Screening of indeno[1,2-b]indoloquinones by MALDI-MS: a new set of potential CDC25 phosphatase inhibitors brought to light

Alchab F, Sibillie E, Ettouati L, Bana E, Bouaziz Z, Mularoni A, Monnio E, Bagrel D, Jose J, Le Borgne M, Chaimbault P

Abstract

Quinones and quinones-like compounds are potential candidates for the inhibition of CDC25 phosphatases. The combination of MALDI-MS analyses and biological studies was used to develop a rapid screening of a targeted library of indeno[1,2-b]indoloquinone derivatives. The screening protocol using MALDI-TOFMS and MALDI-FTICRMS highlighted four new promising candidates. Biological investigations showed that only compounds 5c–f inhibited CDC25A and -C phosphatases, with IC50 values around the micromolar range. The direct use of a screening method based on MALDI-MS technology allowed achieving fast scaffold identification of a new class of potent inhibitors of CDC25 phosphatases. These four molecules appeared as novel molecules of a new class of CDC25 inhibitors. Assessment of 5c–e in an MRC5 proliferation assay provided an early indicator of toxicity to mammalian cells. Compound 5d seems the most promising hit for developing new CDC25 inhibitors.