Discovery of dimeric guaianolides with all carbon linkers as potential antihepatoma agents

HCC is a major malignancy in humans, and the discovery of new anti-HCC agents is urgently needed. In this study, 25 dimeric guaianolides with all carbon linkers were designed and synthesized via a bis-Diels-Alder reaction. An evaluation of the inhibitory effects of these dimers on the proliferation of three hepatoma cell lines indicated that compound 17 was the most active dimer with IC₅₀ values of 1.5 (HepG2), 1.1 (Huh-7), and 1.1 μM (SK-Hep-1), which were 4.7-, 5.5- and 8.0-fold more active than sorafenib, respectively. Bioinformatic analysis predicted CDC45 as a potential target of compound 17, which was confirmed by CETSA, DARTS, and SPR assays. Compound 17 exerted its antiproliferative effect in a CDC45-dependent manner as demonstrated in CDC45 knockdown and overexpression HCC cells, promoted CDC45 nuclear export, arrested the cell cycle at the G2/M phase, induced apoptosis, and inhibited the migration and invasion of Huh-7 and SK-Hep-1 cells. In vivo experiments showed that compound 17 at 30 and 60 mg/kg inhibited tumor weight up to 76 % and 84 % without causing toxicity to major organs or impairing liver and kidney function. This study suggested compound 17 as a potential antihepatoma therapeutic agent targeting CDC45.