Design and optimization of (3-aryl-1H-indazol-6-yl)spiro[cyclopropane-1, 3′-indolin]-2′-ones as potent PLK4 inhibitors with oral antitumor efficacy. Issue 19 (1st October 2016) - Li, Sze-Wan
Graphical abstract: Abstract: Previous efforts from our laboratory demonstrated that ( E )-3-((3-( E )-vinylaryl)-1 H -indazol-6-yl)methylene)-indolin-2-ones are potent PLK4 inhibitors with in vivo anticancer efficacy upon IP dosing. As part of a continued effort to develop selective and orally efficacious inhibitors, we examined variations on this theme wherein 'directly-linked' aromatics, pendant from the indazole core, replace the arylvinyl moiety. Herein, we describe the design and optimization of this series which was ultimately superseded by (3-aryl-1 H -indazol-6-yl)spiro[cyclopropane-1, 3′-indolin]-2′-ones. The latter compounds are potent and selective inhibitors of PLK4 with oral exposure in rodents and in vivo anticancer activity. Compound13b, in particular, has a bioavailability of 22% and achieved a 96% tumor growth inhibition in an MDA-MB-468 xenograft study.