Background: Intrahepatic cholangiocarcinoma (ICC) is a highly aggressive malignancy with a poor prognosis. Aspartate β-hydroxylase (ASPH) is an α-ketoglutarate-dependent dioxygenase involved in the post-translational hydroxylation of target proteins. ASPH has been demonstrated to be upregulated in ICC, yet its role remains to be elucidated. This study aimed to investigate the potential function of ASPH in ICC metastasis.
Methods: Survival curves for the overall survival of pan-cancer data from The Cancer Genome Atlas (TCGA) database was depicted using the Kaplan-Meier method and compared using the log-rank test. The expression of ASPH, glycogen synthase kinase (GSK)-3β, phosphorylation GSK-3β (p-GSK-3β), epithelial-mesenchymal transition (EMT) biomarkers, and sonic hedgehog (SHH) signaling elements in ICC cell lines was analyzed by western blot. Wound healing and transwell assays were conducted to examine the effects of ASPH knockdown and overexpression on cell migration and invasion. An immunofluorescence assay was conducted to evaluate the expression of glioma-associated oncogene 2 (GLI2), GSK-3β and ASPH. The effect of ASPH on tumor in vivo was analyzed using a nude mouse xenograft model.
Results: Pan-cancer data showed that expressed ASPH was significantly correlated with a poor prognosis in patients. ASPH knockdown inhibited the migration and invasion of human ICC cells lines QBC939 and RBE. ASPH overexpression contributed to an increase in the N-cadherin and Vimentin, resulting in the promotion of the EMT process. The p-GSK-3β levels decreased in the presence of ASPH overexpression. The overexpression of ASPH led to an upregulation of the expression of SHH signaling elements GLI2 and SUFU. The results of in vivo experiments with a lung metastasis model in nude mice with ICC cell line RBE are consistent with these results.
Conclusion: ASPH accelerated metastasis of ICC cells by facilitating EMT via a GSK-3β/SHH/GLI2 axis-dependent manner, in which phosphorylation of GSK-3β was downregulated and the SHH signaling pathway was activated.
Keywords: EMT; GLI2; GSK-3β; Intrahepatic cholangiocarcinoma; aspartate β-hydroxylase; sonic hedgehog.
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