Signal transducer and activator of transcription 3 (STAT3) is a member of the family of latent cytoplasmic transcriptional factors that could regulate cell proliferation, survival, and development. It has been reported that Twist is a target gene of STAT3, and STAT3/Twist signaling plays an important role in regulating cancer progress. Here, to explore whether 8-bromo-7-methoxychrysin (BrMC) inhibits liver cancer stem-like cell (LCSLC) properties via disrupting STAT3/Twist signaling, we cultured SMMC-7721 cells in vitro, and evaluated the effects of BrMC on the stemness of spheroids by determining the sphere-forming capability and migration. The sphere formation assay results showed a concentration-dependent decrease of sphere-forming capacity in LCSLCs (P < 0.05) treated with different concentrations of BrMC. Wound-healing assays results demonstrated a concentration-dependent decline in cell migration of LCSLCs treated with different concentrations of BrMC. In addition, CD133, CD44, and ALDH1 levels were decreased in LCSLCs treated with BrMC. Treatment with different concentrations of BrMC also reduced the expressions of p-STAT3 and Twist1 proteins. The effect of BrMC was substantially enhanced by co-treatment with JSI-124, a specific inhibitor of STAT3. Ectopic expression of Twist1 attenuated the inhibitory effects of BrMC on sphere formation, migration, and expression of the markers in LCSLCs. However, it had no affect on p-STAT3 expression in LCSLCs. These results demonstrated that BrMC inhibits the stemness of LCSLCs originated from SMMC-7721 cell line by inhibiting STAT3/Twist signal axis.
Keywords: 8-bromo-7-methoxychysin; STAT3; Twist; cancer stem cell; liver cell carcinoma.
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