Activation of Nerve Growth Factor signaling limits the response to lenvatinib in hepatocellular carcinoma.

Resistance to lenvatinib remains a major barrier in the treatment of advanced hepatocellular carcinoma (HCC), underscoring the urgent need to elucidate the underlying mechanisms and identify actionable therapeutic targets. In this study, we identified a neurosecretory factor derived from HCC cells, Nerve Growth Factor (NGF), as a critical mediator of lenvatinib resistance. Utilizing an innovative in vivo-in vitro cross-circulated strategy, we established a phenotypically stable lenvatinib-resistant HCC cell line (LenR-cells). Through proteomic screening of conditioned media and subsequent functional validation, we demonstrated that NGF secretion progressively increases with the acquisition of resistance. Mechanistically, we uncovered that the SRPK1-SRSF1 axis drives enhanced NGF production by regulating alternative splicing of its precursor transcript, specifically promoting the expression of a shorter, translationally efficient isoform (proNGF-B). Elevated NGF subsequently activates the non-canonical MAPK pathway (MEK5-ERK5) via its high-affinity receptor TrkA, thereby sustaining tumor cell viability and proliferation under sustained tyrosine kinase inhibitor pressure. Critically, pharmacological co-targeting of TrkA with the clinically approved inhibitor larotrectinib restored lenvatinib sensitivity in both patient-derived organoids and xenograft models, producing marked synergistic anti-tumor effects without evidence of exacerbated toxicity. Clinical analyses of two independent patient cohorts further confirmed that elevated NGF expression is significantly associated with poor response to lenvatinib, shorter recurrence-free survival, and worse overall survival. Our findings unveil a critical and previously underappreciated role for tumor-derived NGF in orchestrating adaptive signaling through a precise post-transcriptional regulatory circuit and propose a readily translatable, biomarker-guided combination strategy to overcome lenvatinib resistance in HCC.