2-Phenoxy-3, 4′-bipyridine derivatives inhibit AURKB-dependent mitotic processes by disrupting its localization

An orally bioavailable 4-phenoxy-quinoline compound as a potent AURKB relocation blocker for cancer treatment

“…Previous work with these 4-phenoxy-quinoline-based derivatives focused on structure-activity relationships that could be discerned from systemically modifying side groups attached to varying locations of the 3-ring core (Scheme 1) . 6,7 Our potent in vitro compound, LG182 , harbors an aromatic ring with di-meta substitutions of an OMe group and an acetamide group. Leaving this structural feature alone, we explored substitutions at the position labeled R of the ring most distal to the di-meta ring.…”

“…The minimum effective concentration (MEC) in RPE-MYC H2B-GFP cells that induces phenotypes reminiscent of AURKB inhibition was used to compare compounds, as this was previously found to be an effective metric. 6,7 The most easily discernable outcome from inhibiting the localization of the chromosomal passenger protein complex is the induction of polyploid cells, as AURKB localizes during telophase to the midbody and mediates the induction of cytokinesis. 12 However, the MEC for mitotic arrest, polyploidy, and cell death were the same in this assay as we observed before, 7 and we referred to them as MEC without discrimination ( Table 1) .…”

“…Immunofluorescent (IF) analysis with markers that are used as surrogates for the activity of AURKs can be used to assess the catalytic inhibition of these mitotic kinases as we described before. 6,7 For AURKB, the intensity of Histone 3 phosphorylation at Serine 10 (H3Ser10P), a direct target of AURKB in mitosis, is a well-established surrogate of its kinase activity. We have previously combined phenotypic screening in RPE-MYC H2B-GFP cells with IF for surrogate markers of AURK activity as a MIPS method.…”

“…We have previously combined phenotypic screening in RPE-MYC H2B-GFP cells with IF for surrogate markers of AURK activity as a MIPS method. 6,7 Here, we continued to assess compounds with this combination approach to ensure the halogenated compounds are not catalytic inhibitors but added an IF assay to ensure they also disrupt AURKB positioning at the spindle midzone during anaphase. Halogenated compounds did so, irrespective of which halogen was substituted at R. IF examination of earlier stages of mitosis suggested that localization of AURKB on prometaphase kinetochores was not affected in two human cancer cell lines NCI-H23 and DU-145 and a model cell line RPEMYC Bcl2 ( Figure S1) .…”

“…Also, drug resistance due to compensating AURK mutation has been suggested to contribute to a lack of durable efficacy in clinical trials. 5 We previously described a mechanism-informed, phenotypic screening (MIPS) assay of a synthetic compound library, 6,7 for compounds that disrupt the localization, but not catalytic activity, of the CPP complex. Such compounds prevent cytokinesis, induce polyploidy, and trigger cell death in model rodent and human-derived cancer cell lines.…”