Chios Gum Mastic Induces Cell Cycle Arrest and Apoptosis in Human Osteosarcoma Cells / 대한해부학회지

Chios gum mastic (CGM) is a resin produced from the stem and leaves of Pistiacia lentiscus L var chia, a plant which grows only on Chios Island in Greece. CGM has been used for many centuries as a dietary supplement and folk medicine for stomach and duodenal ulcers in many Mediterranean countries and is also known to induce cell cycle arrest and apoptosis in some cancer cells. This study was undertaken to investigate the alteration of the cell cycle and induction of apoptosis by CGM treatment on human osteosarcoma (HOS) cells. The viability and the growth inhibition of HOS cells were assessed by the MTT assay and clonogenic assay respectively. The hoechst staining, TUNEL assay and DNA electrophoresis were conducted to observe the HOS cells undergoing apoptosis. HOS cells were treated with CGM, and Western blotting, immunocytochemistry, confocal microscopy, FACScan flow cytometry, mitochondrial membrane potential change and proteasome activity were conducted. CGM treatment of HOS cells was found to result in a dose- and time-dependent decrease in cell viability, a dose-dependent inhibition of cell growth, and apoptotic cell death. Tested HOS cells also showed several lines of apoptotic manifestation and G1 arrest in cell cycle progression. In summary, this study clearly demonstrated that CGM induces G1 cell cycle arrest via the modulation of cell cycle-related proteins, and apoptosis via proteasome, mitochondrial and caspase cascades in HOS cells. Therefore, our data provide the possibility that a natural product, CGM could be considered as a novel therapeutic strategy for human osteosarcoma.

Apoptotic Effect of Co-Treatment with a Natural Product, Chios Gum Mastic, and a Synthetic Chenodeoxycholic Acid Derivative, HS-1200, on Human Osteosarcoma Cells / 체질인류학회지

Chios gum mastic (CGM) is a resinous exudate obtained from the stem and the main leaves of Pistacia lenticulus tree native to Mediterranean areas. Recently it reported that CGM induced apoptosis in a few cancer cells in vitro. It has been reported that the synthetic chenodeoxycholic acid (CDCA) derivatives showed apoptosis-inducing activity on various cancer cells in vitro. This study was undertaken to investigate the synergistic apoptotic effect of co-treatment with a natural product, CGM and a CDCA derivative, HS-1200 on human osteosarcoma (HOS) cells. To investigate whether the co-treatment of CGM and HS-1200 compared with each single treatment efficiently reduced the viability of HOS cells, MTT assay was conducted. Induction and augmentation of apoptosis were confirmed by DNA electrophoresis, Hoechst staining and DNA hypoploidy, Westen blot analysis and immunofluorescent staining were performed to study the alterations of the expression level and translocation of apoptosis-related proteins in co-treatment. Furthermore, proteasome activity and mitochondrial membrane potential (MMP) change were also assayed. In this study, HOS cells co-treated with CGM and HS-1200 showed several lines of apoptotic manifestation whereas each single treated HOS cells did not. Although the single treatment of 40 microgram/mL CGM or 25 micrometer HS-1200 for 24 h did not induce apoptosis, the cotreatment of them induced prominently apoptosis. Therefore our data provide the possibility that combination therapy of CGM and HS-1200 could be considered as a novel therapeutic strategy for human osteosarcoma.

Apoptotic Effect of Co-Treatment with a Natural Product, Chios Gum Mastic, and a Proteasome Inhibitor, Lactacystin, on Human Osteosarcoma Cells / 대한해부학회지

Chios gum mastic (CGM) is a resinous exudate obtained from the stem and the main leaves of Pistacia lenticulus tree native to Mediterranean areas. Recently, it was reported that CGM induced apoptosis in a few cancer cells in vitro. Since recent studies indicated the synergistic interactions between the apoptotic stimulus and a proteasome inhibitor, the ubiquintin-proteasome pathway has become an attractive target in cancer therapy. And to date, there has been no report of the synergistic apoptotic effect between CGM and a proteasome inhibitor to become an attractive target in cancer therapy. Therefore, this study was undertaken to investigate the synergistic apoptotic effect of co-treatment with a natural product, CGM, and a proteasome inhibitor, lactacystin, on human osteosarcoma (HOS) cells. To investigate whether the co-treatment of CGM and lactacystin compared with each single treatment efficiently induced apoptosis on HOS cells, MTT assay, DNA electrophoresis, Hoechst staining, DNA hypoploidy assay, Westen blot analysis, immunofluorescent staining, proteasome activity and mitochondrial membrane potential (MMP) change were performed. In this study, HOS cells co-treated with CGM and lactacystin showed several lines of apoptotic manifestation such as nuclear condensation, DNA fragmentation, the reduction of MMP and proteasome activity, the decrease of DNA content, the release of cytochrome c into cytosol, the translocation of AIF and DFF40 (CAD) onto nuclei, and activation of caspase-7, caspase-3, PARP and DFF45 (ICAD) whereas each single treated HOS cells hardly showed. We presented data indicating that the co-treatment of CGM and lactacystin induced potentially apoptosis whereas each single treatment did slightly. Moreover, the co-treatment of CGM and lactacystin potentiated the inhibition of proteasome activity. Therefore, our data provide the possibility that combination therapy of CGM and lactacystin could be considered as a novel therapeutic strategy for human osteosarcoma.