Metabolism-Guided Optimization of Tryptophanol-Derived Isoindolinone p53 Activators

Area of Science:

• Medicinal Chemistry
• Pharmacology
• Cancer Biology

Background:

• Tryptophanol-derived isoindolinones are known p53 activators.
• Understanding their pharmacokinetic (PK) profile and metabolic fate is crucial for drug development.
• Cytochrome P450 (CYP) enzymes play a significant role in drug metabolism.

Purpose of the Study:

• To investigate the PK profile of tryptophanol-derived isoindolinones.
• To identify metabolic liabilities and guide the design of novel p53 activators.
• To synthesize and evaluate new compounds with improved activity and metabolic stability.

Main Methods:

• Liquid chromatography coupled to high resolution tandem mass spectrometry (LC-HRMS/MS) for metabolite identification.
• Synthesis of 16 enantiopure tryptophanol-derived isoindolinones with C2 bromine substitution.
• Antiproliferative activity assays in HCT116 cancer cell lines (p53 wild-type and null).
• Differential scanning fluorimetry (DSF) to assess p53 binding.

Main Results:

• Indole C2 and C3 positions are primary sites for CYP-mediated oxidative metabolism.
• Bromine substitution at indole C2 resulted in a metabolic switch, minimizing Phase I metabolism.
• Two novel (S)-tryptophanol-derived isoindolinones exhibited 3.9-fold and 1.9-fold higher activity than the hit compound.
• The most potent compound increased the melting temperature (Tm) of wild-type p53 core domain by 10.39 °C.

Conclusions:

• C2 bromination enhances metabolic stability and antiproliferative activity of tryptophanol-derived isoindolinones.
• This strategy yields promising novel p53 activators with potential therapeutic applications.
• The findings provide a basis for further optimization of isoindolinone-based anticancer agents.