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The aim of this study was to investigate the effects of bufalin on human nasopharyngeal carcinoma NPC-TW 076 cells in vitro. Bufalin is a cardiotonic steroid and a key active ingredient of the Chinese medicine ChanSu. The extracts of Chansu are used for various cancer treatments in China. In the present study, bufalin induced cell morphological changes, decreased total cell viability and induced G2/M phase arrest of cell cycle in NPC-TW 076 cells. Results also indicated that bufalin induced chromatin condensation (cell apoptosis) and DNA damage by DAPI staining and comet assay, respectively. The induced apoptotic cell death was further confirmed by annexin-V/PI staining assay. In addition, bufalin also increased ROS and Ca 2 + production and decreased the levels of Δ Ψ m . Furthermore, the alterations of ROS, ER stress and apoptosis associated protein expressions were investigated by Western blotting. Results demonstrated that bufalin increased the expressions of ROS associated proteins, including SOD (Cu/Zn), SOD2 (Mn) and GST but decreased that of catalase. Bufalin increased ER stress associated proteins (GRP78, IRE-1 α , IRE-1 β , caspase-4, ATF-6 α , Calpain 1, and GADD153). Bufalin increased the pro-apoptotic proteins Bax, and apoptotic associated proteins (cytochrome c, caspase-3, -8 and -9, AIF and Endo G) but reduced anti-apoptotic protein Bcl-2 in NPC-TW 076 cells. Furthermore, bufalin elevated the expressions of TRAIL-pathway associated proteins (TRAIL, DR4, DR5, and FADD). Based on these findings, we suggest bufalin induced apoptotic cell death via caspase-dependent, mitochondria-dependent and TRAIL pathways in human nasopharyngeal carcinoma NPC-TW 076 cells. [ABSTRACT FROM AUTHOR]

Ethnophamacological relevance Pogostemon cablin is a medicinal herb widely used to treat gastrointestinal diseases in many Asian countries. Pogostone is an important constituent of Pogostemon cablin , and possesses various bioactivitys. In this study, we performed to investigate the anti-colorectal tumor property of Pogostone by inducing aurophagy and apoptosis in human colorectal cancer cells, and to define the potential molecular mechanisms. Materials and methods In vitro, The anti-tumor activity of pogostone was assessed using MTT assay. Autophagy was monitored by transmission electron microscopy observation and mRFP-GFP-LC3 fluorescence analysis in colorectal tumor cell line. Apoptosis was measured by flow cytometry and annexinV-FITC/PI staining. The protein expressions or activition of LC3-Ⅱ, AKT, mTOR, caspase-3 and caspase-7 were detected through western blotting. In vivo, the anti-tumor effect of pogostone was tested with HCT116 colorectal tumor cells transplantation tumor model. The expression of Ki-67 was determined by Immunohistochemistry staining and the apoptosis was evaluated using TUNEL assay. Results In vitro, pogostone exhibits significant anti-tumor activity against human cancer cell lines, especially for HCT116 (18.7±1.93 μg/ml). Transmission electron microscopy observation, mRFP-GFP-LC3 fluorescence analysis, flow cytometry and assay and western blotting detection revealed that the anti-colorectal tumor activity of pogostone was dependent on inducing autophagy and apoptosis through up-regulating the expression of LC3-Ⅱ, cleaved caspase-7 and caspase-3, and decreasing the phosphorylation of AKT/mTOR. In vivo , 150 mg/kg pogostone inhibited the HCT116 tumor growth in immunodeficient mice with an inhibitory rate of 43.3%, decreased the expression of Ki67, and induced apoptosis in three days. Conclusion Pogostone showed anti-colorectal tumor effects by inducing autophagy and apoptosis involving PI3K/Akt/mTOR axis. Thus, pogostone may be a promising lead compound to be further developed for cancer therapy. [ABSTRACT FROM AUTHOR]