Involvement of the hERG1 potassium channel in cholangiocarcinoma cell biology

Background and Aim: hERG1 is a voltage-gated potassium channel normally found in excitable cells, but it is often overex- pressed in tumors, where it interacts with β1 integrin and activates cancer-related 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. Methods: hERG1 expression was assessed in three iCCA cell lines, and functional studies were performed using siRNA-mediated silencing (si hERG1) and pharmacological inhibition. Cellular be- havior was evaluated through standard assays, and molecular and 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 angiogene- sis, as shown by reduced tube formation in HUVECs exposed to si hERG CCA conditioned media. Gene expression analyses revealed downregulation of epithelial mesenchymal transtion (EMT) and angiogenesis markers. Key oncogenic pathways, including FAK, PI3K, and AKT, were notably suppressed. Ultrastructural analysis showed endoplasmic reticulum swelling and increased vesicular traffic, indicating cellular stress and altered membrane turnover. Transcrip- tomic profiling confirmed dysregulation in vesicle trafficking and exocytosis, 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 prolifera- tion. Its inhibition alters key oncogenic and cellular processes, positioning hERG1 as a promising therapeutic target in iCCA.