樟芝子實體乙酸乙酯層及玫瑰樹鹼對肝癌細胞株HepG2和PLC/PRF/5之活性與其作用機轉之探討

Part1: The fruiting body of Antrodia cinnamomea is well known in Taiwan as a traditional medicine for treating cancer and inflammation. The purpose of this study was to evaluate the apoptotic effects of ethylacetate extract from A. cinnamomea (EAC) fruiting bodies in two human liver cancer cell lines, HepG2 and PLC/PRF/5. Treatment with EAC decreased the cell growth of HepG2 and PLC/PRF/5 cells in a dose dependent manner. In Fas/APO-1 positive-HepG2 cells, EAC increased the expression level of Fas/APO-1 and its two forms of ligands, membrane-bound Fas ligand (mFasL) and soluble Fas ligand (sFasL), in a p53-indenpendent manner. In addition, EAC also initiated mitochondrial apoptotic pathway through regulation of Bcl-2 family proteins expression, release of cytochrome c, and activation of caspase-9 both in HepG2 and PLC/PRF/5 cells. Furthermore, EAC also inhibited the cell survival signaling by enhancing the amount of IκBα in cytoplasm and reducing the level and activity of NF-κB in the nucleus, and subsequently attenuated the expression of Bcl-XL in HepG2 and PLC/PRF/5 cells. EAC therefore decreased the cell growth and induced apoptosis both in HepG2 and PLC/PRF/5 cells. Part2: Ellipticine (5,11-dimethyl-6H-pyrido[4,3-b]carbazole), one of the simplest naturally occurring alkaloids, was isolated from the leaves of the evergreen tree Ochrosia elliptica Labill (Apocynaceae). Here, we reported for the first time that ellipticine inhibited the cell growth of human liver cancer cell lines, HepG2 and PLC/PRF/5, and provided molecular mechanism of this effect. The results showed that ellipticine decreased the cell proliferation of HepG2 and PLC/PRF/5 cells in a dose and time- dependent manner by the XTT assay. Ellipticine initiated mitochondrial apoptotic pathway through regulation of Bcl-2 family proteins expression, alteration of mitochondrial membrane potential, and activation of caspase-9 both in HepG2 and PLC/PRF/5 cells. Treatment of HepG2 cells with ellipticine increased the expression level of Fas/APO-1 and its membrane-bound ligands through p53 activation. In PLC/PRF/5 cells, the earliest oxidative event observed after ellipticine treatment was the increase of production of reactive oxygen species (ROS), including O2.-, and H2O2. Furthermore, ellipticine also inhibited the amount of IκBα in cytoplasm and raised the level and activity of NF-κB in the nucleus, in PLC/PRF/5 cells. Ellipticine therefore decreased the cell growth and induced apoptosis both in HepG2 and PLC/PRF/5 cells.