Lefamulin targets ILF3 to overcome targeted therapy resistance in hepatocellular carcinoma

Acquired resistance represents a critical clinical challenge to molecular targeted therapies such as tyrosine kinase inhibitors (TKIs) treatment in hepatocellular carcinoma (HCC). Therefore, it is urgent to explore new mechanisms and therapeutics that can overcome or delay resistance. Here, we identified a U.S. Food and Drug Administration (FDA)-approved pleuromutilin antibiotic that overcomes sorafenib resistance in HCC cell lines, cell line-derived xenograft (CDX) and hydrodynamic injection mouse models. We demonstrated that lefamulin targets and binds Interleukin Enhancer-binding Factor 3 (ILF3) to inhibit sorafenib-induced mitochondrial ribosomal protein L12 (MRPL12) upregulation. Mechanistically, lefamulin directly binds to Ala-99 of ILF3 and interferes with acetyltransferase general control non-depressible 5 (GCN5) and CREB binding protein (CBP) mediated acetylation of Lys-100, which disrupting the ILF3-mediated transcription of MRPL12 and subsequent mitochondrial biogenesis. Clinical data further confirmed that high ILF3 or MRPL12 expression was associated with poor survival and targeted therapy efficacy in HCC. Conclusively, our findings suggest that ILF3 is a potential therapeutic target for overcoming resistance to TKIs, and lefamulin may be a novel combination therapy strategy for HCC treatment with sorafenib and regorafenib. Overall design: To investigate how lefamulin overcomes sorafenib resistance in HCC, we conducted RNA sequencing (RNA-seq) on the HepG2 cells treated with DMSO or lefamulin