Abstract
Octamer 4 (Oct4), a member of the Pit-Oct-Unc transcription factor family required to maintain self-renewal and pluripotency of embryonic stem cells, has been previously identified to be associated with tumorigenesis and malignant transformation of numerous types of cancer including hepatocellular carcinoma (HCC). The present data shows that Oct4 enhances cancer stem cell properties and increases invasion ability in the Huh7 cell line. To increase understanding of the role of Oct4 in HCC, the present study used a functional genomics approach and analyzed the resulting transcriptional profiles to identify Oct4-dependent genes in Huh7. Affymetrix GeneChip Human genome U133 Plus 2.0 Arrays were used to determine differential gene expression profiles and then validated by quantitative polymerase chain reaction. The present study found that altered expression of 673 genes (fold-change ≥2) affected multiple signaling pathways linked with self-renew and metastasis. Among these differentially expressed genes, the present study noticed that the key component of the WNT signaling pathway lymphoid enhancer binding factor 1 (LEF1) and Twist Family BHLH transcription factor 1 were upregulated by Oct4, whilst cadherin 2 was downregulated. Additional studies found that the nuclear β-catenin aggregation was increased in Oct4 overexpressed HCC cell lines. These results suggest that Oct4 regulates LEF1 to active LEF1/β-catenin dependent WNT signaling pathway and promote epithelial-mesenchymal transition. The present findings provide novel mechanistic insight into an important role of Oct4 in HCC.