Purpose: Arsenic trioxide (ATO) has been found effective in several types of cancer cells, including acute promyelocytic leukemia, and recently in hepatocellular carcinoma (HCC). In this study, we investigated the role of ATO in regulating the invasive activity of HCC after transarterial embolization (TAE).
Methods: Cell migration and invasion were observed using Transwell and wound-healing assay. The molecular changes in E-cadherin, N-cadherin, and Vimentin of surviving tumor cells were determined by Western blotting. The effects of ATO on Twist activity of the tumor cells were further analyzed. In animal study, 40 male buffalo rats implanted with McA-RH7777 tumor in the liver were randomly divided into four groups: control, TAE, ATO, and TAE + ATO. TAE procedures were performed on the 14th day after implantation. Lung metastases were observed using fluorescence imaging, and the molecular changes in residual tumor cells were evaluated by Western blotting or immunohistochemistry. Tumor growth and survival analysis were also evaluated.
Results: Arsenic trioxide markedly reduced cell migration and invasiveness, which were enhanced by hypoxia after TAE. Western blot analysis revealed ATO inhibited the expression of epithelial-mesenchymal transition (EMT) markers by suppressing Twist. The marked suppression effect of ATO on invasiveness and metastatic potential related to EMT was also shown in tissue.
Conclusion: The results of this study demonstrated that ATO is an effective anticancer agent in combination with TAE in the treatment of HCC, by suppressing tumor progression and metastasis via selectively inducing tumor cell apoptosis and arresting EMT by inhibiting the Twist activation.