Cedrol, a Sesquiterpene Isolated from Juniperus chinensis, Inhibits Human Colorectal Tumor Growth associated through Downregulation of Minichromosome Maintenance Proteins

Cedrol, a sesquiterpene alcohol, isolated from Juniperus chinensis has been reported to inhibit minichromosome maintenance (MCM) proteins as cancer biomarkers in human lung cancer in vitro. In the present study, we investigated the anti-cancer activity of cedrol in vitro and in vivo using human colorectal cancer HT29 cells and a human colorectal tumor xenograft model. Cedrol inhibited MCM protein expression and cell growth in HT29 cells, which are associated with G1 arrest and the induction of apoptosis. We demonstrated that cedrol effectively reduced HT29 tumor growth without apparent weight loss in a human tumor xenograft model.Compared with vehicle- and adriamycin-treated tumor tissues, cedrol induced changes in the tumor tissue structure, resulting in a reduced cell density within the tumor parenchyma and reduced vascularization. Moreover, the expression of MCM7, an important subunit of MCM helicase, was significantly suppressed by cedrol in tumor tissue. Collectively, these results suggest that cedrol may act as a potential anti-cancer agent for colorectal cancer by inhibiting MCM protein expression and tumor growth.

Sorbus rufopilosa Extract Exhibits Antioxidant and Anticancer Activities by Inducing Cell Cycle Arrest and Apoptosis in Human Colon Adenocarcinoma HT29 Cells

BACKGROUND: Sorbus rufopilosa, a tsema rowan, is a species of the small ornamental trees in the genus Sorbus and the family Rosaceae found in East Asia. The bioactivities of S. rufopilosa have not yet been fully determined. The objective of this study is to evaluate the antioxidant and anticancer effects of ethanol extract of S. rufopilosa (EESR) and to determine the molecular mechanism of its anticancer activity in human colon carcinoma HT29 cells. METHODS: To examine the antioxidant activity of EESR, 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity assay was performed. Inhibitory effect of EESR on cancer cell growth and proliferation was determined by water-soluble tetrazolium salt assay. To investigate the mechanism of EESR-mediated cytotoxicity, HT29 cells were treated with various concentrations of EESR and the induction of cell cycle arrest and apoptosis was analyzed by flow cytometry, 4,6-diamidino-2-phenylindole staining, and Western blot analysis. RESULTS: EESR showed significant antioxidant activity and inhibitory effect on HT29 cell growth in a dose-dependent manner. EESR induced cell cycle arrest at G2/M phase in a dose-dependent manner by modulating cyclin B, cyclin-dependent kinase 1 (CDK1), and CDK inhibitor p21 expression. EESR-induced apoptosis was associated with the upregulation of p53, a death receptor Fas, and a pro-apoptotic protein Bax and the activation of caspase 3, 8, and 9, resulting in the degradation of PARP. CONCLUSIONS: EESR possessing antioxidant activity efficiently inhibits proliferation of HT29 cells by inducing both cell cycle arrest and apoptosis. EESR may be a possible candidate for the anticancer drug development.

Anti-cancer Activity of Osmanthus matsumuranus Extract by Inducing G2/M Arrest and Apoptosis in Human Hepatocellular Carcinoma Hep G2 Cells

BACKGROUND: Osmanthus matsumuranus, a species of Oleaceae, is found in East Asia and Southeast Asia. The bioactivities of O. matsumuranus have not yet been fully understood. Here, we studied on the molecular mechanisms underlying anti-cancer effect of ethanol extract of O. matsumuranus (EEOM). METHODS: Inhibitory effect of EEOM on cell growth and proliferation was determined by WST assay in various cancer cells. To investigate the mechanisms of EEOM-mediated cytotoxicity, HepG2 cells were treated with various concentration of EEOM and analyzed the cell cycle arrest and apoptosis induction by flow cytometry, Western blot analysis, 4,6-diamidino-2-phenylindole (DAPI) staining and DNA fragmentation. RESULTS: EEOM showed the cytotoxic activities in a dose-dependent manner in various cancer cell lines but not in normal cells, and HepG2 cells were most susceptible to EEOM-induced cytotoxicity. EEOM induced G2/M arrest in HepG2 cells associated with decreased expression of cyclin-dependent kinase 1 (CDK1), cyclin A and cylcin B, and increased expression of phospho-checkpoint kinase 2, p53 and CDK inhibitor p21. Immunofluorescence staining showed that EEOM-treated HepG2 increased doublet nuclei and condensed actin, resulting in cell rounding. Furthermore, EEOM-mediated apoptosis was determined by Annexin V staining, chromatin condensation and DNA fragmentation. EEOM caused upregulation of FAS and Bax, activation of caspase-3, -8, -9, and fragmentation of poly ADP ribose polymerase. CONCLUSIONS: These results suggest that EEOM efficiently inhibits proliferation of HepG2 cells by inducing both G2/M arrest and apoptosis via intrinsic and extrinsic pathways, and EEOM may be used as a cancer chemopreventive agent in the food or nutraceutical industry.