Synthesis and Biological Evaluation of 1-(2-(6-Methoxynaphthalen-2-yl)-6-methylnicotinoyl)-4-Substituted Semicarbazides/Thiosemicarbazides as Anti-Tumor Nur77 Modulators

Nur77 is an orphan nuclear receptor that participates in the occurrence and development of a variety of tumors. Many agonists of Nur77 have been reported to have significant anticancer effects. Our previous studies have found that the introduction of bicyclic aromatic rings, such as naphthalyl and quinoline groups, into the <i>N</i>′-methylene position of indoles’ Nur77 modulators can effectively improve the anti-tumor activity of the target compounds. Following our previous studies, a series of novel 1-(2-(6-methoxynaphthalen-2-yl)-6-methylnicotinoyl)-4-substituted semicarbazide/thiosemicarbazide derivatives <b>9a</b>–<b>9w</b> were designed and synthesized in four steps from 6-methoxy-2-acetonaphthone and <i>N</i>-dimethylformamide dimethylacetal. All compounds were characterized by ¹H-NMR, ¹³C-NMR and HRMS, and their anti-tumor activity on various cancer cell lines such as A549, HepG2, HGC-27, MCF-7 and HeLa are also evaluated. From the series of compounds, <b>9h</b> exhibited the most potent anti-proliferative activity against several cancer cells. Colony formation and cell cycle experiments showed that compound <b>9h</b> inhibited cell growth and arrested the cell cycle. Additionally, <b>9h</b> leads to the cleavage of PARP. We initially explored the mechanism of <b>9h</b>-induced apoptosis and found that compound <b>9h</b> can upregulate Nur77 expression and triggered Nur77 nuclear export, indicating the occurrence of Nur77-mediated apoptosis. These results suggested that <b>9h</b> may be a promising anti-tumor leading compound for the further research.