N'-Alkylaminosulfonyl Analogues of 6-Fluorobenzylideneindolinones with Desirable Physicochemical Profiles and Potent Growth Inhibitory Activities on Hepatocellular Carcinoma.

The benzylideneindolinone 6-chloro-3-(3'-trifluoromethylbenzylidene)-1,3-dihydroindol-2-one (4) was reported to exhibit potent and selective growth inhibitory effects on hepatocellular carcinoma (HCC). Corroborative evidence supported multi-receptor tyrosine kinase (RTK) inhibition as a possible mode of action. However, the poor physicochemical properties of 4 limited its furtherance as a lead compound. In this study, the modification of 4 was investigated with the aim of improving its potency and physicochemical profile. The 6-fluorobenzylideneindolinone 3-12 bearing a 3'-N-propylaminosulfonyl substituent was found to be a promising substitute. Compound 3-12 [6-fluoro-3-(3'-N-propylaminosulfonylbenzylidene)-1,3-dihydroindol-2-one] was found to be tenfold more soluble than 4 and to have sub-micromolar growth inhibitory activities on HCC cells. It is apoptogenic and inhibits the phosphorylation of several RTKs in HuH7, of which the inhibition of FGFR4 and HER3 are prominent. Compound 3-12 decreased the tumor load in a physiologically relevant orthotopic HCC xenograft murine model. Structure-activity relationships support pivotal roles for the fluoro and N'-propylaminosulfonyl moieties in enhancing cell-based activity and moderating the physicochemical profile (solubility, permeability) of 3-12.