The expression of the embryonic gene Cripto‐1 is regulated by OCT 4 in human embryonal carcinoma NCCIT cells

Cripto‐1 and OCT 4, expressed in stem cells and cancers, play important roles in tumorigenesis. Here, we demonstrate that Cripto‐1 expression is regulated by OCT 4 in human embryonic carcinoma NCCIT cells. The endogenous expression of Cripto‐1 and OCT 4 is significantly reduced during differentiation. Cripto‐1 expression is increased by OCT 4 overexpression, but decreased by sh RNA ‐mediated OCT 4 knockdown. OCT 4 overexpression significantly activates Cripto‐1 transcriptional activity. A 5′‐upstream minimal promoter sequence in the gene‐encoding Cripto‐1 is significantly activated by OCT 4 overexpression. Mutation of the putative OCT 4‐binding site abolishes OCT 4‐mediated activation of the Cripto‐1 promoter. The OCT 4 transactivation domains mediate transcriptional activity of the Cripto‐1 minimal promoter through direct interaction. Taken together, OCT 4 plays an important role as a transcriptional activator of Cripto‐1 expression in NCCIT cells.