Dkk1 inhibits malignant transformation induced by Bmi1 via the β-catenin signaling axis in WB-F344 oval cells.

Dickkopf-1 (Dkk1) is an inhibitor of Wnt signaling involved in cancer cell proliferation, apoptosis, and migration and angiogenesis. It was previously reported that B cell-specific Moloney mouse leukemia virus integration site 1 (Bmi1) activates the Wnt pathway by inhibiting the expression of DKK1 in breast cancer cell lines and 293T cells. Bmi1 and DKK1 are highly expressed in liver samples taken by biopsy from patients with hepatitis B virus-related hepatocellular carcinoma (HCC), but the effect of both Bmi1 and DKK1 on the carcinogenesis of adult hepatic stem cells (oval cells) has not previously been reported. In this study, we used WB-F344 cells to explore the function and regulation of Dkk1 upon Bmi1 treatment. Overexpression of Dkk1 repressed differentiation, proliferation, and migration induced by Bmi1 but promoted the apoptosis of hepatic WB-F344 oval cells. In addition, Dkk1 reduced the enhancement of β-catenin levels induced by Bmi1. Finally, we used transcriptome sequencing to perform a comprehensive evaluation of the transcriptome-related changes in WB-F344 oval cells induced by Dkk1 and Bmi1. These results may provide evidence for future studies of the pathogenesis of HCC and the design of possible therapies.