Insulin-like growth factor-1 induces epithelial-mesenchymal transition in hepatocellular carcinoma by activating survivin

Insulin-like growth factor-1 (IGF-1), a small polypeptide hormone similar to insulin in protein structures, has been identified as an activator of epithelial-mesenchymal transition (EMT) pathways in several types of cancers. As a member of the inhibitor of apoptosis protein (IAP) family, survivin is implicated in the EMT of some cancers. However, the role of survivin on IGF-1-mediated EMT of hepatocellular carcinoma (HCC) has not been clarified. In the present study, we demonstrated that survivin was involved in the EMT process induced by IGF-1 in HCC cell line SMMC7721. With administration of different concentrations of IGF-1, survivin mRNA and protein expression were significantly increased and stimulated EMT in the tested cell line, while the increased invasive and migratory abilities of HCC cells and activation of the EMT process induced by IGF-1 were reversed after silencing of survivin expression by transfecting small interfering RNA. This was further confirmed by the observation of morphological changes, the decrease of invasive and migratory abilities and the downregulation of EMT markers, N-cadherin, vimentin and Snail, and the upregulation of E-cadherin. In conclusion, survivin may play a vital role in the IGF-1 signaling pathway by mediating EMT in HCC through the upregulation of the expression of EMT markers, and the knockdown of survivin expression may suppress the metastasis of HCC, which may provide new insights for the molecular therapy of HCC patients in clinical treatment.