WED-235 Involvement of the hERG1 potassium channel in cholangiocarcinoma cell biology

Background and aims: hERG1 is avoltage-gated potassium channel normally found in excitable cells, but it is often overexpressed in tumors, where it interacts with β1 integrin and activates cancerrelated pathways. Intrahepatic cholangiocarcinoma (iCCA) is an aggressive liver malignancy with limited treatment options. This study aimed to investigate the role of hERG1 and its downstream signaling in iCCA biology. Method: hERG1expressionwas assessed in three iCCA cell lines, and functional studies were performed using siRNA-mediated silencing (sihERG1) and pharmacological inhibition (E4031). Cellular behavior was evaluated through standard assays, and molecularand structural changes were analyzed using qRT-PCR, Western blotting, electron microscopy, and transcriptomics. Results: hERG1 silencing led to a 75–80% reduction in mRNA and protein expression but did not impact proliferation or viability. In contrast, both genetic silencing and pharmacological inhibition significantly reduced cell motility and impaired angiogenesis, as shownbyreducedtubeformation inHUVECsexposed to sihERGCCA conditioned media. Gene expression analyses revealed downregulation of epithelial mesenchymal transtion (EMT) and angiogenesis markers.Keyoncogenicpathways,includingFAK,PI3K,andAKT,were notably suppressed. Ultrastructural analysis showed endoplasmic reticulum swelling and increased vesicular trafficking, indicating cellular stress and altered membrane turnover. Transcriptomic analysis revealed a common profile of gene alteration, mainly in vesicular trafficking, transmembraneionregulation,andextracellular matrix reorganization, highlithing a broader impact of hERG1 on intracellular dynamics. Conclusion: hERG1 plays a critical role in supporting motility and angiogenic potential in iCCA cells without affecting proliferation. Its inhibition alters key oncogenic and cellular processes, positioning hERG1 as a promising therapeutic target in iCCA.