STAT3 activation mediates epithelial-to-mesenchymal transition in human hepatocellular carcinoma cells.

BACKGROUND/AIMS: Epithelial-to-mesenchymal transition (EMT) is critical for the development of the invasion and metastasis in human cancers. Recently, signal transducer and activator of transcription 3 (STAT3) activation has been linked to EMT program in breast cancer. However, the actual association of STAT3 activation with EMT, and its mediated tumor invasion and metastasis remains elusive in hepatocellular carcinoma (HCC). The aim of this study was to investigate the correlation between STAT3 activation and EMT, as well as the underlying mechanism involved in HCC progression.

METHODOLOGY: We treated SMMC-7721 cells with a known STAT3 activator, epithelial growth factor (EGF); in the absence or presence of JSI-124, a selective STAT3 inhibitor. The EMT-associated morphologic and molecular changes of cells were analyzed. The EMT-mediated HCC cell invasion, migration and adhesion were evaluated.

RESULTS: In this study, we found that STAT3 activation induced by EGF was associated significantly with morphologic changes, cytoskeleton rearrangement and molecular changes consistent with EMT in SMMC-7721 cells; STAT3 activation-mediated EMT may be transcriptionally induced by Twist. STAT3 activation-mediated EMT also promoted HCC cell invasion, migration and adhesion significantly.

CONCLUSIONS: In summary, our study show for the first time that STAT3 activation may induce invasion and metastasis through the mediation of EMT in HCC cells. Activated STAT3 and EMT markers can serve as molecular targets for HCC treatment.