Hypoxia-induced endoplasmic reticulum stress mediates lenvatinib resistance in hepatocellular carcinoma through the IRE1α-XBP1s-HIF1α pathway.

BACKGROUND

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related deaths globally, with a dismal prognosis for advanced patients. Lenvatinib, a first-line anti-angiogenic agent, has improved clinical outcomes, but drug resistance remains a major unmet clinical need. Hypoxia, a hallmark of solid tumors, crosstalks with endoplasmic reticulum stress (ERS), yet their combined role in lenvatinib resistance in HCC remains undefined.

METHODS

TCGA and GEO datasets were analyzed for ERS-related gene expression and prognostic value. In vitro experiments were conducted in HepG2 and HCCLM3 cells under normoxic (21% O₂) or hypoxic (1% O₂) conditions. Cell viability, apoptosis, migration, and protein expression were assessed via standard assays. siRNA silencing and the ERS inhibitor 4-PBA were used for mechanistic validation.

RESULTS

The ERS marker GRP78 was significantly upregulated in HCC tissues and correlated with poor survival. Hypoxia induced ERS in HCC cells, promoting proliferation and migration while attenuating lenvatinib-induced apoptosis. Mechanistically, hypoxia induces activation of the IRE1α-XBP1s-HIF1α axis, and genetic silencing of this axis restores lenvatinib sensitivity. 4-PBA effectively reversed hypoxia-mediated drug resistance.

CONCLUSIONS

Hypoxia-induced ERS mediates lenvatinib resistance in HCC via the IRE1α-XBP1s-HIF1α pathway. Targeting this axis provides a promising strategy to overcome anti-angiogenic therapy resistance in HCC.