Cyclooxygenase-2 and Akt mediate multiple growth-factor-induced epithelial-mesenchymal transition in human hepatocellular carcinoma

Abstract

Background and aim: Cancer invasion and metastasis are characterized by epithelial-mesenchymal transition (EMT). Hepatocellular carcinoma (HCC) causes metastasis and significant mortality. Elucidating factors promoting EMT in HCC are necessary to develop effective therapeutic strategies.

Methods: The LH86 cell line was developed in our laboratory from well-differentiated HCC without associated hepatitis or cirrhosis and used as a model to study EMT in HCC. Effects of transforming growth factor β-1, epidermal growth factor, hepatocyte growth factor and basic fibroblast growth factor (bFGF) were examined using morphology, molecular markers, effects on migration and tumorigenicity. The involvement of cyclooxygenase-2 (COX-2) and Akt were examined.

Results: LH86 cells display epithelial morphology. Transforming-growth-factor-β-1-, epidermal-growth-factor-, hepatocyte-growth-factor- and basic-fibroblast-growth-factor-induced mesenchymal changes in them were associated with loss of E-cadherin, albumin, α-1 anti-trypsin expression and increased expression of vimentin, collagen I and fibronectin. There was associated increased migration, tumorigenicity and increased expression of COX-2, prostaglandin E2 (PGE2), Akt and phosphorylated Akt. Inhibition of COX-2 and Akt pathways led to inhibition of characteristics of EMT.

Conclusions: Multiple growth factors induce EMT in HCC. COX-2 and Akt may mediate EMT-associated development and progression of HCC and molecular targeting of COX-2 and Akt may be an effective therapeutic or chemopreventive strategy in advanced and metastatic HCC.