Background: Taxifolin is a natural flavonoid with anti-oxidant and anti-proliferative properties. In this study, we investigated the stemness-related inhibitory effects of taxifolin in two lung cancer cell lines, A549 and H1975, as well as in A549 xenografts.Methods: A549 and H1975 cells, as well as A549 xenograft BALB/c mice were treated with taxifolin. Cell viability, stemness, mobility and protein expression were tested with Cell counting kit-8 (CCK-8), Colony formation assay, Flow cytometry, Transwell, Western blot and Immunohistochemistry, respectively.Results: CCK-8 exhibited an obvious toxicity of taxifolin to both cell lines at higher dose. Then taxifolin of 0, 25, 50, and 100 μM/L were subsequently used. Taxifolin exhibited inhibitory effects on stemness and sphere formation, reduced protein expression of SOX2 and OCT4, and reduced CD133-positive cells. Furthermore, taxifolin decreased invasive cells, reduced N-cadherin and vimentin while increased E-cadherin expression, indicating that epithelial-mesenchymal transition (EMT) was inhibited. All of the effects observed were exhibited in a dose-dependent manner, and A549 cells proved to be more sensitive to taxifolin than H1975 cells. Taxifolin inactivated PI3K and TCF4 protein phosphorylation; however, taxifolin was not observed to have an effect on NF-κB P65 or STAT3. Taxifolin also suppressed tumor growth in A549xenograft BALB/c mice, with decreased SOX2 and OCT4 expression and inhibited PI3K and TCF4.Conclusions: In summary, taxifolin inhibited stemness and EMT in lung cancer cells possibly via the inactivation of PI3K and OCT4. Taxifolin could be a potential prodrug or serve as an adjuvant in lung cancer treatment.

Embryo development block seriously limits the success of in vitro embryo production and assisted reproductive technology. Although numerous researchers have explored this problem, it remains to be solved. In this study, we found that melatonin supplementation at 10 and 10 M in M16 significantly reduced two-cell block of mouse embryos. When those melatonin-treated four-cell embryos were transplanted into the oviducts of female recipient mice, the litter sizes were significantly increased compared with those of the controls. Mechanism study discovered that melatonin treatment markedly reduced reactive oxygen species and mitochondrial superoxide. Quantitative polymerase chain reaction revealed that melatonin significantly upregulated the transcription of catalase, superoxide dismutase 2, glutathione peroxidase, and the antiapoptotic factors Bcl-2 and Bcl-x while downregulated the transcription of pro-apoptotic genes p53 and Bax. In addition, we found Dux, an important gene which promotes zygotic genome activation, and zygotic genes (zinc finger and SCAN4B and eukaryotic translation initiation factor 1A) were all increased after melatonin treatment. Melatonin membrane receptors have two isoforms, melatonin receptor 1 and 2 (MT1, MT2). Further studies with luzindole (a nonselective MT1 and MT2 antagonist) demonstrated that the beneficial effects of melatonin on reducing two-cell block were not mediated by the melatonin membrane receptors. This study shows that melatonin can be used for improving the embryo quality and production efficiency cultured in vitro and also identifies the underlying mechanism by which melatonin decreases two-cell block.