Compounds were visualized by UV light. selective anti-proliferative activity and specificity than emodin. Moreover, further experiments exhibited that compound 7a displayed a significant efficacy of inducing apoptosis through mitochondrial pathway via release of cytochrome c from mitochondria and subsequent activation of caspase-9 and caspase-3, inducing cell arrest at G0/G1 phase, as well as suppression of cell migration of tumor cells. The preliminary results suggested that compound 7a could be a encouraging lead compound for the discovery of novel anti-tumor drugs and has the potential for further investigations as an anti-cancer drug. Induced Cell Apoptosis through the Mitochondrial Pathway In order to verify whether compound 7a is able to induce apoptosis in HepG2 cells, we utilized FITC-Annexin V/PI staining and estimated the percentage of apoptotic cells by circulation cytometry. We noted a concentration-dependent increase in the percentage of apoptotic cells when the cells were treated with compound 7a for 48 h at concentrations 2.5, 5, and 10 M. As shown in Physique 3A, few (5.5%) apoptotic cells were present in the control panel. In contrast, the percentage of apoptotic cells increased to 22.2% after treatment with compound 7a at 5 M for 48 h and further increased to 50.7% after treatment with 7a at the concentration of 10 M. As illustrated in Physique 3B, the quantitative analysis of apoptosis strongly suggests that treatment with compound 7a effectively induced apoptosis in Tandutinib (MLN518) HepG2 cells in Tandutinib (MLN518) a concentration-dependent manner in comparison to the control. Open in a separate window Physique 3 Compound 7a induced cell apoptosis in HepG2 cells. (A) The representative images and statistical results of cell apoptosis assays. (B) The quantitative analysis of apoptosis. Data are expressed as means SD of the percentages of apoptotic cells from three impartial experiments. Statistical significance is determined by two-tailed Student < 0.001, ** denote < 0.01, respectively (Supplementary Table S1). (C, E) Western blot analysis effect of compound 7a around the levels of Bax, Bcl-2, cytochrome c, procaspase-3, caspase-3 and procaspase-9 expression in HepG2 cells. (D, F) An equal amount of protein was loaded on SDS-PAGE gel for western blot analysis. Data are expressed as means SD of the percentages of apoptotic cells from three impartial experiments. Statistical significance is determined by two-tailed Student < 0.001, ** denote < 0.01, * denote < 0.05, respectively (Supplementary Table S2). To verify the molecular mechanisms of apoptosis induction of compound 7a, we performed a western blot assay. It is well known that this Bcl-2 family of pro-apoptotic and anti-apoptotic proteins regulates the mitochondrial pathway of apoptosis. These Bcl-2 family proteins stimulate the permeabilization of the mitochondrial outer membrane, which results in the release of cytochrome c into the cytosol and in turn promotes the activation of the caspase cascade. The activation of the caspase cascade ultimately prospects to the induction of apoptotic cell death. As shown in Physique 3C and 3D, in comparison with the control cells, compound 7a induced an increase in the levels of Bax and a decrease in the expression of Bcl-2 in a concentration-dependent manner. Meanwhile, the release of cytochrome c from mitochondria increased after the treatment of compound 7a, while procaspase 9 and procaspase 3 decreased after treatment with 7a, indicating that the caspase 9 and caspase 3 were activated. As shown in Physique 3E,F, the increased expression of cleaved caspase-3 after treatment with 7a provided a further evidence that compound 7a induced cell apoptosis through mitochondrial pathway in a concentration-dependent manner. The apoptosis Tandutinib (MLN518) process can be summarized as follows: The mitochondrial apoptosis-induced channel (MAC) of HepG2 cells was created by pro-apoptotic protein Bax after the treatment of compound 7a. The formation of MAC led to the releasing of cytochrome c from mitochondria. Once cytochrome c was released, it binded with apoptotic protease activating factor-1 (Apaf-1) and ATP, which then binded to procaspase-9 to create a protein complex known as apoptosome. The apoptosome cleaved the pro-caspase-9 to its active form of initiator caspase-9, which in turn activated procaspase-3 and then the effector caspase-3 and Mouse monoclonal to Plasma kallikrein3 finally resulted in cell apoptosis. 2.5. Compound Induced G0/G1 Phase Arrest To further examine how compound 7a suppressed the growth of HepG2 cells, the effect of compound 7a on cell cycle distribution with different concentrations was investigated by circulation cytometric analysis following staining the DNA with propidium iodide (PI). The results of a typical experiment are shown in Physique 4A. As determined by circulation cytometry, the exposure of HepG2 cells to compound 7a for 48 h resulted in an obvious increase in the percentage of cells in G0/G1 phase in.