Cinchona Alkaloid-Inspired Urea-Containing Autophagy Inhibitor Shows Single-Agent Anticancer Efficacy.

Autophagy is upregulated in response to metabolic stress, a hypoxic tumor microenvironment, and therapeutic stress in various cancers and mediates tumor progression and resistance to cancer therapy. Herein, we identified a cinchona alkaloid derivative containing urea (C1), which exhibited potential cytotoxicity and inhibited autophagy in hepatocellular carcinoma (HCC) cells. We showed that C1 not only induced apoptosis but also blocked autophagy in HCC cells, as indicated by the increased expression of LC3-II and p62, inhibition of autophagosome-lysosome fusion, and suppression of the Akt/mTOR/S6k pathway in the HCC cells. Finally, to improve its solubility and efficacy, we encapsulated C1 into PEGylated lipid-poly(lactic-co-glycolic acid) (PLGA) nanoscale drug carriers. Systemic administration of nanoscale C1 significantly suppressed primary tumor growth and prevented distant metastasis while maintaining a desirable safety profile. Our findings demonstrate that C1 combines autophagy modulation and apoptosis induction in a single molecule, making it a promising therapeutic option for HCC.