ent-Sauchinone as Potential Anticancer Agent Inhibiting Migration and Invasion of Human Liver Cancer Cells via Suppressing the STAT3 Signaling Pathway.

ent-Sauchinone, a lignan isolated from Saururus chinensis (Lour.) Baill., was reported that it could modulate the expression of signal transducer and activator of transcription 3 (STAT3). Since STAT3 plays a key role in invasion, migration, and metastasis of cancer, we investigated whether ent-sauchinone could exert promising inhibitory effects on the invasion and migration of the metastatic human liver cancer cell line SMMC-7721 in the present study. ent-Sauchinone was extracted from dried herbs of Saururus chinensis (Lour.) Baill. Human liver cancer cell lines SMMC-7721 and HCCLM3 were used to test the effect of ent-sauchinone on cell viability. The IC50 values and time-dependent effect of ent-sauchinone were determined by MTT assay. Cell migration and invasion of SMMC-7721 were evaluated by the wound healing test and transwell assay respectively, the known anti-metastasis agent curcumin was used as a positive control. Western blotting assay was used to investigate relevant molecular mechanisms of cell invasion and migration. Though ent-sauchinone didn't show high cytotoxicity, the wound healing assay and transwell migration assay revealed a profound impairment in the metastatic potential of SMMC-7721 cells due to down-regulation of N-cadherin, MMP-2, and MMP-9 proteins induced by inhibiting the phosphorylation of STAT3. These findings suggest that ent-sauchinone could be used as a promising agent to treat cancer metastasis.

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.