RESUMO
Screening identified 2-(3-((4,6-dioxo-2-thioxotetrahydropyrimidin-5(2H)-ylidene)methyl)-2,5-dimethyl-1H-pyrrol-1-yl)-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carbonitrile as an MDM2-p53 inhibitor (IC50 = 12.3 µM). MDM2-p53 and MDMX-p53 activity was seen for 5-((1-(4-chlorophenyl)-2,5-diphenyl-1H-pyrrol-3-yl)methylene)-2-thioxodihydropyrimidine-4,6(1H,5H)-dione (MDM2 IC50 = 0.11 µM; MDMX IC50 = 4.2 µM) and 5-((1-(4-nitrophenyl)-2,5-diphenyl-1H-pyrrol-3-yl)methylene)pyrimidine-2,4,6(1H,3H,5H)-trione (MDM2 IC50 = 0.15 µM; MDMX IC50 = 4.2 µM), and cellular activity consistent with p53 activation in MDM2 amplified cells. Further SAR studies demonstrated the requirement for the triarylpyrrole moiety for MDMX-p53 activity but not for MDM2-p53 inhibition.
RESUMO
Structure-activity relationships for the MDM2-p53 inhibitory activity of a series of A-ring substituted 2-N-benzyl-3-(4-chlorophenyl)-3-(1-(hydroxymethyl)cyclopropyl)methoxy)isoindolinones have been investigated, giving rise to compounds with improved potency over their unsubstituted counterparts. Isoindolinone A-ring substitution with a 4-chloro group for the 4-nitrobenzyl, 4-bromobenzyl and 4-cyanobenzyl derivatives (10a-c) and substitution with a 6-tert-butyl group for the 4-nitrobenzyl derivative (10j) were found to confer additional potency. Resolution of the enantiomers of 10a showed that potent MDM2-p53 activity resided in the (-)-enantiomer ((-)-10a; IC(50)=44 ± 6 nM). The cellular activity of key compounds has been examined in cell lines with defined p53 and MDM2 status. Compounds 10a and (-)-10a increase p53 protein levels, activate p53-dependent MDM2 and p21 transcription in MDM2 amplified cells, and show improved selectivity for growth inhibition in wild type p53 cell lines over the parent compound.
