Synthetic Retinoid Sulfarotene Selectively Inhibits Tumor-Repopulating Cells of Intrahepatic Cholangiocarcinoma via Disrupting Cytoskeleton by P-Selectin/PSGL1 N-Glycosylation Blockage.

Intrahepatic cholangiocarcinoma (ICC) is a highly lethal malignancy that currently lacks effective clinical treatments. Eliminating stem cell-like cancer cells is an extremely promising but challenging strategy for treating ICC. A recently developed synthetic retinoid, sulfarotene, abrogates proliferation, and induces apoptosis of tumor-repopulating cells (TRCs) that exhibit stem cell-like properties, yet its effect and underlying mechanisms remain elusive in ICC. It is found that although 5-fluorouracil, cisplatin, pemigatinib, and gemcitabine all inhibit ICC-TRCs, sulfarotene demonstrates superior efficacy. Sulfarotene induces retinoic acid receptor alpha (RARɑ) translocation from the cytoplasm to the nucleus, suppressing P-selectin expression at the transcriptional level. Moreover, it directly interacts with fucosyltransferase 8 (FUT8), inhibiting the core fucosylation of P-selectin glycoprotein ligand 1 (PSGL1). These actions collectively inhibit ICC-TRCs via destroying PSGL1-regulated cytoskeleton. The findings provide a strategy of inhibiting P-selectin/PSGL1 interaction and altering PSGL1 glycosylation pattern to compromise the cytoskeletal integrity and eliminate ICC-TRCs.