induction in p53⁺ H116 cancer cells to identify 9 potent apoptosis-inducers (two of them exceeding the activity of Nutlin-3a) which belonged to four different chemotypes. The activation of p53 involved in the proapoptotic activity observed was supported by effective induction of EGFP expression in human osteocarcinoma U2OS-pLV reporter cell line. Moreover, the two most potent apoptosis inducers displayed antiproliferative profile identical to several known advanced p53 activators: they inhibited the growth of p53^+/+ HCT116 cells in much lower concentration range compared to p53^-/- HCT116 cells.

Keywords: Antiproliferative activity; Apoptosis induction; Protein-protein interactions; Transcription factor; Tumor suppressor; Virtual library.