EH-42, a novel small molecule induces apoptosis and inhibits migration and invasion of human hepatoma cells through suppressing STAT3 signaling pathway

BACKGROUND: Since signal transducer and activator of transcription 3 (STAT3) is aberrantly activated in hepatocellular carcinoma (HCC) and plays a key role in this tumor progression. Inhibition of the STAT3 signaling pathway has been considered as an effective therapeutic strategy for suppressing HCC development. OBJECTIVE: In this study, we investigated the anti-cancer effects of EH-42 on HCC cells and tried to explain the underlying mechanism. METHODS: MTT assay, colon formation assay and AnnexinV-FITC/PI double-staining assay were performed to assess the effects of EH-42 on cell growth and survival. Wound healing assay and transwell invasion assay were performed to assess the effects of EH-42 on cell migration and invasion. Western blotting assay was performed to analyze the effects of EH-42 on relative proteins. RESULTS: According to the MTT assay, colon formation assay and AnnexinV-FITC/PI doublestaining assay, EH-42 could suppress the growth and induce apoptosis of HCC cells in a dosedependent manner. Further western blotting assay showed that the inhibitory effects of EH-42 on cell growth and survival were caused by activating caspase 3/9, suppressing the phospho-STAT3 (Tyr 705) and downregulating anti-apoptotic proteins like Bcl-2/Bcl-xL. Moreover, migration and invasion abilities of HCC cells were also inhibited by EH-42 in the wound healing assay and transwell invasion assay. The potential mechanism was that EH-42 could inhibit HCC metastasis via reversing epithelial-mesenchymal transition and downregulating the secretion of MMPs. CONCLUSION: Taken together, these findings suggested that EH-42 could be a potential therapeutic agent for HCC treatment.