Metabolism-Guided Optimization of Tryptophanol-Derived Isoindolinone p53 Activators

• Published in: Pharmaceuticals (Basel, Switzerland) Vol. 16; no. 2; p. 146
• Main Authors: Barcherini, Valentina, Loureiro, Joana B, Sena, Ana, Madeira, Catarina, Leandro, Paula, Saraiva, Lucília, Antunes, Alexandra M M, Santos, Maria M M
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 19.01.2023; MDPI
• Subjects: Acids; Amino acids; Bioavailability; cancer; Cancer therapies; Cell cycle; Chemical properties; Colorectal cancer; Drug metabolism; Drug therapy; Enzymes; Growth factors; Heterocyclic compounds; hit-to-lead optimization; metabolic stability; Metabolism; Metabolites; Optimization; Oxidation; Oxygen; p53; Pharmacokinetics; Pharmacology, Experimental; Physiological aspects; Proteins; tryptophanol-derived isoindolinones; Tumor proteins; Portugal; cancer; hit-to-lead optimization; tryptophanol-derived isoindolinones; metabolic stability; p53
• ISSN: 1424-8247; 1424-8247
• DOI: 10.3390/ph16020146

For the first time, the pharmacokinetic (PK) profile of tryptophanol-derived isoindolinones, previously reported as p53 activators, was investigated. From the metabolites' identification, performed by liquid chromatography coupled to high resolution tandem mass spectrometry (LC-HRMS/MS), followed by their preparation and structural elucidation, it was possible to identify that the indole C2 and C3 are the main target of the cytochrome P450 (CYP)-promoted oxidative metabolism in the tryptophanol-derived isoindolinone scaffold. Based on these findings, to search for novel p53 activators a series of 16 enantiopure tryptophanol-derived isoindolinones substituted with a bromine in indole C2 was prepared, in yields of 62-89%, and their antiproliferative activity evaluated in human colon adenocarcinoma HCT116 cell lines with and without p53. Structural optimization led to the identification of two ( )-tryptophanol-derived isoindolinones 3.9-fold and 1.9-fold more active than hit SLMP53-1, respectively. Compounds' metabolic stability evaluation revealed that this substitution led to a metabolic switch, with the impact of Phase I oxidative metabolism being minimized. Through differential scanning fluorimetry (DSF) experiments, the most active compound of the series in cell assays led to an increase in the protein melting temperature ( ) of 10.39 °C, suggesting an effective binding to wild-type p53 core domain.