A peptide-based PROTAC targeting FOXM1 suppresses fibrosis-associated hepatocarcinogenesis

Liver fibrosis is not only a major cause of cirrhosis but also an important risk factor for hepatocellular carcinoma (HCC). Currently, few drugs can effectively reverse established liver fibrosis. FOXM1, a transcription factor aberrantly activated in chronic liver disease, has been implicated in fibrosis-associated hepatocarcinogenesis. Nevertheless, effective pharmacological strategies for targeting FOXM1 are still lacking.

We developed peptide-based proteolysis-targeting chimeras (PROTACs) by conjugating the FOXM1-binding peptide P49 with different E3 ligase ligands. Among them, P49-PROTAC^VHL showed the most potent FOXM1-degrading activity in HCC cells and was selected for further investigation. Its therapeutic efficacy was then evaluated in CCl₄-induced liver fibrosis and DEN/CCl₄-induced hepatocarcinogenesis mouse models. Transcriptome analysis was performed to elucidate the molecular mechanisms by which FOXM1 promotes fibrosis and tumor progression.

Mechanistically, P49-PROTAC^VHL recruited FOXM1 to the VHL E3 ligase, leading to its polyubiquitination and subsequent proteasomal degradation. In HCC cells, FOXM1 degradation inhibited proliferation, induced cell cycle arrest, and triggered apoptosis. In the CCl₄ model, P49-PROTAC^VHL attenuated liver fibrosis, as evidenced by reduced collagen deposition, decreased α-SMA expression, and improved liver function. Mechanistic analyses, including dual-luciferase reporter assays, revealed that ADAMTS12 is a candidate transcriptional target of FOXM1. In the DEN/CCl₄ model, P49-PROTAC^VHL modulated the FOXM1-ADAMTS12 axis, thereby mitigating fibrosis and suppressing hepatocarcinogenesis.

The FOXM1-ADAMTS12 axis may represent an important molecular link between liver fibrosis and hepatocarcinogenesis. Targeting FOXM1 with peptide-based PROTACs may provide a promising therapeutic strategy to attenuate liver fibrosis and suppress HCC development.