The regulatory effect of the YY1/miR-HCC2/BAMBI axis on the stemness of liver cancer cells

Cancer stem cells serve key roles in liver cancer recurrence and metastasis. Therefore, the present study evaluated novel regulators of stem cell factor expression to identify novel therapeutic strategies that could target liver cancer stem cells. Deep sequencing was performed to identify novel microRNAs (miRNAs) that were specifically altered in liver cancer tissues. The expression levels of stem cell markers were investigated by reverse transcription-quantitative PCR and western blotting. Sphere formation assays and flow cytometry were used to assess tumor sphere-forming ability and evaluate the population of cluster of differentiation 90(+) cells. Tumor xenograft analyses were used to evaluate tumorigenicity, metastasis and stemness in vivo. Bioinformatics analyses and enhanced green fluorescent protein reporter assays or luciferase reporter assays were performed to identify the direct targets of miR-HCC2 and its upstream transcription factors. MiR-HCC2 strongly promoted the cancer stem cell-like properties of liver cancer cells in vitro; it also contributed to tumorigenicity, metastasis and stemness in vivo. Bone morphogenic protein and activin membrane-bound inhibitor homolog, a direct target of miR-HCC2, activated the Wnt/beta-catenin signaling pathway to promote stemness in liver cancer cells. The transcription factor YY1 bound to the promoter of miR-HCC2 and activated its transcription. The present study demonstrated the importance of miR-HCC2 in the induction of stemness in liver cancer, providing new insights into liver cancer metastasis and recurrence.