Homochlorcyclizine Dihydrochloride Inhibits Hepatocellular Carcinoma Progression and Cancer Stem Cell Properties.

[BACKGROUND/AIM] Homochlorcyclizine dihydrochloride, a clinically approved antihistamine for allergic conditions, has not been previously explored for hepatocellular carcinoma (HCC) therapy. This study aimed to investigate homochlorcyclizine dihydrochloride's anti-HCC activity and underlying mechanisms, focusing on its effects on proliferation, migration, cancer stem cell (CSC) characteristics, and key cell cycle regulators.

[MATERIALS AND METHODS] The antiproliferative and anti-migratory effects of homochlorcyclizine dihydrochloride were evaluated using assays, including CCK-8 and wound healing assays, and xenograft mouse models. CSC properties were examined through sphere formation and limiting dilution xenograft assays. RNA-seq analysis was performed to identify differentially expressed genes (DEGs), followed by KEGG pathway enrichment. Cell cycle progression was analyzed by flow cytometry, and CDC20/CDK1 expression was quantified via qRT-PCR and western blot. Clinical relevance was evaluated using TCGA-LIHC data.

[RESULTS] Homochlorcyclizine dihydrochloride significantly inhibited HCC cell proliferation and migration , and suppressed HCC tumor growth in xenograft mouse models. Homochlorcyclizine dihydrochloride also reduced sphere-forming efficiency and tumor-initiating potential, indicating inhibition of CSC characteristics. RNA-seq revealed 915 DEGs in homochlorcyclizine dihydrochloride-treated Huh7 cells, with significant down-regulation of cell cycle pathway genes, including CDC20 and CDK1. HCD down-regulated CDC20 and CDK1 protein expression, impairing cell cycle progression. In the TCGA-LIHC cohort, elevated CDC20 and CDK1 expression in HCC correlated with reduced survival and advanced clinical stage, underscoring their prognostic relevance.

[CONCLUSION] Homochlorcyclizine dihydrochloride exerts potent anti-HCC activity by suppressing proliferation, migration, and CSC characteristics, likely mediated by down-regulation of CDC20 and CDK1. Its established safety profile positions homochlorcyclizine dihydrochloride as a compelling candidate for repurposing as a novel HCC therapy, warranting further clinical exploration.