Discovery of pyrrole-indoline-2-ones as Aurora kinase inhibitors with a different inhibition profile

A series of pyrrole-indolin-2-ones were synthesized, and their inhibition profile for Aurora kinases was studied. The potent compound 33 with phenylsulfonamido at the C-5 position and a carboxyethyl group at the C-3' position selectively inhibited Aurora A over Aurora B with IC50 values of 12 and 156 nM, respectively. Replacement of the carboxyl group with an amino group led to compound 47, which retained the activity for Aurora B and lost activity for Aurora A (IC50=2.19 microM). Computation modeling was used to address the different inhibition profiles of 33 and 47. Compounds 47 and 36 (the ethyl ester analogue of 33) inhibited the proliferation of HCT-116 and HT-29 cells and suppressed levels of the phosphorylated substrates of Aurora A and Aurora B in the Western blots.