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

BACKGROUND

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.

METHODS

We developed peptide-based proteolysis-targeting chimeras (PROTACs) by conjugating the FOXM1-binding peptide P49 with different E3 ligase ligands. Among them, P49-PROTACVHL 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.

RESULTS

Mechanistically, P49-PROTACVHL 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-PROTACVHL 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-PROTACVHL modulated the FOXM1-ADAMTS12 axis, thereby mitigating fibrosis and suppressing hepatocarcinogenesis.

CONCLUSIONS

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.