Cytidine Deaminase Enhances Liver Cancer Invasion by Modulating Epithelial-Mesenchymal Transition via NFκB Signaling

Background: Cancer metastasis is the leading cause of cancer-related deaths, underscoring the importance of understanding its underlying mechanisms. Hepatocellular carcinoma (HCC), a highly malignant type of cancer, was selected as our research model.

Material and methods: We aimed to develop high-metastatic cell lines using in vitro and in vivo selection strategies and identify critical metastasis-related genes through microarray analyses by comparing them with parental cells.

Results: Our results showed that the high-metastatic cell lines exhibited significantly stronger invasion abilities than parental cells. Microarray analyses identified cytidine deaminase (CDA), a gene associated with systemic chemotherapy resistance, as one of the overexpressed genes in the high-metastatic cells. Data analysis from The Cancer Genome Atlas Program revealed that while CDA is downregulated in HCC, patients with high CDA expression tend to have poorer prognoses. Cell models confirmed that CDA overexpression enhances cell migration and invasion, whereas CDA knockdown inhibits these abilities. Investigating the key molecules involved in the epithelial-mesenchymal transition (EMT), we found that CDA overexpression increases the expression of fascin, N-cadherin, β-catenin, and snail while decreasing E-cadherin expression. Conversely, CDA knockdown produced opposite results. Additionally, we discovered that CDA regulates NF-κB signaling, which controls the expression of N-cadherin, thereby promoting the invasion capability of HCC cells.

Conclusions: We isolated highly metastatic cells and identified potential HCC metastasis-related genes. CDA promotes cell invasion by regulating EMT through the NF-κB pathway. Future studies are warranted to explore the potential of CDA as a biomarker for prognosis and therapeutic decision-making.