title: Dihydromethysticin kavalactone induces apoptosis in osteosarcoma cells through modulation of PI3K/Akt pathway, disruption of mitochondrial membrane potential and inducing cell cycle arrest.
abstract: The objective of the present study was to evaluate the tumor and apoptotic effects of dihydromethysticin kavalactone against human osteosarcoma (MG-63) cells. Antiproliferative activity was measured with the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Apoptosis induction by dihydromethysticin was demonstrated by fluorescence microscopy, quantitative videomicroscopy and Annexin V-FITC apoptosis detection kit. Mitochondrial membrane potential disruption was demonstrated by rhodamine-123 dye using flow cytometry. We also evaluated the effect of dihydromethysticin on PI3K/Akt pathway with an immunoblotting analysis. The results showed that the compound induced dose-dependent as well as time-dependent antiproliferative effects against MG-63 cell growth. Cell death and apoptotic body formation was noticed followed dihydromethysticin treatment at various doses. The percentage of apoptotic cells (early apoptosis+late apoptosis) increased from 6.63% in untreated control to 23.92%, 23.81% and 93.9% in 25 µM, 75 µM and 100 µ Mdihydromethysticin-treated cells respectively. Flow cytometric analysis showed dihydromethysticin induced an increase in G0/G1 cells (apoptotic cells). Furthermore, we observed mitochondrial transmembrane depolarization along with decreased phosphorylation levels for PI3K, AKT (Ser 473), AKT (Thr 308), GSK-3β, and BAD. These reductions were associated with down regulation of AKT and upregulation of both GSK-3β and BAD.
authors.affiliation: Department of Orthopaedics, Shanghai Jiao Tong University Affiliated Sixth People's Hospital Shanghai 200233, China.
authors.forename: Jun-Qi
authors.initials: JQ
authors.lastname: Dai
authors.affiliation: Department of Orthopaedics, Shanghai Jiao Tong University Affiliated Sixth People's Hospital Shanghai 200233, China.
authors.forename: Yi-Gang
authors.initials: YG
authors.lastname: Huang
authors.affiliation: Department of Oncology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital Shanghai 200233, China.
authors.forename: Ai-Na
authors.initials: AN
authors.lastname: He
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D001859:Bone Neoplasms / Q000473:pathology*; D059447:Cell Cycle Checkpoints / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D005434:Flow Cytometry; D006801:Humans; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008856:Microscopy, Fluorescence; D012516:Osteosarcoma / Q000473:pathology*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D011753:Pyrones / Q000494:pharmacology*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology
chemical_list: C107882:7,8-dihydromethysticin; D000970:Antineoplastic Agents; D011753:Pyrones; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt
keywords: Osteosarcoma; anticancer effect; apoptosis; dihydromethysticin; flow cytometric