Design, Synthesis, and Mechanistic Evaluation of U12 Derivatives as Potent Anti-Hepatoma Agents Targeting G0/G1 Cell Cycle Arrest and Apoptosis via PI3K/AKT/mTOR Pathway

Ursodeoxycholic acid (UDCA) is a well-established treatment for liver conditions, with its derivative, U12, showing notable anti-hepatoma effects in prior research. However, U12’s low polarity and the requirement for high dosages pose challenges to its druglikeness. In this study, twelve new derivatives of U12 were synthesized using substitution, esterification, and amidation methods, aimed at improving its pharmacological properties. Testing of these derivatives on hepatoma cell lines (HepG2) revealed that compounds U12-I, U12a-d, and U12h exhibited superior cytotoxic effects compared to U12 itself. Among them, U12a showed the most potent activity against hepatocellular carcinoma. Mechanistic investigations demonstrated that U12a inhibited HepG2 cell proliferation by causing G0/G1 phase cell cycle arrest and by suppressing the PI3K/AKT/mTOR pathway. Moreover, U12a induced apoptosis in HepG2 cells through activation of the caspase signaling cascade. In vivo experiments confirmed that U12a significantly reduced tumor growth in HepG2-derived xenografts, without causing notable side effects. Consequently, U12a holds promise as a potential therapeutic agent for hepatocellular carcinoma.