Cytotoxic Effect of a β1,4-Galactosyltransferase Inhibitor in Hepatic Carcinoma Cells

The incidence and mortality of hepatocellular carcinoma (HCC) are increasing worldwide, underscoring the need for novel therapeutic strategies. Synthetic 2-naphthyl 2-butanamido-2-deoxy-1-thio-β-d-glucopyranoside (612) is a selective inhibitor of β1,4-galactosyltransferase 1 (β4GalT1). In this study, we investigated the cytotoxic effects of 612 across multiple cancer cell lines, with a focus on HCC, and explored the underlying mechanisms. We demonstrate that 612 preferentially exhibits cytotoxicity toward cancer cells with elevated expression of β4GalT family members, while human umbilical vein endothelial cells and immortalized human embryonic kidney epithelial cells are comparatively less sensitive. Treatment with 612 suppresses cancer cell migration and invasion and induces pronounced endoplasmic reticulum and Golgi stress, accompanied by G2/M cell cycle arrest. Furthermore, 612 activates apoptosis through ER stress-associated pathways by downregulating the anti-apoptotic protein Bcl-2 and upregulating pro-apoptotic proteins Bax and Bak, along with activation of caspase-3, -8, and -9. Collectively, these findings identify 612 as a promising anti-cancer candidate targeting β4GalTs-overexpressing HCC cells and warrant further therapeutic development.