Currently,
hepatocellular carcinoma (HCC) is characterized by its unfavorable prognosis and resistance to conventional
chemotherapy and
radiotherapy. Drug repositioning, an approach aimed at identifying novel therapeutic applications for existing drugs, presents a cost-effective strategy for developing new
anticancer agents. We explored the anticancer properties of
Ezetimibe, a widely used oral
lipid-lowering drug, in the context of HCC. Our findings demonstrate that
Ezetimibe effectively suppresses HCC cell proliferation through paraptosis, an apoptotic-independent cell death pathway. The examination of HCC cells lines treated with
Ezetimibe using light microscopy and transmission electron microscopy (TEM) showed cytoplasmic vacuolation in the perinuclear region. Notably, the nuclear membrane remained intact in both
Ezetimibe-treated and untreated HCC cell lines. Probe staining assays confirmed that the cytoplasmic vacuoles originated from dilated endoplasmic reticulum (ER) compartments rather than mitochondria. Furthermore, a dose-dependent accumulation of
reactive oxygen species (ROS) was observed in
Ezetimibe-treated HCC cell lines. Co-treatment with the general
antioxidant NAC attenuated vacuolation and improved cell viability in
Ezetimibe-treated HCC cells. Moreover,
Ezetimibe induced paraptosis through
proteasome activity inhibition and initiation of the unfolded protein response (UPR) in HCC cell lines. In our in vivo experiment,
Ezetimibe significantly impeded the growth of HCC
tumors. Furthermore, when combined with
Sorafenib,
Ezetimibe exhibited a synergistic antitumor effect on HCC cell lines. Mechanistically,
Ezetimibe induced paraptosis by targeting NPC1L1 to inhibit the PI3K/AKT/mTOR signaling pathway. In conclusion, our study highlights the potential of
Ezetimibe as an
anticancer agent by triggering paraptosis in HCC cells.