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Phytoestrogens have been demonstrated to inhibit tumor induction; however, their molecular mechanisms of action have remained elusive. The present study aimed to investigate the effects of a phytoestrogen, apigenin, on proliferation and apoptosis of the human epidermal growth factor receptor 2 (HER2)-expressing breast cancer cell line SKBR3. Proliferation assay, MTT assay, fluorescence-activated cell sorting analysis, western blot analysis, immunocytochemistry, reverse transcription-polymerase chain reaction and ELISA assay were used in the present study. The results of the present study indicated that apigenin inhibited the proliferation of SKBR3 cells in a dose- and time-dependent manner. This inhibition of growth was accompanied by an increase in the sub-G0/G1 apoptotic population. Furthermore, apigenin enhanced the expression levels of cleaved caspase-8 and -3, and induced the cleavage of poly(adenosine diphosphate ribose) polymerase in SKBR3 cells, confirming that apigenin promotes apoptosis via a caspase-dependent pathway. Apigenin additionally reduced the expression of phosphorylated (p)-janus kinase 2 and p-signal transducer and activator of transcription 3 (STAT3), inhibited CoCl2-induced vascular endothelial growth factor (VEGF) secretion and decreased the nuclear localization of STAT3. The STAT3 inhibitor S31-201 decreased the cellular proliferation rate and reduced the expression of p-STAT3 and VEGF. Therefore, these results suggested that apigenin induced apoptosis via the inhibition of STAT3 signaling in SKBR3 cells. In conclusion, the results of the present study indicated that apigenin may be a potentially useful compound for the prevention or treatment of HER2-overexpressing breast cancer. [ABSTRACT FROM AUTHOR]

Inflammatory response is a major defense mechanism against pathogens and chemical or mechanical injury. Rhus verniciflua Stokes (RVS) has traditionally been used as an ingredient in East Asian medicine for the treatment of gastritis, stomach cancer and atherosclerosis. The aim of the current study was to analyze the effect of RVS on LPS. induced inflammatory responses in the RAW264.7 mouse macrophage cell line. RAW264.7 cells were treated with various concentrations of RVS and LPS at specific time points. WST assay, trypan blue assay and quantification of activated cells revealed that RVS suppressed cell proliferation in a dose-dependent manner. RVS induced G1 cell cycle arrest, suppressed iNOS and COX-2 mRNA expression induced by LPS and decreased intracellular ROS levels induced by LPS. In addition, RVS induced PARP and caspase-3 cleavage suggesting that RVS causes cell death. Results of the present study indicate that RVS may be advantageous in treating inflammatory disease. [ABSTRACT FROM AUTHOR]