The EGFR-IL-8 Signaling Axis Drives Lenvatinib Acquired Resistance in Hepatocellular Carcinoma Through Modulation of Tumor-Macrophage Interactions

Lenvatinib has been approved as a treatment for advanced hepatocellular carcinoma (HCC), but drug resistance limits its clinical efficacy. Tumor-associated macrophages (TAMs) are abundant in the tumor microenvironment and critically contribute to HCC progression. However, the mechanism of interaction between HCC cells and TAMs in the context of lenvatinib resistance remains unclear. Lenvatinib-resistant HCC (HCC-LR) cells were established by gradually exposing the cells to lenvatinib. Western blot analysis was conducted to assess the expression levels of phosphorylated EGFR and its downstream pathway-associated proteins in HCC cells. Flow cytometry and colony formation assays were utilized to evaluate apoptosis and cell proliferation, respectively. Bioinformatic analyses were performed to investigate the expression of relevant genes, pathway activation, and immune cell infiltration. Additionally, TAMs were generated from THP-1 cells to investigate their role in mediating lenvatinib resistance in HCC. Our results indicated that phosphorylated EGFR and interleukin-8 (IL-8) were overexpressed in HCC-LR cells. Pharmacological inhibition of EGFR in HCC-LR cells increased apoptosis and attenuated cell proliferation upon lenvatinib treatment in vitro. Mechanistically, EGFR activation promoted IL-8 secretion, which recruited macrophages and enhanced lenvatinib resistance in HCC by activating the EGFR-Akt/JNK signaling axis in vitro. Notably, these recruited macrophages differentiated into TAMs, which in turn secreted HB-EGF, a prominent ligand responsible for reactivating EGFR signaling in HCC cells, thus establishing a resistance-promoting feedback loop. Our findings reveal a key tumor cell-TAM crosstalk that mediates lenvatinib resistance in HCC, providing a rational basis for developing improved combination therapies.